1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Simplified MAC Kernel (smack) security module
4  *
5  *  This file contains the smack hook function implementations.
6  *
7  *  Authors:
8  *	Casey Schaufler <casey@schaufler-ca.com>
9  *	Jarkko Sakkinen <jarkko.sakkinen@intel.com>
10  *
11  *  Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
12  *  Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
13  *                Paul Moore <paul@paul-moore.com>
14  *  Copyright (C) 2010 Nokia Corporation
15  *  Copyright (C) 2011 Intel Corporation.
16  */
17 
18 #include <linux/xattr.h>
19 #include <linux/pagemap.h>
20 #include <linux/mount.h>
21 #include <linux/stat.h>
22 #include <linux/kd.h>
23 #include <asm/ioctls.h>
24 #include <linux/ip.h>
25 #include <linux/tcp.h>
26 #include <linux/udp.h>
27 #include <linux/dccp.h>
28 #include <linux/icmpv6.h>
29 #include <linux/slab.h>
30 #include <linux/mutex.h>
31 #include <net/cipso_ipv4.h>
32 #include <net/ip.h>
33 #include <net/ipv6.h>
34 #include <linux/audit.h>
35 #include <linux/magic.h>
36 #include <linux/dcache.h>
37 #include <linux/personality.h>
38 #include <linux/msg.h>
39 #include <linux/shm.h>
40 #include <linux/binfmts.h>
41 #include <linux/parser.h>
42 #include <linux/fs_context.h>
43 #include <linux/fs_parser.h>
44 #include <linux/watch_queue.h>
45 #include "smack.h"
46 
47 #define TRANS_TRUE	"TRUE"
48 #define TRANS_TRUE_SIZE	4
49 
50 #define SMK_CONNECTING	0
51 #define SMK_RECEIVING	1
52 #define SMK_SENDING	2
53 
54 static DEFINE_MUTEX(smack_ipv6_lock);
55 static LIST_HEAD(smk_ipv6_port_list);
56 struct kmem_cache *smack_rule_cache;
57 int smack_enabled;
58 
59 #define A(s) {"smack"#s, sizeof("smack"#s) - 1, Opt_##s}
60 static struct {
61 	const char *name;
62 	int len;
63 	int opt;
64 } smk_mount_opts[] = {
65 	{"smackfsdef", sizeof("smackfsdef") - 1, Opt_fsdefault},
66 	A(fsdefault), A(fsfloor), A(fshat), A(fsroot), A(fstransmute)
67 };
68 #undef A
69 
match_opt_prefix(char * s,int l,char ** arg)70 static int match_opt_prefix(char *s, int l, char **arg)
71 {
72 	int i;
73 
74 	for (i = 0; i < ARRAY_SIZE(smk_mount_opts); i++) {
75 		size_t len = smk_mount_opts[i].len;
76 		if (len > l || memcmp(s, smk_mount_opts[i].name, len))
77 			continue;
78 		if (len == l || s[len] != '=')
79 			continue;
80 		*arg = s + len + 1;
81 		return smk_mount_opts[i].opt;
82 	}
83 	return Opt_error;
84 }
85 
86 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
87 static char *smk_bu_mess[] = {
88 	"Bringup Error",	/* Unused */
89 	"Bringup",		/* SMACK_BRINGUP_ALLOW */
90 	"Unconfined Subject",	/* SMACK_UNCONFINED_SUBJECT */
91 	"Unconfined Object",	/* SMACK_UNCONFINED_OBJECT */
92 };
93 
smk_bu_mode(int mode,char * s)94 static void smk_bu_mode(int mode, char *s)
95 {
96 	int i = 0;
97 
98 	if (mode & MAY_READ)
99 		s[i++] = 'r';
100 	if (mode & MAY_WRITE)
101 		s[i++] = 'w';
102 	if (mode & MAY_EXEC)
103 		s[i++] = 'x';
104 	if (mode & MAY_APPEND)
105 		s[i++] = 'a';
106 	if (mode & MAY_TRANSMUTE)
107 		s[i++] = 't';
108 	if (mode & MAY_LOCK)
109 		s[i++] = 'l';
110 	if (i == 0)
111 		s[i++] = '-';
112 	s[i] = '\0';
113 }
114 #endif
115 
116 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_note(char * note,struct smack_known * sskp,struct smack_known * oskp,int mode,int rc)117 static int smk_bu_note(char *note, struct smack_known *sskp,
118 		       struct smack_known *oskp, int mode, int rc)
119 {
120 	char acc[SMK_NUM_ACCESS_TYPE + 1];
121 
122 	if (rc <= 0)
123 		return rc;
124 	if (rc > SMACK_UNCONFINED_OBJECT)
125 		rc = 0;
126 
127 	smk_bu_mode(mode, acc);
128 	pr_info("Smack %s: (%s %s %s) %s\n", smk_bu_mess[rc],
129 		sskp->smk_known, oskp->smk_known, acc, note);
130 	return 0;
131 }
132 #else
133 #define smk_bu_note(note, sskp, oskp, mode, RC) (RC)
134 #endif
135 
136 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_current(char * note,struct smack_known * oskp,int mode,int rc)137 static int smk_bu_current(char *note, struct smack_known *oskp,
138 			  int mode, int rc)
139 {
140 	struct task_smack *tsp = smack_cred(current_cred());
141 	char acc[SMK_NUM_ACCESS_TYPE + 1];
142 
143 	if (rc <= 0)
144 		return rc;
145 	if (rc > SMACK_UNCONFINED_OBJECT)
146 		rc = 0;
147 
148 	smk_bu_mode(mode, acc);
149 	pr_info("Smack %s: (%s %s %s) %s %s\n", smk_bu_mess[rc],
150 		tsp->smk_task->smk_known, oskp->smk_known,
151 		acc, current->comm, note);
152 	return 0;
153 }
154 #else
155 #define smk_bu_current(note, oskp, mode, RC) (RC)
156 #endif
157 
158 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_task(struct task_struct * otp,int mode,int rc)159 static int smk_bu_task(struct task_struct *otp, int mode, int rc)
160 {
161 	struct task_smack *tsp = smack_cred(current_cred());
162 	struct smack_known *smk_task = smk_of_task_struct_obj(otp);
163 	char acc[SMK_NUM_ACCESS_TYPE + 1];
164 
165 	if (rc <= 0)
166 		return rc;
167 	if (rc > SMACK_UNCONFINED_OBJECT)
168 		rc = 0;
169 
170 	smk_bu_mode(mode, acc);
171 	pr_info("Smack %s: (%s %s %s) %s to %s\n", smk_bu_mess[rc],
172 		tsp->smk_task->smk_known, smk_task->smk_known, acc,
173 		current->comm, otp->comm);
174 	return 0;
175 }
176 #else
177 #define smk_bu_task(otp, mode, RC) (RC)
178 #endif
179 
180 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_inode(struct inode * inode,int mode,int rc)181 static int smk_bu_inode(struct inode *inode, int mode, int rc)
182 {
183 	struct task_smack *tsp = smack_cred(current_cred());
184 	struct inode_smack *isp = smack_inode(inode);
185 	char acc[SMK_NUM_ACCESS_TYPE + 1];
186 
187 	if (isp->smk_flags & SMK_INODE_IMPURE)
188 		pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
189 			inode->i_sb->s_id, inode->i_ino, current->comm);
190 
191 	if (rc <= 0)
192 		return rc;
193 	if (rc > SMACK_UNCONFINED_OBJECT)
194 		rc = 0;
195 	if (rc == SMACK_UNCONFINED_SUBJECT &&
196 	    (mode & (MAY_WRITE | MAY_APPEND)))
197 		isp->smk_flags |= SMK_INODE_IMPURE;
198 
199 	smk_bu_mode(mode, acc);
200 
201 	pr_info("Smack %s: (%s %s %s) inode=(%s %ld) %s\n", smk_bu_mess[rc],
202 		tsp->smk_task->smk_known, isp->smk_inode->smk_known, acc,
203 		inode->i_sb->s_id, inode->i_ino, current->comm);
204 	return 0;
205 }
206 #else
207 #define smk_bu_inode(inode, mode, RC) (RC)
208 #endif
209 
210 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_file(struct file * file,int mode,int rc)211 static int smk_bu_file(struct file *file, int mode, int rc)
212 {
213 	struct task_smack *tsp = smack_cred(current_cred());
214 	struct smack_known *sskp = tsp->smk_task;
215 	struct inode *inode = file_inode(file);
216 	struct inode_smack *isp = smack_inode(inode);
217 	char acc[SMK_NUM_ACCESS_TYPE + 1];
218 
219 	if (isp->smk_flags & SMK_INODE_IMPURE)
220 		pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
221 			inode->i_sb->s_id, inode->i_ino, current->comm);
222 
223 	if (rc <= 0)
224 		return rc;
225 	if (rc > SMACK_UNCONFINED_OBJECT)
226 		rc = 0;
227 
228 	smk_bu_mode(mode, acc);
229 	pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
230 		sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
231 		inode->i_sb->s_id, inode->i_ino, file,
232 		current->comm);
233 	return 0;
234 }
235 #else
236 #define smk_bu_file(file, mode, RC) (RC)
237 #endif
238 
239 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
smk_bu_credfile(const struct cred * cred,struct file * file,int mode,int rc)240 static int smk_bu_credfile(const struct cred *cred, struct file *file,
241 				int mode, int rc)
242 {
243 	struct task_smack *tsp = smack_cred(cred);
244 	struct smack_known *sskp = tsp->smk_task;
245 	struct inode *inode = file_inode(file);
246 	struct inode_smack *isp = smack_inode(inode);
247 	char acc[SMK_NUM_ACCESS_TYPE + 1];
248 
249 	if (isp->smk_flags & SMK_INODE_IMPURE)
250 		pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
251 			inode->i_sb->s_id, inode->i_ino, current->comm);
252 
253 	if (rc <= 0)
254 		return rc;
255 	if (rc > SMACK_UNCONFINED_OBJECT)
256 		rc = 0;
257 
258 	smk_bu_mode(mode, acc);
259 	pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
260 		sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
261 		inode->i_sb->s_id, inode->i_ino, file,
262 		current->comm);
263 	return 0;
264 }
265 #else
266 #define smk_bu_credfile(cred, file, mode, RC) (RC)
267 #endif
268 
269 /**
270  * smk_fetch - Fetch the smack label from a file.
271  * @name: type of the label (attribute)
272  * @ip: a pointer to the inode
273  * @dp: a pointer to the dentry
274  *
275  * Returns a pointer to the master list entry for the Smack label,
276  * NULL if there was no label to fetch, or an error code.
277  */
smk_fetch(const char * name,struct inode * ip,struct dentry * dp)278 static struct smack_known *smk_fetch(const char *name, struct inode *ip,
279 					struct dentry *dp)
280 {
281 	int rc;
282 	char *buffer;
283 	struct smack_known *skp = NULL;
284 
285 	if (!(ip->i_opflags & IOP_XATTR))
286 		return ERR_PTR(-EOPNOTSUPP);
287 
288 	buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS);
289 	if (buffer == NULL)
290 		return ERR_PTR(-ENOMEM);
291 
292 	rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
293 	if (rc < 0)
294 		skp = ERR_PTR(rc);
295 	else if (rc == 0)
296 		skp = NULL;
297 	else
298 		skp = smk_import_entry(buffer, rc);
299 
300 	kfree(buffer);
301 
302 	return skp;
303 }
304 
305 /**
306  * init_inode_smack - initialize an inode security blob
307  * @inode: inode to extract the info from
308  * @skp: a pointer to the Smack label entry to use in the blob
309  *
310  */
init_inode_smack(struct inode * inode,struct smack_known * skp)311 static void init_inode_smack(struct inode *inode, struct smack_known *skp)
312 {
313 	struct inode_smack *isp = smack_inode(inode);
314 
315 	isp->smk_inode = skp;
316 	isp->smk_flags = 0;
317 }
318 
319 /**
320  * init_task_smack - initialize a task security blob
321  * @tsp: blob to initialize
322  * @task: a pointer to the Smack label for the running task
323  * @forked: a pointer to the Smack label for the forked task
324  *
325  */
init_task_smack(struct task_smack * tsp,struct smack_known * task,struct smack_known * forked)326 static void init_task_smack(struct task_smack *tsp, struct smack_known *task,
327 					struct smack_known *forked)
328 {
329 	tsp->smk_task = task;
330 	tsp->smk_forked = forked;
331 	INIT_LIST_HEAD(&tsp->smk_rules);
332 	INIT_LIST_HEAD(&tsp->smk_relabel);
333 	mutex_init(&tsp->smk_rules_lock);
334 }
335 
336 /**
337  * smk_copy_rules - copy a rule set
338  * @nhead: new rules header pointer
339  * @ohead: old rules header pointer
340  * @gfp: type of the memory for the allocation
341  *
342  * Returns 0 on success, -ENOMEM on error
343  */
smk_copy_rules(struct list_head * nhead,struct list_head * ohead,gfp_t gfp)344 static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
345 				gfp_t gfp)
346 {
347 	struct smack_rule *nrp;
348 	struct smack_rule *orp;
349 	int rc = 0;
350 
351 	list_for_each_entry_rcu(orp, ohead, list) {
352 		nrp = kmem_cache_zalloc(smack_rule_cache, gfp);
353 		if (nrp == NULL) {
354 			rc = -ENOMEM;
355 			break;
356 		}
357 		*nrp = *orp;
358 		list_add_rcu(&nrp->list, nhead);
359 	}
360 	return rc;
361 }
362 
363 /**
364  * smk_copy_relabel - copy smk_relabel labels list
365  * @nhead: new rules header pointer
366  * @ohead: old rules header pointer
367  * @gfp: type of the memory for the allocation
368  *
369  * Returns 0 on success, -ENOMEM on error
370  */
smk_copy_relabel(struct list_head * nhead,struct list_head * ohead,gfp_t gfp)371 static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead,
372 				gfp_t gfp)
373 {
374 	struct smack_known_list_elem *nklep;
375 	struct smack_known_list_elem *oklep;
376 
377 	list_for_each_entry(oklep, ohead, list) {
378 		nklep = kzalloc(sizeof(struct smack_known_list_elem), gfp);
379 		if (nklep == NULL) {
380 			smk_destroy_label_list(nhead);
381 			return -ENOMEM;
382 		}
383 		nklep->smk_label = oklep->smk_label;
384 		list_add(&nklep->list, nhead);
385 	}
386 
387 	return 0;
388 }
389 
390 /**
391  * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
392  * @mode - input mode in form of PTRACE_MODE_*
393  *
394  * Returns a converted MAY_* mode usable by smack rules
395  */
smk_ptrace_mode(unsigned int mode)396 static inline unsigned int smk_ptrace_mode(unsigned int mode)
397 {
398 	if (mode & PTRACE_MODE_ATTACH)
399 		return MAY_READWRITE;
400 	if (mode & PTRACE_MODE_READ)
401 		return MAY_READ;
402 
403 	return 0;
404 }
405 
406 /**
407  * smk_ptrace_rule_check - helper for ptrace access
408  * @tracer: tracer process
409  * @tracee_known: label entry of the process that's about to be traced
410  * @mode: ptrace attachment mode (PTRACE_MODE_*)
411  * @func: name of the function that called us, used for audit
412  *
413  * Returns 0 on access granted, -error on error
414  */
smk_ptrace_rule_check(struct task_struct * tracer,struct smack_known * tracee_known,unsigned int mode,const char * func)415 static int smk_ptrace_rule_check(struct task_struct *tracer,
416 				 struct smack_known *tracee_known,
417 				 unsigned int mode, const char *func)
418 {
419 	int rc;
420 	struct smk_audit_info ad, *saip = NULL;
421 	struct task_smack *tsp;
422 	struct smack_known *tracer_known;
423 	const struct cred *tracercred;
424 
425 	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
426 		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
427 		smk_ad_setfield_u_tsk(&ad, tracer);
428 		saip = &ad;
429 	}
430 
431 	rcu_read_lock();
432 	tracercred = __task_cred(tracer);
433 	tsp = smack_cred(tracercred);
434 	tracer_known = smk_of_task(tsp);
435 
436 	if ((mode & PTRACE_MODE_ATTACH) &&
437 	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
438 	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
439 		if (tracer_known->smk_known == tracee_known->smk_known)
440 			rc = 0;
441 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
442 			rc = -EACCES;
443 		else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))
444 			rc = 0;
445 		else
446 			rc = -EACCES;
447 
448 		if (saip)
449 			smack_log(tracer_known->smk_known,
450 				  tracee_known->smk_known,
451 				  0, rc, saip);
452 
453 		rcu_read_unlock();
454 		return rc;
455 	}
456 
457 	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
458 	rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
459 
460 	rcu_read_unlock();
461 	return rc;
462 }
463 
464 /*
465  * LSM hooks.
466  * We he, that is fun!
467  */
468 
469 /**
470  * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
471  * @ctp: child task pointer
472  * @mode: ptrace attachment mode (PTRACE_MODE_*)
473  *
474  * Returns 0 if access is OK, an error code otherwise
475  *
476  * Do the capability checks.
477  */
smack_ptrace_access_check(struct task_struct * ctp,unsigned int mode)478 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
479 {
480 	struct smack_known *skp;
481 
482 	skp = smk_of_task_struct_obj(ctp);
483 
484 	return smk_ptrace_rule_check(current, skp, mode, __func__);
485 }
486 
487 /**
488  * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
489  * @ptp: parent task pointer
490  *
491  * Returns 0 if access is OK, an error code otherwise
492  *
493  * Do the capability checks, and require PTRACE_MODE_ATTACH.
494  */
smack_ptrace_traceme(struct task_struct * ptp)495 static int smack_ptrace_traceme(struct task_struct *ptp)
496 {
497 	int rc;
498 	struct smack_known *skp;
499 
500 	skp = smk_of_task(smack_cred(current_cred()));
501 
502 	rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
503 	return rc;
504 }
505 
506 /**
507  * smack_syslog - Smack approval on syslog
508  * @typefrom_file: unused
509  *
510  * Returns 0 on success, error code otherwise.
511  */
smack_syslog(int typefrom_file)512 static int smack_syslog(int typefrom_file)
513 {
514 	int rc = 0;
515 	struct smack_known *skp = smk_of_current();
516 
517 	if (smack_privileged(CAP_MAC_OVERRIDE))
518 		return 0;
519 
520 	if (smack_syslog_label != NULL && smack_syslog_label != skp)
521 		rc = -EACCES;
522 
523 	return rc;
524 }
525 
526 /*
527  * Superblock Hooks.
528  */
529 
530 /**
531  * smack_sb_alloc_security - allocate a superblock blob
532  * @sb: the superblock getting the blob
533  *
534  * Returns 0 on success or -ENOMEM on error.
535  */
smack_sb_alloc_security(struct super_block * sb)536 static int smack_sb_alloc_security(struct super_block *sb)
537 {
538 	struct superblock_smack *sbsp = smack_superblock(sb);
539 
540 	sbsp->smk_root = &smack_known_floor;
541 	sbsp->smk_default = &smack_known_floor;
542 	sbsp->smk_floor = &smack_known_floor;
543 	sbsp->smk_hat = &smack_known_hat;
544 	/*
545 	 * SMK_SB_INITIALIZED will be zero from kzalloc.
546 	 */
547 
548 	return 0;
549 }
550 
551 struct smack_mnt_opts {
552 	const char *fsdefault, *fsfloor, *fshat, *fsroot, *fstransmute;
553 };
554 
smack_free_mnt_opts(void * mnt_opts)555 static void smack_free_mnt_opts(void *mnt_opts)
556 {
557 	struct smack_mnt_opts *opts = mnt_opts;
558 	kfree(opts->fsdefault);
559 	kfree(opts->fsfloor);
560 	kfree(opts->fshat);
561 	kfree(opts->fsroot);
562 	kfree(opts->fstransmute);
563 	kfree(opts);
564 }
565 
smack_add_opt(int token,const char * s,void ** mnt_opts)566 static int smack_add_opt(int token, const char *s, void **mnt_opts)
567 {
568 	struct smack_mnt_opts *opts = *mnt_opts;
569 
570 	if (!opts) {
571 		opts = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
572 		if (!opts)
573 			return -ENOMEM;
574 		*mnt_opts = opts;
575 	}
576 	if (!s)
577 		return -ENOMEM;
578 
579 	switch (token) {
580 	case Opt_fsdefault:
581 		if (opts->fsdefault)
582 			goto out_opt_err;
583 		opts->fsdefault = s;
584 		break;
585 	case Opt_fsfloor:
586 		if (opts->fsfloor)
587 			goto out_opt_err;
588 		opts->fsfloor = s;
589 		break;
590 	case Opt_fshat:
591 		if (opts->fshat)
592 			goto out_opt_err;
593 		opts->fshat = s;
594 		break;
595 	case Opt_fsroot:
596 		if (opts->fsroot)
597 			goto out_opt_err;
598 		opts->fsroot = s;
599 		break;
600 	case Opt_fstransmute:
601 		if (opts->fstransmute)
602 			goto out_opt_err;
603 		opts->fstransmute = s;
604 		break;
605 	}
606 	return 0;
607 
608 out_opt_err:
609 	pr_warn("Smack: duplicate mount options\n");
610 	return -EINVAL;
611 }
612 
613 /**
614  * smack_fs_context_dup - Duplicate the security data on fs_context duplication
615  * @fc: The new filesystem context.
616  * @src_fc: The source filesystem context being duplicated.
617  *
618  * Returns 0 on success or -ENOMEM on error.
619  */
smack_fs_context_dup(struct fs_context * fc,struct fs_context * src_fc)620 static int smack_fs_context_dup(struct fs_context *fc,
621 				struct fs_context *src_fc)
622 {
623 	struct smack_mnt_opts *dst, *src = src_fc->security;
624 
625 	if (!src)
626 		return 0;
627 
628 	fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
629 	if (!fc->security)
630 		return -ENOMEM;
631 	dst = fc->security;
632 
633 	if (src->fsdefault) {
634 		dst->fsdefault = kstrdup(src->fsdefault, GFP_KERNEL);
635 		if (!dst->fsdefault)
636 			return -ENOMEM;
637 	}
638 	if (src->fsfloor) {
639 		dst->fsfloor = kstrdup(src->fsfloor, GFP_KERNEL);
640 		if (!dst->fsfloor)
641 			return -ENOMEM;
642 	}
643 	if (src->fshat) {
644 		dst->fshat = kstrdup(src->fshat, GFP_KERNEL);
645 		if (!dst->fshat)
646 			return -ENOMEM;
647 	}
648 	if (src->fsroot) {
649 		dst->fsroot = kstrdup(src->fsroot, GFP_KERNEL);
650 		if (!dst->fsroot)
651 			return -ENOMEM;
652 	}
653 	if (src->fstransmute) {
654 		dst->fstransmute = kstrdup(src->fstransmute, GFP_KERNEL);
655 		if (!dst->fstransmute)
656 			return -ENOMEM;
657 	}
658 	return 0;
659 }
660 
661 static const struct fs_parameter_spec smack_fs_parameters[] = {
662 	fsparam_string("smackfsdef",		Opt_fsdefault),
663 	fsparam_string("smackfsdefault",	Opt_fsdefault),
664 	fsparam_string("smackfsfloor",		Opt_fsfloor),
665 	fsparam_string("smackfshat",		Opt_fshat),
666 	fsparam_string("smackfsroot",		Opt_fsroot),
667 	fsparam_string("smackfstransmute",	Opt_fstransmute),
668 	{}
669 };
670 
671 /**
672  * smack_fs_context_parse_param - Parse a single mount parameter
673  * @fc: The new filesystem context being constructed.
674  * @param: The parameter.
675  *
676  * Returns 0 on success, -ENOPARAM to pass the parameter on or anything else on
677  * error.
678  */
smack_fs_context_parse_param(struct fs_context * fc,struct fs_parameter * param)679 static int smack_fs_context_parse_param(struct fs_context *fc,
680 					struct fs_parameter *param)
681 {
682 	struct fs_parse_result result;
683 	int opt, rc;
684 
685 	opt = fs_parse(fc, smack_fs_parameters, param, &result);
686 	if (opt < 0)
687 		return opt;
688 
689 	rc = smack_add_opt(opt, param->string, &fc->security);
690 	if (!rc)
691 		param->string = NULL;
692 	return rc;
693 }
694 
smack_sb_eat_lsm_opts(char * options,void ** mnt_opts)695 static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
696 {
697 	char *from = options, *to = options;
698 	bool first = true;
699 
700 	while (1) {
701 		char *next = strchr(from, ',');
702 		int token, len, rc;
703 		char *arg = NULL;
704 
705 		if (next)
706 			len = next - from;
707 		else
708 			len = strlen(from);
709 
710 		token = match_opt_prefix(from, len, &arg);
711 		if (token != Opt_error) {
712 			arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
713 			rc = smack_add_opt(token, arg, mnt_opts);
714 			if (unlikely(rc)) {
715 				kfree(arg);
716 				if (*mnt_opts)
717 					smack_free_mnt_opts(*mnt_opts);
718 				*mnt_opts = NULL;
719 				return rc;
720 			}
721 		} else {
722 			if (!first) {	// copy with preceding comma
723 				from--;
724 				len++;
725 			}
726 			if (to != from)
727 				memmove(to, from, len);
728 			to += len;
729 			first = false;
730 		}
731 		if (!from[len])
732 			break;
733 		from += len + 1;
734 	}
735 	*to = '\0';
736 	return 0;
737 }
738 
739 /**
740  * smack_set_mnt_opts - set Smack specific mount options
741  * @sb: the file system superblock
742  * @mnt_opts: Smack mount options
743  * @kern_flags: mount option from kernel space or user space
744  * @set_kern_flags: where to store converted mount opts
745  *
746  * Returns 0 on success, an error code on failure
747  *
748  * Allow filesystems with binary mount data to explicitly set Smack mount
749  * labels.
750  */
smack_set_mnt_opts(struct super_block * sb,void * mnt_opts,unsigned long kern_flags,unsigned long * set_kern_flags)751 static int smack_set_mnt_opts(struct super_block *sb,
752 		void *mnt_opts,
753 		unsigned long kern_flags,
754 		unsigned long *set_kern_flags)
755 {
756 	struct dentry *root = sb->s_root;
757 	struct inode *inode = d_backing_inode(root);
758 	struct superblock_smack *sp = smack_superblock(sb);
759 	struct inode_smack *isp;
760 	struct smack_known *skp;
761 	struct smack_mnt_opts *opts = mnt_opts;
762 	bool transmute = false;
763 
764 	if (sp->smk_flags & SMK_SB_INITIALIZED)
765 		return 0;
766 
767 	if (inode->i_security == NULL) {
768 		int rc = lsm_inode_alloc(inode);
769 
770 		if (rc)
771 			return rc;
772 	}
773 
774 	if (!smack_privileged(CAP_MAC_ADMIN)) {
775 		/*
776 		 * Unprivileged mounts don't get to specify Smack values.
777 		 */
778 		if (opts)
779 			return -EPERM;
780 		/*
781 		 * Unprivileged mounts get root and default from the caller.
782 		 */
783 		skp = smk_of_current();
784 		sp->smk_root = skp;
785 		sp->smk_default = skp;
786 		/*
787 		 * For a handful of fs types with no user-controlled
788 		 * backing store it's okay to trust security labels
789 		 * in the filesystem. The rest are untrusted.
790 		 */
791 		if (sb->s_user_ns != &init_user_ns &&
792 		    sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
793 		    sb->s_magic != RAMFS_MAGIC) {
794 			transmute = true;
795 			sp->smk_flags |= SMK_SB_UNTRUSTED;
796 		}
797 	}
798 
799 	sp->smk_flags |= SMK_SB_INITIALIZED;
800 
801 	if (opts) {
802 		if (opts->fsdefault) {
803 			skp = smk_import_entry(opts->fsdefault, 0);
804 			if (IS_ERR(skp))
805 				return PTR_ERR(skp);
806 			sp->smk_default = skp;
807 		}
808 		if (opts->fsfloor) {
809 			skp = smk_import_entry(opts->fsfloor, 0);
810 			if (IS_ERR(skp))
811 				return PTR_ERR(skp);
812 			sp->smk_floor = skp;
813 		}
814 		if (opts->fshat) {
815 			skp = smk_import_entry(opts->fshat, 0);
816 			if (IS_ERR(skp))
817 				return PTR_ERR(skp);
818 			sp->smk_hat = skp;
819 		}
820 		if (opts->fsroot) {
821 			skp = smk_import_entry(opts->fsroot, 0);
822 			if (IS_ERR(skp))
823 				return PTR_ERR(skp);
824 			sp->smk_root = skp;
825 		}
826 		if (opts->fstransmute) {
827 			skp = smk_import_entry(opts->fstransmute, 0);
828 			if (IS_ERR(skp))
829 				return PTR_ERR(skp);
830 			sp->smk_root = skp;
831 			transmute = true;
832 		}
833 	}
834 
835 	/*
836 	 * Initialize the root inode.
837 	 */
838 	init_inode_smack(inode, sp->smk_root);
839 
840 	if (transmute) {
841 		isp = smack_inode(inode);
842 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
843 	}
844 
845 	return 0;
846 }
847 
848 /**
849  * smack_sb_statfs - Smack check on statfs
850  * @dentry: identifies the file system in question
851  *
852  * Returns 0 if current can read the floor of the filesystem,
853  * and error code otherwise
854  */
smack_sb_statfs(struct dentry * dentry)855 static int smack_sb_statfs(struct dentry *dentry)
856 {
857 	struct superblock_smack *sbp = smack_superblock(dentry->d_sb);
858 	int rc;
859 	struct smk_audit_info ad;
860 
861 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
862 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
863 
864 	rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
865 	rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
866 	return rc;
867 }
868 
869 /*
870  * BPRM hooks
871  */
872 
873 /**
874  * smack_bprm_creds_for_exec - Update bprm->cred if needed for exec
875  * @bprm: the exec information
876  *
877  * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
878  */
smack_bprm_creds_for_exec(struct linux_binprm * bprm)879 static int smack_bprm_creds_for_exec(struct linux_binprm *bprm)
880 {
881 	struct inode *inode = file_inode(bprm->file);
882 	struct task_smack *bsp = smack_cred(bprm->cred);
883 	struct inode_smack *isp;
884 	struct superblock_smack *sbsp;
885 	int rc;
886 
887 	isp = smack_inode(inode);
888 	if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
889 		return 0;
890 
891 	sbsp = smack_superblock(inode->i_sb);
892 	if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
893 	    isp->smk_task != sbsp->smk_root)
894 		return 0;
895 
896 	if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
897 		struct task_struct *tracer;
898 		rc = 0;
899 
900 		rcu_read_lock();
901 		tracer = ptrace_parent(current);
902 		if (likely(tracer != NULL))
903 			rc = smk_ptrace_rule_check(tracer,
904 						   isp->smk_task,
905 						   PTRACE_MODE_ATTACH,
906 						   __func__);
907 		rcu_read_unlock();
908 
909 		if (rc != 0)
910 			return rc;
911 	}
912 	if (bprm->unsafe & ~LSM_UNSAFE_PTRACE)
913 		return -EPERM;
914 
915 	bsp->smk_task = isp->smk_task;
916 	bprm->per_clear |= PER_CLEAR_ON_SETID;
917 
918 	/* Decide if this is a secure exec. */
919 	if (bsp->smk_task != bsp->smk_forked)
920 		bprm->secureexec = 1;
921 
922 	return 0;
923 }
924 
925 /*
926  * Inode hooks
927  */
928 
929 /**
930  * smack_inode_alloc_security - allocate an inode blob
931  * @inode: the inode in need of a blob
932  *
933  * Returns 0
934  */
smack_inode_alloc_security(struct inode * inode)935 static int smack_inode_alloc_security(struct inode *inode)
936 {
937 	struct smack_known *skp = smk_of_current();
938 
939 	init_inode_smack(inode, skp);
940 	return 0;
941 }
942 
943 /**
944  * smack_inode_init_security - copy out the smack from an inode
945  * @inode: the newly created inode
946  * @dir: containing directory object
947  * @qstr: unused
948  * @name: where to put the attribute name
949  * @value: where to put the attribute value
950  * @len: where to put the length of the attribute
951  *
952  * Returns 0 if it all works out, -ENOMEM if there's no memory
953  */
smack_inode_init_security(struct inode * inode,struct inode * dir,const struct qstr * qstr,const char ** name,void ** value,size_t * len)954 static int smack_inode_init_security(struct inode *inode, struct inode *dir,
955 				     const struct qstr *qstr, const char **name,
956 				     void **value, size_t *len)
957 {
958 	struct inode_smack *issp = smack_inode(inode);
959 	struct smack_known *skp = smk_of_current();
960 	struct smack_known *isp = smk_of_inode(inode);
961 	struct smack_known *dsp = smk_of_inode(dir);
962 	int may;
963 
964 	if (name)
965 		*name = XATTR_SMACK_SUFFIX;
966 
967 	if (value && len) {
968 		rcu_read_lock();
969 		may = smk_access_entry(skp->smk_known, dsp->smk_known,
970 				       &skp->smk_rules);
971 		rcu_read_unlock();
972 
973 		/*
974 		 * If the access rule allows transmutation and
975 		 * the directory requests transmutation then
976 		 * by all means transmute.
977 		 * Mark the inode as changed.
978 		 */
979 		if (may > 0 && ((may & MAY_TRANSMUTE) != 0) &&
980 		    smk_inode_transmutable(dir)) {
981 			isp = dsp;
982 			issp->smk_flags |= SMK_INODE_CHANGED;
983 		}
984 
985 		*value = kstrdup(isp->smk_known, GFP_NOFS);
986 		if (*value == NULL)
987 			return -ENOMEM;
988 
989 		*len = strlen(isp->smk_known);
990 	}
991 
992 	return 0;
993 }
994 
995 /**
996  * smack_inode_link - Smack check on link
997  * @old_dentry: the existing object
998  * @dir: unused
999  * @new_dentry: the new object
1000  *
1001  * Returns 0 if access is permitted, an error code otherwise
1002  */
smack_inode_link(struct dentry * old_dentry,struct inode * dir,struct dentry * new_dentry)1003 static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
1004 			    struct dentry *new_dentry)
1005 {
1006 	struct smack_known *isp;
1007 	struct smk_audit_info ad;
1008 	int rc;
1009 
1010 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1011 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
1012 
1013 	isp = smk_of_inode(d_backing_inode(old_dentry));
1014 	rc = smk_curacc(isp, MAY_WRITE, &ad);
1015 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_WRITE, rc);
1016 
1017 	if (rc == 0 && d_is_positive(new_dentry)) {
1018 		isp = smk_of_inode(d_backing_inode(new_dentry));
1019 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
1020 		rc = smk_curacc(isp, MAY_WRITE, &ad);
1021 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_WRITE, rc);
1022 	}
1023 
1024 	return rc;
1025 }
1026 
1027 /**
1028  * smack_inode_unlink - Smack check on inode deletion
1029  * @dir: containing directory object
1030  * @dentry: file to unlink
1031  *
1032  * Returns 0 if current can write the containing directory
1033  * and the object, error code otherwise
1034  */
smack_inode_unlink(struct inode * dir,struct dentry * dentry)1035 static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
1036 {
1037 	struct inode *ip = d_backing_inode(dentry);
1038 	struct smk_audit_info ad;
1039 	int rc;
1040 
1041 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1042 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1043 
1044 	/*
1045 	 * You need write access to the thing you're unlinking
1046 	 */
1047 	rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
1048 	rc = smk_bu_inode(ip, MAY_WRITE, rc);
1049 	if (rc == 0) {
1050 		/*
1051 		 * You also need write access to the containing directory
1052 		 */
1053 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
1054 		smk_ad_setfield_u_fs_inode(&ad, dir);
1055 		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
1056 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
1057 	}
1058 	return rc;
1059 }
1060 
1061 /**
1062  * smack_inode_rmdir - Smack check on directory deletion
1063  * @dir: containing directory object
1064  * @dentry: directory to unlink
1065  *
1066  * Returns 0 if current can write the containing directory
1067  * and the directory, error code otherwise
1068  */
smack_inode_rmdir(struct inode * dir,struct dentry * dentry)1069 static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
1070 {
1071 	struct smk_audit_info ad;
1072 	int rc;
1073 
1074 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1075 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1076 
1077 	/*
1078 	 * You need write access to the thing you're removing
1079 	 */
1080 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1081 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1082 	if (rc == 0) {
1083 		/*
1084 		 * You also need write access to the containing directory
1085 		 */
1086 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
1087 		smk_ad_setfield_u_fs_inode(&ad, dir);
1088 		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
1089 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
1090 	}
1091 
1092 	return rc;
1093 }
1094 
1095 /**
1096  * smack_inode_rename - Smack check on rename
1097  * @old_inode: unused
1098  * @old_dentry: the old object
1099  * @new_inode: unused
1100  * @new_dentry: the new object
1101  *
1102  * Read and write access is required on both the old and
1103  * new directories.
1104  *
1105  * Returns 0 if access is permitted, an error code otherwise
1106  */
smack_inode_rename(struct inode * old_inode,struct dentry * old_dentry,struct inode * new_inode,struct dentry * new_dentry)1107 static int smack_inode_rename(struct inode *old_inode,
1108 			      struct dentry *old_dentry,
1109 			      struct inode *new_inode,
1110 			      struct dentry *new_dentry)
1111 {
1112 	int rc;
1113 	struct smack_known *isp;
1114 	struct smk_audit_info ad;
1115 
1116 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1117 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
1118 
1119 	isp = smk_of_inode(d_backing_inode(old_dentry));
1120 	rc = smk_curacc(isp, MAY_READWRITE, &ad);
1121 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_READWRITE, rc);
1122 
1123 	if (rc == 0 && d_is_positive(new_dentry)) {
1124 		isp = smk_of_inode(d_backing_inode(new_dentry));
1125 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
1126 		rc = smk_curacc(isp, MAY_READWRITE, &ad);
1127 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_READWRITE, rc);
1128 	}
1129 	return rc;
1130 }
1131 
1132 /**
1133  * smack_inode_permission - Smack version of permission()
1134  * @inode: the inode in question
1135  * @mask: the access requested
1136  *
1137  * This is the important Smack hook.
1138  *
1139  * Returns 0 if access is permitted, an error code otherwise
1140  */
smack_inode_permission(struct inode * inode,int mask)1141 static int smack_inode_permission(struct inode *inode, int mask)
1142 {
1143 	struct superblock_smack *sbsp = smack_superblock(inode->i_sb);
1144 	struct smk_audit_info ad;
1145 	int no_block = mask & MAY_NOT_BLOCK;
1146 	int rc;
1147 
1148 	mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
1149 	/*
1150 	 * No permission to check. Existence test. Yup, it's there.
1151 	 */
1152 	if (mask == 0)
1153 		return 0;
1154 
1155 	if (sbsp->smk_flags & SMK_SB_UNTRUSTED) {
1156 		if (smk_of_inode(inode) != sbsp->smk_root)
1157 			return -EACCES;
1158 	}
1159 
1160 	/* May be droppable after audit */
1161 	if (no_block)
1162 		return -ECHILD;
1163 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
1164 	smk_ad_setfield_u_fs_inode(&ad, inode);
1165 	rc = smk_curacc(smk_of_inode(inode), mask, &ad);
1166 	rc = smk_bu_inode(inode, mask, rc);
1167 	return rc;
1168 }
1169 
1170 /**
1171  * smack_inode_setattr - Smack check for setting attributes
1172  * @dentry: the object
1173  * @iattr: for the force flag
1174  *
1175  * Returns 0 if access is permitted, an error code otherwise
1176  */
smack_inode_setattr(struct dentry * dentry,struct iattr * iattr)1177 static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
1178 {
1179 	struct smk_audit_info ad;
1180 	int rc;
1181 
1182 	/*
1183 	 * Need to allow for clearing the setuid bit.
1184 	 */
1185 	if (iattr->ia_valid & ATTR_FORCE)
1186 		return 0;
1187 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1188 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1189 
1190 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1191 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1192 	return rc;
1193 }
1194 
1195 /**
1196  * smack_inode_getattr - Smack check for getting attributes
1197  * @path: path to extract the info from
1198  *
1199  * Returns 0 if access is permitted, an error code otherwise
1200  */
smack_inode_getattr(const struct path * path)1201 static int smack_inode_getattr(const struct path *path)
1202 {
1203 	struct smk_audit_info ad;
1204 	struct inode *inode = d_backing_inode(path->dentry);
1205 	int rc;
1206 
1207 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1208 	smk_ad_setfield_u_fs_path(&ad, *path);
1209 	rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
1210 	rc = smk_bu_inode(inode, MAY_READ, rc);
1211 	return rc;
1212 }
1213 
1214 /**
1215  * smack_inode_setxattr - Smack check for setting xattrs
1216  * @dentry: the object
1217  * @name: name of the attribute
1218  * @value: value of the attribute
1219  * @size: size of the value
1220  * @flags: unused
1221  *
1222  * This protects the Smack attribute explicitly.
1223  *
1224  * Returns 0 if access is permitted, an error code otherwise
1225  */
smack_inode_setxattr(struct user_namespace * mnt_userns,struct dentry * dentry,const char * name,const void * value,size_t size,int flags)1226 static int smack_inode_setxattr(struct user_namespace *mnt_userns,
1227 				struct dentry *dentry, const char *name,
1228 				const void *value, size_t size, int flags)
1229 {
1230 	struct smk_audit_info ad;
1231 	struct smack_known *skp;
1232 	int check_priv = 0;
1233 	int check_import = 0;
1234 	int check_star = 0;
1235 	int rc = 0;
1236 
1237 	/*
1238 	 * Check label validity here so import won't fail in post_setxattr
1239 	 */
1240 	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
1241 	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
1242 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
1243 		check_priv = 1;
1244 		check_import = 1;
1245 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
1246 		   strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
1247 		check_priv = 1;
1248 		check_import = 1;
1249 		check_star = 1;
1250 	} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
1251 		check_priv = 1;
1252 		if (size != TRANS_TRUE_SIZE ||
1253 		    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
1254 			rc = -EINVAL;
1255 	} else
1256 		rc = cap_inode_setxattr(dentry, name, value, size, flags);
1257 
1258 	if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
1259 		rc = -EPERM;
1260 
1261 	if (rc == 0 && check_import) {
1262 		skp = size ? smk_import_entry(value, size) : NULL;
1263 		if (IS_ERR(skp))
1264 			rc = PTR_ERR(skp);
1265 		else if (skp == NULL || (check_star &&
1266 		    (skp == &smack_known_star || skp == &smack_known_web)))
1267 			rc = -EINVAL;
1268 	}
1269 
1270 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1271 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1272 
1273 	if (rc == 0) {
1274 		rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1275 		rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1276 	}
1277 
1278 	return rc;
1279 }
1280 
1281 /**
1282  * smack_inode_post_setxattr - Apply the Smack update approved above
1283  * @dentry: object
1284  * @name: attribute name
1285  * @value: attribute value
1286  * @size: attribute size
1287  * @flags: unused
1288  *
1289  * Set the pointer in the inode blob to the entry found
1290  * in the master label list.
1291  */
smack_inode_post_setxattr(struct dentry * dentry,const char * name,const void * value,size_t size,int flags)1292 static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
1293 				      const void *value, size_t size, int flags)
1294 {
1295 	struct smack_known *skp;
1296 	struct inode_smack *isp = smack_inode(d_backing_inode(dentry));
1297 
1298 	if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
1299 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
1300 		return;
1301 	}
1302 
1303 	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
1304 		skp = smk_import_entry(value, size);
1305 		if (!IS_ERR(skp))
1306 			isp->smk_inode = skp;
1307 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
1308 		skp = smk_import_entry(value, size);
1309 		if (!IS_ERR(skp))
1310 			isp->smk_task = skp;
1311 	} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
1312 		skp = smk_import_entry(value, size);
1313 		if (!IS_ERR(skp))
1314 			isp->smk_mmap = skp;
1315 	}
1316 
1317 	return;
1318 }
1319 
1320 /**
1321  * smack_inode_getxattr - Smack check on getxattr
1322  * @dentry: the object
1323  * @name: unused
1324  *
1325  * Returns 0 if access is permitted, an error code otherwise
1326  */
smack_inode_getxattr(struct dentry * dentry,const char * name)1327 static int smack_inode_getxattr(struct dentry *dentry, const char *name)
1328 {
1329 	struct smk_audit_info ad;
1330 	int rc;
1331 
1332 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1333 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1334 
1335 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_READ, &ad);
1336 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_READ, rc);
1337 	return rc;
1338 }
1339 
1340 /**
1341  * smack_inode_removexattr - Smack check on removexattr
1342  * @dentry: the object
1343  * @name: name of the attribute
1344  *
1345  * Removing the Smack attribute requires CAP_MAC_ADMIN
1346  *
1347  * Returns 0 if access is permitted, an error code otherwise
1348  */
smack_inode_removexattr(struct user_namespace * mnt_userns,struct dentry * dentry,const char * name)1349 static int smack_inode_removexattr(struct user_namespace *mnt_userns,
1350 				   struct dentry *dentry, const char *name)
1351 {
1352 	struct inode_smack *isp;
1353 	struct smk_audit_info ad;
1354 	int rc = 0;
1355 
1356 	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
1357 	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
1358 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
1359 	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
1360 	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
1361 	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
1362 		if (!smack_privileged(CAP_MAC_ADMIN))
1363 			rc = -EPERM;
1364 	} else
1365 		rc = cap_inode_removexattr(mnt_userns, dentry, name);
1366 
1367 	if (rc != 0)
1368 		return rc;
1369 
1370 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
1371 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
1372 
1373 	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
1374 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
1375 	if (rc != 0)
1376 		return rc;
1377 
1378 	isp = smack_inode(d_backing_inode(dentry));
1379 	/*
1380 	 * Don't do anything special for these.
1381 	 *	XATTR_NAME_SMACKIPIN
1382 	 *	XATTR_NAME_SMACKIPOUT
1383 	 */
1384 	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
1385 		struct super_block *sbp = dentry->d_sb;
1386 		struct superblock_smack *sbsp = smack_superblock(sbp);
1387 
1388 		isp->smk_inode = sbsp->smk_default;
1389 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0)
1390 		isp->smk_task = NULL;
1391 	else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
1392 		isp->smk_mmap = NULL;
1393 	else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
1394 		isp->smk_flags &= ~SMK_INODE_TRANSMUTE;
1395 
1396 	return 0;
1397 }
1398 
1399 /**
1400  * smack_inode_getsecurity - get smack xattrs
1401  * @inode: the object
1402  * @name: attribute name
1403  * @buffer: where to put the result
1404  * @alloc: duplicate memory
1405  *
1406  * Returns the size of the attribute or an error code
1407  */
smack_inode_getsecurity(struct user_namespace * mnt_userns,struct inode * inode,const char * name,void ** buffer,bool alloc)1408 static int smack_inode_getsecurity(struct user_namespace *mnt_userns,
1409 				   struct inode *inode, const char *name,
1410 				   void **buffer, bool alloc)
1411 {
1412 	struct socket_smack *ssp;
1413 	struct socket *sock;
1414 	struct super_block *sbp;
1415 	struct inode *ip = (struct inode *)inode;
1416 	struct smack_known *isp;
1417 
1418 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0)
1419 		isp = smk_of_inode(inode);
1420 	else {
1421 		/*
1422 		 * The rest of the Smack xattrs are only on sockets.
1423 		 */
1424 		sbp = ip->i_sb;
1425 		if (sbp->s_magic != SOCKFS_MAGIC)
1426 			return -EOPNOTSUPP;
1427 
1428 		sock = SOCKET_I(ip);
1429 		if (sock == NULL || sock->sk == NULL)
1430 			return -EOPNOTSUPP;
1431 
1432 		ssp = sock->sk->sk_security;
1433 
1434 		if (strcmp(name, XATTR_SMACK_IPIN) == 0)
1435 			isp = ssp->smk_in;
1436 		else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
1437 			isp = ssp->smk_out;
1438 		else
1439 			return -EOPNOTSUPP;
1440 	}
1441 
1442 	if (alloc) {
1443 		*buffer = kstrdup(isp->smk_known, GFP_KERNEL);
1444 		if (*buffer == NULL)
1445 			return -ENOMEM;
1446 	}
1447 
1448 	return strlen(isp->smk_known);
1449 }
1450 
1451 
1452 /**
1453  * smack_inode_listsecurity - list the Smack attributes
1454  * @inode: the object
1455  * @buffer: where they go
1456  * @buffer_size: size of buffer
1457  */
smack_inode_listsecurity(struct inode * inode,char * buffer,size_t buffer_size)1458 static int smack_inode_listsecurity(struct inode *inode, char *buffer,
1459 				    size_t buffer_size)
1460 {
1461 	int len = sizeof(XATTR_NAME_SMACK);
1462 
1463 	if (buffer != NULL && len <= buffer_size)
1464 		memcpy(buffer, XATTR_NAME_SMACK, len);
1465 
1466 	return len;
1467 }
1468 
1469 /**
1470  * smack_inode_getsecid - Extract inode's security id
1471  * @inode: inode to extract the info from
1472  * @secid: where result will be saved
1473  */
smack_inode_getsecid(struct inode * inode,u32 * secid)1474 static void smack_inode_getsecid(struct inode *inode, u32 *secid)
1475 {
1476 	struct smack_known *skp = smk_of_inode(inode);
1477 
1478 	*secid = skp->smk_secid;
1479 }
1480 
1481 /*
1482  * File Hooks
1483  */
1484 
1485 /*
1486  * There is no smack_file_permission hook
1487  *
1488  * Should access checks be done on each read or write?
1489  * UNICOS and SELinux say yes.
1490  * Trusted Solaris, Trusted Irix, and just about everyone else says no.
1491  *
1492  * I'll say no for now. Smack does not do the frequent
1493  * label changing that SELinux does.
1494  */
1495 
1496 /**
1497  * smack_file_alloc_security - assign a file security blob
1498  * @file: the object
1499  *
1500  * The security blob for a file is a pointer to the master
1501  * label list, so no allocation is done.
1502  *
1503  * f_security is the owner security information. It
1504  * isn't used on file access checks, it's for send_sigio.
1505  *
1506  * Returns 0
1507  */
smack_file_alloc_security(struct file * file)1508 static int smack_file_alloc_security(struct file *file)
1509 {
1510 	struct smack_known **blob = smack_file(file);
1511 
1512 	*blob = smk_of_current();
1513 	return 0;
1514 }
1515 
1516 /**
1517  * smack_file_ioctl - Smack check on ioctls
1518  * @file: the object
1519  * @cmd: what to do
1520  * @arg: unused
1521  *
1522  * Relies heavily on the correct use of the ioctl command conventions.
1523  *
1524  * Returns 0 if allowed, error code otherwise
1525  */
smack_file_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1526 static int smack_file_ioctl(struct file *file, unsigned int cmd,
1527 			    unsigned long arg)
1528 {
1529 	int rc = 0;
1530 	struct smk_audit_info ad;
1531 	struct inode *inode = file_inode(file);
1532 
1533 	if (unlikely(IS_PRIVATE(inode)))
1534 		return 0;
1535 
1536 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1537 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1538 
1539 	if (_IOC_DIR(cmd) & _IOC_WRITE) {
1540 		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
1541 		rc = smk_bu_file(file, MAY_WRITE, rc);
1542 	}
1543 
1544 	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
1545 		rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
1546 		rc = smk_bu_file(file, MAY_READ, rc);
1547 	}
1548 
1549 	return rc;
1550 }
1551 
1552 /**
1553  * smack_file_lock - Smack check on file locking
1554  * @file: the object
1555  * @cmd: unused
1556  *
1557  * Returns 0 if current has lock access, error code otherwise
1558  */
smack_file_lock(struct file * file,unsigned int cmd)1559 static int smack_file_lock(struct file *file, unsigned int cmd)
1560 {
1561 	struct smk_audit_info ad;
1562 	int rc;
1563 	struct inode *inode = file_inode(file);
1564 
1565 	if (unlikely(IS_PRIVATE(inode)))
1566 		return 0;
1567 
1568 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1569 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1570 	rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
1571 	rc = smk_bu_file(file, MAY_LOCK, rc);
1572 	return rc;
1573 }
1574 
1575 /**
1576  * smack_file_fcntl - Smack check on fcntl
1577  * @file: the object
1578  * @cmd: what action to check
1579  * @arg: unused
1580  *
1581  * Generally these operations are harmless.
1582  * File locking operations present an obvious mechanism
1583  * for passing information, so they require write access.
1584  *
1585  * Returns 0 if current has access, error code otherwise
1586  */
smack_file_fcntl(struct file * file,unsigned int cmd,unsigned long arg)1587 static int smack_file_fcntl(struct file *file, unsigned int cmd,
1588 			    unsigned long arg)
1589 {
1590 	struct smk_audit_info ad;
1591 	int rc = 0;
1592 	struct inode *inode = file_inode(file);
1593 
1594 	if (unlikely(IS_PRIVATE(inode)))
1595 		return 0;
1596 
1597 	switch (cmd) {
1598 	case F_GETLK:
1599 		break;
1600 	case F_SETLK:
1601 	case F_SETLKW:
1602 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1603 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
1604 		rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
1605 		rc = smk_bu_file(file, MAY_LOCK, rc);
1606 		break;
1607 	case F_SETOWN:
1608 	case F_SETSIG:
1609 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1610 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
1611 		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
1612 		rc = smk_bu_file(file, MAY_WRITE, rc);
1613 		break;
1614 	default:
1615 		break;
1616 	}
1617 
1618 	return rc;
1619 }
1620 
1621 /**
1622  * smack_mmap_file :
1623  * Check permissions for a mmap operation.  The @file may be NULL, e.g.
1624  * if mapping anonymous memory.
1625  * @file contains the file structure for file to map (may be NULL).
1626  * @reqprot contains the protection requested by the application.
1627  * @prot contains the protection that will be applied by the kernel.
1628  * @flags contains the operational flags.
1629  * Return 0 if permission is granted.
1630  */
smack_mmap_file(struct file * file,unsigned long reqprot,unsigned long prot,unsigned long flags)1631 static int smack_mmap_file(struct file *file,
1632 			   unsigned long reqprot, unsigned long prot,
1633 			   unsigned long flags)
1634 {
1635 	struct smack_known *skp;
1636 	struct smack_known *mkp;
1637 	struct smack_rule *srp;
1638 	struct task_smack *tsp;
1639 	struct smack_known *okp;
1640 	struct inode_smack *isp;
1641 	struct superblock_smack *sbsp;
1642 	int may;
1643 	int mmay;
1644 	int tmay;
1645 	int rc;
1646 
1647 	if (file == NULL)
1648 		return 0;
1649 
1650 	if (unlikely(IS_PRIVATE(file_inode(file))))
1651 		return 0;
1652 
1653 	isp = smack_inode(file_inode(file));
1654 	if (isp->smk_mmap == NULL)
1655 		return 0;
1656 	sbsp = smack_superblock(file_inode(file)->i_sb);
1657 	if (sbsp->smk_flags & SMK_SB_UNTRUSTED &&
1658 	    isp->smk_mmap != sbsp->smk_root)
1659 		return -EACCES;
1660 	mkp = isp->smk_mmap;
1661 
1662 	tsp = smack_cred(current_cred());
1663 	skp = smk_of_current();
1664 	rc = 0;
1665 
1666 	rcu_read_lock();
1667 	/*
1668 	 * For each Smack rule associated with the subject
1669 	 * label verify that the SMACK64MMAP also has access
1670 	 * to that rule's object label.
1671 	 */
1672 	list_for_each_entry_rcu(srp, &skp->smk_rules, list) {
1673 		okp = srp->smk_object;
1674 		/*
1675 		 * Matching labels always allows access.
1676 		 */
1677 		if (mkp->smk_known == okp->smk_known)
1678 			continue;
1679 		/*
1680 		 * If there is a matching local rule take
1681 		 * that into account as well.
1682 		 */
1683 		may = smk_access_entry(srp->smk_subject->smk_known,
1684 				       okp->smk_known,
1685 				       &tsp->smk_rules);
1686 		if (may == -ENOENT)
1687 			may = srp->smk_access;
1688 		else
1689 			may &= srp->smk_access;
1690 		/*
1691 		 * If may is zero the SMACK64MMAP subject can't
1692 		 * possibly have less access.
1693 		 */
1694 		if (may == 0)
1695 			continue;
1696 
1697 		/*
1698 		 * Fetch the global list entry.
1699 		 * If there isn't one a SMACK64MMAP subject
1700 		 * can't have as much access as current.
1701 		 */
1702 		mmay = smk_access_entry(mkp->smk_known, okp->smk_known,
1703 					&mkp->smk_rules);
1704 		if (mmay == -ENOENT) {
1705 			rc = -EACCES;
1706 			break;
1707 		}
1708 		/*
1709 		 * If there is a local entry it modifies the
1710 		 * potential access, too.
1711 		 */
1712 		tmay = smk_access_entry(mkp->smk_known, okp->smk_known,
1713 					&tsp->smk_rules);
1714 		if (tmay != -ENOENT)
1715 			mmay &= tmay;
1716 
1717 		/*
1718 		 * If there is any access available to current that is
1719 		 * not available to a SMACK64MMAP subject
1720 		 * deny access.
1721 		 */
1722 		if ((may | mmay) != mmay) {
1723 			rc = -EACCES;
1724 			break;
1725 		}
1726 	}
1727 
1728 	rcu_read_unlock();
1729 
1730 	return rc;
1731 }
1732 
1733 /**
1734  * smack_file_set_fowner - set the file security blob value
1735  * @file: object in question
1736  *
1737  */
smack_file_set_fowner(struct file * file)1738 static void smack_file_set_fowner(struct file *file)
1739 {
1740 	struct smack_known **blob = smack_file(file);
1741 
1742 	*blob = smk_of_current();
1743 }
1744 
1745 /**
1746  * smack_file_send_sigiotask - Smack on sigio
1747  * @tsk: The target task
1748  * @fown: the object the signal come from
1749  * @signum: unused
1750  *
1751  * Allow a privileged task to get signals even if it shouldn't
1752  *
1753  * Returns 0 if a subject with the object's smack could
1754  * write to the task, an error code otherwise.
1755  */
smack_file_send_sigiotask(struct task_struct * tsk,struct fown_struct * fown,int signum)1756 static int smack_file_send_sigiotask(struct task_struct *tsk,
1757 				     struct fown_struct *fown, int signum)
1758 {
1759 	struct smack_known **blob;
1760 	struct smack_known *skp;
1761 	struct smack_known *tkp = smk_of_task(smack_cred(tsk->cred));
1762 	const struct cred *tcred;
1763 	struct file *file;
1764 	int rc;
1765 	struct smk_audit_info ad;
1766 
1767 	/*
1768 	 * struct fown_struct is never outside the context of a struct file
1769 	 */
1770 	file = container_of(fown, struct file, f_owner);
1771 
1772 	/* we don't log here as rc can be overriden */
1773 	blob = smack_file(file);
1774 	skp = *blob;
1775 	rc = smk_access(skp, tkp, MAY_DELIVER, NULL);
1776 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);
1777 
1778 	rcu_read_lock();
1779 	tcred = __task_cred(tsk);
1780 	if (rc != 0 && smack_privileged_cred(CAP_MAC_OVERRIDE, tcred))
1781 		rc = 0;
1782 	rcu_read_unlock();
1783 
1784 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
1785 	smk_ad_setfield_u_tsk(&ad, tsk);
1786 	smack_log(skp->smk_known, tkp->smk_known, MAY_DELIVER, rc, &ad);
1787 	return rc;
1788 }
1789 
1790 /**
1791  * smack_file_receive - Smack file receive check
1792  * @file: the object
1793  *
1794  * Returns 0 if current has access, error code otherwise
1795  */
smack_file_receive(struct file * file)1796 static int smack_file_receive(struct file *file)
1797 {
1798 	int rc;
1799 	int may = 0;
1800 	struct smk_audit_info ad;
1801 	struct inode *inode = file_inode(file);
1802 	struct socket *sock;
1803 	struct task_smack *tsp;
1804 	struct socket_smack *ssp;
1805 
1806 	if (unlikely(IS_PRIVATE(inode)))
1807 		return 0;
1808 
1809 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1810 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1811 
1812 	if (inode->i_sb->s_magic == SOCKFS_MAGIC) {
1813 		sock = SOCKET_I(inode);
1814 		ssp = sock->sk->sk_security;
1815 		tsp = smack_cred(current_cred());
1816 		/*
1817 		 * If the receiving process can't write to the
1818 		 * passed socket or if the passed socket can't
1819 		 * write to the receiving process don't accept
1820 		 * the passed socket.
1821 		 */
1822 		rc = smk_access(tsp->smk_task, ssp->smk_out, MAY_WRITE, &ad);
1823 		rc = smk_bu_file(file, may, rc);
1824 		if (rc < 0)
1825 			return rc;
1826 		rc = smk_access(ssp->smk_in, tsp->smk_task, MAY_WRITE, &ad);
1827 		rc = smk_bu_file(file, may, rc);
1828 		return rc;
1829 	}
1830 	/*
1831 	 * This code relies on bitmasks.
1832 	 */
1833 	if (file->f_mode & FMODE_READ)
1834 		may = MAY_READ;
1835 	if (file->f_mode & FMODE_WRITE)
1836 		may |= MAY_WRITE;
1837 
1838 	rc = smk_curacc(smk_of_inode(inode), may, &ad);
1839 	rc = smk_bu_file(file, may, rc);
1840 	return rc;
1841 }
1842 
1843 /**
1844  * smack_file_open - Smack dentry open processing
1845  * @file: the object
1846  *
1847  * Set the security blob in the file structure.
1848  * Allow the open only if the task has read access. There are
1849  * many read operations (e.g. fstat) that you can do with an
1850  * fd even if you have the file open write-only.
1851  *
1852  * Returns 0 if current has access, error code otherwise
1853  */
smack_file_open(struct file * file)1854 static int smack_file_open(struct file *file)
1855 {
1856 	struct task_smack *tsp = smack_cred(file->f_cred);
1857 	struct inode *inode = file_inode(file);
1858 	struct smk_audit_info ad;
1859 	int rc;
1860 
1861 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
1862 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
1863 	rc = smk_tskacc(tsp, smk_of_inode(inode), MAY_READ, &ad);
1864 	rc = smk_bu_credfile(file->f_cred, file, MAY_READ, rc);
1865 
1866 	return rc;
1867 }
1868 
1869 /*
1870  * Task hooks
1871  */
1872 
1873 /**
1874  * smack_cred_alloc_blank - "allocate" blank task-level security credentials
1875  * @cred: the new credentials
1876  * @gfp: the atomicity of any memory allocations
1877  *
1878  * Prepare a blank set of credentials for modification.  This must allocate all
1879  * the memory the LSM module might require such that cred_transfer() can
1880  * complete without error.
1881  */
smack_cred_alloc_blank(struct cred * cred,gfp_t gfp)1882 static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
1883 {
1884 	init_task_smack(smack_cred(cred), NULL, NULL);
1885 	return 0;
1886 }
1887 
1888 
1889 /**
1890  * smack_cred_free - "free" task-level security credentials
1891  * @cred: the credentials in question
1892  *
1893  */
smack_cred_free(struct cred * cred)1894 static void smack_cred_free(struct cred *cred)
1895 {
1896 	struct task_smack *tsp = smack_cred(cred);
1897 	struct smack_rule *rp;
1898 	struct list_head *l;
1899 	struct list_head *n;
1900 
1901 	smk_destroy_label_list(&tsp->smk_relabel);
1902 
1903 	list_for_each_safe(l, n, &tsp->smk_rules) {
1904 		rp = list_entry(l, struct smack_rule, list);
1905 		list_del(&rp->list);
1906 		kmem_cache_free(smack_rule_cache, rp);
1907 	}
1908 }
1909 
1910 /**
1911  * smack_cred_prepare - prepare new set of credentials for modification
1912  * @new: the new credentials
1913  * @old: the original credentials
1914  * @gfp: the atomicity of any memory allocations
1915  *
1916  * Prepare a new set of credentials for modification.
1917  */
smack_cred_prepare(struct cred * new,const struct cred * old,gfp_t gfp)1918 static int smack_cred_prepare(struct cred *new, const struct cred *old,
1919 			      gfp_t gfp)
1920 {
1921 	struct task_smack *old_tsp = smack_cred(old);
1922 	struct task_smack *new_tsp = smack_cred(new);
1923 	int rc;
1924 
1925 	init_task_smack(new_tsp, old_tsp->smk_task, old_tsp->smk_task);
1926 
1927 	rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp);
1928 	if (rc != 0)
1929 		return rc;
1930 
1931 	rc = smk_copy_relabel(&new_tsp->smk_relabel, &old_tsp->smk_relabel,
1932 				gfp);
1933 	return rc;
1934 }
1935 
1936 /**
1937  * smack_cred_transfer - Transfer the old credentials to the new credentials
1938  * @new: the new credentials
1939  * @old: the original credentials
1940  *
1941  * Fill in a set of blank credentials from another set of credentials.
1942  */
smack_cred_transfer(struct cred * new,const struct cred * old)1943 static void smack_cred_transfer(struct cred *new, const struct cred *old)
1944 {
1945 	struct task_smack *old_tsp = smack_cred(old);
1946 	struct task_smack *new_tsp = smack_cred(new);
1947 
1948 	new_tsp->smk_task = old_tsp->smk_task;
1949 	new_tsp->smk_forked = old_tsp->smk_task;
1950 	mutex_init(&new_tsp->smk_rules_lock);
1951 	INIT_LIST_HEAD(&new_tsp->smk_rules);
1952 
1953 	/* cbs copy rule list */
1954 }
1955 
1956 /**
1957  * smack_cred_getsecid - get the secid corresponding to a creds structure
1958  * @cred: the object creds
1959  * @secid: where to put the result
1960  *
1961  * Sets the secid to contain a u32 version of the smack label.
1962  */
smack_cred_getsecid(const struct cred * cred,u32 * secid)1963 static void smack_cred_getsecid(const struct cred *cred, u32 *secid)
1964 {
1965 	struct smack_known *skp;
1966 
1967 	rcu_read_lock();
1968 	skp = smk_of_task(smack_cred(cred));
1969 	*secid = skp->smk_secid;
1970 	rcu_read_unlock();
1971 }
1972 
1973 /**
1974  * smack_kernel_act_as - Set the subjective context in a set of credentials
1975  * @new: points to the set of credentials to be modified.
1976  * @secid: specifies the security ID to be set
1977  *
1978  * Set the security data for a kernel service.
1979  */
smack_kernel_act_as(struct cred * new,u32 secid)1980 static int smack_kernel_act_as(struct cred *new, u32 secid)
1981 {
1982 	struct task_smack *new_tsp = smack_cred(new);
1983 
1984 	new_tsp->smk_task = smack_from_secid(secid);
1985 	return 0;
1986 }
1987 
1988 /**
1989  * smack_kernel_create_files_as - Set the file creation label in a set of creds
1990  * @new: points to the set of credentials to be modified
1991  * @inode: points to the inode to use as a reference
1992  *
1993  * Set the file creation context in a set of credentials to the same
1994  * as the objective context of the specified inode
1995  */
smack_kernel_create_files_as(struct cred * new,struct inode * inode)1996 static int smack_kernel_create_files_as(struct cred *new,
1997 					struct inode *inode)
1998 {
1999 	struct inode_smack *isp = smack_inode(inode);
2000 	struct task_smack *tsp = smack_cred(new);
2001 
2002 	tsp->smk_forked = isp->smk_inode;
2003 	tsp->smk_task = tsp->smk_forked;
2004 	return 0;
2005 }
2006 
2007 /**
2008  * smk_curacc_on_task - helper to log task related access
2009  * @p: the task object
2010  * @access: the access requested
2011  * @caller: name of the calling function for audit
2012  *
2013  * Return 0 if access is permitted
2014  */
smk_curacc_on_task(struct task_struct * p,int access,const char * caller)2015 static int smk_curacc_on_task(struct task_struct *p, int access,
2016 				const char *caller)
2017 {
2018 	struct smk_audit_info ad;
2019 	struct smack_known *skp = smk_of_task_struct_subj(p);
2020 	int rc;
2021 
2022 	smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
2023 	smk_ad_setfield_u_tsk(&ad, p);
2024 	rc = smk_curacc(skp, access, &ad);
2025 	rc = smk_bu_task(p, access, rc);
2026 	return rc;
2027 }
2028 
2029 /**
2030  * smack_task_setpgid - Smack check on setting pgid
2031  * @p: the task object
2032  * @pgid: unused
2033  *
2034  * Return 0 if write access is permitted
2035  */
smack_task_setpgid(struct task_struct * p,pid_t pgid)2036 static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
2037 {
2038 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2039 }
2040 
2041 /**
2042  * smack_task_getpgid - Smack access check for getpgid
2043  * @p: the object task
2044  *
2045  * Returns 0 if current can read the object task, error code otherwise
2046  */
smack_task_getpgid(struct task_struct * p)2047 static int smack_task_getpgid(struct task_struct *p)
2048 {
2049 	return smk_curacc_on_task(p, MAY_READ, __func__);
2050 }
2051 
2052 /**
2053  * smack_task_getsid - Smack access check for getsid
2054  * @p: the object task
2055  *
2056  * Returns 0 if current can read the object task, error code otherwise
2057  */
smack_task_getsid(struct task_struct * p)2058 static int smack_task_getsid(struct task_struct *p)
2059 {
2060 	return smk_curacc_on_task(p, MAY_READ, __func__);
2061 }
2062 
2063 /**
2064  * smack_task_getsecid_subj - get the subjective secid of the task
2065  * @p: the task
2066  * @secid: where to put the result
2067  *
2068  * Sets the secid to contain a u32 version of the task's subjective smack label.
2069  */
smack_task_getsecid_subj(struct task_struct * p,u32 * secid)2070 static void smack_task_getsecid_subj(struct task_struct *p, u32 *secid)
2071 {
2072 	struct smack_known *skp = smk_of_task_struct_subj(p);
2073 
2074 	*secid = skp->smk_secid;
2075 }
2076 
2077 /**
2078  * smack_task_getsecid_obj - get the objective secid of the task
2079  * @p: the task
2080  * @secid: where to put the result
2081  *
2082  * Sets the secid to contain a u32 version of the task's objective smack label.
2083  */
smack_task_getsecid_obj(struct task_struct * p,u32 * secid)2084 static void smack_task_getsecid_obj(struct task_struct *p, u32 *secid)
2085 {
2086 	struct smack_known *skp = smk_of_task_struct_obj(p);
2087 
2088 	*secid = skp->smk_secid;
2089 }
2090 
2091 /**
2092  * smack_task_setnice - Smack check on setting nice
2093  * @p: the task object
2094  * @nice: unused
2095  *
2096  * Return 0 if write access is permitted
2097  */
smack_task_setnice(struct task_struct * p,int nice)2098 static int smack_task_setnice(struct task_struct *p, int nice)
2099 {
2100 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2101 }
2102 
2103 /**
2104  * smack_task_setioprio - Smack check on setting ioprio
2105  * @p: the task object
2106  * @ioprio: unused
2107  *
2108  * Return 0 if write access is permitted
2109  */
smack_task_setioprio(struct task_struct * p,int ioprio)2110 static int smack_task_setioprio(struct task_struct *p, int ioprio)
2111 {
2112 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2113 }
2114 
2115 /**
2116  * smack_task_getioprio - Smack check on reading ioprio
2117  * @p: the task object
2118  *
2119  * Return 0 if read access is permitted
2120  */
smack_task_getioprio(struct task_struct * p)2121 static int smack_task_getioprio(struct task_struct *p)
2122 {
2123 	return smk_curacc_on_task(p, MAY_READ, __func__);
2124 }
2125 
2126 /**
2127  * smack_task_setscheduler - Smack check on setting scheduler
2128  * @p: the task object
2129  *
2130  * Return 0 if read access is permitted
2131  */
smack_task_setscheduler(struct task_struct * p)2132 static int smack_task_setscheduler(struct task_struct *p)
2133 {
2134 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2135 }
2136 
2137 /**
2138  * smack_task_getscheduler - Smack check on reading scheduler
2139  * @p: the task object
2140  *
2141  * Return 0 if read access is permitted
2142  */
smack_task_getscheduler(struct task_struct * p)2143 static int smack_task_getscheduler(struct task_struct *p)
2144 {
2145 	return smk_curacc_on_task(p, MAY_READ, __func__);
2146 }
2147 
2148 /**
2149  * smack_task_movememory - Smack check on moving memory
2150  * @p: the task object
2151  *
2152  * Return 0 if write access is permitted
2153  */
smack_task_movememory(struct task_struct * p)2154 static int smack_task_movememory(struct task_struct *p)
2155 {
2156 	return smk_curacc_on_task(p, MAY_WRITE, __func__);
2157 }
2158 
2159 /**
2160  * smack_task_kill - Smack check on signal delivery
2161  * @p: the task object
2162  * @info: unused
2163  * @sig: unused
2164  * @cred: identifies the cred to use in lieu of current's
2165  *
2166  * Return 0 if write access is permitted
2167  *
2168  */
smack_task_kill(struct task_struct * p,struct kernel_siginfo * info,int sig,const struct cred * cred)2169 static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
2170 			   int sig, const struct cred *cred)
2171 {
2172 	struct smk_audit_info ad;
2173 	struct smack_known *skp;
2174 	struct smack_known *tkp = smk_of_task_struct_obj(p);
2175 	int rc;
2176 
2177 	if (!sig)
2178 		return 0; /* null signal; existence test */
2179 
2180 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
2181 	smk_ad_setfield_u_tsk(&ad, p);
2182 	/*
2183 	 * Sending a signal requires that the sender
2184 	 * can write the receiver.
2185 	 */
2186 	if (cred == NULL) {
2187 		rc = smk_curacc(tkp, MAY_DELIVER, &ad);
2188 		rc = smk_bu_task(p, MAY_DELIVER, rc);
2189 		return rc;
2190 	}
2191 	/*
2192 	 * If the cred isn't NULL we're dealing with some USB IO
2193 	 * specific behavior. This is not clean. For one thing
2194 	 * we can't take privilege into account.
2195 	 */
2196 	skp = smk_of_task(smack_cred(cred));
2197 	rc = smk_access(skp, tkp, MAY_DELIVER, &ad);
2198 	rc = smk_bu_note("USB signal", skp, tkp, MAY_DELIVER, rc);
2199 	return rc;
2200 }
2201 
2202 /**
2203  * smack_task_to_inode - copy task smack into the inode blob
2204  * @p: task to copy from
2205  * @inode: inode to copy to
2206  *
2207  * Sets the smack pointer in the inode security blob
2208  */
smack_task_to_inode(struct task_struct * p,struct inode * inode)2209 static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
2210 {
2211 	struct inode_smack *isp = smack_inode(inode);
2212 	struct smack_known *skp = smk_of_task_struct_obj(p);
2213 
2214 	isp->smk_inode = skp;
2215 	isp->smk_flags |= SMK_INODE_INSTANT;
2216 }
2217 
2218 /*
2219  * Socket hooks.
2220  */
2221 
2222 /**
2223  * smack_sk_alloc_security - Allocate a socket blob
2224  * @sk: the socket
2225  * @family: unused
2226  * @gfp_flags: memory allocation flags
2227  *
2228  * Assign Smack pointers to current
2229  *
2230  * Returns 0 on success, -ENOMEM is there's no memory
2231  */
smack_sk_alloc_security(struct sock * sk,int family,gfp_t gfp_flags)2232 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
2233 {
2234 	struct smack_known *skp = smk_of_current();
2235 	struct socket_smack *ssp;
2236 
2237 	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
2238 	if (ssp == NULL)
2239 		return -ENOMEM;
2240 
2241 	/*
2242 	 * Sockets created by kernel threads receive web label.
2243 	 */
2244 	if (unlikely(current->flags & PF_KTHREAD)) {
2245 		ssp->smk_in = &smack_known_web;
2246 		ssp->smk_out = &smack_known_web;
2247 	} else {
2248 		ssp->smk_in = skp;
2249 		ssp->smk_out = skp;
2250 	}
2251 	ssp->smk_packet = NULL;
2252 
2253 	sk->sk_security = ssp;
2254 
2255 	return 0;
2256 }
2257 
2258 /**
2259  * smack_sk_free_security - Free a socket blob
2260  * @sk: the socket
2261  *
2262  * Clears the blob pointer
2263  */
smack_sk_free_security(struct sock * sk)2264 static void smack_sk_free_security(struct sock *sk)
2265 {
2266 #ifdef SMACK_IPV6_PORT_LABELING
2267 	struct smk_port_label *spp;
2268 
2269 	if (sk->sk_family == PF_INET6) {
2270 		rcu_read_lock();
2271 		list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2272 			if (spp->smk_sock != sk)
2273 				continue;
2274 			spp->smk_can_reuse = 1;
2275 			break;
2276 		}
2277 		rcu_read_unlock();
2278 	}
2279 #endif
2280 	kfree(sk->sk_security);
2281 }
2282 
2283 /**
2284 * smack_ipv4host_label - check host based restrictions
2285 * @sip: the object end
2286 *
2287 * looks for host based access restrictions
2288 *
2289 * This version will only be appropriate for really small sets of single label
2290 * hosts.  The caller is responsible for ensuring that the RCU read lock is
2291 * taken before calling this function.
2292 *
2293 * Returns the label of the far end or NULL if it's not special.
2294 */
smack_ipv4host_label(struct sockaddr_in * sip)2295 static struct smack_known *smack_ipv4host_label(struct sockaddr_in *sip)
2296 {
2297 	struct smk_net4addr *snp;
2298 	struct in_addr *siap = &sip->sin_addr;
2299 
2300 	if (siap->s_addr == 0)
2301 		return NULL;
2302 
2303 	list_for_each_entry_rcu(snp, &smk_net4addr_list, list)
2304 		/*
2305 		 * we break after finding the first match because
2306 		 * the list is sorted from longest to shortest mask
2307 		 * so we have found the most specific match
2308 		 */
2309 		if (snp->smk_host.s_addr ==
2310 		    (siap->s_addr & snp->smk_mask.s_addr))
2311 			return snp->smk_label;
2312 
2313 	return NULL;
2314 }
2315 
2316 /*
2317  * smk_ipv6_localhost - Check for local ipv6 host address
2318  * @sip: the address
2319  *
2320  * Returns boolean true if this is the localhost address
2321  */
smk_ipv6_localhost(struct sockaddr_in6 * sip)2322 static bool smk_ipv6_localhost(struct sockaddr_in6 *sip)
2323 {
2324 	__be16 *be16p = (__be16 *)&sip->sin6_addr;
2325 	__be32 *be32p = (__be32 *)&sip->sin6_addr;
2326 
2327 	if (be32p[0] == 0 && be32p[1] == 0 && be32p[2] == 0 && be16p[6] == 0 &&
2328 	    ntohs(be16p[7]) == 1)
2329 		return true;
2330 	return false;
2331 }
2332 
2333 /**
2334 * smack_ipv6host_label - check host based restrictions
2335 * @sip: the object end
2336 *
2337 * looks for host based access restrictions
2338 *
2339 * This version will only be appropriate for really small sets of single label
2340 * hosts.  The caller is responsible for ensuring that the RCU read lock is
2341 * taken before calling this function.
2342 *
2343 * Returns the label of the far end or NULL if it's not special.
2344 */
smack_ipv6host_label(struct sockaddr_in6 * sip)2345 static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip)
2346 {
2347 	struct smk_net6addr *snp;
2348 	struct in6_addr *sap = &sip->sin6_addr;
2349 	int i;
2350 	int found = 0;
2351 
2352 	/*
2353 	 * It's local. Don't look for a host label.
2354 	 */
2355 	if (smk_ipv6_localhost(sip))
2356 		return NULL;
2357 
2358 	list_for_each_entry_rcu(snp, &smk_net6addr_list, list) {
2359 		/*
2360 		 * If the label is NULL the entry has
2361 		 * been renounced. Ignore it.
2362 		 */
2363 		if (snp->smk_label == NULL)
2364 			continue;
2365 		/*
2366 		* we break after finding the first match because
2367 		* the list is sorted from longest to shortest mask
2368 		* so we have found the most specific match
2369 		*/
2370 		for (found = 1, i = 0; i < 8; i++) {
2371 			if ((sap->s6_addr16[i] & snp->smk_mask.s6_addr16[i]) !=
2372 			    snp->smk_host.s6_addr16[i]) {
2373 				found = 0;
2374 				break;
2375 			}
2376 		}
2377 		if (found)
2378 			return snp->smk_label;
2379 	}
2380 
2381 	return NULL;
2382 }
2383 
2384 /**
2385  * smack_netlbl_add - Set the secattr on a socket
2386  * @sk: the socket
2387  *
2388  * Attach the outbound smack value (smk_out) to the socket.
2389  *
2390  * Returns 0 on success or an error code
2391  */
smack_netlbl_add(struct sock * sk)2392 static int smack_netlbl_add(struct sock *sk)
2393 {
2394 	struct socket_smack *ssp = sk->sk_security;
2395 	struct smack_known *skp = ssp->smk_out;
2396 	int rc;
2397 
2398 	local_bh_disable();
2399 	bh_lock_sock_nested(sk);
2400 
2401 	rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel);
2402 	switch (rc) {
2403 	case 0:
2404 		ssp->smk_state = SMK_NETLBL_LABELED;
2405 		break;
2406 	case -EDESTADDRREQ:
2407 		ssp->smk_state = SMK_NETLBL_REQSKB;
2408 		rc = 0;
2409 		break;
2410 	}
2411 
2412 	bh_unlock_sock(sk);
2413 	local_bh_enable();
2414 
2415 	return rc;
2416 }
2417 
2418 /**
2419  * smack_netlbl_delete - Remove the secattr from a socket
2420  * @sk: the socket
2421  *
2422  * Remove the outbound smack value from a socket
2423  */
smack_netlbl_delete(struct sock * sk)2424 static void smack_netlbl_delete(struct sock *sk)
2425 {
2426 	struct socket_smack *ssp = sk->sk_security;
2427 
2428 	/*
2429 	 * Take the label off the socket if one is set.
2430 	 */
2431 	if (ssp->smk_state != SMK_NETLBL_LABELED)
2432 		return;
2433 
2434 	local_bh_disable();
2435 	bh_lock_sock_nested(sk);
2436 	netlbl_sock_delattr(sk);
2437 	bh_unlock_sock(sk);
2438 	local_bh_enable();
2439 	ssp->smk_state = SMK_NETLBL_UNLABELED;
2440 }
2441 
2442 /**
2443  * smk_ipv4_check - Perform IPv4 host access checks
2444  * @sk: the socket
2445  * @sap: the destination address
2446  *
2447  * Set the correct secattr for the given socket based on the destination
2448  * address and perform any outbound access checks needed.
2449  *
2450  * Returns 0 on success or an error code.
2451  *
2452  */
smk_ipv4_check(struct sock * sk,struct sockaddr_in * sap)2453 static int smk_ipv4_check(struct sock *sk, struct sockaddr_in *sap)
2454 {
2455 	struct smack_known *skp;
2456 	int rc = 0;
2457 	struct smack_known *hkp;
2458 	struct socket_smack *ssp = sk->sk_security;
2459 	struct smk_audit_info ad;
2460 
2461 	rcu_read_lock();
2462 	hkp = smack_ipv4host_label(sap);
2463 	if (hkp != NULL) {
2464 #ifdef CONFIG_AUDIT
2465 		struct lsm_network_audit net;
2466 
2467 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
2468 		ad.a.u.net->family = sap->sin_family;
2469 		ad.a.u.net->dport = sap->sin_port;
2470 		ad.a.u.net->v4info.daddr = sap->sin_addr.s_addr;
2471 #endif
2472 		skp = ssp->smk_out;
2473 		rc = smk_access(skp, hkp, MAY_WRITE, &ad);
2474 		rc = smk_bu_note("IPv4 host check", skp, hkp, MAY_WRITE, rc);
2475 		/*
2476 		 * Clear the socket netlabel if it's set.
2477 		 */
2478 		if (!rc)
2479 			smack_netlbl_delete(sk);
2480 	}
2481 	rcu_read_unlock();
2482 
2483 	return rc;
2484 }
2485 
2486 /**
2487  * smk_ipv6_check - check Smack access
2488  * @subject: subject Smack label
2489  * @object: object Smack label
2490  * @address: address
2491  * @act: the action being taken
2492  *
2493  * Check an IPv6 access
2494  */
smk_ipv6_check(struct smack_known * subject,struct smack_known * object,struct sockaddr_in6 * address,int act)2495 static int smk_ipv6_check(struct smack_known *subject,
2496 				struct smack_known *object,
2497 				struct sockaddr_in6 *address, int act)
2498 {
2499 #ifdef CONFIG_AUDIT
2500 	struct lsm_network_audit net;
2501 #endif
2502 	struct smk_audit_info ad;
2503 	int rc;
2504 
2505 #ifdef CONFIG_AUDIT
2506 	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
2507 	ad.a.u.net->family = PF_INET6;
2508 	ad.a.u.net->dport = ntohs(address->sin6_port);
2509 	if (act == SMK_RECEIVING)
2510 		ad.a.u.net->v6info.saddr = address->sin6_addr;
2511 	else
2512 		ad.a.u.net->v6info.daddr = address->sin6_addr;
2513 #endif
2514 	rc = smk_access(subject, object, MAY_WRITE, &ad);
2515 	rc = smk_bu_note("IPv6 check", subject, object, MAY_WRITE, rc);
2516 	return rc;
2517 }
2518 
2519 #ifdef SMACK_IPV6_PORT_LABELING
2520 /**
2521  * smk_ipv6_port_label - Smack port access table management
2522  * @sock: socket
2523  * @address: address
2524  *
2525  * Create or update the port list entry
2526  */
smk_ipv6_port_label(struct socket * sock,struct sockaddr * address)2527 static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
2528 {
2529 	struct sock *sk = sock->sk;
2530 	struct sockaddr_in6 *addr6;
2531 	struct socket_smack *ssp = sock->sk->sk_security;
2532 	struct smk_port_label *spp;
2533 	unsigned short port = 0;
2534 
2535 	if (address == NULL) {
2536 		/*
2537 		 * This operation is changing the Smack information
2538 		 * on the bound socket. Take the changes to the port
2539 		 * as well.
2540 		 */
2541 		rcu_read_lock();
2542 		list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2543 			if (sk != spp->smk_sock)
2544 				continue;
2545 			spp->smk_in = ssp->smk_in;
2546 			spp->smk_out = ssp->smk_out;
2547 			rcu_read_unlock();
2548 			return;
2549 		}
2550 		/*
2551 		 * A NULL address is only used for updating existing
2552 		 * bound entries. If there isn't one, it's OK.
2553 		 */
2554 		rcu_read_unlock();
2555 		return;
2556 	}
2557 
2558 	addr6 = (struct sockaddr_in6 *)address;
2559 	port = ntohs(addr6->sin6_port);
2560 	/*
2561 	 * This is a special case that is safely ignored.
2562 	 */
2563 	if (port == 0)
2564 		return;
2565 
2566 	/*
2567 	 * Look for an existing port list entry.
2568 	 * This is an indication that a port is getting reused.
2569 	 */
2570 	rcu_read_lock();
2571 	list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2572 		if (spp->smk_port != port || spp->smk_sock_type != sock->type)
2573 			continue;
2574 		if (spp->smk_can_reuse != 1) {
2575 			rcu_read_unlock();
2576 			return;
2577 		}
2578 		spp->smk_port = port;
2579 		spp->smk_sock = sk;
2580 		spp->smk_in = ssp->smk_in;
2581 		spp->smk_out = ssp->smk_out;
2582 		spp->smk_can_reuse = 0;
2583 		rcu_read_unlock();
2584 		return;
2585 	}
2586 	rcu_read_unlock();
2587 	/*
2588 	 * A new port entry is required.
2589 	 */
2590 	spp = kzalloc(sizeof(*spp), GFP_KERNEL);
2591 	if (spp == NULL)
2592 		return;
2593 
2594 	spp->smk_port = port;
2595 	spp->smk_sock = sk;
2596 	spp->smk_in = ssp->smk_in;
2597 	spp->smk_out = ssp->smk_out;
2598 	spp->smk_sock_type = sock->type;
2599 	spp->smk_can_reuse = 0;
2600 
2601 	mutex_lock(&smack_ipv6_lock);
2602 	list_add_rcu(&spp->list, &smk_ipv6_port_list);
2603 	mutex_unlock(&smack_ipv6_lock);
2604 	return;
2605 }
2606 #endif
2607 
2608 /**
2609  * smk_ipv6_port_check - check Smack port access
2610  * @sk: socket
2611  * @address: address
2612  * @act: the action being taken
2613  *
2614  * Create or update the port list entry
2615  */
smk_ipv6_port_check(struct sock * sk,struct sockaddr_in6 * address,int act)2616 static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
2617 				int act)
2618 {
2619 	struct smk_port_label *spp;
2620 	struct socket_smack *ssp = sk->sk_security;
2621 	struct smack_known *skp = NULL;
2622 	unsigned short port;
2623 	struct smack_known *object;
2624 
2625 	if (act == SMK_RECEIVING) {
2626 		skp = smack_ipv6host_label(address);
2627 		object = ssp->smk_in;
2628 	} else {
2629 		skp = ssp->smk_out;
2630 		object = smack_ipv6host_label(address);
2631 	}
2632 
2633 	/*
2634 	 * The other end is a single label host.
2635 	 */
2636 	if (skp != NULL && object != NULL)
2637 		return smk_ipv6_check(skp, object, address, act);
2638 	if (skp == NULL)
2639 		skp = smack_net_ambient;
2640 	if (object == NULL)
2641 		object = smack_net_ambient;
2642 
2643 	/*
2644 	 * It's remote, so port lookup does no good.
2645 	 */
2646 	if (!smk_ipv6_localhost(address))
2647 		return smk_ipv6_check(skp, object, address, act);
2648 
2649 	/*
2650 	 * It's local so the send check has to have passed.
2651 	 */
2652 	if (act == SMK_RECEIVING)
2653 		return 0;
2654 
2655 	port = ntohs(address->sin6_port);
2656 	rcu_read_lock();
2657 	list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
2658 		if (spp->smk_port != port || spp->smk_sock_type != sk->sk_type)
2659 			continue;
2660 		object = spp->smk_in;
2661 		if (act == SMK_CONNECTING)
2662 			ssp->smk_packet = spp->smk_out;
2663 		break;
2664 	}
2665 	rcu_read_unlock();
2666 
2667 	return smk_ipv6_check(skp, object, address, act);
2668 }
2669 
2670 /**
2671  * smack_inode_setsecurity - set smack xattrs
2672  * @inode: the object
2673  * @name: attribute name
2674  * @value: attribute value
2675  * @size: size of the attribute
2676  * @flags: unused
2677  *
2678  * Sets the named attribute in the appropriate blob
2679  *
2680  * Returns 0 on success, or an error code
2681  */
smack_inode_setsecurity(struct inode * inode,const char * name,const void * value,size_t size,int flags)2682 static int smack_inode_setsecurity(struct inode *inode, const char *name,
2683 				   const void *value, size_t size, int flags)
2684 {
2685 	struct smack_known *skp;
2686 	struct inode_smack *nsp = smack_inode(inode);
2687 	struct socket_smack *ssp;
2688 	struct socket *sock;
2689 	int rc = 0;
2690 
2691 	if (value == NULL || size > SMK_LONGLABEL || size == 0)
2692 		return -EINVAL;
2693 
2694 	skp = smk_import_entry(value, size);
2695 	if (IS_ERR(skp))
2696 		return PTR_ERR(skp);
2697 
2698 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
2699 		nsp->smk_inode = skp;
2700 		nsp->smk_flags |= SMK_INODE_INSTANT;
2701 		return 0;
2702 	}
2703 	/*
2704 	 * The rest of the Smack xattrs are only on sockets.
2705 	 */
2706 	if (inode->i_sb->s_magic != SOCKFS_MAGIC)
2707 		return -EOPNOTSUPP;
2708 
2709 	sock = SOCKET_I(inode);
2710 	if (sock == NULL || sock->sk == NULL)
2711 		return -EOPNOTSUPP;
2712 
2713 	ssp = sock->sk->sk_security;
2714 
2715 	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
2716 		ssp->smk_in = skp;
2717 	else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
2718 		ssp->smk_out = skp;
2719 		if (sock->sk->sk_family == PF_INET) {
2720 			rc = smack_netlbl_add(sock->sk);
2721 			if (rc != 0)
2722 				printk(KERN_WARNING
2723 					"Smack: \"%s\" netlbl error %d.\n",
2724 					__func__, -rc);
2725 		}
2726 	} else
2727 		return -EOPNOTSUPP;
2728 
2729 #ifdef SMACK_IPV6_PORT_LABELING
2730 	if (sock->sk->sk_family == PF_INET6)
2731 		smk_ipv6_port_label(sock, NULL);
2732 #endif
2733 
2734 	return 0;
2735 }
2736 
2737 /**
2738  * smack_socket_post_create - finish socket setup
2739  * @sock: the socket
2740  * @family: protocol family
2741  * @type: unused
2742  * @protocol: unused
2743  * @kern: unused
2744  *
2745  * Sets the netlabel information on the socket
2746  *
2747  * Returns 0 on success, and error code otherwise
2748  */
smack_socket_post_create(struct socket * sock,int family,int type,int protocol,int kern)2749 static int smack_socket_post_create(struct socket *sock, int family,
2750 				    int type, int protocol, int kern)
2751 {
2752 	struct socket_smack *ssp;
2753 
2754 	if (sock->sk == NULL)
2755 		return 0;
2756 
2757 	/*
2758 	 * Sockets created by kernel threads receive web label.
2759 	 */
2760 	if (unlikely(current->flags & PF_KTHREAD)) {
2761 		ssp = sock->sk->sk_security;
2762 		ssp->smk_in = &smack_known_web;
2763 		ssp->smk_out = &smack_known_web;
2764 	}
2765 
2766 	if (family != PF_INET)
2767 		return 0;
2768 	/*
2769 	 * Set the outbound netlbl.
2770 	 */
2771 	return smack_netlbl_add(sock->sk);
2772 }
2773 
2774 /**
2775  * smack_socket_socketpair - create socket pair
2776  * @socka: one socket
2777  * @sockb: another socket
2778  *
2779  * Cross reference the peer labels for SO_PEERSEC
2780  *
2781  * Returns 0
2782  */
smack_socket_socketpair(struct socket * socka,struct socket * sockb)2783 static int smack_socket_socketpair(struct socket *socka,
2784 		                   struct socket *sockb)
2785 {
2786 	struct socket_smack *asp = socka->sk->sk_security;
2787 	struct socket_smack *bsp = sockb->sk->sk_security;
2788 
2789 	asp->smk_packet = bsp->smk_out;
2790 	bsp->smk_packet = asp->smk_out;
2791 
2792 	return 0;
2793 }
2794 
2795 #ifdef SMACK_IPV6_PORT_LABELING
2796 /**
2797  * smack_socket_bind - record port binding information.
2798  * @sock: the socket
2799  * @address: the port address
2800  * @addrlen: size of the address
2801  *
2802  * Records the label bound to a port.
2803  *
2804  * Returns 0 on success, and error code otherwise
2805  */
smack_socket_bind(struct socket * sock,struct sockaddr * address,int addrlen)2806 static int smack_socket_bind(struct socket *sock, struct sockaddr *address,
2807 				int addrlen)
2808 {
2809 	if (sock->sk != NULL && sock->sk->sk_family == PF_INET6) {
2810 		if (addrlen < SIN6_LEN_RFC2133 ||
2811 		    address->sa_family != AF_INET6)
2812 			return -EINVAL;
2813 		smk_ipv6_port_label(sock, address);
2814 	}
2815 	return 0;
2816 }
2817 #endif /* SMACK_IPV6_PORT_LABELING */
2818 
2819 /**
2820  * smack_socket_connect - connect access check
2821  * @sock: the socket
2822  * @sap: the other end
2823  * @addrlen: size of sap
2824  *
2825  * Verifies that a connection may be possible
2826  *
2827  * Returns 0 on success, and error code otherwise
2828  */
smack_socket_connect(struct socket * sock,struct sockaddr * sap,int addrlen)2829 static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
2830 				int addrlen)
2831 {
2832 	int rc = 0;
2833 
2834 	if (sock->sk == NULL)
2835 		return 0;
2836 	if (sock->sk->sk_family != PF_INET &&
2837 	    (!IS_ENABLED(CONFIG_IPV6) || sock->sk->sk_family != PF_INET6))
2838 		return 0;
2839 	if (addrlen < offsetofend(struct sockaddr, sa_family))
2840 		return 0;
2841 	if (IS_ENABLED(CONFIG_IPV6) && sap->sa_family == AF_INET6) {
2842 		struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
2843 		struct smack_known *rsp = NULL;
2844 
2845 		if (addrlen < SIN6_LEN_RFC2133)
2846 			return 0;
2847 		if (__is_defined(SMACK_IPV6_SECMARK_LABELING))
2848 			rsp = smack_ipv6host_label(sip);
2849 		if (rsp != NULL) {
2850 			struct socket_smack *ssp = sock->sk->sk_security;
2851 
2852 			rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
2853 					    SMK_CONNECTING);
2854 		}
2855 		if (__is_defined(SMACK_IPV6_PORT_LABELING))
2856 			rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
2857 
2858 		return rc;
2859 	}
2860 	if (sap->sa_family != AF_INET || addrlen < sizeof(struct sockaddr_in))
2861 		return 0;
2862 	rc = smk_ipv4_check(sock->sk, (struct sockaddr_in *)sap);
2863 	return rc;
2864 }
2865 
2866 /**
2867  * smack_flags_to_may - convert S_ to MAY_ values
2868  * @flags: the S_ value
2869  *
2870  * Returns the equivalent MAY_ value
2871  */
smack_flags_to_may(int flags)2872 static int smack_flags_to_may(int flags)
2873 {
2874 	int may = 0;
2875 
2876 	if (flags & S_IRUGO)
2877 		may |= MAY_READ;
2878 	if (flags & S_IWUGO)
2879 		may |= MAY_WRITE;
2880 	if (flags & S_IXUGO)
2881 		may |= MAY_EXEC;
2882 
2883 	return may;
2884 }
2885 
2886 /**
2887  * smack_msg_msg_alloc_security - Set the security blob for msg_msg
2888  * @msg: the object
2889  *
2890  * Returns 0
2891  */
smack_msg_msg_alloc_security(struct msg_msg * msg)2892 static int smack_msg_msg_alloc_security(struct msg_msg *msg)
2893 {
2894 	struct smack_known **blob = smack_msg_msg(msg);
2895 
2896 	*blob = smk_of_current();
2897 	return 0;
2898 }
2899 
2900 /**
2901  * smack_of_ipc - the smack pointer for the ipc
2902  * @isp: the object
2903  *
2904  * Returns a pointer to the smack value
2905  */
smack_of_ipc(struct kern_ipc_perm * isp)2906 static struct smack_known *smack_of_ipc(struct kern_ipc_perm *isp)
2907 {
2908 	struct smack_known **blob = smack_ipc(isp);
2909 
2910 	return *blob;
2911 }
2912 
2913 /**
2914  * smack_ipc_alloc_security - Set the security blob for ipc
2915  * @isp: the object
2916  *
2917  * Returns 0
2918  */
smack_ipc_alloc_security(struct kern_ipc_perm * isp)2919 static int smack_ipc_alloc_security(struct kern_ipc_perm *isp)
2920 {
2921 	struct smack_known **blob = smack_ipc(isp);
2922 
2923 	*blob = smk_of_current();
2924 	return 0;
2925 }
2926 
2927 /**
2928  * smk_curacc_shm : check if current has access on shm
2929  * @isp : the object
2930  * @access : access requested
2931  *
2932  * Returns 0 if current has the requested access, error code otherwise
2933  */
smk_curacc_shm(struct kern_ipc_perm * isp,int access)2934 static int smk_curacc_shm(struct kern_ipc_perm *isp, int access)
2935 {
2936 	struct smack_known *ssp = smack_of_ipc(isp);
2937 	struct smk_audit_info ad;
2938 	int rc;
2939 
2940 #ifdef CONFIG_AUDIT
2941 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
2942 	ad.a.u.ipc_id = isp->id;
2943 #endif
2944 	rc = smk_curacc(ssp, access, &ad);
2945 	rc = smk_bu_current("shm", ssp, access, rc);
2946 	return rc;
2947 }
2948 
2949 /**
2950  * smack_shm_associate - Smack access check for shm
2951  * @isp: the object
2952  * @shmflg: access requested
2953  *
2954  * Returns 0 if current has the requested access, error code otherwise
2955  */
smack_shm_associate(struct kern_ipc_perm * isp,int shmflg)2956 static int smack_shm_associate(struct kern_ipc_perm *isp, int shmflg)
2957 {
2958 	int may;
2959 
2960 	may = smack_flags_to_may(shmflg);
2961 	return smk_curacc_shm(isp, may);
2962 }
2963 
2964 /**
2965  * smack_shm_shmctl - Smack access check for shm
2966  * @isp: the object
2967  * @cmd: what it wants to do
2968  *
2969  * Returns 0 if current has the requested access, error code otherwise
2970  */
smack_shm_shmctl(struct kern_ipc_perm * isp,int cmd)2971 static int smack_shm_shmctl(struct kern_ipc_perm *isp, int cmd)
2972 {
2973 	int may;
2974 
2975 	switch (cmd) {
2976 	case IPC_STAT:
2977 	case SHM_STAT:
2978 	case SHM_STAT_ANY:
2979 		may = MAY_READ;
2980 		break;
2981 	case IPC_SET:
2982 	case SHM_LOCK:
2983 	case SHM_UNLOCK:
2984 	case IPC_RMID:
2985 		may = MAY_READWRITE;
2986 		break;
2987 	case IPC_INFO:
2988 	case SHM_INFO:
2989 		/*
2990 		 * System level information.
2991 		 */
2992 		return 0;
2993 	default:
2994 		return -EINVAL;
2995 	}
2996 	return smk_curacc_shm(isp, may);
2997 }
2998 
2999 /**
3000  * smack_shm_shmat - Smack access for shmat
3001  * @isp: the object
3002  * @shmaddr: unused
3003  * @shmflg: access requested
3004  *
3005  * Returns 0 if current has the requested access, error code otherwise
3006  */
smack_shm_shmat(struct kern_ipc_perm * isp,char __user * shmaddr,int shmflg)3007 static int smack_shm_shmat(struct kern_ipc_perm *isp, char __user *shmaddr,
3008 			   int shmflg)
3009 {
3010 	int may;
3011 
3012 	may = smack_flags_to_may(shmflg);
3013 	return smk_curacc_shm(isp, may);
3014 }
3015 
3016 /**
3017  * smk_curacc_sem : check if current has access on sem
3018  * @isp : the object
3019  * @access : access requested
3020  *
3021  * Returns 0 if current has the requested access, error code otherwise
3022  */
smk_curacc_sem(struct kern_ipc_perm * isp,int access)3023 static int smk_curacc_sem(struct kern_ipc_perm *isp, int access)
3024 {
3025 	struct smack_known *ssp = smack_of_ipc(isp);
3026 	struct smk_audit_info ad;
3027 	int rc;
3028 
3029 #ifdef CONFIG_AUDIT
3030 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
3031 	ad.a.u.ipc_id = isp->id;
3032 #endif
3033 	rc = smk_curacc(ssp, access, &ad);
3034 	rc = smk_bu_current("sem", ssp, access, rc);
3035 	return rc;
3036 }
3037 
3038 /**
3039  * smack_sem_associate - Smack access check for sem
3040  * @isp: the object
3041  * @semflg: access requested
3042  *
3043  * Returns 0 if current has the requested access, error code otherwise
3044  */
smack_sem_associate(struct kern_ipc_perm * isp,int semflg)3045 static int smack_sem_associate(struct kern_ipc_perm *isp, int semflg)
3046 {
3047 	int may;
3048 
3049 	may = smack_flags_to_may(semflg);
3050 	return smk_curacc_sem(isp, may);
3051 }
3052 
3053 /**
3054  * smack_sem_shmctl - Smack access check for sem
3055  * @isp: the object
3056  * @cmd: what it wants to do
3057  *
3058  * Returns 0 if current has the requested access, error code otherwise
3059  */
smack_sem_semctl(struct kern_ipc_perm * isp,int cmd)3060 static int smack_sem_semctl(struct kern_ipc_perm *isp, int cmd)
3061 {
3062 	int may;
3063 
3064 	switch (cmd) {
3065 	case GETPID:
3066 	case GETNCNT:
3067 	case GETZCNT:
3068 	case GETVAL:
3069 	case GETALL:
3070 	case IPC_STAT:
3071 	case SEM_STAT:
3072 	case SEM_STAT_ANY:
3073 		may = MAY_READ;
3074 		break;
3075 	case SETVAL:
3076 	case SETALL:
3077 	case IPC_RMID:
3078 	case IPC_SET:
3079 		may = MAY_READWRITE;
3080 		break;
3081 	case IPC_INFO:
3082 	case SEM_INFO:
3083 		/*
3084 		 * System level information
3085 		 */
3086 		return 0;
3087 	default:
3088 		return -EINVAL;
3089 	}
3090 
3091 	return smk_curacc_sem(isp, may);
3092 }
3093 
3094 /**
3095  * smack_sem_semop - Smack checks of semaphore operations
3096  * @isp: the object
3097  * @sops: unused
3098  * @nsops: unused
3099  * @alter: unused
3100  *
3101  * Treated as read and write in all cases.
3102  *
3103  * Returns 0 if access is allowed, error code otherwise
3104  */
smack_sem_semop(struct kern_ipc_perm * isp,struct sembuf * sops,unsigned nsops,int alter)3105 static int smack_sem_semop(struct kern_ipc_perm *isp, struct sembuf *sops,
3106 			   unsigned nsops, int alter)
3107 {
3108 	return smk_curacc_sem(isp, MAY_READWRITE);
3109 }
3110 
3111 /**
3112  * smk_curacc_msq : helper to check if current has access on msq
3113  * @isp : the msq
3114  * @access : access requested
3115  *
3116  * return 0 if current has access, error otherwise
3117  */
smk_curacc_msq(struct kern_ipc_perm * isp,int access)3118 static int smk_curacc_msq(struct kern_ipc_perm *isp, int access)
3119 {
3120 	struct smack_known *msp = smack_of_ipc(isp);
3121 	struct smk_audit_info ad;
3122 	int rc;
3123 
3124 #ifdef CONFIG_AUDIT
3125 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
3126 	ad.a.u.ipc_id = isp->id;
3127 #endif
3128 	rc = smk_curacc(msp, access, &ad);
3129 	rc = smk_bu_current("msq", msp, access, rc);
3130 	return rc;
3131 }
3132 
3133 /**
3134  * smack_msg_queue_associate - Smack access check for msg_queue
3135  * @isp: the object
3136  * @msqflg: access requested
3137  *
3138  * Returns 0 if current has the requested access, error code otherwise
3139  */
smack_msg_queue_associate(struct kern_ipc_perm * isp,int msqflg)3140 static int smack_msg_queue_associate(struct kern_ipc_perm *isp, int msqflg)
3141 {
3142 	int may;
3143 
3144 	may = smack_flags_to_may(msqflg);
3145 	return smk_curacc_msq(isp, may);
3146 }
3147 
3148 /**
3149  * smack_msg_queue_msgctl - Smack access check for msg_queue
3150  * @isp: the object
3151  * @cmd: what it wants to do
3152  *
3153  * Returns 0 if current has the requested access, error code otherwise
3154  */
smack_msg_queue_msgctl(struct kern_ipc_perm * isp,int cmd)3155 static int smack_msg_queue_msgctl(struct kern_ipc_perm *isp, int cmd)
3156 {
3157 	int may;
3158 
3159 	switch (cmd) {
3160 	case IPC_STAT:
3161 	case MSG_STAT:
3162 	case MSG_STAT_ANY:
3163 		may = MAY_READ;
3164 		break;
3165 	case IPC_SET:
3166 	case IPC_RMID:
3167 		may = MAY_READWRITE;
3168 		break;
3169 	case IPC_INFO:
3170 	case MSG_INFO:
3171 		/*
3172 		 * System level information
3173 		 */
3174 		return 0;
3175 	default:
3176 		return -EINVAL;
3177 	}
3178 
3179 	return smk_curacc_msq(isp, may);
3180 }
3181 
3182 /**
3183  * smack_msg_queue_msgsnd - Smack access check for msg_queue
3184  * @isp: the object
3185  * @msg: unused
3186  * @msqflg: access requested
3187  *
3188  * Returns 0 if current has the requested access, error code otherwise
3189  */
smack_msg_queue_msgsnd(struct kern_ipc_perm * isp,struct msg_msg * msg,int msqflg)3190 static int smack_msg_queue_msgsnd(struct kern_ipc_perm *isp, struct msg_msg *msg,
3191 				  int msqflg)
3192 {
3193 	int may;
3194 
3195 	may = smack_flags_to_may(msqflg);
3196 	return smk_curacc_msq(isp, may);
3197 }
3198 
3199 /**
3200  * smack_msg_queue_msgsnd - Smack access check for msg_queue
3201  * @isp: the object
3202  * @msg: unused
3203  * @target: unused
3204  * @type: unused
3205  * @mode: unused
3206  *
3207  * Returns 0 if current has read and write access, error code otherwise
3208  */
smack_msg_queue_msgrcv(struct kern_ipc_perm * isp,struct msg_msg * msg,struct task_struct * target,long type,int mode)3209 static int smack_msg_queue_msgrcv(struct kern_ipc_perm *isp, struct msg_msg *msg,
3210 			struct task_struct *target, long type, int mode)
3211 {
3212 	return smk_curacc_msq(isp, MAY_READWRITE);
3213 }
3214 
3215 /**
3216  * smack_ipc_permission - Smack access for ipc_permission()
3217  * @ipp: the object permissions
3218  * @flag: access requested
3219  *
3220  * Returns 0 if current has read and write access, error code otherwise
3221  */
smack_ipc_permission(struct kern_ipc_perm * ipp,short flag)3222 static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
3223 {
3224 	struct smack_known **blob = smack_ipc(ipp);
3225 	struct smack_known *iskp = *blob;
3226 	int may = smack_flags_to_may(flag);
3227 	struct smk_audit_info ad;
3228 	int rc;
3229 
3230 #ifdef CONFIG_AUDIT
3231 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
3232 	ad.a.u.ipc_id = ipp->id;
3233 #endif
3234 	rc = smk_curacc(iskp, may, &ad);
3235 	rc = smk_bu_current("svipc", iskp, may, rc);
3236 	return rc;
3237 }
3238 
3239 /**
3240  * smack_ipc_getsecid - Extract smack security id
3241  * @ipp: the object permissions
3242  * @secid: where result will be saved
3243  */
smack_ipc_getsecid(struct kern_ipc_perm * ipp,u32 * secid)3244 static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
3245 {
3246 	struct smack_known **blob = smack_ipc(ipp);
3247 	struct smack_known *iskp = *blob;
3248 
3249 	*secid = iskp->smk_secid;
3250 }
3251 
3252 /**
3253  * smack_d_instantiate - Make sure the blob is correct on an inode
3254  * @opt_dentry: dentry where inode will be attached
3255  * @inode: the object
3256  *
3257  * Set the inode's security blob if it hasn't been done already.
3258  */
smack_d_instantiate(struct dentry * opt_dentry,struct inode * inode)3259 static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
3260 {
3261 	struct super_block *sbp;
3262 	struct superblock_smack *sbsp;
3263 	struct inode_smack *isp;
3264 	struct smack_known *skp;
3265 	struct smack_known *ckp = smk_of_current();
3266 	struct smack_known *final;
3267 	char trattr[TRANS_TRUE_SIZE];
3268 	int transflag = 0;
3269 	int rc;
3270 	struct dentry *dp;
3271 
3272 	if (inode == NULL)
3273 		return;
3274 
3275 	isp = smack_inode(inode);
3276 
3277 	/*
3278 	 * If the inode is already instantiated
3279 	 * take the quick way out
3280 	 */
3281 	if (isp->smk_flags & SMK_INODE_INSTANT)
3282 		return;
3283 
3284 	sbp = inode->i_sb;
3285 	sbsp = smack_superblock(sbp);
3286 	/*
3287 	 * We're going to use the superblock default label
3288 	 * if there's no label on the file.
3289 	 */
3290 	final = sbsp->smk_default;
3291 
3292 	/*
3293 	 * If this is the root inode the superblock
3294 	 * may be in the process of initialization.
3295 	 * If that is the case use the root value out
3296 	 * of the superblock.
3297 	 */
3298 	if (opt_dentry->d_parent == opt_dentry) {
3299 		switch (sbp->s_magic) {
3300 		case CGROUP_SUPER_MAGIC:
3301 		case CGROUP2_SUPER_MAGIC:
3302 			/*
3303 			 * The cgroup filesystem is never mounted,
3304 			 * so there's no opportunity to set the mount
3305 			 * options.
3306 			 */
3307 			sbsp->smk_root = &smack_known_star;
3308 			sbsp->smk_default = &smack_known_star;
3309 			isp->smk_inode = sbsp->smk_root;
3310 			break;
3311 		case TMPFS_MAGIC:
3312 			/*
3313 			 * What about shmem/tmpfs anonymous files with dentry
3314 			 * obtained from d_alloc_pseudo()?
3315 			 */
3316 			isp->smk_inode = smk_of_current();
3317 			break;
3318 		case PIPEFS_MAGIC:
3319 			isp->smk_inode = smk_of_current();
3320 			break;
3321 		case SOCKFS_MAGIC:
3322 			/*
3323 			 * Socket access is controlled by the socket
3324 			 * structures associated with the task involved.
3325 			 */
3326 			isp->smk_inode = &smack_known_star;
3327 			break;
3328 		default:
3329 			isp->smk_inode = sbsp->smk_root;
3330 			break;
3331 		}
3332 		isp->smk_flags |= SMK_INODE_INSTANT;
3333 		return;
3334 	}
3335 
3336 	/*
3337 	 * This is pretty hackish.
3338 	 * Casey says that we shouldn't have to do
3339 	 * file system specific code, but it does help
3340 	 * with keeping it simple.
3341 	 */
3342 	switch (sbp->s_magic) {
3343 	case SMACK_MAGIC:
3344 	case CGROUP_SUPER_MAGIC:
3345 	case CGROUP2_SUPER_MAGIC:
3346 		/*
3347 		 * Casey says that it's a little embarrassing
3348 		 * that the smack file system doesn't do
3349 		 * extended attributes.
3350 		 *
3351 		 * Cgroupfs is special
3352 		 */
3353 		final = &smack_known_star;
3354 		break;
3355 	case DEVPTS_SUPER_MAGIC:
3356 		/*
3357 		 * devpts seems content with the label of the task.
3358 		 * Programs that change smack have to treat the
3359 		 * pty with respect.
3360 		 */
3361 		final = ckp;
3362 		break;
3363 	case PROC_SUPER_MAGIC:
3364 		/*
3365 		 * Casey says procfs appears not to care.
3366 		 * The superblock default suffices.
3367 		 */
3368 		break;
3369 	case TMPFS_MAGIC:
3370 		/*
3371 		 * Device labels should come from the filesystem,
3372 		 * but watch out, because they're volitile,
3373 		 * getting recreated on every reboot.
3374 		 */
3375 		final = &smack_known_star;
3376 		/*
3377 		 * If a smack value has been set we want to use it,
3378 		 * but since tmpfs isn't giving us the opportunity
3379 		 * to set mount options simulate setting the
3380 		 * superblock default.
3381 		 */
3382 		fallthrough;
3383 	default:
3384 		/*
3385 		 * This isn't an understood special case.
3386 		 * Get the value from the xattr.
3387 		 */
3388 
3389 		/*
3390 		 * UNIX domain sockets use lower level socket data.
3391 		 */
3392 		if (S_ISSOCK(inode->i_mode)) {
3393 			final = &smack_known_star;
3394 			break;
3395 		}
3396 		/*
3397 		 * No xattr support means, alas, no SMACK label.
3398 		 * Use the aforeapplied default.
3399 		 * It would be curious if the label of the task
3400 		 * does not match that assigned.
3401 		 */
3402 		if (!(inode->i_opflags & IOP_XATTR))
3403 		        break;
3404 		/*
3405 		 * Get the dentry for xattr.
3406 		 */
3407 		dp = dget(opt_dentry);
3408 		skp = smk_fetch(XATTR_NAME_SMACK, inode, dp);
3409 		if (!IS_ERR_OR_NULL(skp))
3410 			final = skp;
3411 
3412 		/*
3413 		 * Transmuting directory
3414 		 */
3415 		if (S_ISDIR(inode->i_mode)) {
3416 			/*
3417 			 * If this is a new directory and the label was
3418 			 * transmuted when the inode was initialized
3419 			 * set the transmute attribute on the directory
3420 			 * and mark the inode.
3421 			 *
3422 			 * If there is a transmute attribute on the
3423 			 * directory mark the inode.
3424 			 */
3425 			if (isp->smk_flags & SMK_INODE_CHANGED) {
3426 				isp->smk_flags &= ~SMK_INODE_CHANGED;
3427 				rc = __vfs_setxattr(&init_user_ns, dp, inode,
3428 					XATTR_NAME_SMACKTRANSMUTE,
3429 					TRANS_TRUE, TRANS_TRUE_SIZE,
3430 					0);
3431 			} else {
3432 				rc = __vfs_getxattr(dp, inode,
3433 					XATTR_NAME_SMACKTRANSMUTE, trattr,
3434 					TRANS_TRUE_SIZE);
3435 				if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
3436 						       TRANS_TRUE_SIZE) != 0)
3437 					rc = -EINVAL;
3438 			}
3439 			if (rc >= 0)
3440 				transflag = SMK_INODE_TRANSMUTE;
3441 		}
3442 		/*
3443 		 * Don't let the exec or mmap label be "*" or "@".
3444 		 */
3445 		skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
3446 		if (IS_ERR(skp) || skp == &smack_known_star ||
3447 		    skp == &smack_known_web)
3448 			skp = NULL;
3449 		isp->smk_task = skp;
3450 
3451 		skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
3452 		if (IS_ERR(skp) || skp == &smack_known_star ||
3453 		    skp == &smack_known_web)
3454 			skp = NULL;
3455 		isp->smk_mmap = skp;
3456 
3457 		dput(dp);
3458 		break;
3459 	}
3460 
3461 	if (final == NULL)
3462 		isp->smk_inode = ckp;
3463 	else
3464 		isp->smk_inode = final;
3465 
3466 	isp->smk_flags |= (SMK_INODE_INSTANT | transflag);
3467 
3468 	return;
3469 }
3470 
3471 /**
3472  * smack_getprocattr - Smack process attribute access
3473  * @p: the object task
3474  * @name: the name of the attribute in /proc/.../attr
3475  * @value: where to put the result
3476  *
3477  * Places a copy of the task Smack into value
3478  *
3479  * Returns the length of the smack label or an error code
3480  */
smack_getprocattr(struct task_struct * p,char * name,char ** value)3481 static int smack_getprocattr(struct task_struct *p, char *name, char **value)
3482 {
3483 	struct smack_known *skp = smk_of_task_struct_subj(p);
3484 	char *cp;
3485 	int slen;
3486 
3487 	if (strcmp(name, "current") != 0)
3488 		return -EINVAL;
3489 
3490 	cp = kstrdup(skp->smk_known, GFP_KERNEL);
3491 	if (cp == NULL)
3492 		return -ENOMEM;
3493 
3494 	slen = strlen(cp);
3495 	*value = cp;
3496 	return slen;
3497 }
3498 
3499 /**
3500  * smack_setprocattr - Smack process attribute setting
3501  * @name: the name of the attribute in /proc/.../attr
3502  * @value: the value to set
3503  * @size: the size of the value
3504  *
3505  * Sets the Smack value of the task. Only setting self
3506  * is permitted and only with privilege
3507  *
3508  * Returns the length of the smack label or an error code
3509  */
smack_setprocattr(const char * name,void * value,size_t size)3510 static int smack_setprocattr(const char *name, void *value, size_t size)
3511 {
3512 	struct task_smack *tsp = smack_cred(current_cred());
3513 	struct cred *new;
3514 	struct smack_known *skp;
3515 	struct smack_known_list_elem *sklep;
3516 	int rc;
3517 
3518 	if (!smack_privileged(CAP_MAC_ADMIN) && list_empty(&tsp->smk_relabel))
3519 		return -EPERM;
3520 
3521 	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
3522 		return -EINVAL;
3523 
3524 	if (strcmp(name, "current") != 0)
3525 		return -EINVAL;
3526 
3527 	skp = smk_import_entry(value, size);
3528 	if (IS_ERR(skp))
3529 		return PTR_ERR(skp);
3530 
3531 	/*
3532 	 * No process is ever allowed the web ("@") label
3533 	 * and the star ("*") label.
3534 	 */
3535 	if (skp == &smack_known_web || skp == &smack_known_star)
3536 		return -EINVAL;
3537 
3538 	if (!smack_privileged(CAP_MAC_ADMIN)) {
3539 		rc = -EPERM;
3540 		list_for_each_entry(sklep, &tsp->smk_relabel, list)
3541 			if (sklep->smk_label == skp) {
3542 				rc = 0;
3543 				break;
3544 			}
3545 		if (rc)
3546 			return rc;
3547 	}
3548 
3549 	new = prepare_creds();
3550 	if (new == NULL)
3551 		return -ENOMEM;
3552 
3553 	tsp = smack_cred(new);
3554 	tsp->smk_task = skp;
3555 	/*
3556 	 * process can change its label only once
3557 	 */
3558 	smk_destroy_label_list(&tsp->smk_relabel);
3559 
3560 	commit_creds(new);
3561 	return size;
3562 }
3563 
3564 /**
3565  * smack_unix_stream_connect - Smack access on UDS
3566  * @sock: one sock
3567  * @other: the other sock
3568  * @newsk: unused
3569  *
3570  * Return 0 if a subject with the smack of sock could access
3571  * an object with the smack of other, otherwise an error code
3572  */
smack_unix_stream_connect(struct sock * sock,struct sock * other,struct sock * newsk)3573 static int smack_unix_stream_connect(struct sock *sock,
3574 				     struct sock *other, struct sock *newsk)
3575 {
3576 	struct smack_known *skp;
3577 	struct smack_known *okp;
3578 	struct socket_smack *ssp = sock->sk_security;
3579 	struct socket_smack *osp = other->sk_security;
3580 	struct socket_smack *nsp = newsk->sk_security;
3581 	struct smk_audit_info ad;
3582 	int rc = 0;
3583 #ifdef CONFIG_AUDIT
3584 	struct lsm_network_audit net;
3585 #endif
3586 
3587 	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
3588 		skp = ssp->smk_out;
3589 		okp = osp->smk_in;
3590 #ifdef CONFIG_AUDIT
3591 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3592 		smk_ad_setfield_u_net_sk(&ad, other);
3593 #endif
3594 		rc = smk_access(skp, okp, MAY_WRITE, &ad);
3595 		rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
3596 		if (rc == 0) {
3597 			okp = osp->smk_out;
3598 			skp = ssp->smk_in;
3599 			rc = smk_access(okp, skp, MAY_WRITE, &ad);
3600 			rc = smk_bu_note("UDS connect", okp, skp,
3601 						MAY_WRITE, rc);
3602 		}
3603 	}
3604 
3605 	/*
3606 	 * Cross reference the peer labels for SO_PEERSEC.
3607 	 */
3608 	if (rc == 0) {
3609 		nsp->smk_packet = ssp->smk_out;
3610 		ssp->smk_packet = osp->smk_out;
3611 	}
3612 
3613 	return rc;
3614 }
3615 
3616 /**
3617  * smack_unix_may_send - Smack access on UDS
3618  * @sock: one socket
3619  * @other: the other socket
3620  *
3621  * Return 0 if a subject with the smack of sock could access
3622  * an object with the smack of other, otherwise an error code
3623  */
smack_unix_may_send(struct socket * sock,struct socket * other)3624 static int smack_unix_may_send(struct socket *sock, struct socket *other)
3625 {
3626 	struct socket_smack *ssp = sock->sk->sk_security;
3627 	struct socket_smack *osp = other->sk->sk_security;
3628 	struct smk_audit_info ad;
3629 	int rc;
3630 
3631 #ifdef CONFIG_AUDIT
3632 	struct lsm_network_audit net;
3633 
3634 	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3635 	smk_ad_setfield_u_net_sk(&ad, other->sk);
3636 #endif
3637 
3638 	if (smack_privileged(CAP_MAC_OVERRIDE))
3639 		return 0;
3640 
3641 	rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
3642 	rc = smk_bu_note("UDS send", ssp->smk_out, osp->smk_in, MAY_WRITE, rc);
3643 	return rc;
3644 }
3645 
3646 /**
3647  * smack_socket_sendmsg - Smack check based on destination host
3648  * @sock: the socket
3649  * @msg: the message
3650  * @size: the size of the message
3651  *
3652  * Return 0 if the current subject can write to the destination host.
3653  * For IPv4 this is only a question if the destination is a single label host.
3654  * For IPv6 this is a check against the label of the port.
3655  */
smack_socket_sendmsg(struct socket * sock,struct msghdr * msg,int size)3656 static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
3657 				int size)
3658 {
3659 	struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
3660 #if IS_ENABLED(CONFIG_IPV6)
3661 	struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
3662 #endif
3663 #ifdef SMACK_IPV6_SECMARK_LABELING
3664 	struct socket_smack *ssp = sock->sk->sk_security;
3665 	struct smack_known *rsp;
3666 #endif
3667 	int rc = 0;
3668 
3669 	/*
3670 	 * Perfectly reasonable for this to be NULL
3671 	 */
3672 	if (sip == NULL)
3673 		return 0;
3674 
3675 	switch (sock->sk->sk_family) {
3676 	case AF_INET:
3677 		if (msg->msg_namelen < sizeof(struct sockaddr_in) ||
3678 		    sip->sin_family != AF_INET)
3679 			return -EINVAL;
3680 		rc = smk_ipv4_check(sock->sk, sip);
3681 		break;
3682 #if IS_ENABLED(CONFIG_IPV6)
3683 	case AF_INET6:
3684 		if (msg->msg_namelen < SIN6_LEN_RFC2133 ||
3685 		    sap->sin6_family != AF_INET6)
3686 			return -EINVAL;
3687 #ifdef SMACK_IPV6_SECMARK_LABELING
3688 		rsp = smack_ipv6host_label(sap);
3689 		if (rsp != NULL)
3690 			rc = smk_ipv6_check(ssp->smk_out, rsp, sap,
3691 						SMK_CONNECTING);
3692 #endif
3693 #ifdef SMACK_IPV6_PORT_LABELING
3694 		rc = smk_ipv6_port_check(sock->sk, sap, SMK_SENDING);
3695 #endif
3696 #endif /* IS_ENABLED(CONFIG_IPV6) */
3697 		break;
3698 	}
3699 	return rc;
3700 }
3701 
3702 /**
3703  * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
3704  * @sap: netlabel secattr
3705  * @ssp: socket security information
3706  *
3707  * Returns a pointer to a Smack label entry found on the label list.
3708  */
smack_from_secattr(struct netlbl_lsm_secattr * sap,struct socket_smack * ssp)3709 static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
3710 						struct socket_smack *ssp)
3711 {
3712 	struct smack_known *skp;
3713 	int found = 0;
3714 	int acat;
3715 	int kcat;
3716 
3717 	/*
3718 	 * Netlabel found it in the cache.
3719 	 */
3720 	if ((sap->flags & NETLBL_SECATTR_CACHE) != 0)
3721 		return (struct smack_known *)sap->cache->data;
3722 
3723 	if ((sap->flags & NETLBL_SECATTR_SECID) != 0)
3724 		/*
3725 		 * Looks like a fallback, which gives us a secid.
3726 		 */
3727 		return smack_from_secid(sap->attr.secid);
3728 
3729 	if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
3730 		/*
3731 		 * Looks like a CIPSO packet.
3732 		 * If there are flags but no level netlabel isn't
3733 		 * behaving the way we expect it to.
3734 		 *
3735 		 * Look it up in the label table
3736 		 * Without guidance regarding the smack value
3737 		 * for the packet fall back on the network
3738 		 * ambient value.
3739 		 */
3740 		rcu_read_lock();
3741 		list_for_each_entry_rcu(skp, &smack_known_list, list) {
3742 			if (sap->attr.mls.lvl != skp->smk_netlabel.attr.mls.lvl)
3743 				continue;
3744 			/*
3745 			 * Compare the catsets. Use the netlbl APIs.
3746 			 */
3747 			if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) {
3748 				if ((skp->smk_netlabel.flags &
3749 				     NETLBL_SECATTR_MLS_CAT) == 0)
3750 					found = 1;
3751 				break;
3752 			}
3753 			for (acat = -1, kcat = -1; acat == kcat; ) {
3754 				acat = netlbl_catmap_walk(sap->attr.mls.cat,
3755 							  acat + 1);
3756 				kcat = netlbl_catmap_walk(
3757 					skp->smk_netlabel.attr.mls.cat,
3758 					kcat + 1);
3759 				if (acat < 0 || kcat < 0)
3760 					break;
3761 			}
3762 			if (acat == kcat) {
3763 				found = 1;
3764 				break;
3765 			}
3766 		}
3767 		rcu_read_unlock();
3768 
3769 		if (found)
3770 			return skp;
3771 
3772 		if (ssp != NULL && ssp->smk_in == &smack_known_star)
3773 			return &smack_known_web;
3774 		return &smack_known_star;
3775 	}
3776 	/*
3777 	 * Without guidance regarding the smack value
3778 	 * for the packet fall back on the network
3779 	 * ambient value.
3780 	 */
3781 	return smack_net_ambient;
3782 }
3783 
3784 #if IS_ENABLED(CONFIG_IPV6)
smk_skb_to_addr_ipv6(struct sk_buff * skb,struct sockaddr_in6 * sip)3785 static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
3786 {
3787 	u8 nexthdr;
3788 	int offset;
3789 	int proto = -EINVAL;
3790 	struct ipv6hdr _ipv6h;
3791 	struct ipv6hdr *ip6;
3792 	__be16 frag_off;
3793 	struct tcphdr _tcph, *th;
3794 	struct udphdr _udph, *uh;
3795 	struct dccp_hdr _dccph, *dh;
3796 
3797 	sip->sin6_port = 0;
3798 
3799 	offset = skb_network_offset(skb);
3800 	ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
3801 	if (ip6 == NULL)
3802 		return -EINVAL;
3803 	sip->sin6_addr = ip6->saddr;
3804 
3805 	nexthdr = ip6->nexthdr;
3806 	offset += sizeof(_ipv6h);
3807 	offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
3808 	if (offset < 0)
3809 		return -EINVAL;
3810 
3811 	proto = nexthdr;
3812 	switch (proto) {
3813 	case IPPROTO_TCP:
3814 		th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
3815 		if (th != NULL)
3816 			sip->sin6_port = th->source;
3817 		break;
3818 	case IPPROTO_UDP:
3819 	case IPPROTO_UDPLITE:
3820 		uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
3821 		if (uh != NULL)
3822 			sip->sin6_port = uh->source;
3823 		break;
3824 	case IPPROTO_DCCP:
3825 		dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
3826 		if (dh != NULL)
3827 			sip->sin6_port = dh->dccph_sport;
3828 		break;
3829 	}
3830 	return proto;
3831 }
3832 #endif /* CONFIG_IPV6 */
3833 
3834 /**
3835  * smack_from_skb - Smack data from the secmark in an skb
3836  * @skb: packet
3837  *
3838  * Returns smack_known of the secmark or NULL if that won't work.
3839  */
3840 #ifdef CONFIG_NETWORK_SECMARK
smack_from_skb(struct sk_buff * skb)3841 static struct smack_known *smack_from_skb(struct sk_buff *skb)
3842 {
3843 	if (skb == NULL || skb->secmark == 0)
3844 		return NULL;
3845 
3846 	return smack_from_secid(skb->secmark);
3847 }
3848 #else
smack_from_skb(struct sk_buff * skb)3849 static inline struct smack_known *smack_from_skb(struct sk_buff *skb)
3850 {
3851 	return NULL;
3852 }
3853 #endif
3854 
3855 /**
3856  * smack_from_netlbl - Smack data from the IP options in an skb
3857  * @sk: socket data came in on
3858  * @family: address family
3859  * @skb: packet
3860  *
3861  * Find the Smack label in the IP options. If it hasn't been
3862  * added to the netlabel cache, add it here.
3863  *
3864  * Returns smack_known of the IP options or NULL if that won't work.
3865  */
smack_from_netlbl(const struct sock * sk,u16 family,struct sk_buff * skb)3866 static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family,
3867 					     struct sk_buff *skb)
3868 {
3869 	struct netlbl_lsm_secattr secattr;
3870 	struct socket_smack *ssp = NULL;
3871 	struct smack_known *skp = NULL;
3872 
3873 	netlbl_secattr_init(&secattr);
3874 
3875 	if (sk)
3876 		ssp = sk->sk_security;
3877 
3878 	if (netlbl_skbuff_getattr(skb, family, &secattr) == 0) {
3879 		skp = smack_from_secattr(&secattr, ssp);
3880 		if (secattr.flags & NETLBL_SECATTR_CACHEABLE)
3881 			netlbl_cache_add(skb, family, &skp->smk_netlabel);
3882 	}
3883 
3884 	netlbl_secattr_destroy(&secattr);
3885 
3886 	return skp;
3887 }
3888 
3889 /**
3890  * smack_socket_sock_rcv_skb - Smack packet delivery access check
3891  * @sk: socket
3892  * @skb: packet
3893  *
3894  * Returns 0 if the packet should be delivered, an error code otherwise
3895  */
smack_socket_sock_rcv_skb(struct sock * sk,struct sk_buff * skb)3896 static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
3897 {
3898 	struct socket_smack *ssp = sk->sk_security;
3899 	struct smack_known *skp = NULL;
3900 	int rc = 0;
3901 	struct smk_audit_info ad;
3902 	u16 family = sk->sk_family;
3903 #ifdef CONFIG_AUDIT
3904 	struct lsm_network_audit net;
3905 #endif
3906 #if IS_ENABLED(CONFIG_IPV6)
3907 	struct sockaddr_in6 sadd;
3908 	int proto;
3909 
3910 	if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
3911 		family = PF_INET;
3912 #endif /* CONFIG_IPV6 */
3913 
3914 	switch (family) {
3915 	case PF_INET:
3916 		/*
3917 		 * If there is a secmark use it rather than the CIPSO label.
3918 		 * If there is no secmark fall back to CIPSO.
3919 		 * The secmark is assumed to reflect policy better.
3920 		 */
3921 		skp = smack_from_skb(skb);
3922 		if (skp == NULL) {
3923 			skp = smack_from_netlbl(sk, family, skb);
3924 			if (skp == NULL)
3925 				skp = smack_net_ambient;
3926 		}
3927 
3928 #ifdef CONFIG_AUDIT
3929 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3930 		ad.a.u.net->family = family;
3931 		ad.a.u.net->netif = skb->skb_iif;
3932 		ipv4_skb_to_auditdata(skb, &ad.a, NULL);
3933 #endif
3934 		/*
3935 		 * Receiving a packet requires that the other end
3936 		 * be able to write here. Read access is not required.
3937 		 * This is the simplist possible security model
3938 		 * for networking.
3939 		 */
3940 		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
3941 		rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
3942 					MAY_WRITE, rc);
3943 		if (rc != 0)
3944 			netlbl_skbuff_err(skb, family, rc, 0);
3945 		break;
3946 #if IS_ENABLED(CONFIG_IPV6)
3947 	case PF_INET6:
3948 		proto = smk_skb_to_addr_ipv6(skb, &sadd);
3949 		if (proto != IPPROTO_UDP && proto != IPPROTO_UDPLITE &&
3950 		    proto != IPPROTO_TCP && proto != IPPROTO_DCCP)
3951 			break;
3952 #ifdef SMACK_IPV6_SECMARK_LABELING
3953 		skp = smack_from_skb(skb);
3954 		if (skp == NULL) {
3955 			if (smk_ipv6_localhost(&sadd))
3956 				break;
3957 			skp = smack_ipv6host_label(&sadd);
3958 			if (skp == NULL)
3959 				skp = smack_net_ambient;
3960 		}
3961 #ifdef CONFIG_AUDIT
3962 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
3963 		ad.a.u.net->family = family;
3964 		ad.a.u.net->netif = skb->skb_iif;
3965 		ipv6_skb_to_auditdata(skb, &ad.a, NULL);
3966 #endif /* CONFIG_AUDIT */
3967 		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
3968 		rc = smk_bu_note("IPv6 delivery", skp, ssp->smk_in,
3969 					MAY_WRITE, rc);
3970 #endif /* SMACK_IPV6_SECMARK_LABELING */
3971 #ifdef SMACK_IPV6_PORT_LABELING
3972 		rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING);
3973 #endif /* SMACK_IPV6_PORT_LABELING */
3974 		if (rc != 0)
3975 			icmpv6_send(skb, ICMPV6_DEST_UNREACH,
3976 					ICMPV6_ADM_PROHIBITED, 0);
3977 		break;
3978 #endif /* CONFIG_IPV6 */
3979 	}
3980 
3981 	return rc;
3982 }
3983 
3984 /**
3985  * smack_socket_getpeersec_stream - pull in packet label
3986  * @sock: the socket
3987  * @optval: user's destination
3988  * @optlen: size thereof
3989  * @len: max thereof
3990  *
3991  * returns zero on success, an error code otherwise
3992  */
smack_socket_getpeersec_stream(struct socket * sock,char __user * optval,int __user * optlen,unsigned len)3993 static int smack_socket_getpeersec_stream(struct socket *sock,
3994 					  char __user *optval,
3995 					  int __user *optlen, unsigned len)
3996 {
3997 	struct socket_smack *ssp;
3998 	char *rcp = "";
3999 	int slen = 1;
4000 	int rc = 0;
4001 
4002 	ssp = sock->sk->sk_security;
4003 	if (ssp->smk_packet != NULL) {
4004 		rcp = ssp->smk_packet->smk_known;
4005 		slen = strlen(rcp) + 1;
4006 	}
4007 
4008 	if (slen > len)
4009 		rc = -ERANGE;
4010 	else if (copy_to_user(optval, rcp, slen) != 0)
4011 		rc = -EFAULT;
4012 
4013 	if (put_user(slen, optlen) != 0)
4014 		rc = -EFAULT;
4015 
4016 	return rc;
4017 }
4018 
4019 
4020 /**
4021  * smack_socket_getpeersec_dgram - pull in packet label
4022  * @sock: the peer socket
4023  * @skb: packet data
4024  * @secid: pointer to where to put the secid of the packet
4025  *
4026  * Sets the netlabel socket state on sk from parent
4027  */
smack_socket_getpeersec_dgram(struct socket * sock,struct sk_buff * skb,u32 * secid)4028 static int smack_socket_getpeersec_dgram(struct socket *sock,
4029 					 struct sk_buff *skb, u32 *secid)
4030 
4031 {
4032 	struct socket_smack *ssp = NULL;
4033 	struct smack_known *skp;
4034 	struct sock *sk = NULL;
4035 	int family = PF_UNSPEC;
4036 	u32 s = 0;	/* 0 is the invalid secid */
4037 
4038 	if (skb != NULL) {
4039 		if (skb->protocol == htons(ETH_P_IP))
4040 			family = PF_INET;
4041 #if IS_ENABLED(CONFIG_IPV6)
4042 		else if (skb->protocol == htons(ETH_P_IPV6))
4043 			family = PF_INET6;
4044 #endif /* CONFIG_IPV6 */
4045 	}
4046 	if (family == PF_UNSPEC && sock != NULL)
4047 		family = sock->sk->sk_family;
4048 
4049 	switch (family) {
4050 	case PF_UNIX:
4051 		ssp = sock->sk->sk_security;
4052 		s = ssp->smk_out->smk_secid;
4053 		break;
4054 	case PF_INET:
4055 		skp = smack_from_skb(skb);
4056 		if (skp) {
4057 			s = skp->smk_secid;
4058 			break;
4059 		}
4060 		/*
4061 		 * Translate what netlabel gave us.
4062 		 */
4063 		if (sock != NULL)
4064 			sk = sock->sk;
4065 		skp = smack_from_netlbl(sk, family, skb);
4066 		if (skp != NULL)
4067 			s = skp->smk_secid;
4068 		break;
4069 	case PF_INET6:
4070 #ifdef SMACK_IPV6_SECMARK_LABELING
4071 		skp = smack_from_skb(skb);
4072 		if (skp)
4073 			s = skp->smk_secid;
4074 #endif
4075 		break;
4076 	}
4077 	*secid = s;
4078 	if (s == 0)
4079 		return -EINVAL;
4080 	return 0;
4081 }
4082 
4083 /**
4084  * smack_sock_graft - Initialize a newly created socket with an existing sock
4085  * @sk: child sock
4086  * @parent: parent socket
4087  *
4088  * Set the smk_{in,out} state of an existing sock based on the process that
4089  * is creating the new socket.
4090  */
smack_sock_graft(struct sock * sk,struct socket * parent)4091 static void smack_sock_graft(struct sock *sk, struct socket *parent)
4092 {
4093 	struct socket_smack *ssp;
4094 	struct smack_known *skp = smk_of_current();
4095 
4096 	if (sk == NULL ||
4097 	    (sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
4098 		return;
4099 
4100 	ssp = sk->sk_security;
4101 	ssp->smk_in = skp;
4102 	ssp->smk_out = skp;
4103 	/* cssp->smk_packet is already set in smack_inet_csk_clone() */
4104 }
4105 
4106 /**
4107  * smack_inet_conn_request - Smack access check on connect
4108  * @sk: socket involved
4109  * @skb: packet
4110  * @req: unused
4111  *
4112  * Returns 0 if a task with the packet label could write to
4113  * the socket, otherwise an error code
4114  */
smack_inet_conn_request(const struct sock * sk,struct sk_buff * skb,struct request_sock * req)4115 static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
4116 				   struct request_sock *req)
4117 {
4118 	u16 family = sk->sk_family;
4119 	struct smack_known *skp;
4120 	struct socket_smack *ssp = sk->sk_security;
4121 	struct sockaddr_in addr;
4122 	struct iphdr *hdr;
4123 	struct smack_known *hskp;
4124 	int rc;
4125 	struct smk_audit_info ad;
4126 #ifdef CONFIG_AUDIT
4127 	struct lsm_network_audit net;
4128 #endif
4129 
4130 #if IS_ENABLED(CONFIG_IPV6)
4131 	if (family == PF_INET6) {
4132 		/*
4133 		 * Handle mapped IPv4 packets arriving
4134 		 * via IPv6 sockets. Don't set up netlabel
4135 		 * processing on IPv6.
4136 		 */
4137 		if (skb->protocol == htons(ETH_P_IP))
4138 			family = PF_INET;
4139 		else
4140 			return 0;
4141 	}
4142 #endif /* CONFIG_IPV6 */
4143 
4144 	/*
4145 	 * If there is a secmark use it rather than the CIPSO label.
4146 	 * If there is no secmark fall back to CIPSO.
4147 	 * The secmark is assumed to reflect policy better.
4148 	 */
4149 	skp = smack_from_skb(skb);
4150 	if (skp == NULL) {
4151 		skp = smack_from_netlbl(sk, family, skb);
4152 		if (skp == NULL)
4153 			skp = &smack_known_huh;
4154 	}
4155 
4156 #ifdef CONFIG_AUDIT
4157 	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
4158 	ad.a.u.net->family = family;
4159 	ad.a.u.net->netif = skb->skb_iif;
4160 	ipv4_skb_to_auditdata(skb, &ad.a, NULL);
4161 #endif
4162 	/*
4163 	 * Receiving a packet requires that the other end be able to write
4164 	 * here. Read access is not required.
4165 	 */
4166 	rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
4167 	rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in, MAY_WRITE, rc);
4168 	if (rc != 0)
4169 		return rc;
4170 
4171 	/*
4172 	 * Save the peer's label in the request_sock so we can later setup
4173 	 * smk_packet in the child socket so that SO_PEERCRED can report it.
4174 	 */
4175 	req->peer_secid = skp->smk_secid;
4176 
4177 	/*
4178 	 * We need to decide if we want to label the incoming connection here
4179 	 * if we do we only need to label the request_sock and the stack will
4180 	 * propagate the wire-label to the sock when it is created.
4181 	 */
4182 	hdr = ip_hdr(skb);
4183 	addr.sin_addr.s_addr = hdr->saddr;
4184 	rcu_read_lock();
4185 	hskp = smack_ipv4host_label(&addr);
4186 	rcu_read_unlock();
4187 
4188 	if (hskp == NULL)
4189 		rc = netlbl_req_setattr(req, &skp->smk_netlabel);
4190 	else
4191 		netlbl_req_delattr(req);
4192 
4193 	return rc;
4194 }
4195 
4196 /**
4197  * smack_inet_csk_clone - Copy the connection information to the new socket
4198  * @sk: the new socket
4199  * @req: the connection's request_sock
4200  *
4201  * Transfer the connection's peer label to the newly created socket.
4202  */
smack_inet_csk_clone(struct sock * sk,const struct request_sock * req)4203 static void smack_inet_csk_clone(struct sock *sk,
4204 				 const struct request_sock *req)
4205 {
4206 	struct socket_smack *ssp = sk->sk_security;
4207 	struct smack_known *skp;
4208 
4209 	if (req->peer_secid != 0) {
4210 		skp = smack_from_secid(req->peer_secid);
4211 		ssp->smk_packet = skp;
4212 	} else
4213 		ssp->smk_packet = NULL;
4214 }
4215 
4216 /*
4217  * Key management security hooks
4218  *
4219  * Casey has not tested key support very heavily.
4220  * The permission check is most likely too restrictive.
4221  * If you care about keys please have a look.
4222  */
4223 #ifdef CONFIG_KEYS
4224 
4225 /**
4226  * smack_key_alloc - Set the key security blob
4227  * @key: object
4228  * @cred: the credentials to use
4229  * @flags: unused
4230  *
4231  * No allocation required
4232  *
4233  * Returns 0
4234  */
smack_key_alloc(struct key * key,const struct cred * cred,unsigned long flags)4235 static int smack_key_alloc(struct key *key, const struct cred *cred,
4236 			   unsigned long flags)
4237 {
4238 	struct smack_known *skp = smk_of_task(smack_cred(cred));
4239 
4240 	key->security = skp;
4241 	return 0;
4242 }
4243 
4244 /**
4245  * smack_key_free - Clear the key security blob
4246  * @key: the object
4247  *
4248  * Clear the blob pointer
4249  */
smack_key_free(struct key * key)4250 static void smack_key_free(struct key *key)
4251 {
4252 	key->security = NULL;
4253 }
4254 
4255 /**
4256  * smack_key_permission - Smack access on a key
4257  * @key_ref: gets to the object
4258  * @cred: the credentials to use
4259  * @need_perm: requested key permission
4260  *
4261  * Return 0 if the task has read and write to the object,
4262  * an error code otherwise
4263  */
smack_key_permission(key_ref_t key_ref,const struct cred * cred,enum key_need_perm need_perm)4264 static int smack_key_permission(key_ref_t key_ref,
4265 				const struct cred *cred,
4266 				enum key_need_perm need_perm)
4267 {
4268 	struct key *keyp;
4269 	struct smk_audit_info ad;
4270 	struct smack_known *tkp = smk_of_task(smack_cred(cred));
4271 	int request = 0;
4272 	int rc;
4273 
4274 	/*
4275 	 * Validate requested permissions
4276 	 */
4277 	switch (need_perm) {
4278 	case KEY_NEED_READ:
4279 	case KEY_NEED_SEARCH:
4280 	case KEY_NEED_VIEW:
4281 		request |= MAY_READ;
4282 		break;
4283 	case KEY_NEED_WRITE:
4284 	case KEY_NEED_LINK:
4285 	case KEY_NEED_SETATTR:
4286 		request |= MAY_WRITE;
4287 		break;
4288 	case KEY_NEED_UNSPECIFIED:
4289 	case KEY_NEED_UNLINK:
4290 	case KEY_SYSADMIN_OVERRIDE:
4291 	case KEY_AUTHTOKEN_OVERRIDE:
4292 	case KEY_DEFER_PERM_CHECK:
4293 		return 0;
4294 	default:
4295 		return -EINVAL;
4296 	}
4297 
4298 	keyp = key_ref_to_ptr(key_ref);
4299 	if (keyp == NULL)
4300 		return -EINVAL;
4301 	/*
4302 	 * If the key hasn't been initialized give it access so that
4303 	 * it may do so.
4304 	 */
4305 	if (keyp->security == NULL)
4306 		return 0;
4307 	/*
4308 	 * This should not occur
4309 	 */
4310 	if (tkp == NULL)
4311 		return -EACCES;
4312 
4313 	if (smack_privileged(CAP_MAC_OVERRIDE))
4314 		return 0;
4315 
4316 #ifdef CONFIG_AUDIT
4317 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
4318 	ad.a.u.key_struct.key = keyp->serial;
4319 	ad.a.u.key_struct.key_desc = keyp->description;
4320 #endif
4321 	rc = smk_access(tkp, keyp->security, request, &ad);
4322 	rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
4323 	return rc;
4324 }
4325 
4326 /*
4327  * smack_key_getsecurity - Smack label tagging the key
4328  * @key points to the key to be queried
4329  * @_buffer points to a pointer that should be set to point to the
4330  * resulting string (if no label or an error occurs).
4331  * Return the length of the string (including terminating NUL) or -ve if
4332  * an error.
4333  * May also return 0 (and a NULL buffer pointer) if there is no label.
4334  */
smack_key_getsecurity(struct key * key,char ** _buffer)4335 static int smack_key_getsecurity(struct key *key, char **_buffer)
4336 {
4337 	struct smack_known *skp = key->security;
4338 	size_t length;
4339 	char *copy;
4340 
4341 	if (key->security == NULL) {
4342 		*_buffer = NULL;
4343 		return 0;
4344 	}
4345 
4346 	copy = kstrdup(skp->smk_known, GFP_KERNEL);
4347 	if (copy == NULL)
4348 		return -ENOMEM;
4349 	length = strlen(copy) + 1;
4350 
4351 	*_buffer = copy;
4352 	return length;
4353 }
4354 
4355 
4356 #ifdef CONFIG_KEY_NOTIFICATIONS
4357 /**
4358  * smack_watch_key - Smack access to watch a key for notifications.
4359  * @key: The key to be watched
4360  *
4361  * Return 0 if the @watch->cred has permission to read from the key object and
4362  * an error otherwise.
4363  */
smack_watch_key(struct key * key)4364 static int smack_watch_key(struct key *key)
4365 {
4366 	struct smk_audit_info ad;
4367 	struct smack_known *tkp = smk_of_current();
4368 	int rc;
4369 
4370 	if (key == NULL)
4371 		return -EINVAL;
4372 	/*
4373 	 * If the key hasn't been initialized give it access so that
4374 	 * it may do so.
4375 	 */
4376 	if (key->security == NULL)
4377 		return 0;
4378 	/*
4379 	 * This should not occur
4380 	 */
4381 	if (tkp == NULL)
4382 		return -EACCES;
4383 
4384 	if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()))
4385 		return 0;
4386 
4387 #ifdef CONFIG_AUDIT
4388 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
4389 	ad.a.u.key_struct.key = key->serial;
4390 	ad.a.u.key_struct.key_desc = key->description;
4391 #endif
4392 	rc = smk_access(tkp, key->security, MAY_READ, &ad);
4393 	rc = smk_bu_note("key watch", tkp, key->security, MAY_READ, rc);
4394 	return rc;
4395 }
4396 #endif /* CONFIG_KEY_NOTIFICATIONS */
4397 #endif /* CONFIG_KEYS */
4398 
4399 #ifdef CONFIG_WATCH_QUEUE
4400 /**
4401  * smack_post_notification - Smack access to post a notification to a queue
4402  * @w_cred: The credentials of the watcher.
4403  * @cred: The credentials of the event source (may be NULL).
4404  * @n: The notification message to be posted.
4405  */
smack_post_notification(const struct cred * w_cred,const struct cred * cred,struct watch_notification * n)4406 static int smack_post_notification(const struct cred *w_cred,
4407 				   const struct cred *cred,
4408 				   struct watch_notification *n)
4409 {
4410 	struct smk_audit_info ad;
4411 	struct smack_known *subj, *obj;
4412 	int rc;
4413 
4414 	/* Always let maintenance notifications through. */
4415 	if (n->type == WATCH_TYPE_META)
4416 		return 0;
4417 
4418 	if (!cred)
4419 		return 0;
4420 	subj = smk_of_task(smack_cred(cred));
4421 	obj = smk_of_task(smack_cred(w_cred));
4422 
4423 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NOTIFICATION);
4424 	rc = smk_access(subj, obj, MAY_WRITE, &ad);
4425 	rc = smk_bu_note("notification", subj, obj, MAY_WRITE, rc);
4426 	return rc;
4427 }
4428 #endif /* CONFIG_WATCH_QUEUE */
4429 
4430 /*
4431  * Smack Audit hooks
4432  *
4433  * Audit requires a unique representation of each Smack specific
4434  * rule. This unique representation is used to distinguish the
4435  * object to be audited from remaining kernel objects and also
4436  * works as a glue between the audit hooks.
4437  *
4438  * Since repository entries are added but never deleted, we'll use
4439  * the smack_known label address related to the given audit rule as
4440  * the needed unique representation. This also better fits the smack
4441  * model where nearly everything is a label.
4442  */
4443 #ifdef CONFIG_AUDIT
4444 
4445 /**
4446  * smack_audit_rule_init - Initialize a smack audit rule
4447  * @field: audit rule fields given from user-space (audit.h)
4448  * @op: required testing operator (=, !=, >, <, ...)
4449  * @rulestr: smack label to be audited
4450  * @vrule: pointer to save our own audit rule representation
4451  *
4452  * Prepare to audit cases where (@field @op @rulestr) is true.
4453  * The label to be audited is created if necessay.
4454  */
smack_audit_rule_init(u32 field,u32 op,char * rulestr,void ** vrule)4455 static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
4456 {
4457 	struct smack_known *skp;
4458 	char **rule = (char **)vrule;
4459 	*rule = NULL;
4460 
4461 	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
4462 		return -EINVAL;
4463 
4464 	if (op != Audit_equal && op != Audit_not_equal)
4465 		return -EINVAL;
4466 
4467 	skp = smk_import_entry(rulestr, 0);
4468 	if (IS_ERR(skp))
4469 		return PTR_ERR(skp);
4470 
4471 	*rule = skp->smk_known;
4472 
4473 	return 0;
4474 }
4475 
4476 /**
4477  * smack_audit_rule_known - Distinguish Smack audit rules
4478  * @krule: rule of interest, in Audit kernel representation format
4479  *
4480  * This is used to filter Smack rules from remaining Audit ones.
4481  * If it's proved that this rule belongs to us, the
4482  * audit_rule_match hook will be called to do the final judgement.
4483  */
smack_audit_rule_known(struct audit_krule * krule)4484 static int smack_audit_rule_known(struct audit_krule *krule)
4485 {
4486 	struct audit_field *f;
4487 	int i;
4488 
4489 	for (i = 0; i < krule->field_count; i++) {
4490 		f = &krule->fields[i];
4491 
4492 		if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
4493 			return 1;
4494 	}
4495 
4496 	return 0;
4497 }
4498 
4499 /**
4500  * smack_audit_rule_match - Audit given object ?
4501  * @secid: security id for identifying the object to test
4502  * @field: audit rule flags given from user-space
4503  * @op: required testing operator
4504  * @vrule: smack internal rule presentation
4505  *
4506  * The core Audit hook. It's used to take the decision of
4507  * whether to audit or not to audit a given object.
4508  */
smack_audit_rule_match(u32 secid,u32 field,u32 op,void * vrule)4509 static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule)
4510 {
4511 	struct smack_known *skp;
4512 	char *rule = vrule;
4513 
4514 	if (unlikely(!rule)) {
4515 		WARN_ONCE(1, "Smack: missing rule\n");
4516 		return -ENOENT;
4517 	}
4518 
4519 	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
4520 		return 0;
4521 
4522 	skp = smack_from_secid(secid);
4523 
4524 	/*
4525 	 * No need to do string comparisons. If a match occurs,
4526 	 * both pointers will point to the same smack_known
4527 	 * label.
4528 	 */
4529 	if (op == Audit_equal)
4530 		return (rule == skp->smk_known);
4531 	if (op == Audit_not_equal)
4532 		return (rule != skp->smk_known);
4533 
4534 	return 0;
4535 }
4536 
4537 /*
4538  * There is no need for a smack_audit_rule_free hook.
4539  * No memory was allocated.
4540  */
4541 
4542 #endif /* CONFIG_AUDIT */
4543 
4544 /**
4545  * smack_ismaclabel - check if xattr @name references a smack MAC label
4546  * @name: Full xattr name to check.
4547  */
smack_ismaclabel(const char * name)4548 static int smack_ismaclabel(const char *name)
4549 {
4550 	return (strcmp(name, XATTR_SMACK_SUFFIX) == 0);
4551 }
4552 
4553 
4554 /**
4555  * smack_secid_to_secctx - return the smack label for a secid
4556  * @secid: incoming integer
4557  * @secdata: destination
4558  * @seclen: how long it is
4559  *
4560  * Exists for networking code.
4561  */
smack_secid_to_secctx(u32 secid,char ** secdata,u32 * seclen)4562 static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
4563 {
4564 	struct smack_known *skp = smack_from_secid(secid);
4565 
4566 	if (secdata)
4567 		*secdata = skp->smk_known;
4568 	*seclen = strlen(skp->smk_known);
4569 	return 0;
4570 }
4571 
4572 /**
4573  * smack_secctx_to_secid - return the secid for a smack label
4574  * @secdata: smack label
4575  * @seclen: how long result is
4576  * @secid: outgoing integer
4577  *
4578  * Exists for audit and networking code.
4579  */
smack_secctx_to_secid(const char * secdata,u32 seclen,u32 * secid)4580 static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
4581 {
4582 	struct smack_known *skp = smk_find_entry(secdata);
4583 
4584 	if (skp)
4585 		*secid = skp->smk_secid;
4586 	else
4587 		*secid = 0;
4588 	return 0;
4589 }
4590 
4591 /*
4592  * There used to be a smack_release_secctx hook
4593  * that did nothing back when hooks were in a vector.
4594  * Now that there's a list such a hook adds cost.
4595  */
4596 
smack_inode_notifysecctx(struct inode * inode,void * ctx,u32 ctxlen)4597 static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
4598 {
4599 	return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx,
4600 				       ctxlen, 0);
4601 }
4602 
smack_inode_setsecctx(struct dentry * dentry,void * ctx,u32 ctxlen)4603 static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
4604 {
4605 	return __vfs_setxattr_noperm(&init_user_ns, dentry, XATTR_NAME_SMACK,
4606 				     ctx, ctxlen, 0);
4607 }
4608 
smack_inode_getsecctx(struct inode * inode,void ** ctx,u32 * ctxlen)4609 static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
4610 {
4611 	struct smack_known *skp = smk_of_inode(inode);
4612 
4613 	*ctx = skp->smk_known;
4614 	*ctxlen = strlen(skp->smk_known);
4615 	return 0;
4616 }
4617 
smack_inode_copy_up(struct dentry * dentry,struct cred ** new)4618 static int smack_inode_copy_up(struct dentry *dentry, struct cred **new)
4619 {
4620 
4621 	struct task_smack *tsp;
4622 	struct smack_known *skp;
4623 	struct inode_smack *isp;
4624 	struct cred *new_creds = *new;
4625 
4626 	if (new_creds == NULL) {
4627 		new_creds = prepare_creds();
4628 		if (new_creds == NULL)
4629 			return -ENOMEM;
4630 	}
4631 
4632 	tsp = smack_cred(new_creds);
4633 
4634 	/*
4635 	 * Get label from overlay inode and set it in create_sid
4636 	 */
4637 	isp = smack_inode(d_inode(dentry->d_parent));
4638 	skp = isp->smk_inode;
4639 	tsp->smk_task = skp;
4640 	*new = new_creds;
4641 	return 0;
4642 }
4643 
smack_inode_copy_up_xattr(const char * name)4644 static int smack_inode_copy_up_xattr(const char *name)
4645 {
4646 	/*
4647 	 * Return 1 if this is the smack access Smack attribute.
4648 	 */
4649 	if (strcmp(name, XATTR_NAME_SMACK) == 0)
4650 		return 1;
4651 
4652 	return -EOPNOTSUPP;
4653 }
4654 
smack_dentry_create_files_as(struct dentry * dentry,int mode,struct qstr * name,const struct cred * old,struct cred * new)4655 static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
4656 					struct qstr *name,
4657 					const struct cred *old,
4658 					struct cred *new)
4659 {
4660 	struct task_smack *otsp = smack_cred(old);
4661 	struct task_smack *ntsp = smack_cred(new);
4662 	struct inode_smack *isp;
4663 	int may;
4664 
4665 	/*
4666 	 * Use the process credential unless all of
4667 	 * the transmuting criteria are met
4668 	 */
4669 	ntsp->smk_task = otsp->smk_task;
4670 
4671 	/*
4672 	 * the attribute of the containing directory
4673 	 */
4674 	isp = smack_inode(d_inode(dentry->d_parent));
4675 
4676 	if (isp->smk_flags & SMK_INODE_TRANSMUTE) {
4677 		rcu_read_lock();
4678 		may = smk_access_entry(otsp->smk_task->smk_known,
4679 				       isp->smk_inode->smk_known,
4680 				       &otsp->smk_task->smk_rules);
4681 		rcu_read_unlock();
4682 
4683 		/*
4684 		 * If the directory is transmuting and the rule
4685 		 * providing access is transmuting use the containing
4686 		 * directory label instead of the process label.
4687 		 */
4688 		if (may > 0 && (may & MAY_TRANSMUTE))
4689 			ntsp->smk_task = isp->smk_inode;
4690 	}
4691 	return 0;
4692 }
4693 
4694 struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
4695 	.lbs_cred = sizeof(struct task_smack),
4696 	.lbs_file = sizeof(struct smack_known *),
4697 	.lbs_inode = sizeof(struct inode_smack),
4698 	.lbs_ipc = sizeof(struct smack_known *),
4699 	.lbs_msg_msg = sizeof(struct smack_known *),
4700 	.lbs_superblock = sizeof(struct superblock_smack),
4701 };
4702 
4703 static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
4704 	LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
4705 	LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
4706 	LSM_HOOK_INIT(syslog, smack_syslog),
4707 
4708 	LSM_HOOK_INIT(fs_context_dup, smack_fs_context_dup),
4709 	LSM_HOOK_INIT(fs_context_parse_param, smack_fs_context_parse_param),
4710 
4711 	LSM_HOOK_INIT(sb_alloc_security, smack_sb_alloc_security),
4712 	LSM_HOOK_INIT(sb_free_mnt_opts, smack_free_mnt_opts),
4713 	LSM_HOOK_INIT(sb_eat_lsm_opts, smack_sb_eat_lsm_opts),
4714 	LSM_HOOK_INIT(sb_statfs, smack_sb_statfs),
4715 	LSM_HOOK_INIT(sb_set_mnt_opts, smack_set_mnt_opts),
4716 
4717 	LSM_HOOK_INIT(bprm_creds_for_exec, smack_bprm_creds_for_exec),
4718 
4719 	LSM_HOOK_INIT(inode_alloc_security, smack_inode_alloc_security),
4720 	LSM_HOOK_INIT(inode_init_security, smack_inode_init_security),
4721 	LSM_HOOK_INIT(inode_link, smack_inode_link),
4722 	LSM_HOOK_INIT(inode_unlink, smack_inode_unlink),
4723 	LSM_HOOK_INIT(inode_rmdir, smack_inode_rmdir),
4724 	LSM_HOOK_INIT(inode_rename, smack_inode_rename),
4725 	LSM_HOOK_INIT(inode_permission, smack_inode_permission),
4726 	LSM_HOOK_INIT(inode_setattr, smack_inode_setattr),
4727 	LSM_HOOK_INIT(inode_getattr, smack_inode_getattr),
4728 	LSM_HOOK_INIT(inode_setxattr, smack_inode_setxattr),
4729 	LSM_HOOK_INIT(inode_post_setxattr, smack_inode_post_setxattr),
4730 	LSM_HOOK_INIT(inode_getxattr, smack_inode_getxattr),
4731 	LSM_HOOK_INIT(inode_removexattr, smack_inode_removexattr),
4732 	LSM_HOOK_INIT(inode_getsecurity, smack_inode_getsecurity),
4733 	LSM_HOOK_INIT(inode_setsecurity, smack_inode_setsecurity),
4734 	LSM_HOOK_INIT(inode_listsecurity, smack_inode_listsecurity),
4735 	LSM_HOOK_INIT(inode_getsecid, smack_inode_getsecid),
4736 
4737 	LSM_HOOK_INIT(file_alloc_security, smack_file_alloc_security),
4738 	LSM_HOOK_INIT(file_ioctl, smack_file_ioctl),
4739 	LSM_HOOK_INIT(file_lock, smack_file_lock),
4740 	LSM_HOOK_INIT(file_fcntl, smack_file_fcntl),
4741 	LSM_HOOK_INIT(mmap_file, smack_mmap_file),
4742 	LSM_HOOK_INIT(mmap_addr, cap_mmap_addr),
4743 	LSM_HOOK_INIT(file_set_fowner, smack_file_set_fowner),
4744 	LSM_HOOK_INIT(file_send_sigiotask, smack_file_send_sigiotask),
4745 	LSM_HOOK_INIT(file_receive, smack_file_receive),
4746 
4747 	LSM_HOOK_INIT(file_open, smack_file_open),
4748 
4749 	LSM_HOOK_INIT(cred_alloc_blank, smack_cred_alloc_blank),
4750 	LSM_HOOK_INIT(cred_free, smack_cred_free),
4751 	LSM_HOOK_INIT(cred_prepare, smack_cred_prepare),
4752 	LSM_HOOK_INIT(cred_transfer, smack_cred_transfer),
4753 	LSM_HOOK_INIT(cred_getsecid, smack_cred_getsecid),
4754 	LSM_HOOK_INIT(kernel_act_as, smack_kernel_act_as),
4755 	LSM_HOOK_INIT(kernel_create_files_as, smack_kernel_create_files_as),
4756 	LSM_HOOK_INIT(task_setpgid, smack_task_setpgid),
4757 	LSM_HOOK_INIT(task_getpgid, smack_task_getpgid),
4758 	LSM_HOOK_INIT(task_getsid, smack_task_getsid),
4759 	LSM_HOOK_INIT(task_getsecid_subj, smack_task_getsecid_subj),
4760 	LSM_HOOK_INIT(task_getsecid_obj, smack_task_getsecid_obj),
4761 	LSM_HOOK_INIT(task_setnice, smack_task_setnice),
4762 	LSM_HOOK_INIT(task_setioprio, smack_task_setioprio),
4763 	LSM_HOOK_INIT(task_getioprio, smack_task_getioprio),
4764 	LSM_HOOK_INIT(task_setscheduler, smack_task_setscheduler),
4765 	LSM_HOOK_INIT(task_getscheduler, smack_task_getscheduler),
4766 	LSM_HOOK_INIT(task_movememory, smack_task_movememory),
4767 	LSM_HOOK_INIT(task_kill, smack_task_kill),
4768 	LSM_HOOK_INIT(task_to_inode, smack_task_to_inode),
4769 
4770 	LSM_HOOK_INIT(ipc_permission, smack_ipc_permission),
4771 	LSM_HOOK_INIT(ipc_getsecid, smack_ipc_getsecid),
4772 
4773 	LSM_HOOK_INIT(msg_msg_alloc_security, smack_msg_msg_alloc_security),
4774 
4775 	LSM_HOOK_INIT(msg_queue_alloc_security, smack_ipc_alloc_security),
4776 	LSM_HOOK_INIT(msg_queue_associate, smack_msg_queue_associate),
4777 	LSM_HOOK_INIT(msg_queue_msgctl, smack_msg_queue_msgctl),
4778 	LSM_HOOK_INIT(msg_queue_msgsnd, smack_msg_queue_msgsnd),
4779 	LSM_HOOK_INIT(msg_queue_msgrcv, smack_msg_queue_msgrcv),
4780 
4781 	LSM_HOOK_INIT(shm_alloc_security, smack_ipc_alloc_security),
4782 	LSM_HOOK_INIT(shm_associate, smack_shm_associate),
4783 	LSM_HOOK_INIT(shm_shmctl, smack_shm_shmctl),
4784 	LSM_HOOK_INIT(shm_shmat, smack_shm_shmat),
4785 
4786 	LSM_HOOK_INIT(sem_alloc_security, smack_ipc_alloc_security),
4787 	LSM_HOOK_INIT(sem_associate, smack_sem_associate),
4788 	LSM_HOOK_INIT(sem_semctl, smack_sem_semctl),
4789 	LSM_HOOK_INIT(sem_semop, smack_sem_semop),
4790 
4791 	LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),
4792 
4793 	LSM_HOOK_INIT(getprocattr, smack_getprocattr),
4794 	LSM_HOOK_INIT(setprocattr, smack_setprocattr),
4795 
4796 	LSM_HOOK_INIT(unix_stream_connect, smack_unix_stream_connect),
4797 	LSM_HOOK_INIT(unix_may_send, smack_unix_may_send),
4798 
4799 	LSM_HOOK_INIT(socket_post_create, smack_socket_post_create),
4800 	LSM_HOOK_INIT(socket_socketpair, smack_socket_socketpair),
4801 #ifdef SMACK_IPV6_PORT_LABELING
4802 	LSM_HOOK_INIT(socket_bind, smack_socket_bind),
4803 #endif
4804 	LSM_HOOK_INIT(socket_connect, smack_socket_connect),
4805 	LSM_HOOK_INIT(socket_sendmsg, smack_socket_sendmsg),
4806 	LSM_HOOK_INIT(socket_sock_rcv_skb, smack_socket_sock_rcv_skb),
4807 	LSM_HOOK_INIT(socket_getpeersec_stream, smack_socket_getpeersec_stream),
4808 	LSM_HOOK_INIT(socket_getpeersec_dgram, smack_socket_getpeersec_dgram),
4809 	LSM_HOOK_INIT(sk_alloc_security, smack_sk_alloc_security),
4810 	LSM_HOOK_INIT(sk_free_security, smack_sk_free_security),
4811 	LSM_HOOK_INIT(sock_graft, smack_sock_graft),
4812 	LSM_HOOK_INIT(inet_conn_request, smack_inet_conn_request),
4813 	LSM_HOOK_INIT(inet_csk_clone, smack_inet_csk_clone),
4814 
4815  /* key management security hooks */
4816 #ifdef CONFIG_KEYS
4817 	LSM_HOOK_INIT(key_alloc, smack_key_alloc),
4818 	LSM_HOOK_INIT(key_free, smack_key_free),
4819 	LSM_HOOK_INIT(key_permission, smack_key_permission),
4820 	LSM_HOOK_INIT(key_getsecurity, smack_key_getsecurity),
4821 #ifdef CONFIG_KEY_NOTIFICATIONS
4822 	LSM_HOOK_INIT(watch_key, smack_watch_key),
4823 #endif
4824 #endif /* CONFIG_KEYS */
4825 
4826 #ifdef CONFIG_WATCH_QUEUE
4827 	LSM_HOOK_INIT(post_notification, smack_post_notification),
4828 #endif
4829 
4830  /* Audit hooks */
4831 #ifdef CONFIG_AUDIT
4832 	LSM_HOOK_INIT(audit_rule_init, smack_audit_rule_init),
4833 	LSM_HOOK_INIT(audit_rule_known, smack_audit_rule_known),
4834 	LSM_HOOK_INIT(audit_rule_match, smack_audit_rule_match),
4835 #endif /* CONFIG_AUDIT */
4836 
4837 	LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
4838 	LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
4839 	LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
4840 	LSM_HOOK_INIT(inode_notifysecctx, smack_inode_notifysecctx),
4841 	LSM_HOOK_INIT(inode_setsecctx, smack_inode_setsecctx),
4842 	LSM_HOOK_INIT(inode_getsecctx, smack_inode_getsecctx),
4843 	LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up),
4844 	LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr),
4845 	LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as),
4846 };
4847 
4848 
init_smack_known_list(void)4849 static __init void init_smack_known_list(void)
4850 {
4851 	/*
4852 	 * Initialize rule list locks
4853 	 */
4854 	mutex_init(&smack_known_huh.smk_rules_lock);
4855 	mutex_init(&smack_known_hat.smk_rules_lock);
4856 	mutex_init(&smack_known_floor.smk_rules_lock);
4857 	mutex_init(&smack_known_star.smk_rules_lock);
4858 	mutex_init(&smack_known_web.smk_rules_lock);
4859 	/*
4860 	 * Initialize rule lists
4861 	 */
4862 	INIT_LIST_HEAD(&smack_known_huh.smk_rules);
4863 	INIT_LIST_HEAD(&smack_known_hat.smk_rules);
4864 	INIT_LIST_HEAD(&smack_known_star.smk_rules);
4865 	INIT_LIST_HEAD(&smack_known_floor.smk_rules);
4866 	INIT_LIST_HEAD(&smack_known_web.smk_rules);
4867 	/*
4868 	 * Create the known labels list
4869 	 */
4870 	smk_insert_entry(&smack_known_huh);
4871 	smk_insert_entry(&smack_known_hat);
4872 	smk_insert_entry(&smack_known_star);
4873 	smk_insert_entry(&smack_known_floor);
4874 	smk_insert_entry(&smack_known_web);
4875 }
4876 
4877 /**
4878  * smack_init - initialize the smack system
4879  *
4880  * Returns 0 on success, -ENOMEM is there's no memory
4881  */
smack_init(void)4882 static __init int smack_init(void)
4883 {
4884 	struct cred *cred = (struct cred *) current->cred;
4885 	struct task_smack *tsp;
4886 
4887 	smack_rule_cache = KMEM_CACHE(smack_rule, 0);
4888 	if (!smack_rule_cache)
4889 		return -ENOMEM;
4890 
4891 	/*
4892 	 * Set the security state for the initial task.
4893 	 */
4894 	tsp = smack_cred(cred);
4895 	init_task_smack(tsp, &smack_known_floor, &smack_known_floor);
4896 
4897 	/*
4898 	 * Register with LSM
4899 	 */
4900 	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
4901 	smack_enabled = 1;
4902 
4903 	pr_info("Smack:  Initializing.\n");
4904 #ifdef CONFIG_SECURITY_SMACK_NETFILTER
4905 	pr_info("Smack:  Netfilter enabled.\n");
4906 #endif
4907 #ifdef SMACK_IPV6_PORT_LABELING
4908 	pr_info("Smack:  IPv6 port labeling enabled.\n");
4909 #endif
4910 #ifdef SMACK_IPV6_SECMARK_LABELING
4911 	pr_info("Smack:  IPv6 Netfilter enabled.\n");
4912 #endif
4913 
4914 	/* initialize the smack_known_list */
4915 	init_smack_known_list();
4916 
4917 	return 0;
4918 }
4919 
4920 /*
4921  * Smack requires early initialization in order to label
4922  * all processes and objects when they are created.
4923  */
4924 DEFINE_LSM(smack) = {
4925 	.name = "smack",
4926 	.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
4927 	.blobs = &smack_blob_sizes,
4928 	.init = smack_init,
4929 };
4930