1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1993, David Greenman
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include "opt_capsicum.h"
31 #include "opt_hwpmc_hooks.h"
32 #include "opt_ktrace.h"
33 #include "opt_vm.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/acct.h>
38 #include <sys/asan.h>
39 #include <sys/capsicum.h>
40 #include <sys/compressor.h>
41 #include <sys/eventhandler.h>
42 #include <sys/exec.h>
43 #include <sys/fcntl.h>
44 #include <sys/filedesc.h>
45 #include <sys/imgact.h>
46 #include <sys/imgact_elf.h>
47 #include <sys/kernel.h>
48 #include <sys/lock.h>
49 #include <sys/malloc.h>
50 #include <sys/mman.h>
51 #include <sys/mount.h>
52 #include <sys/mutex.h>
53 #include <sys/namei.h>
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/ptrace.h>
57 #include <sys/reg.h>
58 #include <sys/resourcevar.h>
59 #include <sys/rwlock.h>
60 #include <sys/sched.h>
61 #include <sys/sdt.h>
62 #include <sys/sf_buf.h>
63 #include <sys/shm.h>
64 #include <sys/signalvar.h>
65 #include <sys/smp.h>
66 #include <sys/stat.h>
67 #include <sys/syscallsubr.h>
68 #include <sys/sysctl.h>
69 #include <sys/sysent.h>
70 #include <sys/sysproto.h>
71 #include <sys/timers.h>
72 #include <sys/umtxvar.h>
73 #include <sys/vnode.h>
74 #include <sys/wait.h>
75 #ifdef KTRACE
76 #include <sys/ktrace.h>
77 #endif
78
79 #include <vm/vm.h>
80 #include <vm/vm_param.h>
81 #include <vm/pmap.h>
82 #include <vm/vm_page.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_kern.h>
85 #include <vm/vm_extern.h>
86 #include <vm/vm_object.h>
87 #include <vm/vm_pager.h>
88
89 #ifdef HWPMC_HOOKS
90 #include <sys/pmckern.h>
91 #endif
92
93 #include <security/audit/audit.h>
94 #include <security/mac/mac_framework.h>
95
96 #ifdef KDTRACE_HOOKS
97 #include <sys/dtrace_bsd.h>
98 dtrace_execexit_func_t dtrace_fasttrap_exec;
99 #endif
100
101 SDT_PROVIDER_DECLARE(proc);
102 SDT_PROBE_DEFINE1(proc, , , exec, "char *");
103 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int");
104 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *");
105
106 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
107
108 int coredump_pack_fileinfo = 1;
109 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN,
110 &coredump_pack_fileinfo, 0,
111 "Enable file path packing in 'procstat -f' coredump notes");
112
113 int coredump_pack_vmmapinfo = 1;
114 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN,
115 &coredump_pack_vmmapinfo, 0,
116 "Enable file path packing in 'procstat -v' coredump notes");
117
118 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
119 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
120 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
121 static int do_execve(struct thread *td, struct image_args *args,
122 struct mac *mac_p, struct vmspace *oldvmspace);
123
124 /* XXX This should be vm_size_t. */
125 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD|
126 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU",
127 "Location of process' ps_strings structure");
128
129 /* XXX This should be vm_size_t. */
130 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD|
131 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU",
132 "Top of process stack");
133
134 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE,
135 NULL, 0, sysctl_kern_stackprot, "I",
136 "Stack memory permissions");
137
138 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
139 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
140 &ps_arg_cache_limit, 0,
141 "Process' command line characters cache limit");
142
143 static int disallow_high_osrel;
144 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW,
145 &disallow_high_osrel, 0,
146 "Disallow execution of binaries built for higher version of the world");
147
148 static int map_at_zero = 0;
149 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0,
150 "Permit processes to map an object at virtual address 0.");
151
152 static int core_dump_can_intr = 1;
153 SYSCTL_INT(_kern, OID_AUTO, core_dump_can_intr, CTLFLAG_RWTUN,
154 &core_dump_can_intr, 0,
155 "Core dumping interruptible with SIGKILL");
156
157 static int
sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)158 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
159 {
160 struct proc *p;
161 vm_offset_t ps_strings;
162
163 p = curproc;
164 #ifdef SCTL_MASK32
165 if (req->flags & SCTL_MASK32) {
166 unsigned int val;
167 val = (unsigned int)PROC_PS_STRINGS(p);
168 return (SYSCTL_OUT(req, &val, sizeof(val)));
169 }
170 #endif
171 ps_strings = PROC_PS_STRINGS(p);
172 return (SYSCTL_OUT(req, &ps_strings, sizeof(ps_strings)));
173 }
174
175 static int
sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)176 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
177 {
178 struct proc *p;
179 vm_offset_t val;
180
181 p = curproc;
182 #ifdef SCTL_MASK32
183 if (req->flags & SCTL_MASK32) {
184 unsigned int val32;
185
186 val32 = round_page((unsigned int)p->p_vmspace->vm_stacktop);
187 return (SYSCTL_OUT(req, &val32, sizeof(val32)));
188 }
189 #endif
190 val = round_page(p->p_vmspace->vm_stacktop);
191 return (SYSCTL_OUT(req, &val, sizeof(val)));
192 }
193
194 static int
sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)195 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
196 {
197 struct proc *p;
198
199 p = curproc;
200 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
201 sizeof(p->p_sysent->sv_stackprot)));
202 }
203
204 /*
205 * Each of the items is a pointer to a `const struct execsw', hence the
206 * double pointer here.
207 */
208 static const struct execsw **execsw;
209
210 #ifndef _SYS_SYSPROTO_H_
211 struct execve_args {
212 char *fname;
213 char **argv;
214 char **envv;
215 };
216 #endif
217
218 int
sys_execve(struct thread * td,struct execve_args * uap)219 sys_execve(struct thread *td, struct execve_args *uap)
220 {
221 struct image_args args;
222 struct vmspace *oldvmspace;
223 int error;
224
225 error = pre_execve(td, &oldvmspace);
226 if (error != 0)
227 return (error);
228 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
229 uap->argv, uap->envv);
230 if (error == 0)
231 error = kern_execve(td, &args, NULL, oldvmspace);
232 post_execve(td, error, oldvmspace);
233 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
234 return (error);
235 }
236
237 #ifndef _SYS_SYSPROTO_H_
238 struct fexecve_args {
239 int fd;
240 char **argv;
241 char **envv;
242 };
243 #endif
244 int
sys_fexecve(struct thread * td,struct fexecve_args * uap)245 sys_fexecve(struct thread *td, struct fexecve_args *uap)
246 {
247 struct image_args args;
248 struct vmspace *oldvmspace;
249 int error;
250
251 error = pre_execve(td, &oldvmspace);
252 if (error != 0)
253 return (error);
254 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
255 uap->argv, uap->envv);
256 if (error == 0) {
257 args.fd = uap->fd;
258 error = kern_execve(td, &args, NULL, oldvmspace);
259 }
260 post_execve(td, error, oldvmspace);
261 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
262 return (error);
263 }
264
265 #ifndef _SYS_SYSPROTO_H_
266 struct __mac_execve_args {
267 char *fname;
268 char **argv;
269 char **envv;
270 struct mac *mac_p;
271 };
272 #endif
273
274 int
sys___mac_execve(struct thread * td,struct __mac_execve_args * uap)275 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap)
276 {
277 #ifdef MAC
278 struct image_args args;
279 struct vmspace *oldvmspace;
280 int error;
281
282 error = pre_execve(td, &oldvmspace);
283 if (error != 0)
284 return (error);
285 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
286 uap->argv, uap->envv);
287 if (error == 0)
288 error = kern_execve(td, &args, uap->mac_p, oldvmspace);
289 post_execve(td, error, oldvmspace);
290 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td);
291 return (error);
292 #else
293 return (ENOSYS);
294 #endif
295 }
296
297 int
pre_execve(struct thread * td,struct vmspace ** oldvmspace)298 pre_execve(struct thread *td, struct vmspace **oldvmspace)
299 {
300 struct proc *p;
301 int error;
302
303 KASSERT(td == curthread, ("non-current thread %p", td));
304 error = 0;
305 p = td->td_proc;
306 if ((p->p_flag & P_HADTHREADS) != 0) {
307 PROC_LOCK(p);
308 if (thread_single(p, SINGLE_BOUNDARY) != 0)
309 error = ERESTART;
310 PROC_UNLOCK(p);
311 }
312 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0,
313 ("nested execve"));
314 *oldvmspace = p->p_vmspace;
315 return (error);
316 }
317
318 void
post_execve(struct thread * td,int error,struct vmspace * oldvmspace)319 post_execve(struct thread *td, int error, struct vmspace *oldvmspace)
320 {
321 struct proc *p;
322
323 KASSERT(td == curthread, ("non-current thread %p", td));
324 p = td->td_proc;
325 if ((p->p_flag & P_HADTHREADS) != 0) {
326 PROC_LOCK(p);
327 /*
328 * If success, we upgrade to SINGLE_EXIT state to
329 * force other threads to suicide.
330 */
331 if (error == EJUSTRETURN)
332 thread_single(p, SINGLE_EXIT);
333 else
334 thread_single_end(p, SINGLE_BOUNDARY);
335 PROC_UNLOCK(p);
336 }
337 exec_cleanup(td, oldvmspace);
338 }
339
340 /*
341 * kern_execve() has the astonishing property of not always returning to
342 * the caller. If sufficiently bad things happen during the call to
343 * do_execve(), it can end up calling exit1(); as a result, callers must
344 * avoid doing anything which they might need to undo (e.g., allocating
345 * memory).
346 */
347 int
kern_execve(struct thread * td,struct image_args * args,struct mac * mac_p,struct vmspace * oldvmspace)348 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p,
349 struct vmspace *oldvmspace)
350 {
351
352 TSEXEC(td->td_proc->p_pid, args->begin_argv);
353 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
354 exec_args_get_begin_envv(args) - args->begin_argv);
355 AUDIT_ARG_ENVV(exec_args_get_begin_envv(args), args->envc,
356 args->endp - exec_args_get_begin_envv(args));
357
358 /* Must have at least one argument. */
359 if (args->argc == 0) {
360 exec_free_args(args);
361 return (EINVAL);
362 }
363 return (do_execve(td, args, mac_p, oldvmspace));
364 }
365
366 static void
execve_nosetid(struct image_params * imgp)367 execve_nosetid(struct image_params *imgp)
368 {
369 imgp->credential_setid = false;
370 if (imgp->newcred != NULL) {
371 crfree(imgp->newcred);
372 imgp->newcred = NULL;
373 }
374 }
375
376 /*
377 * In-kernel implementation of execve(). All arguments are assumed to be
378 * userspace pointers from the passed thread.
379 */
380 static int
do_execve(struct thread * td,struct image_args * args,struct mac * mac_p,struct vmspace * oldvmspace)381 do_execve(struct thread *td, struct image_args *args, struct mac *mac_p,
382 struct vmspace *oldvmspace)
383 {
384 struct proc *p = td->td_proc;
385 struct nameidata nd;
386 struct ucred *oldcred;
387 struct uidinfo *euip = NULL;
388 uintptr_t stack_base;
389 struct image_params image_params, *imgp;
390 struct vattr attr;
391 struct pargs *oldargs = NULL, *newargs = NULL;
392 struct sigacts *oldsigacts = NULL, *newsigacts = NULL;
393 #ifdef KTRACE
394 struct ktr_io_params *kiop;
395 #endif
396 struct vnode *oldtextvp, *newtextvp;
397 struct vnode *oldtextdvp, *newtextdvp;
398 char *oldbinname, *newbinname;
399 bool credential_changing;
400 #ifdef MAC
401 struct label *interpvplabel = NULL;
402 bool will_transition;
403 #endif
404 #ifdef HWPMC_HOOKS
405 struct pmckern_procexec pe;
406 #endif
407 int error, i, orig_osrel;
408 uint32_t orig_fctl0;
409 Elf_Brandinfo *orig_brandinfo;
410 size_t freepath_size;
411 static const char fexecv_proc_title[] = "(fexecv)";
412
413 imgp = &image_params;
414 oldtextvp = oldtextdvp = NULL;
415 newtextvp = newtextdvp = NULL;
416 newbinname = oldbinname = NULL;
417 #ifdef KTRACE
418 kiop = NULL;
419 #endif
420
421 /*
422 * Lock the process and set the P_INEXEC flag to indicate that
423 * it should be left alone until we're done here. This is
424 * necessary to avoid race conditions - e.g. in ptrace() -
425 * that might allow a local user to illicitly obtain elevated
426 * privileges.
427 */
428 PROC_LOCK(p);
429 KASSERT((p->p_flag & P_INEXEC) == 0,
430 ("%s(): process already has P_INEXEC flag", __func__));
431 p->p_flag |= P_INEXEC;
432 PROC_UNLOCK(p);
433
434 /*
435 * Initialize part of the common data
436 */
437 bzero(imgp, sizeof(*imgp));
438 imgp->proc = p;
439 imgp->attr = &attr;
440 imgp->args = args;
441 oldcred = p->p_ucred;
442 orig_osrel = p->p_osrel;
443 orig_fctl0 = p->p_fctl0;
444 orig_brandinfo = p->p_elf_brandinfo;
445
446 #ifdef MAC
447 error = mac_execve_enter(imgp, mac_p);
448 if (error)
449 goto exec_fail;
450 #endif
451
452 SDT_PROBE1(proc, , , exec, args->fname);
453
454 interpret:
455 if (args->fname != NULL) {
456 #ifdef CAPABILITY_MODE
457 if (CAP_TRACING(td))
458 ktrcapfail(CAPFAIL_NAMEI, args->fname);
459 /*
460 * While capability mode can't reach this point via direct
461 * path arguments to execve(), we also don't allow
462 * interpreters to be used in capability mode (for now).
463 * Catch indirect lookups and return a permissions error.
464 */
465 if (IN_CAPABILITY_MODE(td)) {
466 error = ECAPMODE;
467 goto exec_fail;
468 }
469 #endif
470
471 /*
472 * Translate the file name. namei() returns a vnode
473 * pointer in ni_vp among other things.
474 */
475 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW |
476 AUDITVNODE1 | WANTPARENT, UIO_SYSSPACE,
477 args->fname);
478
479 error = namei(&nd);
480 if (error)
481 goto exec_fail;
482
483 newtextvp = nd.ni_vp;
484 newtextdvp = nd.ni_dvp;
485 nd.ni_dvp = NULL;
486 newbinname = malloc(nd.ni_cnd.cn_namelen + 1, M_PARGS,
487 M_WAITOK);
488 memcpy(newbinname, nd.ni_cnd.cn_nameptr, nd.ni_cnd.cn_namelen);
489 newbinname[nd.ni_cnd.cn_namelen] = '\0';
490 imgp->vp = newtextvp;
491
492 /*
493 * Do the best to calculate the full path to the image file.
494 */
495 if (args->fname[0] == '/') {
496 imgp->execpath = args->fname;
497 } else {
498 VOP_UNLOCK(imgp->vp);
499 freepath_size = MAXPATHLEN;
500 if (vn_fullpath_hardlink(newtextvp, newtextdvp,
501 newbinname, nd.ni_cnd.cn_namelen, &imgp->execpath,
502 &imgp->freepath, &freepath_size) != 0)
503 imgp->execpath = args->fname;
504 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
505 }
506 } else if (imgp->interpreter_vp) {
507 /*
508 * An image activator has already provided an open vnode
509 */
510 newtextvp = imgp->interpreter_vp;
511 imgp->interpreter_vp = NULL;
512 if (vn_fullpath(newtextvp, &imgp->execpath,
513 &imgp->freepath) != 0)
514 imgp->execpath = args->fname;
515 vn_lock(newtextvp, LK_SHARED | LK_RETRY);
516 AUDIT_ARG_VNODE1(newtextvp);
517 imgp->vp = newtextvp;
518 } else {
519 AUDIT_ARG_FD(args->fd);
520
521 /*
522 * If the descriptors was not opened with O_PATH, then
523 * we require that it was opened with O_EXEC or
524 * O_RDONLY. In either case, exec_check_permissions()
525 * below checks _current_ file access mode regardless
526 * of the permissions additionally checked at the
527 * open(2).
528 */
529 error = fgetvp_exec(td, args->fd, &cap_fexecve_rights,
530 &newtextvp);
531 if (error != 0)
532 goto exec_fail;
533
534 if (vn_fullpath(newtextvp, &imgp->execpath,
535 &imgp->freepath) != 0)
536 imgp->execpath = args->fname;
537 vn_lock(newtextvp, LK_SHARED | LK_RETRY);
538 AUDIT_ARG_VNODE1(newtextvp);
539 imgp->vp = newtextvp;
540 }
541
542 /*
543 * Check file permissions. Also 'opens' file and sets its vnode to
544 * text mode.
545 */
546 error = exec_check_permissions(imgp);
547 if (error)
548 goto exec_fail_dealloc;
549
550 imgp->object = imgp->vp->v_object;
551 if (imgp->object != NULL)
552 vm_object_reference(imgp->object);
553
554 error = exec_map_first_page(imgp);
555 if (error)
556 goto exec_fail_dealloc;
557
558 imgp->proc->p_osrel = 0;
559 imgp->proc->p_fctl0 = 0;
560 imgp->proc->p_elf_brandinfo = NULL;
561
562 /*
563 * Implement image setuid/setgid.
564 *
565 * Determine new credentials before attempting image activators
566 * so that it can be used by process_exec handlers to determine
567 * credential/setid changes.
568 *
569 * Don't honor setuid/setgid if the filesystem prohibits it or if
570 * the process is being traced.
571 *
572 * We disable setuid/setgid/etc in capability mode on the basis
573 * that most setugid applications are not written with that
574 * environment in mind, and will therefore almost certainly operate
575 * incorrectly. In principle there's no reason that setugid
576 * applications might not be useful in capability mode, so we may want
577 * to reconsider this conservative design choice in the future.
578 *
579 * XXXMAC: For the time being, use NOSUID to also prohibit
580 * transitions on the file system.
581 */
582 credential_changing = false;
583 credential_changing |= (attr.va_mode & S_ISUID) &&
584 oldcred->cr_uid != attr.va_uid;
585 credential_changing |= (attr.va_mode & S_ISGID) &&
586 oldcred->cr_gid != attr.va_gid;
587 #ifdef MAC
588 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
589 interpvplabel, imgp) != 0;
590 credential_changing |= will_transition;
591 #endif
592
593 /* Don't inherit PROC_PDEATHSIG_CTL value if setuid/setgid. */
594 if (credential_changing)
595 imgp->proc->p_pdeathsig = 0;
596
597 if (credential_changing &&
598 #ifdef CAPABILITY_MODE
599 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) &&
600 #endif
601 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
602 (p->p_flag & P_TRACED) == 0) {
603 imgp->credential_setid = true;
604 VOP_UNLOCK(imgp->vp);
605 imgp->newcred = crdup(oldcred);
606 if (attr.va_mode & S_ISUID) {
607 euip = uifind(attr.va_uid);
608 change_euid(imgp->newcred, euip);
609 }
610 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
611 if (attr.va_mode & S_ISGID)
612 change_egid(imgp->newcred, attr.va_gid);
613 /*
614 * Implement correct POSIX saved-id behavior.
615 *
616 * XXXMAC: Note that the current logic will save the
617 * uid and gid if a MAC domain transition occurs, even
618 * though maybe it shouldn't.
619 */
620 change_svuid(imgp->newcred, imgp->newcred->cr_uid);
621 change_svgid(imgp->newcred, imgp->newcred->cr_gid);
622 } else {
623 /*
624 * Implement correct POSIX saved-id behavior.
625 *
626 * XXX: It's not clear that the existing behavior is
627 * POSIX-compliant. A number of sources indicate that the
628 * saved uid/gid should only be updated if the new ruid is
629 * not equal to the old ruid, or the new euid is not equal
630 * to the old euid and the new euid is not equal to the old
631 * ruid. The FreeBSD code always updates the saved uid/gid.
632 * Also, this code uses the new (replaced) euid and egid as
633 * the source, which may or may not be the right ones to use.
634 */
635 if (oldcred->cr_svuid != oldcred->cr_uid ||
636 oldcred->cr_svgid != oldcred->cr_gid) {
637 VOP_UNLOCK(imgp->vp);
638 imgp->newcred = crdup(oldcred);
639 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
640 change_svuid(imgp->newcred, imgp->newcred->cr_uid);
641 change_svgid(imgp->newcred, imgp->newcred->cr_gid);
642 }
643 }
644 /* The new credentials are installed into the process later. */
645
646 /*
647 * Loop through the list of image activators, calling each one.
648 * An activator returns -1 if there is no match, 0 on success,
649 * and an error otherwise.
650 */
651 error = -1;
652 for (i = 0; error == -1 && execsw[i]; ++i) {
653 if (execsw[i]->ex_imgact == NULL)
654 continue;
655 error = (*execsw[i]->ex_imgact)(imgp);
656 }
657
658 if (error) {
659 if (error == -1)
660 error = ENOEXEC;
661 goto exec_fail_dealloc;
662 }
663
664 /*
665 * Special interpreter operation, cleanup and loop up to try to
666 * activate the interpreter.
667 */
668 if (imgp->interpreted) {
669 exec_unmap_first_page(imgp);
670 /*
671 * The text reference needs to be removed for scripts.
672 * There is a short period before we determine that
673 * something is a script where text reference is active.
674 * The vnode lock is held over this entire period
675 * so nothing should illegitimately be blocked.
676 */
677 MPASS(imgp->textset);
678 VOP_UNSET_TEXT_CHECKED(newtextvp);
679 imgp->textset = false;
680 /* free name buffer and old vnode */
681 #ifdef MAC
682 mac_execve_interpreter_enter(newtextvp, &interpvplabel);
683 #endif
684 if (imgp->opened) {
685 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td);
686 imgp->opened = false;
687 }
688 vput(newtextvp);
689 imgp->vp = newtextvp = NULL;
690 if (args->fname != NULL) {
691 if (newtextdvp != NULL) {
692 vrele(newtextdvp);
693 newtextdvp = NULL;
694 }
695 NDFREE_PNBUF(&nd);
696 free(newbinname, M_PARGS);
697 newbinname = NULL;
698 }
699 vm_object_deallocate(imgp->object);
700 imgp->object = NULL;
701 execve_nosetid(imgp);
702 imgp->execpath = NULL;
703 free(imgp->freepath, M_TEMP);
704 imgp->freepath = NULL;
705 /* set new name to that of the interpreter */
706 if (imgp->interpreter_vp) {
707 args->fname = NULL;
708 } else {
709 args->fname = imgp->interpreter_name;
710 }
711 goto interpret;
712 }
713
714 /*
715 * NB: We unlock the vnode here because it is believed that none
716 * of the sv_copyout_strings/sv_fixup operations require the vnode.
717 */
718 VOP_UNLOCK(imgp->vp);
719
720 if (disallow_high_osrel &&
721 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) {
722 error = ENOEXEC;
723 uprintf("Osrel %d for image %s too high\n", p->p_osrel,
724 imgp->execpath != NULL ? imgp->execpath : "<unresolved>");
725 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
726 goto exec_fail_dealloc;
727 }
728
729 /*
730 * Copy out strings (args and env) and initialize stack base.
731 */
732 error = (*p->p_sysent->sv_copyout_strings)(imgp, &stack_base);
733 if (error != 0) {
734 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
735 goto exec_fail_dealloc;
736 }
737
738 /*
739 * Stack setup.
740 */
741 error = (*p->p_sysent->sv_fixup)(&stack_base, imgp);
742 if (error != 0) {
743 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
744 goto exec_fail_dealloc;
745 }
746
747 /*
748 * For security and other reasons, the file descriptor table cannot be
749 * shared after an exec.
750 */
751 fdunshare(td);
752 pdunshare(td);
753 /* close files on exec */
754 fdcloseexec(td);
755
756 /*
757 * Malloc things before we need locks.
758 */
759 i = exec_args_get_begin_envv(imgp->args) - imgp->args->begin_argv;
760 /* Cache arguments if they fit inside our allowance */
761 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
762 newargs = pargs_alloc(i);
763 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
764 }
765
766 /*
767 * For security and other reasons, signal handlers cannot
768 * be shared after an exec. The new process gets a copy of the old
769 * handlers. In execsigs(), the new process will have its signals
770 * reset.
771 */
772 if (sigacts_shared(p->p_sigacts)) {
773 oldsigacts = p->p_sigacts;
774 newsigacts = sigacts_alloc();
775 sigacts_copy(newsigacts, oldsigacts);
776 }
777
778 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
779
780 PROC_LOCK(p);
781 if (oldsigacts)
782 p->p_sigacts = newsigacts;
783 /* Stop profiling */
784 stopprofclock(p);
785
786 /* reset caught signals */
787 execsigs(p);
788
789 /* name this process - nameiexec(p, ndp) */
790 bzero(p->p_comm, sizeof(p->p_comm));
791 if (args->fname)
792 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm,
793 min(nd.ni_cnd.cn_namelen, MAXCOMLEN));
794 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0)
795 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title));
796 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
797 #ifdef KTR
798 sched_clear_tdname(td);
799 #endif
800
801 /*
802 * mark as execed, wakeup the process that vforked (if any) and tell
803 * it that it now has its own resources back
804 */
805 p->p_flag |= P_EXEC;
806 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0)
807 p->p_flag2 &= ~P2_NOTRACE;
808 if ((p->p_flag2 & P2_STKGAP_DISABLE_EXEC) == 0)
809 p->p_flag2 &= ~P2_STKGAP_DISABLE;
810 p->p_flag2 &= ~(P2_MEMBAR_PRIVE | P2_MEMBAR_PRIVE_SYNCORE |
811 P2_MEMBAR_GLOBE);
812 if (p->p_flag & P_PPWAIT) {
813 p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
814 cv_broadcast(&p->p_pwait);
815 /* STOPs are no longer ignored, arrange for AST */
816 signotify(td);
817 }
818
819 if ((imgp->sysent->sv_setid_allowed != NULL &&
820 !(*imgp->sysent->sv_setid_allowed)(td, imgp)) ||
821 (p->p_flag2 & P2_NO_NEW_PRIVS) != 0)
822 execve_nosetid(imgp);
823
824 /*
825 * Implement image setuid/setgid installation.
826 */
827 if (imgp->credential_setid) {
828 /*
829 * Turn off syscall tracing for set-id programs, except for
830 * root. Record any set-id flags first to make sure that
831 * we do not regain any tracing during a possible block.
832 */
833 setsugid(p);
834 #ifdef KTRACE
835 kiop = ktrprocexec(p);
836 #endif
837 /*
838 * Close any file descriptors 0..2 that reference procfs,
839 * then make sure file descriptors 0..2 are in use.
840 *
841 * Both fdsetugidsafety() and fdcheckstd() may call functions
842 * taking sleepable locks, so temporarily drop our locks.
843 */
844 PROC_UNLOCK(p);
845 VOP_UNLOCK(imgp->vp);
846 fdsetugidsafety(td);
847 error = fdcheckstd(td);
848 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
849 if (error != 0)
850 goto exec_fail_dealloc;
851 PROC_LOCK(p);
852 #ifdef MAC
853 if (will_transition) {
854 mac_vnode_execve_transition(oldcred, imgp->newcred,
855 imgp->vp, interpvplabel, imgp);
856 }
857 #endif
858 } else {
859 if (oldcred->cr_uid == oldcred->cr_ruid &&
860 oldcred->cr_gid == oldcred->cr_rgid)
861 p->p_flag &= ~P_SUGID;
862 }
863 /*
864 * Set the new credentials.
865 */
866 if (imgp->newcred != NULL) {
867 proc_set_cred(p, imgp->newcred);
868 crfree(oldcred);
869 oldcred = NULL;
870 }
871
872 /*
873 * Store the vp for use in kern.proc.pathname. This vnode was
874 * referenced by namei() or by fexecve variant of fname handling.
875 */
876 oldtextvp = p->p_textvp;
877 p->p_textvp = newtextvp;
878 oldtextdvp = p->p_textdvp;
879 p->p_textdvp = newtextdvp;
880 newtextdvp = NULL;
881 oldbinname = p->p_binname;
882 p->p_binname = newbinname;
883 newbinname = NULL;
884
885 #ifdef KDTRACE_HOOKS
886 /*
887 * Tell the DTrace fasttrap provider about the exec if it
888 * has declared an interest.
889 */
890 if (dtrace_fasttrap_exec)
891 dtrace_fasttrap_exec(p);
892 #endif
893
894 /*
895 * Notify others that we exec'd, and clear the P_INEXEC flag
896 * as we're now a bona fide freshly-execed process.
897 */
898 KNOTE_LOCKED(p->p_klist, NOTE_EXEC);
899 p->p_flag &= ~P_INEXEC;
900
901 /* clear "fork but no exec" flag, as we _are_ execing */
902 p->p_acflag &= ~AFORK;
903
904 /*
905 * Free any previous argument cache and replace it with
906 * the new argument cache, if any.
907 */
908 oldargs = p->p_args;
909 p->p_args = newargs;
910 newargs = NULL;
911
912 PROC_UNLOCK(p);
913
914 #ifdef HWPMC_HOOKS
915 /*
916 * Check if system-wide sampling is in effect or if the
917 * current process is using PMCs. If so, do exec() time
918 * processing. This processing needs to happen AFTER the
919 * P_INEXEC flag is cleared.
920 */
921 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
922 VOP_UNLOCK(imgp->vp);
923 pe.pm_credentialschanged = credential_changing;
924 pe.pm_baseaddr = imgp->reloc_base;
925 pe.pm_dynaddr = imgp->et_dyn_addr;
926
927 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
928 vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
929 }
930 #endif
931
932 /* Set values passed into the program in registers. */
933 (*p->p_sysent->sv_setregs)(td, imgp, stack_base);
934
935 VOP_MMAPPED(imgp->vp);
936
937 SDT_PROBE1(proc, , , exec__success, args->fname);
938
939 exec_fail_dealloc:
940 if (error != 0) {
941 p->p_osrel = orig_osrel;
942 p->p_fctl0 = orig_fctl0;
943 p->p_elf_brandinfo = orig_brandinfo;
944 }
945
946 if (imgp->firstpage != NULL)
947 exec_unmap_first_page(imgp);
948
949 if (imgp->vp != NULL) {
950 if (imgp->opened)
951 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
952 if (imgp->textset)
953 VOP_UNSET_TEXT_CHECKED(imgp->vp);
954 if (error != 0)
955 vput(imgp->vp);
956 else
957 VOP_UNLOCK(imgp->vp);
958 if (args->fname != NULL)
959 NDFREE_PNBUF(&nd);
960 if (newtextdvp != NULL)
961 vrele(newtextdvp);
962 free(newbinname, M_PARGS);
963 }
964
965 if (imgp->object != NULL)
966 vm_object_deallocate(imgp->object);
967
968 free(imgp->freepath, M_TEMP);
969
970 if (error == 0) {
971 if (p->p_ptevents & PTRACE_EXEC) {
972 PROC_LOCK(p);
973 if (p->p_ptevents & PTRACE_EXEC)
974 td->td_dbgflags |= TDB_EXEC;
975 PROC_UNLOCK(p);
976 }
977 } else {
978 exec_fail:
979 /* we're done here, clear P_INEXEC */
980 PROC_LOCK(p);
981 p->p_flag &= ~P_INEXEC;
982 PROC_UNLOCK(p);
983
984 SDT_PROBE1(proc, , , exec__failure, error);
985 }
986
987 if (imgp->newcred != NULL && oldcred != NULL)
988 crfree(imgp->newcred);
989
990 #ifdef MAC
991 mac_execve_exit(imgp);
992 mac_execve_interpreter_exit(interpvplabel);
993 #endif
994 exec_free_args(args);
995
996 /*
997 * Handle deferred decrement of ref counts.
998 */
999 if (oldtextvp != NULL)
1000 vrele(oldtextvp);
1001 if (oldtextdvp != NULL)
1002 vrele(oldtextdvp);
1003 free(oldbinname, M_PARGS);
1004 #ifdef KTRACE
1005 ktr_io_params_free(kiop);
1006 #endif
1007 pargs_drop(oldargs);
1008 pargs_drop(newargs);
1009 if (oldsigacts != NULL)
1010 sigacts_free(oldsigacts);
1011 if (euip != NULL)
1012 uifree(euip);
1013
1014 if (error && imgp->vmspace_destroyed) {
1015 /* sorry, no more process anymore. exit gracefully */
1016 exec_cleanup(td, oldvmspace);
1017 exit1(td, 0, SIGABRT);
1018 /* NOT REACHED */
1019 }
1020
1021 #ifdef KTRACE
1022 if (error == 0)
1023 ktrprocctor(p);
1024 #endif
1025
1026 /*
1027 * We don't want cpu_set_syscall_retval() to overwrite any of
1028 * the register values put in place by exec_setregs().
1029 * Implementations of cpu_set_syscall_retval() will leave
1030 * registers unmodified when returning EJUSTRETURN.
1031 */
1032 return (error == 0 ? EJUSTRETURN : error);
1033 }
1034
1035 void
exec_cleanup(struct thread * td,struct vmspace * oldvmspace)1036 exec_cleanup(struct thread *td, struct vmspace *oldvmspace)
1037 {
1038 if ((td->td_pflags & TDP_EXECVMSPC) != 0) {
1039 KASSERT(td->td_proc->p_vmspace != oldvmspace,
1040 ("oldvmspace still used"));
1041 vmspace_free(oldvmspace);
1042 td->td_pflags &= ~TDP_EXECVMSPC;
1043 }
1044 }
1045
1046 int
exec_map_first_page(struct image_params * imgp)1047 exec_map_first_page(struct image_params *imgp)
1048 {
1049 vm_object_t object;
1050 vm_page_t m;
1051 int error;
1052
1053 if (imgp->firstpage != NULL)
1054 exec_unmap_first_page(imgp);
1055
1056 object = imgp->vp->v_object;
1057 if (object == NULL)
1058 return (EACCES);
1059 #if VM_NRESERVLEVEL > 0
1060 if ((object->flags & OBJ_COLORED) == 0) {
1061 VM_OBJECT_WLOCK(object);
1062 vm_object_color(object, 0);
1063 VM_OBJECT_WUNLOCK(object);
1064 }
1065 #endif
1066 error = vm_page_grab_valid_unlocked(&m, object, 0,
1067 VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) |
1068 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
1069
1070 if (error != VM_PAGER_OK)
1071 return (EIO);
1072 imgp->firstpage = sf_buf_alloc(m, 0);
1073 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
1074
1075 return (0);
1076 }
1077
1078 void
exec_unmap_first_page(struct image_params * imgp)1079 exec_unmap_first_page(struct image_params *imgp)
1080 {
1081 vm_page_t m;
1082
1083 if (imgp->firstpage != NULL) {
1084 m = sf_buf_page(imgp->firstpage);
1085 sf_buf_free(imgp->firstpage);
1086 imgp->firstpage = NULL;
1087 vm_page_unwire(m, PQ_ACTIVE);
1088 }
1089 }
1090
1091 void
exec_onexec_old(struct thread * td)1092 exec_onexec_old(struct thread *td)
1093 {
1094 sigfastblock_clear(td);
1095 umtx_exec(td->td_proc);
1096 }
1097
1098 /*
1099 * This is an optimization which removes the unmanaged shared page
1100 * mapping. In combination with pmap_remove_pages(), which cleans all
1101 * managed mappings in the process' vmspace pmap, no work will be left
1102 * for pmap_remove(min, max).
1103 */
1104 void
exec_free_abi_mappings(struct proc * p)1105 exec_free_abi_mappings(struct proc *p)
1106 {
1107 struct vmspace *vmspace;
1108
1109 vmspace = p->p_vmspace;
1110 if (refcount_load(&vmspace->vm_refcnt) != 1)
1111 return;
1112
1113 if (!PROC_HAS_SHP(p))
1114 return;
1115
1116 pmap_remove(vmspace_pmap(vmspace), vmspace->vm_shp_base,
1117 vmspace->vm_shp_base + p->p_sysent->sv_shared_page_len);
1118 }
1119
1120 /*
1121 * Run down the current address space and install a new one.
1122 */
1123 int
exec_new_vmspace(struct image_params * imgp,struct sysentvec * sv)1124 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv)
1125 {
1126 int error;
1127 struct proc *p = imgp->proc;
1128 struct vmspace *vmspace = p->p_vmspace;
1129 struct thread *td = curthread;
1130 vm_offset_t sv_minuser;
1131 vm_map_t map;
1132
1133 imgp->vmspace_destroyed = true;
1134 imgp->sysent = sv;
1135
1136 if (p->p_sysent->sv_onexec_old != NULL)
1137 p->p_sysent->sv_onexec_old(td);
1138 itimers_exec(p);
1139
1140 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp);
1141
1142 /*
1143 * Blow away entire process VM, if address space not shared,
1144 * otherwise, create a new VM space so that other threads are
1145 * not disrupted
1146 */
1147 map = &vmspace->vm_map;
1148 if (map_at_zero)
1149 sv_minuser = sv->sv_minuser;
1150 else
1151 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1152 if (refcount_load(&vmspace->vm_refcnt) == 1 &&
1153 vm_map_min(map) == sv_minuser &&
1154 vm_map_max(map) == sv->sv_maxuser &&
1155 cpu_exec_vmspace_reuse(p, map)) {
1156 exec_free_abi_mappings(p);
1157 shmexit(vmspace);
1158 pmap_remove_pages(vmspace_pmap(vmspace));
1159 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1160 /*
1161 * An exec terminates mlockall(MCL_FUTURE).
1162 * ASLR and W^X states must be re-evaluated.
1163 */
1164 vm_map_lock(map);
1165 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR |
1166 MAP_ASLR_IGNSTART | MAP_ASLR_STACK | MAP_WXORX);
1167 vm_map_unlock(map);
1168 } else {
1169 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1170 if (error)
1171 return (error);
1172 vmspace = p->p_vmspace;
1173 map = &vmspace->vm_map;
1174 }
1175 map->flags |= imgp->map_flags;
1176
1177 return (sv->sv_onexec != NULL ? sv->sv_onexec(p, imgp) : 0);
1178 }
1179
1180 /*
1181 * Compute the stack size limit and map the main process stack.
1182 * Map the shared page.
1183 */
1184 int
exec_map_stack(struct image_params * imgp)1185 exec_map_stack(struct image_params *imgp)
1186 {
1187 struct rlimit rlim_stack;
1188 struct sysentvec *sv;
1189 struct proc *p;
1190 vm_map_t map;
1191 struct vmspace *vmspace;
1192 vm_offset_t stack_addr, stack_top;
1193 vm_offset_t sharedpage_addr;
1194 u_long ssiz;
1195 int error, find_space, stack_off;
1196 vm_prot_t stack_prot;
1197 vm_object_t obj;
1198
1199 p = imgp->proc;
1200 sv = p->p_sysent;
1201
1202 if (imgp->stack_sz != 0) {
1203 ssiz = trunc_page(imgp->stack_sz);
1204 PROC_LOCK(p);
1205 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack);
1206 PROC_UNLOCK(p);
1207 if (ssiz > rlim_stack.rlim_max)
1208 ssiz = rlim_stack.rlim_max;
1209 if (ssiz > rlim_stack.rlim_cur) {
1210 rlim_stack.rlim_cur = ssiz;
1211 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack);
1212 }
1213 } else if (sv->sv_maxssiz != NULL) {
1214 ssiz = *sv->sv_maxssiz;
1215 } else {
1216 ssiz = maxssiz;
1217 }
1218
1219 vmspace = p->p_vmspace;
1220 map = &vmspace->vm_map;
1221
1222 stack_prot = sv->sv_shared_page_obj != NULL && imgp->stack_prot != 0 ?
1223 imgp->stack_prot : sv->sv_stackprot;
1224 if ((map->flags & MAP_ASLR_STACK) != 0) {
1225 stack_addr = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
1226 lim_max(curthread, RLIMIT_DATA));
1227 find_space = VMFS_ANY_SPACE;
1228 } else {
1229 stack_addr = sv->sv_usrstack - ssiz;
1230 find_space = VMFS_NO_SPACE;
1231 }
1232 error = vm_map_find(map, NULL, 0, &stack_addr, (vm_size_t)ssiz,
1233 sv->sv_usrstack, find_space, stack_prot, VM_PROT_ALL,
1234 MAP_STACK_GROWS_DOWN);
1235 if (error != KERN_SUCCESS) {
1236 uprintf("exec_new_vmspace: mapping stack size %#jx prot %#x "
1237 "failed, mach error %d errno %d\n", (uintmax_t)ssiz,
1238 stack_prot, error, vm_mmap_to_errno(error));
1239 return (vm_mmap_to_errno(error));
1240 }
1241
1242 stack_top = stack_addr + ssiz;
1243 if ((map->flags & MAP_ASLR_STACK) != 0) {
1244 /* Randomize within the first page of the stack. */
1245 arc4rand(&stack_off, sizeof(stack_off), 0);
1246 stack_top -= rounddown2(stack_off & PAGE_MASK, sizeof(void *));
1247 }
1248
1249 /* Map a shared page */
1250 obj = sv->sv_shared_page_obj;
1251 if (obj == NULL) {
1252 sharedpage_addr = 0;
1253 goto out;
1254 }
1255
1256 /*
1257 * If randomization is disabled then the shared page will
1258 * be mapped at address specified in sysentvec.
1259 * Otherwise any address above .data section can be selected.
1260 * Same logic is used for stack address randomization.
1261 * If the address randomization is applied map a guard page
1262 * at the top of UVA.
1263 */
1264 vm_object_reference(obj);
1265 if ((imgp->imgp_flags & IMGP_ASLR_SHARED_PAGE) != 0) {
1266 sharedpage_addr = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
1267 lim_max(curthread, RLIMIT_DATA));
1268
1269 error = vm_map_fixed(map, NULL, 0,
1270 sv->sv_maxuser - PAGE_SIZE, PAGE_SIZE,
1271 VM_PROT_NONE, VM_PROT_NONE, MAP_CREATE_GUARD);
1272 if (error != KERN_SUCCESS) {
1273 /*
1274 * This is not fatal, so let's just print a warning
1275 * and continue.
1276 */
1277 uprintf("%s: Mapping guard page at the top of UVA failed"
1278 " mach error %d errno %d",
1279 __func__, error, vm_mmap_to_errno(error));
1280 }
1281
1282 error = vm_map_find(map, obj, 0,
1283 &sharedpage_addr, sv->sv_shared_page_len,
1284 sv->sv_maxuser, VMFS_ANY_SPACE,
1285 VM_PROT_READ | VM_PROT_EXECUTE,
1286 VM_PROT_READ | VM_PROT_EXECUTE,
1287 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1288 } else {
1289 sharedpage_addr = sv->sv_shared_page_base;
1290 vm_map_fixed(map, obj, 0,
1291 sharedpage_addr, sv->sv_shared_page_len,
1292 VM_PROT_READ | VM_PROT_EXECUTE,
1293 VM_PROT_READ | VM_PROT_EXECUTE,
1294 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE);
1295 }
1296 if (error != KERN_SUCCESS) {
1297 uprintf("%s: mapping shared page at addr: %p"
1298 "failed, mach error %d errno %d\n", __func__,
1299 (void *)sharedpage_addr, error, vm_mmap_to_errno(error));
1300 vm_object_deallocate(obj);
1301 return (vm_mmap_to_errno(error));
1302 }
1303 out:
1304 /*
1305 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they
1306 * are still used to enforce the stack rlimit on the process stack.
1307 */
1308 vmspace->vm_maxsaddr = (char *)stack_addr;
1309 vmspace->vm_stacktop = stack_top;
1310 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1311 vmspace->vm_shp_base = sharedpage_addr;
1312
1313 return (0);
1314 }
1315
1316 /*
1317 * Copy out argument and environment strings from the old process address
1318 * space into the temporary string buffer.
1319 */
1320 int
exec_copyin_args(struct image_args * args,const char * fname,enum uio_seg segflg,char ** argv,char ** envv)1321 exec_copyin_args(struct image_args *args, const char *fname,
1322 enum uio_seg segflg, char **argv, char **envv)
1323 {
1324 u_long arg, env;
1325 int error;
1326
1327 bzero(args, sizeof(*args));
1328 if (argv == NULL)
1329 return (EFAULT);
1330
1331 /*
1332 * Allocate demand-paged memory for the file name, argument, and
1333 * environment strings.
1334 */
1335 error = exec_alloc_args(args);
1336 if (error != 0)
1337 return (error);
1338
1339 /*
1340 * Copy the file name.
1341 */
1342 error = exec_args_add_fname(args, fname, segflg);
1343 if (error != 0)
1344 goto err_exit;
1345
1346 /*
1347 * extract arguments first
1348 */
1349 for (;;) {
1350 error = fueword(argv++, &arg);
1351 if (error == -1) {
1352 error = EFAULT;
1353 goto err_exit;
1354 }
1355 if (arg == 0)
1356 break;
1357 error = exec_args_add_arg(args, (char *)(uintptr_t)arg,
1358 UIO_USERSPACE);
1359 if (error != 0)
1360 goto err_exit;
1361 }
1362
1363 /*
1364 * extract environment strings
1365 */
1366 if (envv) {
1367 for (;;) {
1368 error = fueword(envv++, &env);
1369 if (error == -1) {
1370 error = EFAULT;
1371 goto err_exit;
1372 }
1373 if (env == 0)
1374 break;
1375 error = exec_args_add_env(args,
1376 (char *)(uintptr_t)env, UIO_USERSPACE);
1377 if (error != 0)
1378 goto err_exit;
1379 }
1380 }
1381
1382 return (0);
1383
1384 err_exit:
1385 exec_free_args(args);
1386 return (error);
1387 }
1388
1389 struct exec_args_kva {
1390 vm_offset_t addr;
1391 u_int gen;
1392 SLIST_ENTRY(exec_args_kva) next;
1393 };
1394
1395 DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva);
1396
1397 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist;
1398 static struct mtx exec_args_kva_mtx;
1399 static u_int exec_args_gen;
1400
1401 static void
exec_prealloc_args_kva(void * arg __unused)1402 exec_prealloc_args_kva(void *arg __unused)
1403 {
1404 struct exec_args_kva *argkva;
1405 u_int i;
1406
1407 SLIST_INIT(&exec_args_kva_freelist);
1408 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF);
1409 for (i = 0; i < exec_map_entries; i++) {
1410 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK);
1411 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size);
1412 argkva->gen = exec_args_gen;
1413 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next);
1414 }
1415 }
1416 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL);
1417
1418 static vm_offset_t
exec_alloc_args_kva(void ** cookie)1419 exec_alloc_args_kva(void **cookie)
1420 {
1421 struct exec_args_kva *argkva;
1422
1423 argkva = (void *)atomic_readandclear_ptr(
1424 (uintptr_t *)DPCPU_PTR(exec_args_kva));
1425 if (argkva == NULL) {
1426 mtx_lock(&exec_args_kva_mtx);
1427 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL)
1428 (void)mtx_sleep(&exec_args_kva_freelist,
1429 &exec_args_kva_mtx, 0, "execkva", 0);
1430 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next);
1431 mtx_unlock(&exec_args_kva_mtx);
1432 }
1433 kasan_mark((void *)argkva->addr, exec_map_entry_size,
1434 exec_map_entry_size, 0);
1435 *(struct exec_args_kva **)cookie = argkva;
1436 return (argkva->addr);
1437 }
1438
1439 static void
exec_release_args_kva(struct exec_args_kva * argkva,u_int gen)1440 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen)
1441 {
1442 vm_offset_t base;
1443
1444 base = argkva->addr;
1445 kasan_mark((void *)argkva->addr, 0, exec_map_entry_size,
1446 KASAN_EXEC_ARGS_FREED);
1447 if (argkva->gen != gen) {
1448 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size,
1449 MADV_FREE);
1450 argkva->gen = gen;
1451 }
1452 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva),
1453 (uintptr_t)NULL, (uintptr_t)argkva)) {
1454 mtx_lock(&exec_args_kva_mtx);
1455 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next);
1456 wakeup_one(&exec_args_kva_freelist);
1457 mtx_unlock(&exec_args_kva_mtx);
1458 }
1459 }
1460
1461 static void
exec_free_args_kva(void * cookie)1462 exec_free_args_kva(void *cookie)
1463 {
1464
1465 exec_release_args_kva(cookie, exec_args_gen);
1466 }
1467
1468 static void
exec_args_kva_lowmem(void * arg __unused)1469 exec_args_kva_lowmem(void *arg __unused)
1470 {
1471 SLIST_HEAD(, exec_args_kva) head;
1472 struct exec_args_kva *argkva;
1473 u_int gen;
1474 int i;
1475
1476 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1;
1477
1478 /*
1479 * Force an madvise of each KVA range. Any currently allocated ranges
1480 * will have MADV_FREE applied once they are freed.
1481 */
1482 SLIST_INIT(&head);
1483 mtx_lock(&exec_args_kva_mtx);
1484 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva);
1485 mtx_unlock(&exec_args_kva_mtx);
1486 while ((argkva = SLIST_FIRST(&head)) != NULL) {
1487 SLIST_REMOVE_HEAD(&head, next);
1488 exec_release_args_kva(argkva, gen);
1489 }
1490
1491 CPU_FOREACH(i) {
1492 argkva = (void *)atomic_readandclear_ptr(
1493 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva));
1494 if (argkva != NULL)
1495 exec_release_args_kva(argkva, gen);
1496 }
1497 }
1498 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL,
1499 EVENTHANDLER_PRI_ANY);
1500
1501 /*
1502 * Allocate temporary demand-paged, zero-filled memory for the file name,
1503 * argument, and environment strings.
1504 */
1505 int
exec_alloc_args(struct image_args * args)1506 exec_alloc_args(struct image_args *args)
1507 {
1508
1509 args->buf = (char *)exec_alloc_args_kva(&args->bufkva);
1510 return (0);
1511 }
1512
1513 void
exec_free_args(struct image_args * args)1514 exec_free_args(struct image_args *args)
1515 {
1516
1517 if (args->buf != NULL) {
1518 exec_free_args_kva(args->bufkva);
1519 args->buf = NULL;
1520 }
1521 if (args->fname_buf != NULL) {
1522 free(args->fname_buf, M_TEMP);
1523 args->fname_buf = NULL;
1524 }
1525 }
1526
1527 /*
1528 * A set to functions to fill struct image args.
1529 *
1530 * NOTE: exec_args_add_fname() must be called (possibly with a NULL
1531 * fname) before the other functions. All exec_args_add_arg() calls must
1532 * be made before any exec_args_add_env() calls. exec_args_adjust_args()
1533 * may be called any time after exec_args_add_fname().
1534 *
1535 * exec_args_add_fname() - install path to be executed
1536 * exec_args_add_arg() - append an argument string
1537 * exec_args_add_env() - append an env string
1538 * exec_args_adjust_args() - adjust location of the argument list to
1539 * allow new arguments to be prepended
1540 */
1541 int
exec_args_add_fname(struct image_args * args,const char * fname,enum uio_seg segflg)1542 exec_args_add_fname(struct image_args *args, const char *fname,
1543 enum uio_seg segflg)
1544 {
1545 int error;
1546 size_t length;
1547
1548 KASSERT(args->fname == NULL, ("fname already appended"));
1549 KASSERT(args->endp == NULL, ("already appending to args"));
1550
1551 if (fname != NULL) {
1552 args->fname = args->buf;
1553 error = segflg == UIO_SYSSPACE ?
1554 copystr(fname, args->fname, PATH_MAX, &length) :
1555 copyinstr(fname, args->fname, PATH_MAX, &length);
1556 if (error != 0)
1557 return (error == ENAMETOOLONG ? E2BIG : error);
1558 } else
1559 length = 0;
1560
1561 /* Set up for _arg_*()/_env_*() */
1562 args->endp = args->buf + length;
1563 /* begin_argv must be set and kept updated */
1564 args->begin_argv = args->endp;
1565 KASSERT(exec_map_entry_size - length >= ARG_MAX,
1566 ("too little space remaining for arguments %zu < %zu",
1567 exec_map_entry_size - length, (size_t)ARG_MAX));
1568 args->stringspace = ARG_MAX;
1569
1570 return (0);
1571 }
1572
1573 static int
exec_args_add_str(struct image_args * args,const char * str,enum uio_seg segflg,int * countp)1574 exec_args_add_str(struct image_args *args, const char *str,
1575 enum uio_seg segflg, int *countp)
1576 {
1577 int error;
1578 size_t length;
1579
1580 KASSERT(args->endp != NULL, ("endp not initialized"));
1581 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized"));
1582
1583 error = (segflg == UIO_SYSSPACE) ?
1584 copystr(str, args->endp, args->stringspace, &length) :
1585 copyinstr(str, args->endp, args->stringspace, &length);
1586 if (error != 0)
1587 return (error == ENAMETOOLONG ? E2BIG : error);
1588 args->stringspace -= length;
1589 args->endp += length;
1590 (*countp)++;
1591
1592 return (0);
1593 }
1594
1595 int
exec_args_add_arg(struct image_args * args,const char * argp,enum uio_seg segflg)1596 exec_args_add_arg(struct image_args *args, const char *argp,
1597 enum uio_seg segflg)
1598 {
1599
1600 KASSERT(args->envc == 0, ("appending args after env"));
1601
1602 return (exec_args_add_str(args, argp, segflg, &args->argc));
1603 }
1604
1605 int
exec_args_add_env(struct image_args * args,const char * envp,enum uio_seg segflg)1606 exec_args_add_env(struct image_args *args, const char *envp,
1607 enum uio_seg segflg)
1608 {
1609
1610 if (args->envc == 0)
1611 args->begin_envv = args->endp;
1612
1613 return (exec_args_add_str(args, envp, segflg, &args->envc));
1614 }
1615
1616 int
exec_args_adjust_args(struct image_args * args,size_t consume,ssize_t extend)1617 exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend)
1618 {
1619 ssize_t offset;
1620
1621 KASSERT(args->endp != NULL, ("endp not initialized"));
1622 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized"));
1623
1624 offset = extend - consume;
1625 if (args->stringspace < offset)
1626 return (E2BIG);
1627 memmove(args->begin_argv + extend, args->begin_argv + consume,
1628 args->endp - args->begin_argv + consume);
1629 if (args->envc > 0)
1630 args->begin_envv += offset;
1631 args->endp += offset;
1632 args->stringspace -= offset;
1633 return (0);
1634 }
1635
1636 char *
exec_args_get_begin_envv(struct image_args * args)1637 exec_args_get_begin_envv(struct image_args *args)
1638 {
1639
1640 KASSERT(args->endp != NULL, ("endp not initialized"));
1641
1642 if (args->envc > 0)
1643 return (args->begin_envv);
1644 return (args->endp);
1645 }
1646
1647 /*
1648 * Copy strings out to the new process address space, constructing new arg
1649 * and env vector tables. Return a pointer to the base so that it can be used
1650 * as the initial stack pointer.
1651 */
1652 int
exec_copyout_strings(struct image_params * imgp,uintptr_t * stack_base)1653 exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
1654 {
1655 int argc, envc;
1656 char **vectp;
1657 char *stringp;
1658 uintptr_t destp, ustringp;
1659 struct ps_strings *arginfo;
1660 struct proc *p;
1661 struct sysentvec *sysent;
1662 size_t execpath_len;
1663 int error, szsigcode;
1664 char canary[sizeof(long) * 8];
1665
1666 p = imgp->proc;
1667 sysent = p->p_sysent;
1668
1669 destp = PROC_PS_STRINGS(p);
1670 arginfo = imgp->ps_strings = (void *)destp;
1671
1672 /*
1673 * Install sigcode.
1674 */
1675 if (sysent->sv_shared_page_base == 0 && sysent->sv_szsigcode != NULL) {
1676 szsigcode = *(sysent->sv_szsigcode);
1677 destp -= szsigcode;
1678 destp = rounddown2(destp, sizeof(void *));
1679 error = copyout(sysent->sv_sigcode, (void *)destp, szsigcode);
1680 if (error != 0)
1681 return (error);
1682 }
1683
1684 /*
1685 * Copy the image path for the rtld.
1686 */
1687 if (imgp->execpath != NULL && imgp->auxargs != NULL) {
1688 execpath_len = strlen(imgp->execpath) + 1;
1689 destp -= execpath_len;
1690 destp = rounddown2(destp, sizeof(void *));
1691 imgp->execpathp = (void *)destp;
1692 error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
1693 if (error != 0)
1694 return (error);
1695 }
1696
1697 /*
1698 * Prepare the canary for SSP.
1699 */
1700 arc4rand(canary, sizeof(canary), 0);
1701 destp -= sizeof(canary);
1702 imgp->canary = (void *)destp;
1703 error = copyout(canary, imgp->canary, sizeof(canary));
1704 if (error != 0)
1705 return (error);
1706 imgp->canarylen = sizeof(canary);
1707
1708 /*
1709 * Prepare the pagesizes array.
1710 */
1711 imgp->pagesizeslen = sizeof(pagesizes[0]) * MAXPAGESIZES;
1712 destp -= imgp->pagesizeslen;
1713 destp = rounddown2(destp, sizeof(void *));
1714 imgp->pagesizes = (void *)destp;
1715 error = copyout(pagesizes, imgp->pagesizes, imgp->pagesizeslen);
1716 if (error != 0)
1717 return (error);
1718
1719 /*
1720 * Allocate room for the argument and environment strings.
1721 */
1722 destp -= ARG_MAX - imgp->args->stringspace;
1723 destp = rounddown2(destp, sizeof(void *));
1724 ustringp = destp;
1725
1726 if (imgp->auxargs) {
1727 /*
1728 * Allocate room on the stack for the ELF auxargs
1729 * array. It has up to AT_COUNT entries.
1730 */
1731 destp -= AT_COUNT * sizeof(Elf_Auxinfo);
1732 destp = rounddown2(destp, sizeof(void *));
1733 }
1734
1735 vectp = (char **)destp;
1736
1737 /*
1738 * Allocate room for the argv[] and env vectors including the
1739 * terminating NULL pointers.
1740 */
1741 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
1742
1743 /*
1744 * vectp also becomes our initial stack base
1745 */
1746 *stack_base = (uintptr_t)vectp;
1747
1748 stringp = imgp->args->begin_argv;
1749 argc = imgp->args->argc;
1750 envc = imgp->args->envc;
1751
1752 /*
1753 * Copy out strings - arguments and environment.
1754 */
1755 error = copyout(stringp, (void *)ustringp,
1756 ARG_MAX - imgp->args->stringspace);
1757 if (error != 0)
1758 return (error);
1759
1760 /*
1761 * Fill in "ps_strings" struct for ps, w, etc.
1762 */
1763 imgp->argv = vectp;
1764 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 ||
1765 suword32(&arginfo->ps_nargvstr, argc) != 0)
1766 return (EFAULT);
1767
1768 /*
1769 * Fill in argument portion of vector table.
1770 */
1771 for (; argc > 0; --argc) {
1772 if (suword(vectp++, ustringp) != 0)
1773 return (EFAULT);
1774 while (*stringp++ != 0)
1775 ustringp++;
1776 ustringp++;
1777 }
1778
1779 /* a null vector table pointer separates the argp's from the envp's */
1780 if (suword(vectp++, 0) != 0)
1781 return (EFAULT);
1782
1783 imgp->envv = vectp;
1784 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 ||
1785 suword32(&arginfo->ps_nenvstr, envc) != 0)
1786 return (EFAULT);
1787
1788 /*
1789 * Fill in environment portion of vector table.
1790 */
1791 for (; envc > 0; --envc) {
1792 if (suword(vectp++, ustringp) != 0)
1793 return (EFAULT);
1794 while (*stringp++ != 0)
1795 ustringp++;
1796 ustringp++;
1797 }
1798
1799 /* end of vector table is a null pointer */
1800 if (suword(vectp, 0) != 0)
1801 return (EFAULT);
1802
1803 if (imgp->auxargs) {
1804 vectp++;
1805 error = imgp->sysent->sv_copyout_auxargs(imgp,
1806 (uintptr_t)vectp);
1807 if (error != 0)
1808 return (error);
1809 }
1810
1811 return (0);
1812 }
1813
1814 /*
1815 * Check permissions of file to execute.
1816 * Called with imgp->vp locked.
1817 * Return 0 for success or error code on failure.
1818 */
1819 int
exec_check_permissions(struct image_params * imgp)1820 exec_check_permissions(struct image_params *imgp)
1821 {
1822 struct vnode *vp = imgp->vp;
1823 struct vattr *attr = imgp->attr;
1824 struct thread *td;
1825 int error;
1826
1827 td = curthread;
1828
1829 /* Get file attributes */
1830 error = VOP_GETATTR(vp, attr, td->td_ucred);
1831 if (error)
1832 return (error);
1833
1834 #ifdef MAC
1835 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1836 if (error)
1837 return (error);
1838 #endif
1839
1840 /*
1841 * 1) Check if file execution is disabled for the filesystem that
1842 * this file resides on.
1843 * 2) Ensure that at least one execute bit is on. Otherwise, a
1844 * privileged user will always succeed, and we don't want this
1845 * to happen unless the file really is executable.
1846 * 3) Ensure that the file is a regular file.
1847 */
1848 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1849 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 ||
1850 (attr->va_type != VREG))
1851 return (EACCES);
1852
1853 /*
1854 * Zero length files can't be exec'd
1855 */
1856 if (attr->va_size == 0)
1857 return (ENOEXEC);
1858
1859 /*
1860 * Check for execute permission to file based on current credentials.
1861 */
1862 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1863 if (error)
1864 return (error);
1865
1866 /*
1867 * Check number of open-for-writes on the file and deny execution
1868 * if there are any.
1869 *
1870 * Add a text reference now so no one can write to the
1871 * executable while we're activating it.
1872 *
1873 * Remember if this was set before and unset it in case this is not
1874 * actually an executable image.
1875 */
1876 error = VOP_SET_TEXT(vp);
1877 if (error != 0)
1878 return (error);
1879 imgp->textset = true;
1880
1881 /*
1882 * Call filesystem specific open routine (which does nothing in the
1883 * general case).
1884 */
1885 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1886 if (error == 0)
1887 imgp->opened = true;
1888 return (error);
1889 }
1890
1891 /*
1892 * Exec handler registration
1893 */
1894 int
exec_register(const struct execsw * execsw_arg)1895 exec_register(const struct execsw *execsw_arg)
1896 {
1897 const struct execsw **es, **xs, **newexecsw;
1898 u_int count = 2; /* New slot and trailing NULL */
1899
1900 if (execsw)
1901 for (es = execsw; *es; es++)
1902 count++;
1903 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1904 xs = newexecsw;
1905 if (execsw)
1906 for (es = execsw; *es; es++)
1907 *xs++ = *es;
1908 *xs++ = execsw_arg;
1909 *xs = NULL;
1910 if (execsw)
1911 free(execsw, M_TEMP);
1912 execsw = newexecsw;
1913 return (0);
1914 }
1915
1916 int
exec_unregister(const struct execsw * execsw_arg)1917 exec_unregister(const struct execsw *execsw_arg)
1918 {
1919 const struct execsw **es, **xs, **newexecsw;
1920 int count = 1;
1921
1922 if (execsw == NULL)
1923 panic("unregister with no handlers left?\n");
1924
1925 for (es = execsw; *es; es++) {
1926 if (*es == execsw_arg)
1927 break;
1928 }
1929 if (*es == NULL)
1930 return (ENOENT);
1931 for (es = execsw; *es; es++)
1932 if (*es != execsw_arg)
1933 count++;
1934 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1935 xs = newexecsw;
1936 for (es = execsw; *es; es++)
1937 if (*es != execsw_arg)
1938 *xs++ = *es;
1939 *xs = NULL;
1940 if (execsw)
1941 free(execsw, M_TEMP);
1942 execsw = newexecsw;
1943 return (0);
1944 }
1945
1946 /*
1947 * Write out a core segment to the compression stream.
1948 */
1949 static int
compress_chunk(struct coredump_params * cp,char * base,char * buf,size_t len)1950 compress_chunk(struct coredump_params *cp, char *base, char *buf, size_t len)
1951 {
1952 size_t chunk_len;
1953 int error;
1954
1955 while (len > 0) {
1956 chunk_len = MIN(len, CORE_BUF_SIZE);
1957
1958 /*
1959 * We can get EFAULT error here.
1960 * In that case zero out the current chunk of the segment.
1961 */
1962 error = copyin(base, buf, chunk_len);
1963 if (error != 0)
1964 bzero(buf, chunk_len);
1965 error = compressor_write(cp->comp, buf, chunk_len);
1966 if (error != 0)
1967 break;
1968 base += chunk_len;
1969 len -= chunk_len;
1970 }
1971 return (error);
1972 }
1973
1974 int
core_write(struct coredump_params * cp,const void * base,size_t len,off_t offset,enum uio_seg seg,size_t * resid)1975 core_write(struct coredump_params *cp, const void *base, size_t len,
1976 off_t offset, enum uio_seg seg, size_t *resid)
1977 {
1978
1979 return (vn_rdwr_inchunks(UIO_WRITE, cp->vp, __DECONST(void *, base),
1980 len, offset, seg, IO_UNIT | IO_DIRECT | IO_RANGELOCKED,
1981 cp->active_cred, cp->file_cred, resid, cp->td));
1982 }
1983
1984 int
core_output(char * base,size_t len,off_t offset,struct coredump_params * cp,void * tmpbuf)1985 core_output(char *base, size_t len, off_t offset, struct coredump_params *cp,
1986 void *tmpbuf)
1987 {
1988 vm_map_t map;
1989 struct mount *mp;
1990 size_t resid, runlen;
1991 int error;
1992 bool success;
1993
1994 KASSERT((uintptr_t)base % PAGE_SIZE == 0,
1995 ("%s: user address %p is not page-aligned", __func__, base));
1996
1997 if (cp->comp != NULL)
1998 return (compress_chunk(cp, base, tmpbuf, len));
1999
2000 map = &cp->td->td_proc->p_vmspace->vm_map;
2001 for (; len > 0; base += runlen, offset += runlen, len -= runlen) {
2002 /*
2003 * Attempt to page in all virtual pages in the range. If a
2004 * virtual page is not backed by the pager, it is represented as
2005 * a hole in the file. This can occur with zero-filled
2006 * anonymous memory or truncated files, for example.
2007 */
2008 for (runlen = 0; runlen < len; runlen += PAGE_SIZE) {
2009 if (core_dump_can_intr && curproc_sigkilled())
2010 return (EINTR);
2011 error = vm_fault(map, (uintptr_t)base + runlen,
2012 VM_PROT_READ, VM_FAULT_NOFILL, NULL);
2013 if (runlen == 0)
2014 success = error == KERN_SUCCESS;
2015 else if ((error == KERN_SUCCESS) != success)
2016 break;
2017 }
2018
2019 if (success) {
2020 error = core_write(cp, base, runlen, offset,
2021 UIO_USERSPACE, &resid);
2022 if (error != 0) {
2023 if (error != EFAULT)
2024 break;
2025
2026 /*
2027 * EFAULT may be returned if the user mapping
2028 * could not be accessed, e.g., because a mapped
2029 * file has been truncated. Skip the page if no
2030 * progress was made, to protect against a
2031 * hypothetical scenario where vm_fault() was
2032 * successful but core_write() returns EFAULT
2033 * anyway.
2034 */
2035 runlen -= resid;
2036 if (runlen == 0) {
2037 success = false;
2038 runlen = PAGE_SIZE;
2039 }
2040 }
2041 }
2042 if (!success) {
2043 error = vn_start_write(cp->vp, &mp, V_WAIT);
2044 if (error != 0)
2045 break;
2046 vn_lock(cp->vp, LK_EXCLUSIVE | LK_RETRY);
2047 error = vn_truncate_locked(cp->vp, offset + runlen,
2048 false, cp->td->td_ucred);
2049 VOP_UNLOCK(cp->vp);
2050 vn_finished_write(mp);
2051 if (error != 0)
2052 break;
2053 }
2054 }
2055 return (error);
2056 }
2057
2058 /*
2059 * Drain into a core file.
2060 */
2061 int
sbuf_drain_core_output(void * arg,const char * data,int len)2062 sbuf_drain_core_output(void *arg, const char *data, int len)
2063 {
2064 struct coredump_params *cp;
2065 struct proc *p;
2066 int error, locked;
2067
2068 cp = arg;
2069 p = cp->td->td_proc;
2070
2071 /*
2072 * Some kern_proc out routines that print to this sbuf may
2073 * call us with the process lock held. Draining with the
2074 * non-sleepable lock held is unsafe. The lock is needed for
2075 * those routines when dumping a live process. In our case we
2076 * can safely release the lock before draining and acquire
2077 * again after.
2078 */
2079 locked = PROC_LOCKED(p);
2080 if (locked)
2081 PROC_UNLOCK(p);
2082 if (cp->comp != NULL)
2083 error = compressor_write(cp->comp, __DECONST(char *, data),
2084 len);
2085 else
2086 error = core_write(cp, __DECONST(void *, data), len, cp->offset,
2087 UIO_SYSSPACE, NULL);
2088 if (locked)
2089 PROC_LOCK(p);
2090 if (error != 0)
2091 return (-error);
2092 cp->offset += len;
2093 return (len);
2094 }
2095