1 /* $OpenBSD: sftp-server.c,v 1.114 2019/01/16 23:22:10 djm Exp $ */
2 /*
3  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include "includes.h"
19 
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #ifdef HAVE_SYS_TIME_H
23 # include <sys/time.h>
24 #endif
25 #ifdef HAVE_SYS_MOUNT_H
26 #include <sys/mount.h>
27 #endif
28 #ifdef HAVE_SYS_STATVFS_H
29 #include <sys/statvfs.h>
30 #endif
31 
32 #include <dirent.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <pwd.h>
36 #include <stdlib.h>
37 #include <stdio.h>
38 #include <string.h>
39 #include <time.h>
40 #include <unistd.h>
41 #include <stdarg.h>
42 
43 #include "xmalloc.h"
44 #include "sshbuf.h"
45 #include "ssherr.h"
46 #include "log.h"
47 #include "misc.h"
48 #include "match.h"
49 #include "uidswap.h"
50 
51 #include "sftp.h"
52 #include "sftp-common.h"
53 
54 /* Our verbosity */
55 static LogLevel log_level = SYSLOG_LEVEL_ERROR;
56 
57 /* Our client */
58 static struct passwd *pw = NULL;
59 static char *client_addr = NULL;
60 
61 /* input and output queue */
62 struct sshbuf *iqueue;
63 struct sshbuf *oqueue;
64 
65 /* Version of client */
66 static u_int version;
67 
68 /* SSH2_FXP_INIT received */
69 static int init_done;
70 
71 /* Disable writes */
72 static int readonly;
73 
74 /* Requests that are allowed/denied */
75 static char *request_whitelist, *request_blacklist;
76 
77 /* portable attributes, etc. */
78 typedef struct Stat Stat;
79 
80 struct Stat {
81 	char *name;
82 	char *long_name;
83 	Attrib attrib;
84 };
85 
86 /* Packet handlers */
87 static void process_open(u_int32_t id);
88 static void process_close(u_int32_t id);
89 static void process_read(u_int32_t id);
90 static void process_write(u_int32_t id);
91 static void process_stat(u_int32_t id);
92 static void process_lstat(u_int32_t id);
93 static void process_fstat(u_int32_t id);
94 static void process_setstat(u_int32_t id);
95 static void process_fsetstat(u_int32_t id);
96 static void process_opendir(u_int32_t id);
97 static void process_readdir(u_int32_t id);
98 static void process_remove(u_int32_t id);
99 static void process_mkdir(u_int32_t id);
100 static void process_rmdir(u_int32_t id);
101 static void process_realpath(u_int32_t id);
102 static void process_rename(u_int32_t id);
103 static void process_readlink(u_int32_t id);
104 static void process_symlink(u_int32_t id);
105 static void process_extended_posix_rename(u_int32_t id);
106 static void process_extended_statvfs(u_int32_t id);
107 static void process_extended_fstatvfs(u_int32_t id);
108 static void process_extended_hardlink(u_int32_t id);
109 static void process_extended_fsync(u_int32_t id);
110 static void process_extended_lsetstat(u_int32_t id);
111 static void process_extended(u_int32_t id);
112 
113 struct sftp_handler {
114 	const char *name;	/* user-visible name for fine-grained perms */
115 	const char *ext_name;	/* extended request name */
116 	u_int type;		/* packet type, for non extended packets */
117 	void (*handler)(u_int32_t);
118 	int does_write;		/* if nonzero, banned for readonly mode */
119 };
120 
121 static const struct sftp_handler handlers[] = {
122 	/* NB. SSH2_FXP_OPEN does the readonly check in the handler itself */
123 	{ "open", NULL, SSH2_FXP_OPEN, process_open, 0 },
124 	{ "close", NULL, SSH2_FXP_CLOSE, process_close, 0 },
125 	{ "read", NULL, SSH2_FXP_READ, process_read, 0 },
126 	{ "write", NULL, SSH2_FXP_WRITE, process_write, 1 },
127 	{ "lstat", NULL, SSH2_FXP_LSTAT, process_lstat, 0 },
128 	{ "fstat", NULL, SSH2_FXP_FSTAT, process_fstat, 0 },
129 	{ "setstat", NULL, SSH2_FXP_SETSTAT, process_setstat, 1 },
130 	{ "fsetstat", NULL, SSH2_FXP_FSETSTAT, process_fsetstat, 1 },
131 	{ "opendir", NULL, SSH2_FXP_OPENDIR, process_opendir, 0 },
132 	{ "readdir", NULL, SSH2_FXP_READDIR, process_readdir, 0 },
133 	{ "remove", NULL, SSH2_FXP_REMOVE, process_remove, 1 },
134 	{ "mkdir", NULL, SSH2_FXP_MKDIR, process_mkdir, 1 },
135 	{ "rmdir", NULL, SSH2_FXP_RMDIR, process_rmdir, 1 },
136 	{ "realpath", NULL, SSH2_FXP_REALPATH, process_realpath, 0 },
137 	{ "stat", NULL, SSH2_FXP_STAT, process_stat, 0 },
138 	{ "rename", NULL, SSH2_FXP_RENAME, process_rename, 1 },
139 	{ "readlink", NULL, SSH2_FXP_READLINK, process_readlink, 0 },
140 	{ "symlink", NULL, SSH2_FXP_SYMLINK, process_symlink, 1 },
141 	{ NULL, NULL, 0, NULL, 0 }
142 };
143 
144 /* SSH2_FXP_EXTENDED submessages */
145 static const struct sftp_handler extended_handlers[] = {
146 	{ "posix-rename", "posix-rename@openssh.com", 0,
147 	   process_extended_posix_rename, 1 },
148 	{ "statvfs", "statvfs@openssh.com", 0, process_extended_statvfs, 0 },
149 	{ "fstatvfs", "fstatvfs@openssh.com", 0, process_extended_fstatvfs, 0 },
150 	{ "hardlink", "hardlink@openssh.com", 0, process_extended_hardlink, 1 },
151 	{ "fsync", "fsync@openssh.com", 0, process_extended_fsync, 1 },
152 	{ "lsetstat", "lsetstat@openssh.com", 0, process_extended_lsetstat, 1 },
153 	{ NULL, NULL, 0, NULL, 0 }
154 };
155 
156 static int
request_permitted(const struct sftp_handler * h)157 request_permitted(const struct sftp_handler *h)
158 {
159 	char *result;
160 
161 	if (readonly && h->does_write) {
162 		verbose("Refusing %s request in read-only mode", h->name);
163 		return 0;
164 	}
165 	if (request_blacklist != NULL &&
166 	    ((result = match_list(h->name, request_blacklist, NULL))) != NULL) {
167 		free(result);
168 		verbose("Refusing blacklisted %s request", h->name);
169 		return 0;
170 	}
171 	if (request_whitelist != NULL &&
172 	    ((result = match_list(h->name, request_whitelist, NULL))) != NULL) {
173 		free(result);
174 		debug2("Permitting whitelisted %s request", h->name);
175 		return 1;
176 	}
177 	if (request_whitelist != NULL) {
178 		verbose("Refusing non-whitelisted %s request", h->name);
179 		return 0;
180 	}
181 	return 1;
182 }
183 
184 static int
errno_to_portable(int unixerrno)185 errno_to_portable(int unixerrno)
186 {
187 	int ret = 0;
188 
189 	switch (unixerrno) {
190 	case 0:
191 		ret = SSH2_FX_OK;
192 		break;
193 	case ENOENT:
194 	case ENOTDIR:
195 	case EBADF:
196 	case ELOOP:
197 		ret = SSH2_FX_NO_SUCH_FILE;
198 		break;
199 	case EPERM:
200 	case EACCES:
201 	case EFAULT:
202 		ret = SSH2_FX_PERMISSION_DENIED;
203 		break;
204 	case ENAMETOOLONG:
205 	case EINVAL:
206 		ret = SSH2_FX_BAD_MESSAGE;
207 		break;
208 	case ENOSYS:
209 		ret = SSH2_FX_OP_UNSUPPORTED;
210 		break;
211 	default:
212 		ret = SSH2_FX_FAILURE;
213 		break;
214 	}
215 	return ret;
216 }
217 
218 static int
flags_from_portable(int pflags)219 flags_from_portable(int pflags)
220 {
221 	int flags = 0;
222 
223 	if ((pflags & SSH2_FXF_READ) &&
224 	    (pflags & SSH2_FXF_WRITE)) {
225 		flags = O_RDWR;
226 	} else if (pflags & SSH2_FXF_READ) {
227 		flags = O_RDONLY;
228 	} else if (pflags & SSH2_FXF_WRITE) {
229 		flags = O_WRONLY;
230 	}
231 	if (pflags & SSH2_FXF_APPEND)
232 		flags |= O_APPEND;
233 	if (pflags & SSH2_FXF_CREAT)
234 		flags |= O_CREAT;
235 	if (pflags & SSH2_FXF_TRUNC)
236 		flags |= O_TRUNC;
237 	if (pflags & SSH2_FXF_EXCL)
238 		flags |= O_EXCL;
239 	return flags;
240 }
241 
242 static const char *
string_from_portable(int pflags)243 string_from_portable(int pflags)
244 {
245 	static char ret[128];
246 
247 	*ret = '\0';
248 
249 #define PAPPEND(str)	{				\
250 		if (*ret != '\0')			\
251 			strlcat(ret, ",", sizeof(ret));	\
252 		strlcat(ret, str, sizeof(ret));		\
253 	}
254 
255 	if (pflags & SSH2_FXF_READ)
256 		PAPPEND("READ")
257 	if (pflags & SSH2_FXF_WRITE)
258 		PAPPEND("WRITE")
259 	if (pflags & SSH2_FXF_APPEND)
260 		PAPPEND("APPEND")
261 	if (pflags & SSH2_FXF_CREAT)
262 		PAPPEND("CREATE")
263 	if (pflags & SSH2_FXF_TRUNC)
264 		PAPPEND("TRUNCATE")
265 	if (pflags & SSH2_FXF_EXCL)
266 		PAPPEND("EXCL")
267 
268 	return ret;
269 }
270 
271 /* handle handles */
272 
273 typedef struct Handle Handle;
274 struct Handle {
275 	int use;
276 	DIR *dirp;
277 	int fd;
278 	int flags;
279 	char *name;
280 	u_int64_t bytes_read, bytes_write;
281 	int next_unused;
282 };
283 
284 enum {
285 	HANDLE_UNUSED,
286 	HANDLE_DIR,
287 	HANDLE_FILE
288 };
289 
290 static Handle *handles = NULL;
291 static u_int num_handles = 0;
292 static int first_unused_handle = -1;
293 
handle_unused(int i)294 static void handle_unused(int i)
295 {
296 	handles[i].use = HANDLE_UNUSED;
297 	handles[i].next_unused = first_unused_handle;
298 	first_unused_handle = i;
299 }
300 
301 static int
handle_new(int use,const char * name,int fd,int flags,DIR * dirp)302 handle_new(int use, const char *name, int fd, int flags, DIR *dirp)
303 {
304 	int i;
305 
306 	if (first_unused_handle == -1) {
307 		if (num_handles + 1 <= num_handles)
308 			return -1;
309 		num_handles++;
310 		handles = xreallocarray(handles, num_handles, sizeof(Handle));
311 		handle_unused(num_handles - 1);
312 	}
313 
314 	i = first_unused_handle;
315 	first_unused_handle = handles[i].next_unused;
316 
317 	handles[i].use = use;
318 	handles[i].dirp = dirp;
319 	handles[i].fd = fd;
320 	handles[i].flags = flags;
321 	handles[i].name = xstrdup(name);
322 	handles[i].bytes_read = handles[i].bytes_write = 0;
323 
324 	return i;
325 }
326 
327 static int
handle_is_ok(int i,int type)328 handle_is_ok(int i, int type)
329 {
330 	return i >= 0 && (u_int)i < num_handles && handles[i].use == type;
331 }
332 
333 static int
handle_to_string(int handle,u_char ** stringp,int * hlenp)334 handle_to_string(int handle, u_char **stringp, int *hlenp)
335 {
336 	if (stringp == NULL || hlenp == NULL)
337 		return -1;
338 	*stringp = xmalloc(sizeof(int32_t));
339 	put_u32(*stringp, handle);
340 	*hlenp = sizeof(int32_t);
341 	return 0;
342 }
343 
344 static int
handle_from_string(const u_char * handle,u_int hlen)345 handle_from_string(const u_char *handle, u_int hlen)
346 {
347 	int val;
348 
349 	if (hlen != sizeof(int32_t))
350 		return -1;
351 	val = get_u32(handle);
352 	if (handle_is_ok(val, HANDLE_FILE) ||
353 	    handle_is_ok(val, HANDLE_DIR))
354 		return val;
355 	return -1;
356 }
357 
358 static char *
handle_to_name(int handle)359 handle_to_name(int handle)
360 {
361 	if (handle_is_ok(handle, HANDLE_DIR)||
362 	    handle_is_ok(handle, HANDLE_FILE))
363 		return handles[handle].name;
364 	return NULL;
365 }
366 
367 static DIR *
handle_to_dir(int handle)368 handle_to_dir(int handle)
369 {
370 	if (handle_is_ok(handle, HANDLE_DIR))
371 		return handles[handle].dirp;
372 	return NULL;
373 }
374 
375 static int
handle_to_fd(int handle)376 handle_to_fd(int handle)
377 {
378 	if (handle_is_ok(handle, HANDLE_FILE))
379 		return handles[handle].fd;
380 	return -1;
381 }
382 
383 static int
handle_to_flags(int handle)384 handle_to_flags(int handle)
385 {
386 	if (handle_is_ok(handle, HANDLE_FILE))
387 		return handles[handle].flags;
388 	return 0;
389 }
390 
391 static void
handle_update_read(int handle,ssize_t bytes)392 handle_update_read(int handle, ssize_t bytes)
393 {
394 	if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
395 		handles[handle].bytes_read += bytes;
396 }
397 
398 static void
handle_update_write(int handle,ssize_t bytes)399 handle_update_write(int handle, ssize_t bytes)
400 {
401 	if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
402 		handles[handle].bytes_write += bytes;
403 }
404 
405 static u_int64_t
handle_bytes_read(int handle)406 handle_bytes_read(int handle)
407 {
408 	if (handle_is_ok(handle, HANDLE_FILE))
409 		return (handles[handle].bytes_read);
410 	return 0;
411 }
412 
413 static u_int64_t
handle_bytes_write(int handle)414 handle_bytes_write(int handle)
415 {
416 	if (handle_is_ok(handle, HANDLE_FILE))
417 		return (handles[handle].bytes_write);
418 	return 0;
419 }
420 
421 static int
handle_close(int handle)422 handle_close(int handle)
423 {
424 	int ret = -1;
425 
426 	if (handle_is_ok(handle, HANDLE_FILE)) {
427 		ret = close(handles[handle].fd);
428 		free(handles[handle].name);
429 		handle_unused(handle);
430 	} else if (handle_is_ok(handle, HANDLE_DIR)) {
431 		ret = closedir(handles[handle].dirp);
432 		free(handles[handle].name);
433 		handle_unused(handle);
434 	} else {
435 		errno = ENOENT;
436 	}
437 	return ret;
438 }
439 
440 static void
handle_log_close(int handle,char * emsg)441 handle_log_close(int handle, char *emsg)
442 {
443 	if (handle_is_ok(handle, HANDLE_FILE)) {
444 		logit("%s%sclose \"%s\" bytes read %llu written %llu",
445 		    emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
446 		    handle_to_name(handle),
447 		    (unsigned long long)handle_bytes_read(handle),
448 		    (unsigned long long)handle_bytes_write(handle));
449 	} else {
450 		logit("%s%sclosedir \"%s\"",
451 		    emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
452 		    handle_to_name(handle));
453 	}
454 }
455 
456 static void
handle_log_exit(void)457 handle_log_exit(void)
458 {
459 	u_int i;
460 
461 	for (i = 0; i < num_handles; i++)
462 		if (handles[i].use != HANDLE_UNUSED)
463 			handle_log_close(i, "forced");
464 }
465 
466 static int
get_handle(struct sshbuf * queue,int * hp)467 get_handle(struct sshbuf *queue, int *hp)
468 {
469 	u_char *handle;
470 	int r;
471 	size_t hlen;
472 
473 	*hp = -1;
474 	if ((r = sshbuf_get_string(queue, &handle, &hlen)) != 0)
475 		return r;
476 	if (hlen < 256)
477 		*hp = handle_from_string(handle, hlen);
478 	free(handle);
479 	return 0;
480 }
481 
482 /* send replies */
483 
484 static void
send_msg(struct sshbuf * m)485 send_msg(struct sshbuf *m)
486 {
487 	int r;
488 
489 	if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
490 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
491 	sshbuf_reset(m);
492 }
493 
494 static const char *
status_to_message(u_int32_t status)495 status_to_message(u_int32_t status)
496 {
497 	const char *status_messages[] = {
498 		"Success",			/* SSH_FX_OK */
499 		"End of file",			/* SSH_FX_EOF */
500 		"No such file",			/* SSH_FX_NO_SUCH_FILE */
501 		"Permission denied",		/* SSH_FX_PERMISSION_DENIED */
502 		"Failure",			/* SSH_FX_FAILURE */
503 		"Bad message",			/* SSH_FX_BAD_MESSAGE */
504 		"No connection",		/* SSH_FX_NO_CONNECTION */
505 		"Connection lost",		/* SSH_FX_CONNECTION_LOST */
506 		"Operation unsupported",	/* SSH_FX_OP_UNSUPPORTED */
507 		"Unknown error"			/* Others */
508 	};
509 	return (status_messages[MINIMUM(status,SSH2_FX_MAX)]);
510 }
511 
512 static void
send_status(u_int32_t id,u_int32_t status)513 send_status(u_int32_t id, u_int32_t status)
514 {
515 	struct sshbuf *msg;
516 	int r;
517 
518 	debug3("request %u: sent status %u", id, status);
519 	if (log_level > SYSLOG_LEVEL_VERBOSE ||
520 	    (status != SSH2_FX_OK && status != SSH2_FX_EOF))
521 		logit("sent status %s", status_to_message(status));
522 	if ((msg = sshbuf_new()) == NULL)
523 		fatal("%s: sshbuf_new failed", __func__);
524 	if ((r = sshbuf_put_u8(msg, SSH2_FXP_STATUS)) != 0 ||
525 	    (r = sshbuf_put_u32(msg, id)) != 0 ||
526 	    (r = sshbuf_put_u32(msg, status)) != 0)
527 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
528 	if (version >= 3) {
529 		if ((r = sshbuf_put_cstring(msg,
530 		    status_to_message(status))) != 0 ||
531 		    (r = sshbuf_put_cstring(msg, "")) != 0)
532 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
533 	}
534 	send_msg(msg);
535 	sshbuf_free(msg);
536 }
537 static void
send_data_or_handle(char type,u_int32_t id,const u_char * data,int dlen)538 send_data_or_handle(char type, u_int32_t id, const u_char *data, int dlen)
539 {
540 	struct sshbuf *msg;
541 	int r;
542 
543 	if ((msg = sshbuf_new()) == NULL)
544 		fatal("%s: sshbuf_new failed", __func__);
545 	if ((r = sshbuf_put_u8(msg, type)) != 0 ||
546 	    (r = sshbuf_put_u32(msg, id)) != 0 ||
547 	    (r = sshbuf_put_string(msg, data, dlen)) != 0)
548 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
549 	send_msg(msg);
550 	sshbuf_free(msg);
551 }
552 
553 static void
send_data(u_int32_t id,const u_char * data,int dlen)554 send_data(u_int32_t id, const u_char *data, int dlen)
555 {
556 	debug("request %u: sent data len %d", id, dlen);
557 	send_data_or_handle(SSH2_FXP_DATA, id, data, dlen);
558 }
559 
560 static void
send_handle(u_int32_t id,int handle)561 send_handle(u_int32_t id, int handle)
562 {
563 	u_char *string;
564 	int hlen;
565 
566 	handle_to_string(handle, &string, &hlen);
567 	debug("request %u: sent handle handle %d", id, handle);
568 	send_data_or_handle(SSH2_FXP_HANDLE, id, string, hlen);
569 	free(string);
570 }
571 
572 static void
send_names(u_int32_t id,int count,const Stat * stats)573 send_names(u_int32_t id, int count, const Stat *stats)
574 {
575 	struct sshbuf *msg;
576 	int i, r;
577 
578 	if ((msg = sshbuf_new()) == NULL)
579 		fatal("%s: sshbuf_new failed", __func__);
580 	if ((r = sshbuf_put_u8(msg, SSH2_FXP_NAME)) != 0 ||
581 	    (r = sshbuf_put_u32(msg, id)) != 0 ||
582 	    (r = sshbuf_put_u32(msg, count)) != 0)
583 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
584 	debug("request %u: sent names count %d", id, count);
585 	for (i = 0; i < count; i++) {
586 		if ((r = sshbuf_put_cstring(msg, stats[i].name)) != 0 ||
587 		    (r = sshbuf_put_cstring(msg, stats[i].long_name)) != 0 ||
588 		    (r = encode_attrib(msg, &stats[i].attrib)) != 0)
589 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
590 	}
591 	send_msg(msg);
592 	sshbuf_free(msg);
593 }
594 
595 static void
send_attrib(u_int32_t id,const Attrib * a)596 send_attrib(u_int32_t id, const Attrib *a)
597 {
598 	struct sshbuf *msg;
599 	int r;
600 
601 	debug("request %u: sent attrib have 0x%x", id, a->flags);
602 	if ((msg = sshbuf_new()) == NULL)
603 		fatal("%s: sshbuf_new failed", __func__);
604 	if ((r = sshbuf_put_u8(msg, SSH2_FXP_ATTRS)) != 0 ||
605 	    (r = sshbuf_put_u32(msg, id)) != 0 ||
606 	    (r = encode_attrib(msg, a)) != 0)
607 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
608 	send_msg(msg);
609 	sshbuf_free(msg);
610 }
611 
612 static void
send_statvfs(u_int32_t id,struct statvfs * st)613 send_statvfs(u_int32_t id, struct statvfs *st)
614 {
615 	struct sshbuf *msg;
616 	u_int64_t flag;
617 	int r;
618 
619 	flag = (st->f_flag & ST_RDONLY) ? SSH2_FXE_STATVFS_ST_RDONLY : 0;
620 	flag |= (st->f_flag & ST_NOSUID) ? SSH2_FXE_STATVFS_ST_NOSUID : 0;
621 
622 	if ((msg = sshbuf_new()) == NULL)
623 		fatal("%s: sshbuf_new failed", __func__);
624 	if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
625 	    (r = sshbuf_put_u32(msg, id)) != 0 ||
626 	    (r = sshbuf_put_u64(msg, st->f_bsize)) != 0 ||
627 	    (r = sshbuf_put_u64(msg, st->f_frsize)) != 0 ||
628 	    (r = sshbuf_put_u64(msg, st->f_blocks)) != 0 ||
629 	    (r = sshbuf_put_u64(msg, st->f_bfree)) != 0 ||
630 	    (r = sshbuf_put_u64(msg, st->f_bavail)) != 0 ||
631 	    (r = sshbuf_put_u64(msg, st->f_files)) != 0 ||
632 	    (r = sshbuf_put_u64(msg, st->f_ffree)) != 0 ||
633 	    (r = sshbuf_put_u64(msg, st->f_favail)) != 0 ||
634 	    (r = sshbuf_put_u64(msg, FSID_TO_ULONG(st->f_fsid))) != 0 ||
635 	    (r = sshbuf_put_u64(msg, flag)) != 0 ||
636 	    (r = sshbuf_put_u64(msg, st->f_namemax)) != 0)
637 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
638 	send_msg(msg);
639 	sshbuf_free(msg);
640 }
641 
642 /* parse incoming */
643 
644 static void
process_init(void)645 process_init(void)
646 {
647 	struct sshbuf *msg;
648 	int r;
649 
650 	if ((r = sshbuf_get_u32(iqueue, &version)) != 0)
651 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
652 	verbose("received client version %u", version);
653 	if ((msg = sshbuf_new()) == NULL)
654 		fatal("%s: sshbuf_new failed", __func__);
655 	if ((r = sshbuf_put_u8(msg, SSH2_FXP_VERSION)) != 0 ||
656 	    (r = sshbuf_put_u32(msg, SSH2_FILEXFER_VERSION)) != 0 ||
657 	    /* POSIX rename extension */
658 	    (r = sshbuf_put_cstring(msg, "posix-rename@openssh.com")) != 0 ||
659 	    (r = sshbuf_put_cstring(msg, "1")) != 0 || /* version */
660 	    /* statvfs extension */
661 	    (r = sshbuf_put_cstring(msg, "statvfs@openssh.com")) != 0 ||
662 	    (r = sshbuf_put_cstring(msg, "2")) != 0 || /* version */
663 	    /* fstatvfs extension */
664 	    (r = sshbuf_put_cstring(msg, "fstatvfs@openssh.com")) != 0 ||
665 	    (r = sshbuf_put_cstring(msg, "2")) != 0 || /* version */
666 	    /* hardlink extension */
667 	    (r = sshbuf_put_cstring(msg, "hardlink@openssh.com")) != 0 ||
668 	    (r = sshbuf_put_cstring(msg, "1")) != 0 || /* version */
669 	    /* fsync extension */
670 	    (r = sshbuf_put_cstring(msg, "fsync@openssh.com")) != 0 ||
671 	    (r = sshbuf_put_cstring(msg, "1")) != 0 || /* version */
672 	    (r = sshbuf_put_cstring(msg, "lsetstat@openssh.com")) != 0 ||
673 	    (r = sshbuf_put_cstring(msg, "1")) != 0) /* version */
674 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
675 	send_msg(msg);
676 	sshbuf_free(msg);
677 }
678 
679 static void
process_open(u_int32_t id)680 process_open(u_int32_t id)
681 {
682 	u_int32_t pflags;
683 	Attrib a;
684 	char *name;
685 	int r, handle, fd, flags, mode, status = SSH2_FX_FAILURE;
686 
687 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
688 	    (r = sshbuf_get_u32(iqueue, &pflags)) != 0 || /* portable flags */
689 	    (r = decode_attrib(iqueue, &a)) != 0)
690 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
691 
692 	debug3("request %u: open flags %d", id, pflags);
693 	flags = flags_from_portable(pflags);
694 	mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm : 0666;
695 	logit("open \"%s\" flags %s mode 0%o",
696 	    name, string_from_portable(pflags), mode);
697 	if (readonly &&
698 	    ((flags & O_ACCMODE) != O_RDONLY ||
699 	    (flags & (O_CREAT|O_TRUNC)) != 0)) {
700 		verbose("Refusing open request in read-only mode");
701 		status = SSH2_FX_PERMISSION_DENIED;
702 	} else {
703 		fd = open(name, flags, mode);
704 		if (fd < 0) {
705 			status = errno_to_portable(errno);
706 		} else {
707 			handle = handle_new(HANDLE_FILE, name, fd, flags, NULL);
708 			if (handle < 0) {
709 				close(fd);
710 			} else {
711 				send_handle(id, handle);
712 				status = SSH2_FX_OK;
713 			}
714 		}
715 	}
716 	if (status != SSH2_FX_OK)
717 		send_status(id, status);
718 	free(name);
719 }
720 
721 static void
process_close(u_int32_t id)722 process_close(u_int32_t id)
723 {
724 	int r, handle, ret, status = SSH2_FX_FAILURE;
725 
726 	if ((r = get_handle(iqueue, &handle)) != 0)
727 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
728 
729 	debug3("request %u: close handle %u", id, handle);
730 	handle_log_close(handle, NULL);
731 	ret = handle_close(handle);
732 	status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
733 	send_status(id, status);
734 }
735 
736 static void
process_read(u_int32_t id)737 process_read(u_int32_t id)
738 {
739 	u_char buf[64*1024];
740 	u_int32_t len;
741 	int r, handle, fd, ret, status = SSH2_FX_FAILURE;
742 	u_int64_t off;
743 
744 	if ((r = get_handle(iqueue, &handle)) != 0 ||
745 	    (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
746 	    (r = sshbuf_get_u32(iqueue, &len)) != 0)
747 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
748 
749 	debug("request %u: read \"%s\" (handle %d) off %llu len %d",
750 	    id, handle_to_name(handle), handle, (unsigned long long)off, len);
751 	if (len > sizeof buf) {
752 		len = sizeof buf;
753 		debug2("read change len %d", len);
754 	}
755 	fd = handle_to_fd(handle);
756 	if (fd >= 0) {
757 		if (lseek(fd, off, SEEK_SET) < 0) {
758 			error("process_read: seek failed");
759 			status = errno_to_portable(errno);
760 		} else {
761 			ret = read(fd, buf, len);
762 			if (ret < 0) {
763 				status = errno_to_portable(errno);
764 			} else if (ret == 0) {
765 				status = SSH2_FX_EOF;
766 			} else {
767 				send_data(id, buf, ret);
768 				status = SSH2_FX_OK;
769 				handle_update_read(handle, ret);
770 			}
771 		}
772 	}
773 	if (status != SSH2_FX_OK)
774 		send_status(id, status);
775 }
776 
777 static void
process_write(u_int32_t id)778 process_write(u_int32_t id)
779 {
780 	u_int64_t off;
781 	size_t len;
782 	int r, handle, fd, ret, status;
783 	u_char *data;
784 
785 	if ((r = get_handle(iqueue, &handle)) != 0 ||
786 	    (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
787 	    (r = sshbuf_get_string(iqueue, &data, &len)) != 0)
788 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
789 
790 	debug("request %u: write \"%s\" (handle %d) off %llu len %zu",
791 	    id, handle_to_name(handle), handle, (unsigned long long)off, len);
792 	fd = handle_to_fd(handle);
793 
794 	if (fd < 0)
795 		status = SSH2_FX_FAILURE;
796 	else {
797 		if (!(handle_to_flags(handle) & O_APPEND) &&
798 				lseek(fd, off, SEEK_SET) < 0) {
799 			status = errno_to_portable(errno);
800 			error("process_write: seek failed");
801 		} else {
802 /* XXX ATOMICIO ? */
803 			ret = write(fd, data, len);
804 			if (ret < 0) {
805 				error("process_write: write failed");
806 				status = errno_to_portable(errno);
807 			} else if ((size_t)ret == len) {
808 				status = SSH2_FX_OK;
809 				handle_update_write(handle, ret);
810 			} else {
811 				debug2("nothing at all written");
812 				status = SSH2_FX_FAILURE;
813 			}
814 		}
815 	}
816 	send_status(id, status);
817 	free(data);
818 }
819 
820 static void
process_do_stat(u_int32_t id,int do_lstat)821 process_do_stat(u_int32_t id, int do_lstat)
822 {
823 	Attrib a;
824 	struct stat st;
825 	char *name;
826 	int r, status = SSH2_FX_FAILURE;
827 
828 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
829 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
830 
831 	debug3("request %u: %sstat", id, do_lstat ? "l" : "");
832 	verbose("%sstat name \"%s\"", do_lstat ? "l" : "", name);
833 	r = do_lstat ? lstat(name, &st) : stat(name, &st);
834 	if (r < 0) {
835 		status = errno_to_portable(errno);
836 	} else {
837 		stat_to_attrib(&st, &a);
838 		send_attrib(id, &a);
839 		status = SSH2_FX_OK;
840 	}
841 	if (status != SSH2_FX_OK)
842 		send_status(id, status);
843 	free(name);
844 }
845 
846 static void
process_stat(u_int32_t id)847 process_stat(u_int32_t id)
848 {
849 	process_do_stat(id, 0);
850 }
851 
852 static void
process_lstat(u_int32_t id)853 process_lstat(u_int32_t id)
854 {
855 	process_do_stat(id, 1);
856 }
857 
858 static void
process_fstat(u_int32_t id)859 process_fstat(u_int32_t id)
860 {
861 	Attrib a;
862 	struct stat st;
863 	int fd, r, handle, status = SSH2_FX_FAILURE;
864 
865 	if ((r = get_handle(iqueue, &handle)) != 0)
866 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
867 	debug("request %u: fstat \"%s\" (handle %u)",
868 	    id, handle_to_name(handle), handle);
869 	fd = handle_to_fd(handle);
870 	if (fd >= 0) {
871 		r = fstat(fd, &st);
872 		if (r < 0) {
873 			status = errno_to_portable(errno);
874 		} else {
875 			stat_to_attrib(&st, &a);
876 			send_attrib(id, &a);
877 			status = SSH2_FX_OK;
878 		}
879 	}
880 	if (status != SSH2_FX_OK)
881 		send_status(id, status);
882 }
883 
884 static struct timeval *
attrib_to_tv(const Attrib * a)885 attrib_to_tv(const Attrib *a)
886 {
887 	static struct timeval tv[2];
888 
889 	tv[0].tv_sec = a->atime;
890 	tv[0].tv_usec = 0;
891 	tv[1].tv_sec = a->mtime;
892 	tv[1].tv_usec = 0;
893 	return tv;
894 }
895 
896 static struct timespec *
attrib_to_ts(const Attrib * a)897 attrib_to_ts(const Attrib *a)
898 {
899 	static struct timespec ts[2];
900 
901 	ts[0].tv_sec = a->atime;
902 	ts[0].tv_nsec = 0;
903 	ts[1].tv_sec = a->mtime;
904 	ts[1].tv_nsec = 0;
905 	return ts;
906 }
907 
908 static void
process_setstat(u_int32_t id)909 process_setstat(u_int32_t id)
910 {
911 	Attrib a;
912 	char *name;
913 	int r, status = SSH2_FX_OK;
914 
915 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
916 	    (r = decode_attrib(iqueue, &a)) != 0)
917 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
918 
919 	debug("request %u: setstat name \"%s\"", id, name);
920 	if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
921 		logit("set \"%s\" size %llu",
922 		    name, (unsigned long long)a.size);
923 		r = truncate(name, a.size);
924 		if (r == -1)
925 			status = errno_to_portable(errno);
926 	}
927 	if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
928 		logit("set \"%s\" mode %04o", name, a.perm);
929 		r = chmod(name, a.perm & 07777);
930 		if (r == -1)
931 			status = errno_to_portable(errno);
932 	}
933 	if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
934 		char buf[64];
935 		time_t t = a.mtime;
936 
937 		strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
938 		    localtime(&t));
939 		logit("set \"%s\" modtime %s", name, buf);
940 		r = utimes(name, attrib_to_tv(&a));
941 		if (r == -1)
942 			status = errno_to_portable(errno);
943 	}
944 	if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
945 		logit("set \"%s\" owner %lu group %lu", name,
946 		    (u_long)a.uid, (u_long)a.gid);
947 		r = chown(name, a.uid, a.gid);
948 		if (r == -1)
949 			status = errno_to_portable(errno);
950 	}
951 	send_status(id, status);
952 	free(name);
953 }
954 
955 static void
process_fsetstat(u_int32_t id)956 process_fsetstat(u_int32_t id)
957 {
958 	Attrib a;
959 	int handle, fd, r;
960 	int status = SSH2_FX_OK;
961 
962 	if ((r = get_handle(iqueue, &handle)) != 0 ||
963 	    (r = decode_attrib(iqueue, &a)) != 0)
964 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
965 
966 	debug("request %u: fsetstat handle %d", id, handle);
967 	fd = handle_to_fd(handle);
968 	if (fd < 0)
969 		status = SSH2_FX_FAILURE;
970 	else {
971 		char *name = handle_to_name(handle);
972 
973 		if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
974 			logit("set \"%s\" size %llu",
975 			    name, (unsigned long long)a.size);
976 			r = ftruncate(fd, a.size);
977 			if (r == -1)
978 				status = errno_to_portable(errno);
979 		}
980 		if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
981 			logit("set \"%s\" mode %04o", name, a.perm);
982 #ifdef HAVE_FCHMOD
983 			r = fchmod(fd, a.perm & 07777);
984 #else
985 			r = chmod(name, a.perm & 07777);
986 #endif
987 			if (r == -1)
988 				status = errno_to_portable(errno);
989 		}
990 		if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
991 			char buf[64];
992 			time_t t = a.mtime;
993 
994 			strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
995 			    localtime(&t));
996 			logit("set \"%s\" modtime %s", name, buf);
997 #ifdef HAVE_FUTIMES
998 			r = futimes(fd, attrib_to_tv(&a));
999 #else
1000 			r = utimes(name, attrib_to_tv(&a));
1001 #endif
1002 			if (r == -1)
1003 				status = errno_to_portable(errno);
1004 		}
1005 		if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1006 			logit("set \"%s\" owner %lu group %lu", name,
1007 			    (u_long)a.uid, (u_long)a.gid);
1008 #ifdef HAVE_FCHOWN
1009 			r = fchown(fd, a.uid, a.gid);
1010 #else
1011 			r = chown(name, a.uid, a.gid);
1012 #endif
1013 			if (r == -1)
1014 				status = errno_to_portable(errno);
1015 		}
1016 	}
1017 	send_status(id, status);
1018 }
1019 
1020 static void
process_opendir(u_int32_t id)1021 process_opendir(u_int32_t id)
1022 {
1023 	DIR *dirp = NULL;
1024 	char *path;
1025 	int r, handle, status = SSH2_FX_FAILURE;
1026 
1027 	if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1028 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1029 
1030 	debug3("request %u: opendir", id);
1031 	logit("opendir \"%s\"", path);
1032 	dirp = opendir(path);
1033 	if (dirp == NULL) {
1034 		status = errno_to_portable(errno);
1035 	} else {
1036 		handle = handle_new(HANDLE_DIR, path, 0, 0, dirp);
1037 		if (handle < 0) {
1038 			closedir(dirp);
1039 		} else {
1040 			send_handle(id, handle);
1041 			status = SSH2_FX_OK;
1042 		}
1043 
1044 	}
1045 	if (status != SSH2_FX_OK)
1046 		send_status(id, status);
1047 	free(path);
1048 }
1049 
1050 static void
process_readdir(u_int32_t id)1051 process_readdir(u_int32_t id)
1052 {
1053 	DIR *dirp;
1054 	struct dirent *dp;
1055 	char *path;
1056 	int r, handle;
1057 
1058 	if ((r = get_handle(iqueue, &handle)) != 0)
1059 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1060 
1061 	debug("request %u: readdir \"%s\" (handle %d)", id,
1062 	    handle_to_name(handle), handle);
1063 	dirp = handle_to_dir(handle);
1064 	path = handle_to_name(handle);
1065 	if (dirp == NULL || path == NULL) {
1066 		send_status(id, SSH2_FX_FAILURE);
1067 	} else {
1068 		struct stat st;
1069 		char pathname[PATH_MAX];
1070 		Stat *stats;
1071 		int nstats = 10, count = 0, i;
1072 
1073 		stats = xcalloc(nstats, sizeof(Stat));
1074 		while ((dp = readdir(dirp)) != NULL) {
1075 			if (count >= nstats) {
1076 				nstats *= 2;
1077 				stats = xreallocarray(stats, nstats, sizeof(Stat));
1078 			}
1079 /* XXX OVERFLOW ? */
1080 			snprintf(pathname, sizeof pathname, "%s%s%s", path,
1081 			    strcmp(path, "/") ? "/" : "", dp->d_name);
1082 			if (lstat(pathname, &st) < 0)
1083 				continue;
1084 			stat_to_attrib(&st, &(stats[count].attrib));
1085 			stats[count].name = xstrdup(dp->d_name);
1086 			stats[count].long_name = ls_file(dp->d_name, &st, 0, 0);
1087 			count++;
1088 			/* send up to 100 entries in one message */
1089 			/* XXX check packet size instead */
1090 			if (count == 100)
1091 				break;
1092 		}
1093 		if (count > 0) {
1094 			send_names(id, count, stats);
1095 			for (i = 0; i < count; i++) {
1096 				free(stats[i].name);
1097 				free(stats[i].long_name);
1098 			}
1099 		} else {
1100 			send_status(id, SSH2_FX_EOF);
1101 		}
1102 		free(stats);
1103 	}
1104 }
1105 
1106 static void
process_remove(u_int32_t id)1107 process_remove(u_int32_t id)
1108 {
1109 	char *name;
1110 	int r, status = SSH2_FX_FAILURE;
1111 
1112 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
1113 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1114 
1115 	debug3("request %u: remove", id);
1116 	logit("remove name \"%s\"", name);
1117 	r = unlink(name);
1118 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1119 	send_status(id, status);
1120 	free(name);
1121 }
1122 
1123 static void
process_mkdir(u_int32_t id)1124 process_mkdir(u_int32_t id)
1125 {
1126 	Attrib a;
1127 	char *name;
1128 	int r, mode, status = SSH2_FX_FAILURE;
1129 
1130 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
1131 	    (r = decode_attrib(iqueue, &a)) != 0)
1132 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1133 
1134 	mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
1135 	    a.perm & 07777 : 0777;
1136 	debug3("request %u: mkdir", id);
1137 	logit("mkdir name \"%s\" mode 0%o", name, mode);
1138 	r = mkdir(name, mode);
1139 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1140 	send_status(id, status);
1141 	free(name);
1142 }
1143 
1144 static void
process_rmdir(u_int32_t id)1145 process_rmdir(u_int32_t id)
1146 {
1147 	char *name;
1148 	int r, status;
1149 
1150 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
1151 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1152 
1153 	debug3("request %u: rmdir", id);
1154 	logit("rmdir name \"%s\"", name);
1155 	r = rmdir(name);
1156 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1157 	send_status(id, status);
1158 	free(name);
1159 }
1160 
1161 static void
process_realpath(u_int32_t id)1162 process_realpath(u_int32_t id)
1163 {
1164 	char resolvedname[PATH_MAX];
1165 	char *path;
1166 	int r;
1167 
1168 	if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1169 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1170 
1171 	if (path[0] == '\0') {
1172 		free(path);
1173 		path = xstrdup(".");
1174 	}
1175 	debug3("request %u: realpath", id);
1176 	verbose("realpath \"%s\"", path);
1177 	if (realpath(path, resolvedname) == NULL) {
1178 		send_status(id, errno_to_portable(errno));
1179 	} else {
1180 		Stat s;
1181 		attrib_clear(&s.attrib);
1182 		s.name = s.long_name = resolvedname;
1183 		send_names(id, 1, &s);
1184 	}
1185 	free(path);
1186 }
1187 
1188 static void
process_rename(u_int32_t id)1189 process_rename(u_int32_t id)
1190 {
1191 	char *oldpath, *newpath;
1192 	int r, status;
1193 	struct stat sb;
1194 
1195 	if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1196 	    (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1197 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1198 
1199 	debug3("request %u: rename", id);
1200 	logit("rename old \"%s\" new \"%s\"", oldpath, newpath);
1201 	status = SSH2_FX_FAILURE;
1202 	if (lstat(oldpath, &sb) == -1)
1203 		status = errno_to_portable(errno);
1204 	else if (S_ISREG(sb.st_mode)) {
1205 		/* Race-free rename of regular files */
1206 		if (link(oldpath, newpath) == -1) {
1207 			if (errno == EOPNOTSUPP || errno == ENOSYS
1208 #ifdef EXDEV
1209 			    || errno == EXDEV
1210 #endif
1211 #ifdef LINK_OPNOTSUPP_ERRNO
1212 			    || errno == LINK_OPNOTSUPP_ERRNO
1213 #endif
1214 			    ) {
1215 				struct stat st;
1216 
1217 				/*
1218 				 * fs doesn't support links, so fall back to
1219 				 * stat+rename.  This is racy.
1220 				 */
1221 				if (stat(newpath, &st) == -1) {
1222 					if (rename(oldpath, newpath) == -1)
1223 						status =
1224 						    errno_to_portable(errno);
1225 					else
1226 						status = SSH2_FX_OK;
1227 				}
1228 			} else {
1229 				status = errno_to_portable(errno);
1230 			}
1231 		} else if (unlink(oldpath) == -1) {
1232 			status = errno_to_portable(errno);
1233 			/* clean spare link */
1234 			unlink(newpath);
1235 		} else
1236 			status = SSH2_FX_OK;
1237 	} else if (stat(newpath, &sb) == -1) {
1238 		if (rename(oldpath, newpath) == -1)
1239 			status = errno_to_portable(errno);
1240 		else
1241 			status = SSH2_FX_OK;
1242 	}
1243 	send_status(id, status);
1244 	free(oldpath);
1245 	free(newpath);
1246 }
1247 
1248 static void
process_readlink(u_int32_t id)1249 process_readlink(u_int32_t id)
1250 {
1251 	int r, len;
1252 	char buf[PATH_MAX];
1253 	char *path;
1254 
1255 	if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1256 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1257 
1258 	debug3("request %u: readlink", id);
1259 	verbose("readlink \"%s\"", path);
1260 	if ((len = readlink(path, buf, sizeof(buf) - 1)) == -1)
1261 		send_status(id, errno_to_portable(errno));
1262 	else {
1263 		Stat s;
1264 
1265 		buf[len] = '\0';
1266 		attrib_clear(&s.attrib);
1267 		s.name = s.long_name = buf;
1268 		send_names(id, 1, &s);
1269 	}
1270 	free(path);
1271 }
1272 
1273 static void
process_symlink(u_int32_t id)1274 process_symlink(u_int32_t id)
1275 {
1276 	char *oldpath, *newpath;
1277 	int r, status;
1278 
1279 	if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1280 	    (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1281 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1282 
1283 	debug3("request %u: symlink", id);
1284 	logit("symlink old \"%s\" new \"%s\"", oldpath, newpath);
1285 	/* this will fail if 'newpath' exists */
1286 	r = symlink(oldpath, newpath);
1287 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1288 	send_status(id, status);
1289 	free(oldpath);
1290 	free(newpath);
1291 }
1292 
1293 static void
process_extended_posix_rename(u_int32_t id)1294 process_extended_posix_rename(u_int32_t id)
1295 {
1296 	char *oldpath, *newpath;
1297 	int r, status;
1298 
1299 	if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1300 	    (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1301 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1302 
1303 	debug3("request %u: posix-rename", id);
1304 	logit("posix-rename old \"%s\" new \"%s\"", oldpath, newpath);
1305 	r = rename(oldpath, newpath);
1306 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1307 	send_status(id, status);
1308 	free(oldpath);
1309 	free(newpath);
1310 }
1311 
1312 static void
process_extended_statvfs(u_int32_t id)1313 process_extended_statvfs(u_int32_t id)
1314 {
1315 	char *path;
1316 	struct statvfs st;
1317 	int r;
1318 
1319 	if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1320 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1321 	debug3("request %u: statvfs", id);
1322 	logit("statvfs \"%s\"", path);
1323 
1324 	if (statvfs(path, &st) != 0)
1325 		send_status(id, errno_to_portable(errno));
1326 	else
1327 		send_statvfs(id, &st);
1328         free(path);
1329 }
1330 
1331 static void
process_extended_fstatvfs(u_int32_t id)1332 process_extended_fstatvfs(u_int32_t id)
1333 {
1334 	int r, handle, fd;
1335 	struct statvfs st;
1336 
1337 	if ((r = get_handle(iqueue, &handle)) != 0)
1338 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1339 	debug("request %u: fstatvfs \"%s\" (handle %u)",
1340 	    id, handle_to_name(handle), handle);
1341 	if ((fd = handle_to_fd(handle)) < 0) {
1342 		send_status(id, SSH2_FX_FAILURE);
1343 		return;
1344 	}
1345 	if (fstatvfs(fd, &st) != 0)
1346 		send_status(id, errno_to_portable(errno));
1347 	else
1348 		send_statvfs(id, &st);
1349 }
1350 
1351 static void
process_extended_hardlink(u_int32_t id)1352 process_extended_hardlink(u_int32_t id)
1353 {
1354 	char *oldpath, *newpath;
1355 	int r, status;
1356 
1357 	if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1358 	    (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1359 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1360 
1361 	debug3("request %u: hardlink", id);
1362 	logit("hardlink old \"%s\" new \"%s\"", oldpath, newpath);
1363 	r = link(oldpath, newpath);
1364 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1365 	send_status(id, status);
1366 	free(oldpath);
1367 	free(newpath);
1368 }
1369 
1370 static void
process_extended_fsync(u_int32_t id)1371 process_extended_fsync(u_int32_t id)
1372 {
1373 	int handle, fd, r, status = SSH2_FX_OP_UNSUPPORTED;
1374 
1375 	if ((r = get_handle(iqueue, &handle)) != 0)
1376 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1377 	debug3("request %u: fsync (handle %u)", id, handle);
1378 	verbose("fsync \"%s\"", handle_to_name(handle));
1379 	if ((fd = handle_to_fd(handle)) < 0)
1380 		status = SSH2_FX_NO_SUCH_FILE;
1381 	else if (handle_is_ok(handle, HANDLE_FILE)) {
1382 		r = fsync(fd);
1383 		status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1384 	}
1385 	send_status(id, status);
1386 }
1387 
1388 static void
process_extended_lsetstat(u_int32_t id)1389 process_extended_lsetstat(u_int32_t id)
1390 {
1391 	Attrib a;
1392 	char *name;
1393 	int r, status = SSH2_FX_OK;
1394 
1395 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
1396 	    (r = decode_attrib(iqueue, &a)) != 0)
1397 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1398 
1399 	debug("request %u: lsetstat name \"%s\"", id, name);
1400 	if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
1401 		/* nonsensical for links */
1402 		status = SSH2_FX_BAD_MESSAGE;
1403 		goto out;
1404 	}
1405 	if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1406 		logit("set \"%s\" mode %04o", name, a.perm);
1407 		r = fchmodat(AT_FDCWD, name,
1408 		    a.perm & 07777, AT_SYMLINK_NOFOLLOW);
1409 		if (r == -1)
1410 			status = errno_to_portable(errno);
1411 	}
1412 	if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1413 		char buf[64];
1414 		time_t t = a.mtime;
1415 
1416 		strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1417 		    localtime(&t));
1418 		logit("set \"%s\" modtime %s", name, buf);
1419 		r = utimensat(AT_FDCWD, name,
1420 		    attrib_to_ts(&a), AT_SYMLINK_NOFOLLOW);
1421 		if (r == -1)
1422 			status = errno_to_portable(errno);
1423 	}
1424 	if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1425 		logit("set \"%s\" owner %lu group %lu", name,
1426 		    (u_long)a.uid, (u_long)a.gid);
1427 		r = fchownat(AT_FDCWD, name, a.uid, a.gid,
1428 		    AT_SYMLINK_NOFOLLOW);
1429 		if (r == -1)
1430 			status = errno_to_portable(errno);
1431 	}
1432  out:
1433 	send_status(id, status);
1434 	free(name);
1435 }
1436 
1437 static void
process_extended(u_int32_t id)1438 process_extended(u_int32_t id)
1439 {
1440 	char *request;
1441 	int i, r;
1442 
1443 	if ((r = sshbuf_get_cstring(iqueue, &request, NULL)) != 0)
1444 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1445 	for (i = 0; extended_handlers[i].handler != NULL; i++) {
1446 		if (strcmp(request, extended_handlers[i].ext_name) == 0) {
1447 			if (!request_permitted(&extended_handlers[i]))
1448 				send_status(id, SSH2_FX_PERMISSION_DENIED);
1449 			else
1450 				extended_handlers[i].handler(id);
1451 			break;
1452 		}
1453 	}
1454 	if (extended_handlers[i].handler == NULL) {
1455 		error("Unknown extended request \"%.100s\"", request);
1456 		send_status(id, SSH2_FX_OP_UNSUPPORTED);	/* MUST */
1457 	}
1458 	free(request);
1459 }
1460 
1461 /* stolen from ssh-agent */
1462 
1463 static void
process(void)1464 process(void)
1465 {
1466 	u_int msg_len;
1467 	u_int buf_len;
1468 	u_int consumed;
1469 	u_char type;
1470 	const u_char *cp;
1471 	int i, r;
1472 	u_int32_t id;
1473 
1474 	buf_len = sshbuf_len(iqueue);
1475 	if (buf_len < 5)
1476 		return;		/* Incomplete message. */
1477 	cp = sshbuf_ptr(iqueue);
1478 	msg_len = get_u32(cp);
1479 	if (msg_len > SFTP_MAX_MSG_LENGTH) {
1480 		error("bad message from %s local user %s",
1481 		    client_addr, pw->pw_name);
1482 		sftp_server_cleanup_exit(11);
1483 	}
1484 	if (buf_len < msg_len + 4)
1485 		return;
1486 	if ((r = sshbuf_consume(iqueue, 4)) != 0)
1487 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1488 	buf_len -= 4;
1489 	if ((r = sshbuf_get_u8(iqueue, &type)) != 0)
1490 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1491 
1492 	switch (type) {
1493 	case SSH2_FXP_INIT:
1494 		process_init();
1495 		init_done = 1;
1496 		break;
1497 	case SSH2_FXP_EXTENDED:
1498 		if (!init_done)
1499 			fatal("Received extended request before init");
1500 		if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
1501 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
1502 		process_extended(id);
1503 		break;
1504 	default:
1505 		if (!init_done)
1506 			fatal("Received %u request before init", type);
1507 		if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
1508 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
1509 		for (i = 0; handlers[i].handler != NULL; i++) {
1510 			if (type == handlers[i].type) {
1511 				if (!request_permitted(&handlers[i])) {
1512 					send_status(id,
1513 					    SSH2_FX_PERMISSION_DENIED);
1514 				} else {
1515 					handlers[i].handler(id);
1516 				}
1517 				break;
1518 			}
1519 		}
1520 		if (handlers[i].handler == NULL)
1521 			error("Unknown message %u", type);
1522 	}
1523 	/* discard the remaining bytes from the current packet */
1524 	if (buf_len < sshbuf_len(iqueue)) {
1525 		error("iqueue grew unexpectedly");
1526 		sftp_server_cleanup_exit(255);
1527 	}
1528 	consumed = buf_len - sshbuf_len(iqueue);
1529 	if (msg_len < consumed) {
1530 		error("msg_len %u < consumed %u", msg_len, consumed);
1531 		sftp_server_cleanup_exit(255);
1532 	}
1533 	if (msg_len > consumed &&
1534 	    (r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
1535 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
1536 }
1537 
1538 /* Cleanup handler that logs active handles upon normal exit */
1539 void
sftp_server_cleanup_exit(int i)1540 sftp_server_cleanup_exit(int i)
1541 {
1542 	if (pw != NULL && client_addr != NULL) {
1543 		handle_log_exit();
1544 		logit("session closed for local user %s from [%s]",
1545 		    pw->pw_name, client_addr);
1546 	}
1547 	_exit(i);
1548 }
1549 
1550 static void
sftp_server_usage(void)1551 sftp_server_usage(void)
1552 {
1553 	extern char *__progname;
1554 
1555 	fprintf(stderr,
1556 	    "usage: %s [-ehR] [-d start_directory] [-f log_facility] "
1557 	    "[-l log_level]\n\t[-P blacklisted_requests] "
1558 	    "[-p whitelisted_requests] [-u umask]\n"
1559 	    "       %s -Q protocol_feature\n",
1560 	    __progname, __progname);
1561 	exit(1);
1562 }
1563 
1564 int
sftp_server_main(int argc,char ** argv,struct passwd * user_pw)1565 sftp_server_main(int argc, char **argv, struct passwd *user_pw)
1566 {
1567 	fd_set *rset, *wset;
1568 	int i, r, in, out, max, ch, skipargs = 0, log_stderr = 0;
1569 	ssize_t len, olen, set_size;
1570 	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
1571 	char *cp, *homedir = NULL, uidstr[32], buf[4*4096];
1572 	long mask;
1573 
1574 	extern char *optarg;
1575 	extern char *__progname;
1576 
1577 	ssh_malloc_init();	/* must be called before any mallocs */
1578 	__progname = ssh_get_progname(argv[0]);
1579 	log_init(__progname, log_level, log_facility, log_stderr);
1580 
1581 	pw = pwcopy(user_pw);
1582 
1583 	while (!skipargs && (ch = getopt(argc, argv,
1584 	    "d:f:l:P:p:Q:u:cehR")) != -1) {
1585 		switch (ch) {
1586 		case 'Q':
1587 			if (strcasecmp(optarg, "requests") != 0) {
1588 				fprintf(stderr, "Invalid query type\n");
1589 				exit(1);
1590 			}
1591 			for (i = 0; handlers[i].handler != NULL; i++)
1592 				printf("%s\n", handlers[i].name);
1593 			for (i = 0; extended_handlers[i].handler != NULL; i++)
1594 				printf("%s\n", extended_handlers[i].name);
1595 			exit(0);
1596 			break;
1597 		case 'R':
1598 			readonly = 1;
1599 			break;
1600 		case 'c':
1601 			/*
1602 			 * Ignore all arguments if we are invoked as a
1603 			 * shell using "sftp-server -c command"
1604 			 */
1605 			skipargs = 1;
1606 			break;
1607 		case 'e':
1608 			log_stderr = 1;
1609 			break;
1610 		case 'l':
1611 			log_level = log_level_number(optarg);
1612 			if (log_level == SYSLOG_LEVEL_NOT_SET)
1613 				error("Invalid log level \"%s\"", optarg);
1614 			break;
1615 		case 'f':
1616 			log_facility = log_facility_number(optarg);
1617 			if (log_facility == SYSLOG_FACILITY_NOT_SET)
1618 				error("Invalid log facility \"%s\"", optarg);
1619 			break;
1620 		case 'd':
1621 			cp = tilde_expand_filename(optarg, user_pw->pw_uid);
1622 			snprintf(uidstr, sizeof(uidstr), "%llu",
1623 			    (unsigned long long)pw->pw_uid);
1624 			homedir = percent_expand(cp, "d", user_pw->pw_dir,
1625 			    "u", user_pw->pw_name, "U", uidstr, (char *)NULL);
1626 			free(cp);
1627 			break;
1628 		case 'p':
1629 			if (request_whitelist != NULL)
1630 				fatal("Permitted requests already set");
1631 			request_whitelist = xstrdup(optarg);
1632 			break;
1633 		case 'P':
1634 			if (request_blacklist != NULL)
1635 				fatal("Refused requests already set");
1636 			request_blacklist = xstrdup(optarg);
1637 			break;
1638 		case 'u':
1639 			errno = 0;
1640 			mask = strtol(optarg, &cp, 8);
1641 			if (mask < 0 || mask > 0777 || *cp != '\0' ||
1642 			    cp == optarg || (mask == 0 && errno != 0))
1643 				fatal("Invalid umask \"%s\"", optarg);
1644 			(void)umask((mode_t)mask);
1645 			break;
1646 		case 'h':
1647 		default:
1648 			sftp_server_usage();
1649 		}
1650 	}
1651 
1652 	log_init(__progname, log_level, log_facility, log_stderr);
1653 
1654 	/*
1655 	 * On platforms where we can, avoid making /proc/self/{mem,maps}
1656 	 * available to the user so that sftp access doesn't automatically
1657 	 * imply arbitrary code execution access that will break
1658 	 * restricted configurations.
1659 	 */
1660 	platform_disable_tracing(1);	/* strict */
1661 
1662 	/* Drop any fine-grained privileges we don't need */
1663 	platform_pledge_sftp_server();
1664 
1665 	if ((cp = getenv("SSH_CONNECTION")) != NULL) {
1666 		client_addr = xstrdup(cp);
1667 		if ((cp = strchr(client_addr, ' ')) == NULL) {
1668 			error("Malformed SSH_CONNECTION variable: \"%s\"",
1669 			    getenv("SSH_CONNECTION"));
1670 			sftp_server_cleanup_exit(255);
1671 		}
1672 		*cp = '\0';
1673 	} else
1674 		client_addr = xstrdup("UNKNOWN");
1675 
1676 	logit("session opened for local user %s from [%s]",
1677 	    pw->pw_name, client_addr);
1678 
1679 	in = STDIN_FILENO;
1680 	out = STDOUT_FILENO;
1681 
1682 #ifdef HAVE_CYGWIN
1683 	setmode(in, O_BINARY);
1684 	setmode(out, O_BINARY);
1685 #endif
1686 
1687 	max = 0;
1688 	if (in > max)
1689 		max = in;
1690 	if (out > max)
1691 		max = out;
1692 
1693 	if ((iqueue = sshbuf_new()) == NULL)
1694 		fatal("%s: sshbuf_new failed", __func__);
1695 	if ((oqueue = sshbuf_new()) == NULL)
1696 		fatal("%s: sshbuf_new failed", __func__);
1697 
1698 	rset = xcalloc(howmany(max + 1, NFDBITS), sizeof(fd_mask));
1699 	wset = xcalloc(howmany(max + 1, NFDBITS), sizeof(fd_mask));
1700 
1701 	if (homedir != NULL) {
1702 		if (chdir(homedir) != 0) {
1703 			error("chdir to \"%s\" failed: %s", homedir,
1704 			    strerror(errno));
1705 		}
1706 	}
1707 
1708 	set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
1709 	for (;;) {
1710 		memset(rset, 0, set_size);
1711 		memset(wset, 0, set_size);
1712 
1713 		/*
1714 		 * Ensure that we can read a full buffer and handle
1715 		 * the worst-case length packet it can generate,
1716 		 * otherwise apply backpressure by stopping reads.
1717 		 */
1718 		if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
1719 		    (r = sshbuf_check_reserve(oqueue,
1720 		    SFTP_MAX_MSG_LENGTH)) == 0)
1721 			FD_SET(in, rset);
1722 		else if (r != SSH_ERR_NO_BUFFER_SPACE)
1723 			fatal("%s: sshbuf_check_reserve failed: %s",
1724 			    __func__, ssh_err(r));
1725 
1726 		olen = sshbuf_len(oqueue);
1727 		if (olen > 0)
1728 			FD_SET(out, wset);
1729 
1730 		if (select(max+1, rset, wset, NULL, NULL) < 0) {
1731 			if (errno == EINTR)
1732 				continue;
1733 			error("select: %s", strerror(errno));
1734 			sftp_server_cleanup_exit(2);
1735 		}
1736 
1737 		/* copy stdin to iqueue */
1738 		if (FD_ISSET(in, rset)) {
1739 			len = read(in, buf, sizeof buf);
1740 			if (len == 0) {
1741 				debug("read eof");
1742 				sftp_server_cleanup_exit(0);
1743 			} else if (len < 0) {
1744 				error("read: %s", strerror(errno));
1745 				sftp_server_cleanup_exit(1);
1746 			} else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
1747 				fatal("%s: buffer error: %s",
1748 				    __func__, ssh_err(r));
1749 			}
1750 		}
1751 		/* send oqueue to stdout */
1752 		if (FD_ISSET(out, wset)) {
1753 			len = write(out, sshbuf_ptr(oqueue), olen);
1754 			if (len < 0) {
1755 				error("write: %s", strerror(errno));
1756 				sftp_server_cleanup_exit(1);
1757 			} else if ((r = sshbuf_consume(oqueue, len)) != 0) {
1758 				fatal("%s: buffer error: %s",
1759 				    __func__, ssh_err(r));
1760 			}
1761 		}
1762 
1763 		/*
1764 		 * Process requests from client if we can fit the results
1765 		 * into the output buffer, otherwise stop processing input
1766 		 * and let the output queue drain.
1767 		 */
1768 		r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH);
1769 		if (r == 0)
1770 			process();
1771 		else if (r != SSH_ERR_NO_BUFFER_SPACE)
1772 			fatal("%s: sshbuf_check_reserve: %s",
1773 			    __func__, ssh_err(r));
1774 	}
1775 }
1776