1 /* $NetBSD: sftp-server.c,v 1.31 2024/07/08 22:33:44 christos Exp $ */
2 /* $OpenBSD: sftp-server.c,v 1.148 2024/04/30 06:23:51 djm Exp $ */
3
4 /*
5 * Copyright (c) 2000-2004 Markus Friedl. All rights reserved.
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #include "includes.h"
21 __RCSID("$NetBSD: sftp-server.c,v 1.31 2024/07/08 22:33:44 christos Exp $");
22
23 #include <sys/param.h> /* MIN */
24 #include <sys/types.h>
25 #include <sys/resource.h>
26 #include <sys/stat.h>
27 #include <sys/time.h>
28 #include <sys/mount.h>
29 #include <sys/statvfs.h>
30
31 #include <dirent.h>
32 #include <errno.h>
33 #include <fcntl.h>
34 #include <poll.h>
35 #include <stdlib.h>
36 #include <stdio.h>
37 #include <string.h>
38 #include <pwd.h>
39 #include <grp.h>
40 #include <time.h>
41 #include <unistd.h>
42 #include <stdarg.h>
43
44 #include "atomicio.h"
45 #include "xmalloc.h"
46 #include "sshbuf.h"
47 #include "ssherr.h"
48 #include "log.h"
49 #include "misc.h"
50 #include "match.h"
51 #include "uidswap.h"
52
53 #include "sftp.h"
54 #include "sftp-common.h"
55
56 char *sftp_realpath(const char *, char *); /* sftp-realpath.c */
57
58 /* Maximum data read that we are willing to accept */
59 #define SFTP_MAX_READ_LENGTH (SFTP_MAX_MSG_LENGTH - 1024)
60
61 /* Our verbosity */
62 static LogLevel log_level = SYSLOG_LEVEL_ERROR;
63
64 /* Our client */
65 static struct passwd *pw = NULL;
66 static char *client_addr = NULL;
67
68 /* input and output queue */
69 struct sshbuf *iqueue;
70 struct sshbuf *oqueue;
71
72 /* Version of client */
73 static u_int version;
74
75 /* SSH2_FXP_INIT received */
76 static int init_done;
77
78 /* Disable writes */
79 static int readonly;
80
81 /* Requests that are allowed/denied */
82 static char *request_allowlist, *request_denylist;
83
84 /* portable attributes, etc. */
85 typedef struct Stat Stat;
86
87 struct Stat {
88 char *name;
89 char *long_name;
90 Attrib attrib;
91 };
92
93 /* Packet handlers */
94 static void process_open(u_int32_t id);
95 static void process_close(u_int32_t id);
96 static void process_read(u_int32_t id);
97 static void process_write(u_int32_t id);
98 static void process_stat(u_int32_t id);
99 static void process_lstat(u_int32_t id);
100 static void process_fstat(u_int32_t id);
101 static void process_setstat(u_int32_t id);
102 static void process_fsetstat(u_int32_t id);
103 static void process_opendir(u_int32_t id);
104 static void process_readdir(u_int32_t id);
105 static void process_remove(u_int32_t id);
106 static void process_mkdir(u_int32_t id);
107 static void process_rmdir(u_int32_t id);
108 static void process_realpath(u_int32_t id);
109 static void process_rename(u_int32_t id);
110 static void process_readlink(u_int32_t id);
111 static void process_symlink(u_int32_t id);
112 static void process_extended_posix_rename(u_int32_t id);
113 static void process_extended_statvfs(u_int32_t id);
114 static void process_extended_fstatvfs(u_int32_t id);
115 static void process_extended_hardlink(u_int32_t id);
116 static void process_extended_fsync(u_int32_t id);
117 static void process_extended_lsetstat(u_int32_t id);
118 static void process_extended_limits(u_int32_t id);
119 static void process_extended_expand(u_int32_t id);
120 static void process_extended_copy_data(u_int32_t id);
121 static void process_extended_home_directory(u_int32_t id);
122 static void process_extended_get_users_groups_by_id(u_int32_t id);
123 static void process_extended(u_int32_t id);
124
125 struct sftp_handler {
126 const char *name; /* user-visible name for fine-grained perms */
127 const char *ext_name; /* extended request name */
128 u_int type; /* packet type, for non extended packets */
129 void (*handler)(u_int32_t);
130 int does_write; /* if nonzero, banned for readonly mode */
131 };
132
133 static const struct sftp_handler handlers[] = {
134 /* NB. SSH2_FXP_OPEN does the readonly check in the handler itself */
135 { "open", NULL, SSH2_FXP_OPEN, process_open, 0 },
136 { "close", NULL, SSH2_FXP_CLOSE, process_close, 0 },
137 { "read", NULL, SSH2_FXP_READ, process_read, 0 },
138 { "write", NULL, SSH2_FXP_WRITE, process_write, 1 },
139 { "lstat", NULL, SSH2_FXP_LSTAT, process_lstat, 0 },
140 { "fstat", NULL, SSH2_FXP_FSTAT, process_fstat, 0 },
141 { "setstat", NULL, SSH2_FXP_SETSTAT, process_setstat, 1 },
142 { "fsetstat", NULL, SSH2_FXP_FSETSTAT, process_fsetstat, 1 },
143 { "opendir", NULL, SSH2_FXP_OPENDIR, process_opendir, 0 },
144 { "readdir", NULL, SSH2_FXP_READDIR, process_readdir, 0 },
145 { "remove", NULL, SSH2_FXP_REMOVE, process_remove, 1 },
146 { "mkdir", NULL, SSH2_FXP_MKDIR, process_mkdir, 1 },
147 { "rmdir", NULL, SSH2_FXP_RMDIR, process_rmdir, 1 },
148 { "realpath", NULL, SSH2_FXP_REALPATH, process_realpath, 0 },
149 { "stat", NULL, SSH2_FXP_STAT, process_stat, 0 },
150 { "rename", NULL, SSH2_FXP_RENAME, process_rename, 1 },
151 { "readlink", NULL, SSH2_FXP_READLINK, process_readlink, 0 },
152 { "symlink", NULL, SSH2_FXP_SYMLINK, process_symlink, 1 },
153 { NULL, NULL, 0, NULL, 0 }
154 };
155
156 /* SSH2_FXP_EXTENDED submessages */
157 static const struct sftp_handler extended_handlers[] = {
158 { "posix-rename", "posix-rename@openssh.com", 0,
159 process_extended_posix_rename, 1 },
160 { "statvfs", "statvfs@openssh.com", 0, process_extended_statvfs, 0 },
161 { "fstatvfs", "fstatvfs@openssh.com", 0, process_extended_fstatvfs, 0 },
162 { "hardlink", "hardlink@openssh.com", 0, process_extended_hardlink, 1 },
163 { "fsync", "fsync@openssh.com", 0, process_extended_fsync, 1 },
164 { "lsetstat", "lsetstat@openssh.com", 0, process_extended_lsetstat, 1 },
165 { "limits", "limits@openssh.com", 0, process_extended_limits, 0 },
166 { "expand-path", "expand-path@openssh.com", 0,
167 process_extended_expand, 0 },
168 { "copy-data", "copy-data", 0, process_extended_copy_data, 1 },
169 { "home-directory", "home-directory", 0,
170 process_extended_home_directory, 0 },
171 { "users-groups-by-id", "users-groups-by-id@openssh.com", 0,
172 process_extended_get_users_groups_by_id, 0 },
173 { NULL, NULL, 0, NULL, 0 }
174 };
175
176 static const struct sftp_handler *
extended_handler_byname(const char * name)177 extended_handler_byname(const char *name)
178 {
179 int i;
180
181 for (i = 0; extended_handlers[i].handler != NULL; i++) {
182 if (strcmp(name, extended_handlers[i].ext_name) == 0)
183 return &extended_handlers[i];
184 }
185 return NULL;
186 }
187
188 static int
request_permitted(const struct sftp_handler * h)189 request_permitted(const struct sftp_handler *h)
190 {
191 char *result;
192
193 if (readonly && h->does_write) {
194 verbose("Refusing %s request in read-only mode", h->name);
195 return 0;
196 }
197 if (request_denylist != NULL &&
198 ((result = match_list(h->name, request_denylist, NULL))) != NULL) {
199 free(result);
200 verbose("Refusing denylisted %s request", h->name);
201 return 0;
202 }
203 if (request_allowlist != NULL &&
204 ((result = match_list(h->name, request_allowlist, NULL))) != NULL) {
205 free(result);
206 debug2("Permitting allowlisted %s request", h->name);
207 return 1;
208 }
209 if (request_allowlist != NULL) {
210 verbose("Refusing non-allowlisted %s request", h->name);
211 return 0;
212 }
213 return 1;
214 }
215
216 static int
errno_to_portable(int unixerrno)217 errno_to_portable(int unixerrno)
218 {
219 int ret = 0;
220
221 switch (unixerrno) {
222 case 0:
223 ret = SSH2_FX_OK;
224 break;
225 case ENOENT:
226 case ENOTDIR:
227 case EBADF:
228 case ELOOP:
229 ret = SSH2_FX_NO_SUCH_FILE;
230 break;
231 case EPERM:
232 case EACCES:
233 case EFAULT:
234 ret = SSH2_FX_PERMISSION_DENIED;
235 break;
236 case ENAMETOOLONG:
237 case EINVAL:
238 ret = SSH2_FX_BAD_MESSAGE;
239 break;
240 case ENOSYS:
241 ret = SSH2_FX_OP_UNSUPPORTED;
242 break;
243 default:
244 ret = SSH2_FX_FAILURE;
245 break;
246 }
247 return ret;
248 }
249
250 static int
flags_from_portable(int pflags)251 flags_from_portable(int pflags)
252 {
253 int flags = 0;
254
255 if ((pflags & SSH2_FXF_READ) &&
256 (pflags & SSH2_FXF_WRITE)) {
257 flags = O_RDWR;
258 } else if (pflags & SSH2_FXF_READ) {
259 flags = O_RDONLY;
260 } else if (pflags & SSH2_FXF_WRITE) {
261 flags = O_WRONLY;
262 }
263 if (pflags & SSH2_FXF_APPEND)
264 flags |= O_APPEND;
265 if (pflags & SSH2_FXF_CREAT)
266 flags |= O_CREAT;
267 if (pflags & SSH2_FXF_TRUNC)
268 flags |= O_TRUNC;
269 if (pflags & SSH2_FXF_EXCL)
270 flags |= O_EXCL;
271 return flags;
272 }
273
274 static const char *
string_from_portable(int pflags)275 string_from_portable(int pflags)
276 {
277 static char ret[128];
278
279 *ret = '\0';
280
281 #define PAPPEND(str) { \
282 if (*ret != '\0') \
283 strlcat(ret, ",", sizeof(ret)); \
284 strlcat(ret, str, sizeof(ret)); \
285 }
286
287 if (pflags & SSH2_FXF_READ)
288 PAPPEND("READ")
289 if (pflags & SSH2_FXF_WRITE)
290 PAPPEND("WRITE")
291 if (pflags & SSH2_FXF_APPEND)
292 PAPPEND("APPEND")
293 if (pflags & SSH2_FXF_CREAT)
294 PAPPEND("CREATE")
295 if (pflags & SSH2_FXF_TRUNC)
296 PAPPEND("TRUNCATE")
297 if (pflags & SSH2_FXF_EXCL)
298 PAPPEND("EXCL")
299
300 return ret;
301 }
302
303 /* handle handles */
304
305 typedef struct Handle Handle;
306 struct Handle {
307 int use;
308 DIR *dirp;
309 int fd;
310 int flags;
311 char *name;
312 u_int64_t bytes_read, bytes_write;
313 int next_unused;
314 };
315
316 enum {
317 HANDLE_UNUSED,
318 HANDLE_DIR,
319 HANDLE_FILE
320 };
321
322 static Handle *handles = NULL;
323 static u_int num_handles = 0;
324 static int first_unused_handle = -1;
325
handle_unused(int i)326 static void handle_unused(int i)
327 {
328 handles[i].use = HANDLE_UNUSED;
329 handles[i].next_unused = first_unused_handle;
330 first_unused_handle = i;
331 }
332
333 static int
handle_new(int use,const char * name,int fd,int flags,DIR * dirp)334 handle_new(int use, const char *name, int fd, int flags, DIR *dirp)
335 {
336 int i;
337
338 if (first_unused_handle == -1) {
339 if (num_handles + 1 <= num_handles)
340 return -1;
341 num_handles++;
342 handles = xreallocarray(handles, num_handles, sizeof(Handle));
343 handle_unused(num_handles - 1);
344 }
345
346 i = first_unused_handle;
347 first_unused_handle = handles[i].next_unused;
348
349 handles[i].use = use;
350 handles[i].dirp = dirp;
351 handles[i].fd = fd;
352 handles[i].flags = flags;
353 handles[i].name = xstrdup(name);
354 handles[i].bytes_read = handles[i].bytes_write = 0;
355
356 return i;
357 }
358
359 static int
handle_is_ok(int i,int type)360 handle_is_ok(int i, int type)
361 {
362 return i >= 0 && (u_int)i < num_handles && handles[i].use == type;
363 }
364
365 static int
handle_to_string(int handle,u_char ** stringp,int * hlenp)366 handle_to_string(int handle, u_char **stringp, int *hlenp)
367 {
368 if (stringp == NULL || hlenp == NULL)
369 return -1;
370 *stringp = xmalloc(sizeof(int32_t));
371 put_u32(*stringp, handle);
372 *hlenp = sizeof(int32_t);
373 return 0;
374 }
375
376 static int
handle_from_string(const u_char * handle,u_int hlen)377 handle_from_string(const u_char *handle, u_int hlen)
378 {
379 int val;
380
381 if (hlen != sizeof(int32_t))
382 return -1;
383 val = get_u32(handle);
384 if (handle_is_ok(val, HANDLE_FILE) ||
385 handle_is_ok(val, HANDLE_DIR))
386 return val;
387 return -1;
388 }
389
390 static char *
handle_to_name(int handle)391 handle_to_name(int handle)
392 {
393 if (handle_is_ok(handle, HANDLE_DIR)||
394 handle_is_ok(handle, HANDLE_FILE))
395 return handles[handle].name;
396 return NULL;
397 }
398
399 static DIR *
handle_to_dir(int handle)400 handle_to_dir(int handle)
401 {
402 if (handle_is_ok(handle, HANDLE_DIR))
403 return handles[handle].dirp;
404 return NULL;
405 }
406
407 static int
handle_to_fd(int handle)408 handle_to_fd(int handle)
409 {
410 if (handle_is_ok(handle, HANDLE_FILE))
411 return handles[handle].fd;
412 return -1;
413 }
414
415 static int
handle_to_flags(int handle)416 handle_to_flags(int handle)
417 {
418 if (handle_is_ok(handle, HANDLE_FILE))
419 return handles[handle].flags;
420 return 0;
421 }
422
423 static void
handle_update_read(int handle,ssize_t bytes)424 handle_update_read(int handle, ssize_t bytes)
425 {
426 if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
427 handles[handle].bytes_read += bytes;
428 }
429
430 static void
handle_update_write(int handle,ssize_t bytes)431 handle_update_write(int handle, ssize_t bytes)
432 {
433 if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
434 handles[handle].bytes_write += bytes;
435 }
436
437 static u_int64_t
handle_bytes_read(int handle)438 handle_bytes_read(int handle)
439 {
440 if (handle_is_ok(handle, HANDLE_FILE))
441 return (handles[handle].bytes_read);
442 return 0;
443 }
444
445 static u_int64_t
handle_bytes_write(int handle)446 handle_bytes_write(int handle)
447 {
448 if (handle_is_ok(handle, HANDLE_FILE))
449 return (handles[handle].bytes_write);
450 return 0;
451 }
452
453 static int
handle_close(int handle)454 handle_close(int handle)
455 {
456 int ret = -1;
457
458 if (handle_is_ok(handle, HANDLE_FILE)) {
459 ret = close(handles[handle].fd);
460 free(handles[handle].name);
461 handle_unused(handle);
462 } else if (handle_is_ok(handle, HANDLE_DIR)) {
463 ret = closedir(handles[handle].dirp);
464 free(handles[handle].name);
465 handle_unused(handle);
466 } else {
467 errno = ENOENT;
468 }
469 return ret;
470 }
471
472 static void
handle_log_close(int handle,const char * emsg)473 handle_log_close(int handle, const char *emsg)
474 {
475 if (handle_is_ok(handle, HANDLE_FILE)) {
476 logit("%s%sclose \"%s\" bytes read %llu written %llu",
477 emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
478 handle_to_name(handle),
479 (unsigned long long)handle_bytes_read(handle),
480 (unsigned long long)handle_bytes_write(handle));
481 } else {
482 logit("%s%sclosedir \"%s\"",
483 emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
484 handle_to_name(handle));
485 }
486 }
487
488 static void
handle_log_exit(void)489 handle_log_exit(void)
490 {
491 u_int i;
492
493 for (i = 0; i < num_handles; i++)
494 if (handles[i].use != HANDLE_UNUSED)
495 handle_log_close(i, "forced");
496 }
497
498 static int
get_handle(struct sshbuf * queue,int * hp)499 get_handle(struct sshbuf *queue, int *hp)
500 {
501 u_char *handle;
502 int r;
503 size_t hlen;
504
505 *hp = -1;
506 if ((r = sshbuf_get_string(queue, &handle, &hlen)) != 0)
507 return r;
508 if (hlen < 256)
509 *hp = handle_from_string(handle, hlen);
510 free(handle);
511 return 0;
512 }
513
514 /* send replies */
515
516 static void
send_msg(struct sshbuf * m)517 send_msg(struct sshbuf *m)
518 {
519 int r;
520
521 if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
522 fatal_fr(r, "enqueue");
523 sshbuf_reset(m);
524 }
525
526 static const char *
status_to_message(u_int32_t status)527 status_to_message(u_int32_t status)
528 {
529 static const char * const status_messages[] = {
530 "Success", /* SSH_FX_OK */
531 "End of file", /* SSH_FX_EOF */
532 "No such file", /* SSH_FX_NO_SUCH_FILE */
533 "Permission denied", /* SSH_FX_PERMISSION_DENIED */
534 "Failure", /* SSH_FX_FAILURE */
535 "Bad message", /* SSH_FX_BAD_MESSAGE */
536 "No connection", /* SSH_FX_NO_CONNECTION */
537 "Connection lost", /* SSH_FX_CONNECTION_LOST */
538 "Operation unsupported", /* SSH_FX_OP_UNSUPPORTED */
539 "Unknown error" /* Others */
540 };
541 return (status_messages[MINIMUM(status,SSH2_FX_MAX)]);
542 }
543
544 static void
send_status_errmsg(u_int32_t id,u_int32_t status,const char * errmsg)545 send_status_errmsg(u_int32_t id, u_int32_t status, const char *errmsg)
546 {
547 struct sshbuf *msg;
548 int r;
549
550 debug3("request %u: sent status %u", id, status);
551 if (log_level > SYSLOG_LEVEL_VERBOSE ||
552 (status != SSH2_FX_OK && status != SSH2_FX_EOF))
553 logit("sent status %s", status_to_message(status));
554 if ((msg = sshbuf_new()) == NULL)
555 fatal_f("sshbuf_new failed");
556 if ((r = sshbuf_put_u8(msg, SSH2_FXP_STATUS)) != 0 ||
557 (r = sshbuf_put_u32(msg, id)) != 0 ||
558 (r = sshbuf_put_u32(msg, status)) != 0)
559 fatal_fr(r, "compose");
560 if (version >= 3) {
561 if ((r = sshbuf_put_cstring(msg, errmsg == NULL ?
562 status_to_message(status) : errmsg)) != 0 ||
563 (r = sshbuf_put_cstring(msg, "")) != 0)
564 fatal_fr(r, "compose message");
565 }
566 send_msg(msg);
567 sshbuf_free(msg);
568 }
569
570 static void
send_status(u_int32_t id,u_int32_t status)571 send_status(u_int32_t id, u_int32_t status)
572 {
573 send_status_errmsg(id, status, NULL);
574 }
575
576 static void
send_data_or_handle(char type,u_int32_t id,const u_char * data,int dlen)577 send_data_or_handle(char type, u_int32_t id, const u_char *data, int dlen)
578 {
579 struct sshbuf *msg;
580 int r;
581
582 if ((msg = sshbuf_new()) == NULL)
583 fatal_f("sshbuf_new failed");
584 if ((r = sshbuf_put_u8(msg, type)) != 0 ||
585 (r = sshbuf_put_u32(msg, id)) != 0 ||
586 (r = sshbuf_put_string(msg, data, dlen)) != 0)
587 fatal_fr(r, "compose");
588 send_msg(msg);
589 sshbuf_free(msg);
590 }
591
592 static void
send_data(u_int32_t id,const u_char * data,int dlen)593 send_data(u_int32_t id, const u_char *data, int dlen)
594 {
595 debug("request %u: sent data len %d", id, dlen);
596 send_data_or_handle(SSH2_FXP_DATA, id, data, dlen);
597 }
598
599 static void
send_handle(u_int32_t id,int handle)600 send_handle(u_int32_t id, int handle)
601 {
602 u_char *string;
603 int hlen;
604
605 handle_to_string(handle, &string, &hlen);
606 debug("request %u: sent handle %d", id, handle);
607 send_data_or_handle(SSH2_FXP_HANDLE, id, string, hlen);
608 free(string);
609 }
610
611 static void
send_names(u_int32_t id,int count,const Stat * stats)612 send_names(u_int32_t id, int count, const Stat *stats)
613 {
614 struct sshbuf *msg;
615 int i, r;
616
617 if ((msg = sshbuf_new()) == NULL)
618 fatal_f("sshbuf_new failed");
619 if ((r = sshbuf_put_u8(msg, SSH2_FXP_NAME)) != 0 ||
620 (r = sshbuf_put_u32(msg, id)) != 0 ||
621 (r = sshbuf_put_u32(msg, count)) != 0)
622 fatal_fr(r, "compose");
623 debug("request %u: sent names count %d", id, count);
624 for (i = 0; i < count; i++) {
625 if ((r = sshbuf_put_cstring(msg, stats[i].name)) != 0 ||
626 (r = sshbuf_put_cstring(msg, stats[i].long_name)) != 0 ||
627 (r = encode_attrib(msg, &stats[i].attrib)) != 0)
628 fatal_fr(r, "compose filenames/attrib");
629 }
630 send_msg(msg);
631 sshbuf_free(msg);
632 }
633
634 static void
send_attrib(u_int32_t id,const Attrib * a)635 send_attrib(u_int32_t id, const Attrib *a)
636 {
637 struct sshbuf *msg;
638 int r;
639
640 debug("request %u: sent attrib have 0x%x", id, a->flags);
641 if ((msg = sshbuf_new()) == NULL)
642 fatal_f("sshbuf_new failed");
643 if ((r = sshbuf_put_u8(msg, SSH2_FXP_ATTRS)) != 0 ||
644 (r = sshbuf_put_u32(msg, id)) != 0 ||
645 (r = encode_attrib(msg, a)) != 0)
646 fatal_fr(r, "compose");
647 send_msg(msg);
648 sshbuf_free(msg);
649 }
650
651 static void
send_statvfs(u_int32_t id,struct statvfs * st)652 send_statvfs(u_int32_t id, struct statvfs *st)
653 {
654 struct sshbuf *msg;
655 u_int64_t flag;
656 int r;
657
658 flag = (st->f_flag & ST_RDONLY) ? SSH2_FXE_STATVFS_ST_RDONLY : 0;
659 flag |= (st->f_flag & ST_NOSUID) ? SSH2_FXE_STATVFS_ST_NOSUID : 0;
660
661 if ((msg = sshbuf_new()) == NULL)
662 fatal_f("sshbuf_new failed");
663 if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
664 (r = sshbuf_put_u32(msg, id)) != 0 ||
665 (r = sshbuf_put_u64(msg, st->f_bsize)) != 0 ||
666 (r = sshbuf_put_u64(msg, st->f_frsize)) != 0 ||
667 (r = sshbuf_put_u64(msg, st->f_blocks)) != 0 ||
668 (r = sshbuf_put_u64(msg, st->f_bfree)) != 0 ||
669 (r = sshbuf_put_u64(msg, st->f_bavail)) != 0 ||
670 (r = sshbuf_put_u64(msg, st->f_files)) != 0 ||
671 (r = sshbuf_put_u64(msg, st->f_ffree)) != 0 ||
672 (r = sshbuf_put_u64(msg, st->f_favail)) != 0 ||
673 (r = sshbuf_put_u64(msg, st->f_fsid)) != 0 ||
674 (r = sshbuf_put_u64(msg, flag)) != 0 ||
675 (r = sshbuf_put_u64(msg, st->f_namemax)) != 0)
676 fatal_fr(r, "compose");
677 send_msg(msg);
678 sshbuf_free(msg);
679 }
680
681 /*
682 * Prepare SSH2_FXP_VERSION extension advertisement for a single extension.
683 * The extension is checked for permission prior to advertisement.
684 */
685 static int
compose_extension(struct sshbuf * msg,const char * name,const char * ver)686 compose_extension(struct sshbuf *msg, const char *name, const char *ver)
687 {
688 int r;
689 const struct sftp_handler *exthnd;
690
691 if ((exthnd = extended_handler_byname(name)) == NULL)
692 fatal_f("internal error: no handler for %s", name);
693 if (!request_permitted(exthnd)) {
694 debug2_f("refusing to advertise disallowed extension %s", name);
695 return 0;
696 }
697 if ((r = sshbuf_put_cstring(msg, name)) != 0 ||
698 (r = sshbuf_put_cstring(msg, ver)) != 0)
699 fatal_fr(r, "compose %s", name);
700 return 0;
701 }
702
703 /* parse incoming */
704
705 static void
process_init(void)706 process_init(void)
707 {
708 struct sshbuf *msg;
709 int r;
710
711 if ((r = sshbuf_get_u32(iqueue, &version)) != 0)
712 fatal_fr(r, "parse");
713 verbose("received client version %u", version);
714 if ((msg = sshbuf_new()) == NULL)
715 fatal_f("sshbuf_new failed");
716 if ((r = sshbuf_put_u8(msg, SSH2_FXP_VERSION)) != 0 ||
717 (r = sshbuf_put_u32(msg, SSH2_FILEXFER_VERSION)) != 0)
718 fatal_fr(r, "compose");
719
720 /* extension advertisements */
721 compose_extension(msg, "posix-rename@openssh.com", "1");
722 compose_extension(msg, "statvfs@openssh.com", "2");
723 compose_extension(msg, "fstatvfs@openssh.com", "2");
724 compose_extension(msg, "hardlink@openssh.com", "1");
725 compose_extension(msg, "fsync@openssh.com", "1");
726 compose_extension(msg, "lsetstat@openssh.com", "1");
727 compose_extension(msg, "limits@openssh.com", "1");
728 compose_extension(msg, "expand-path@openssh.com", "1");
729 compose_extension(msg, "copy-data", "1");
730 compose_extension(msg, "home-directory", "1");
731 compose_extension(msg, "users-groups-by-id@openssh.com", "1");
732
733 send_msg(msg);
734 sshbuf_free(msg);
735 }
736
737 static void
process_open(u_int32_t id)738 process_open(u_int32_t id)
739 {
740 u_int32_t pflags;
741 Attrib a;
742 char *name;
743 int r, handle, fd, flags, mode, status = SSH2_FX_FAILURE;
744
745 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
746 (r = sshbuf_get_u32(iqueue, &pflags)) != 0 || /* portable flags */
747 (r = decode_attrib(iqueue, &a)) != 0)
748 fatal_fr(r, "parse");
749
750 debug3("request %u: open flags %d", id, pflags);
751 flags = flags_from_portable(pflags);
752 mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm : 0666;
753 logit("open \"%s\" flags %s mode 0%o",
754 name, string_from_portable(pflags), mode);
755 if (readonly &&
756 ((flags & O_ACCMODE) != O_RDONLY ||
757 (flags & (O_CREAT|O_TRUNC)) != 0)) {
758 verbose("Refusing open request in read-only mode");
759 status = SSH2_FX_PERMISSION_DENIED;
760 } else {
761 fd = open(name, flags, mode);
762 if (fd == -1) {
763 status = errno_to_portable(errno);
764 } else {
765 handle = handle_new(HANDLE_FILE, name, fd, flags, NULL);
766 if (handle < 0) {
767 close(fd);
768 } else {
769 send_handle(id, handle);
770 status = SSH2_FX_OK;
771 }
772 }
773 }
774 if (status != SSH2_FX_OK)
775 send_status(id, status);
776 free(name);
777 }
778
779 static void
process_close(u_int32_t id)780 process_close(u_int32_t id)
781 {
782 int r, handle, ret, status = SSH2_FX_FAILURE;
783
784 if ((r = get_handle(iqueue, &handle)) != 0)
785 fatal_fr(r, "parse");
786
787 debug3("request %u: close handle %u", id, handle);
788 handle_log_close(handle, NULL);
789 ret = handle_close(handle);
790 status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
791 send_status(id, status);
792 }
793
794 static void
process_read(u_int32_t id)795 process_read(u_int32_t id)
796 {
797 static u_char *buf;
798 static size_t buflen;
799 u_int32_t len;
800 int r, handle, fd, ret, status = SSH2_FX_FAILURE;
801 u_int64_t off;
802
803 if ((r = get_handle(iqueue, &handle)) != 0 ||
804 (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
805 (r = sshbuf_get_u32(iqueue, &len)) != 0)
806 fatal_fr(r, "parse");
807
808 debug("request %u: read \"%s\" (handle %d) off %llu len %u",
809 id, handle_to_name(handle), handle, (unsigned long long)off, len);
810 if ((fd = handle_to_fd(handle)) == -1)
811 goto out;
812 if (len > SFTP_MAX_READ_LENGTH) {
813 debug2("read change len %u to %u", len, SFTP_MAX_READ_LENGTH);
814 len = SFTP_MAX_READ_LENGTH;
815 }
816 if (len > buflen) {
817 debug3_f("allocate %zu => %u", buflen, len);
818 if ((buf = realloc(buf, len)) == NULL)
819 fatal_f("realloc failed");
820 buflen = len;
821 }
822 if (lseek(fd, off, SEEK_SET) == -1) {
823 status = errno_to_portable(errno);
824 error_f("seek \"%.100s\": %s", handle_to_name(handle),
825 strerror(errno));
826 goto out;
827 }
828 if (len == 0) {
829 /* weird, but not strictly disallowed */
830 ret = 0;
831 } else if ((ret = read(fd, buf, len)) == -1) {
832 status = errno_to_portable(errno);
833 error_f("read \"%.100s\": %s", handle_to_name(handle),
834 strerror(errno));
835 goto out;
836 } else if (ret == 0) {
837 status = SSH2_FX_EOF;
838 goto out;
839 }
840 send_data(id, buf, ret);
841 handle_update_read(handle, ret);
842 /* success */
843 status = SSH2_FX_OK;
844 out:
845 if (status != SSH2_FX_OK)
846 send_status(id, status);
847 }
848
849 static void
process_write(u_int32_t id)850 process_write(u_int32_t id)
851 {
852 u_int64_t off;
853 size_t len;
854 int r, handle, fd, ret, status;
855 u_char *data;
856
857 if ((r = get_handle(iqueue, &handle)) != 0 ||
858 (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
859 (r = sshbuf_get_string(iqueue, &data, &len)) != 0)
860 fatal_fr(r, "parse");
861
862 debug("request %u: write \"%s\" (handle %d) off %llu len %zu",
863 id, handle_to_name(handle), handle, (unsigned long long)off, len);
864 fd = handle_to_fd(handle);
865
866 if (fd < 0)
867 status = SSH2_FX_FAILURE;
868 else {
869 if (!(handle_to_flags(handle) & O_APPEND) &&
870 lseek(fd, off, SEEK_SET) == -1) {
871 status = errno_to_portable(errno);
872 error_f("seek \"%.100s\": %s", handle_to_name(handle),
873 strerror(errno));
874 } else {
875 /* XXX ATOMICIO ? */
876 ret = write(fd, data, len);
877 if (ret == -1) {
878 status = errno_to_portable(errno);
879 error_f("write \"%.100s\": %s",
880 handle_to_name(handle), strerror(errno));
881 } else if ((size_t)ret == len) {
882 status = SSH2_FX_OK;
883 handle_update_write(handle, ret);
884 } else {
885 debug2_f("nothing at all written");
886 status = SSH2_FX_FAILURE;
887 }
888 }
889 }
890 send_status(id, status);
891 free(data);
892 }
893
894 static void
process_do_stat(u_int32_t id,int do_lstat)895 process_do_stat(u_int32_t id, int do_lstat)
896 {
897 Attrib a;
898 struct stat st;
899 char *name;
900 int r, status = SSH2_FX_FAILURE;
901
902 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
903 fatal_fr(r, "parse");
904
905 debug3("request %u: %sstat", id, do_lstat ? "l" : "");
906 verbose("%sstat name \"%s\"", do_lstat ? "l" : "", name);
907 r = do_lstat ? lstat(name, &st) : stat(name, &st);
908 if (r == -1) {
909 status = errno_to_portable(errno);
910 } else {
911 stat_to_attrib(&st, &a);
912 send_attrib(id, &a);
913 status = SSH2_FX_OK;
914 }
915 if (status != SSH2_FX_OK)
916 send_status(id, status);
917 free(name);
918 }
919
920 static void
process_stat(u_int32_t id)921 process_stat(u_int32_t id)
922 {
923 process_do_stat(id, 0);
924 }
925
926 static void
process_lstat(u_int32_t id)927 process_lstat(u_int32_t id)
928 {
929 process_do_stat(id, 1);
930 }
931
932 static void
process_fstat(u_int32_t id)933 process_fstat(u_int32_t id)
934 {
935 Attrib a;
936 struct stat st;
937 int fd, r, handle, status = SSH2_FX_FAILURE;
938
939 if ((r = get_handle(iqueue, &handle)) != 0)
940 fatal_fr(r, "parse");
941 debug("request %u: fstat \"%s\" (handle %u)",
942 id, handle_to_name(handle), handle);
943 fd = handle_to_fd(handle);
944 if (fd >= 0) {
945 r = fstat(fd, &st);
946 if (r == -1) {
947 status = errno_to_portable(errno);
948 } else {
949 stat_to_attrib(&st, &a);
950 send_attrib(id, &a);
951 status = SSH2_FX_OK;
952 }
953 }
954 if (status != SSH2_FX_OK)
955 send_status(id, status);
956 }
957
958 static struct timeval *
attrib_to_tv(const Attrib * a)959 attrib_to_tv(const Attrib *a)
960 {
961 static struct timeval tv[2];
962
963 tv[0].tv_sec = a->atime;
964 tv[0].tv_usec = 0;
965 tv[1].tv_sec = a->mtime;
966 tv[1].tv_usec = 0;
967 return tv;
968 }
969
970 static struct timespec *
attrib_to_ts(const Attrib * a)971 attrib_to_ts(const Attrib *a)
972 {
973 static struct timespec ts[2];
974
975 ts[0].tv_sec = a->atime;
976 ts[0].tv_nsec = 0;
977 ts[1].tv_sec = a->mtime;
978 ts[1].tv_nsec = 0;
979 return ts;
980 }
981
982 static void
process_setstat(u_int32_t id)983 process_setstat(u_int32_t id)
984 {
985 Attrib a;
986 char *name;
987 int r, status = SSH2_FX_OK;
988
989 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
990 (r = decode_attrib(iqueue, &a)) != 0)
991 fatal_fr(r, "parse");
992
993 debug("request %u: setstat name \"%s\"", id, name);
994 if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
995 logit("set \"%s\" size %llu",
996 name, (unsigned long long)a.size);
997 r = truncate(name, a.size);
998 if (r == -1)
999 status = errno_to_portable(errno);
1000 }
1001 if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1002 logit("set \"%s\" mode %04o", name, a.perm);
1003 r = chmod(name, a.perm & 07777);
1004 if (r == -1)
1005 status = errno_to_portable(errno);
1006 }
1007 if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1008 char buf[64];
1009 time_t t = a.mtime;
1010
1011 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1012 localtime(&t));
1013 logit("set \"%s\" modtime %s", name, buf);
1014 r = utimes(name, attrib_to_tv(&a));
1015 if (r == -1)
1016 status = errno_to_portable(errno);
1017 }
1018 if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1019 logit("set \"%s\" owner %lu group %lu", name,
1020 (u_long)a.uid, (u_long)a.gid);
1021 r = chown(name, a.uid, a.gid);
1022 if (r == -1)
1023 status = errno_to_portable(errno);
1024 }
1025 send_status(id, status);
1026 free(name);
1027 }
1028
1029 static void
process_fsetstat(u_int32_t id)1030 process_fsetstat(u_int32_t id)
1031 {
1032 Attrib a;
1033 int handle, fd, r;
1034 int status = SSH2_FX_OK;
1035
1036 if ((r = get_handle(iqueue, &handle)) != 0 ||
1037 (r = decode_attrib(iqueue, &a)) != 0)
1038 fatal_fr(r, "parse");
1039
1040 debug("request %u: fsetstat handle %d", id, handle);
1041 fd = handle_to_fd(handle);
1042 if (fd < 0)
1043 status = SSH2_FX_FAILURE;
1044 else {
1045 char *name = handle_to_name(handle);
1046
1047 if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
1048 logit("set \"%s\" size %llu",
1049 name, (unsigned long long)a.size);
1050 r = ftruncate(fd, a.size);
1051 if (r == -1)
1052 status = errno_to_portable(errno);
1053 }
1054 if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1055 logit("set \"%s\" mode %04o", name, a.perm);
1056 r = fchmod(fd, a.perm & 07777);
1057 if (r == -1)
1058 status = errno_to_portable(errno);
1059 }
1060 if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1061 char buf[64];
1062 time_t t = a.mtime;
1063
1064 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1065 localtime(&t));
1066 logit("set \"%s\" modtime %s", name, buf);
1067 r = futimes(fd, attrib_to_tv(&a));
1068 if (r == -1)
1069 status = errno_to_portable(errno);
1070 }
1071 if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1072 logit("set \"%s\" owner %lu group %lu", name,
1073 (u_long)a.uid, (u_long)a.gid);
1074 r = fchown(fd, a.uid, a.gid);
1075 if (r == -1)
1076 status = errno_to_portable(errno);
1077 }
1078 }
1079 send_status(id, status);
1080 }
1081
1082 static void
process_opendir(u_int32_t id)1083 process_opendir(u_int32_t id)
1084 {
1085 DIR *dirp = NULL;
1086 char *path;
1087 int r, handle, status = SSH2_FX_FAILURE;
1088
1089 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1090 fatal_fr(r, "parse");
1091
1092 debug3("request %u: opendir", id);
1093 logit("opendir \"%s\"", path);
1094 dirp = opendir(path);
1095 if (dirp == NULL) {
1096 status = errno_to_portable(errno);
1097 } else {
1098 handle = handle_new(HANDLE_DIR, path, 0, 0, dirp);
1099 if (handle < 0) {
1100 closedir(dirp);
1101 } else {
1102 send_handle(id, handle);
1103 status = SSH2_FX_OK;
1104 }
1105
1106 }
1107 if (status != SSH2_FX_OK)
1108 send_status(id, status);
1109 free(path);
1110 }
1111
1112 static void
process_readdir(u_int32_t id)1113 process_readdir(u_int32_t id)
1114 {
1115 DIR *dirp;
1116 struct dirent *dp;
1117 char *path;
1118 int r, handle;
1119
1120 if ((r = get_handle(iqueue, &handle)) != 0)
1121 fatal_fr(r, "parse");
1122
1123 debug("request %u: readdir \"%s\" (handle %d)", id,
1124 handle_to_name(handle), handle);
1125 dirp = handle_to_dir(handle);
1126 path = handle_to_name(handle);
1127 if (dirp == NULL || path == NULL) {
1128 send_status(id, SSH2_FX_FAILURE);
1129 } else {
1130 struct stat st;
1131 char pathname[PATH_MAX];
1132 Stat *stats;
1133 int nstats = 10, count = 0, i;
1134
1135 stats = xcalloc(nstats, sizeof(Stat));
1136 while ((dp = readdir(dirp)) != NULL) {
1137 if (count >= nstats) {
1138 nstats *= 2;
1139 stats = xreallocarray(stats, nstats, sizeof(Stat));
1140 }
1141 /* XXX OVERFLOW ? */
1142 snprintf(pathname, sizeof pathname, "%s%s%s", path,
1143 strcmp(path, "/") ? "/" : "", dp->d_name);
1144 if (lstat(pathname, &st) == -1)
1145 continue;
1146 stat_to_attrib(&st, &(stats[count].attrib));
1147 stats[count].name = xstrdup(dp->d_name);
1148 stats[count].long_name = ls_file(dp->d_name, &st,
1149 0, 0, NULL, NULL);
1150 count++;
1151 /* send up to 100 entries in one message */
1152 /* XXX check packet size instead */
1153 if (count == 100)
1154 break;
1155 }
1156 if (count > 0) {
1157 send_names(id, count, stats);
1158 for (i = 0; i < count; i++) {
1159 free(stats[i].name);
1160 free(stats[i].long_name);
1161 }
1162 } else {
1163 send_status(id, SSH2_FX_EOF);
1164 }
1165 free(stats);
1166 }
1167 }
1168
1169 static void
process_remove(u_int32_t id)1170 process_remove(u_int32_t id)
1171 {
1172 char *name;
1173 int r, status = SSH2_FX_FAILURE;
1174
1175 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
1176 fatal_fr(r, "parse");
1177
1178 debug3("request %u: remove", id);
1179 logit("remove name \"%s\"", name);
1180 r = unlink(name);
1181 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1182 send_status(id, status);
1183 free(name);
1184 }
1185
1186 static void
process_mkdir(u_int32_t id)1187 process_mkdir(u_int32_t id)
1188 {
1189 Attrib a;
1190 char *name;
1191 int r, mode, status = SSH2_FX_FAILURE;
1192
1193 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
1194 (r = decode_attrib(iqueue, &a)) != 0)
1195 fatal_fr(r, "parse");
1196
1197 mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
1198 a.perm & 07777 : 0777;
1199 debug3("request %u: mkdir", id);
1200 logit("mkdir name \"%s\" mode 0%o", name, mode);
1201 r = mkdir(name, mode);
1202 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1203 send_status(id, status);
1204 free(name);
1205 }
1206
1207 static void
process_rmdir(u_int32_t id)1208 process_rmdir(u_int32_t id)
1209 {
1210 char *name;
1211 int r, status;
1212
1213 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
1214 fatal_fr(r, "parse");
1215
1216 debug3("request %u: rmdir", id);
1217 logit("rmdir name \"%s\"", name);
1218 r = rmdir(name);
1219 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1220 send_status(id, status);
1221 free(name);
1222 }
1223
1224 static void
process_realpath(u_int32_t id)1225 process_realpath(u_int32_t id)
1226 {
1227 char resolvedname[PATH_MAX];
1228 char *path;
1229 int r;
1230
1231 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1232 fatal_fr(r, "parse");
1233
1234 if (path[0] == '\0') {
1235 free(path);
1236 path = xstrdup(".");
1237 }
1238 debug3("request %u: realpath", id);
1239 verbose("realpath \"%s\"", path);
1240 if (sftp_realpath(path, resolvedname) == NULL) {
1241 send_status(id, errno_to_portable(errno));
1242 } else {
1243 Stat s;
1244 attrib_clear(&s.attrib);
1245 s.name = s.long_name = resolvedname;
1246 send_names(id, 1, &s);
1247 }
1248 free(path);
1249 }
1250
1251 static void
process_rename(u_int32_t id)1252 process_rename(u_int32_t id)
1253 {
1254 char *oldpath, *newpath;
1255 int r, status;
1256 struct stat sb;
1257
1258 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1259 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1260 fatal_fr(r, "parse");
1261
1262 debug3("request %u: rename", id);
1263 logit("rename old \"%s\" new \"%s\"", oldpath, newpath);
1264 status = SSH2_FX_FAILURE;
1265 if (lstat(oldpath, &sb) == -1)
1266 status = errno_to_portable(errno);
1267 else if (S_ISREG(sb.st_mode)) {
1268 /* Race-free rename of regular files */
1269 if (link(oldpath, newpath) == -1) {
1270 if (errno == EOPNOTSUPP) {
1271 struct stat st;
1272
1273 /*
1274 * fs doesn't support links, so fall back to
1275 * stat+rename. This is racy.
1276 */
1277 if (stat(newpath, &st) == -1) {
1278 if (rename(oldpath, newpath) == -1)
1279 status =
1280 errno_to_portable(errno);
1281 else
1282 status = SSH2_FX_OK;
1283 }
1284 } else {
1285 status = errno_to_portable(errno);
1286 }
1287 } else if (unlink(oldpath) == -1) {
1288 status = errno_to_portable(errno);
1289 /* clean spare link */
1290 unlink(newpath);
1291 } else
1292 status = SSH2_FX_OK;
1293 } else if (stat(newpath, &sb) == -1) {
1294 if (rename(oldpath, newpath) == -1)
1295 status = errno_to_portable(errno);
1296 else
1297 status = SSH2_FX_OK;
1298 }
1299 send_status(id, status);
1300 free(oldpath);
1301 free(newpath);
1302 }
1303
1304 static void
process_readlink(u_int32_t id)1305 process_readlink(u_int32_t id)
1306 {
1307 int r, len;
1308 char buf[PATH_MAX];
1309 char *path;
1310
1311 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1312 fatal_fr(r, "parse");
1313
1314 debug3("request %u: readlink", id);
1315 verbose("readlink \"%s\"", path);
1316 if ((len = readlink(path, buf, sizeof(buf) - 1)) == -1)
1317 send_status(id, errno_to_portable(errno));
1318 else {
1319 Stat s;
1320
1321 buf[len] = '\0';
1322 attrib_clear(&s.attrib);
1323 s.name = s.long_name = buf;
1324 send_names(id, 1, &s);
1325 }
1326 free(path);
1327 }
1328
1329 static void
process_symlink(u_int32_t id)1330 process_symlink(u_int32_t id)
1331 {
1332 char *oldpath, *newpath;
1333 int r, status;
1334
1335 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1336 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1337 fatal_fr(r, "parse");
1338
1339 debug3("request %u: symlink", id);
1340 logit("symlink old \"%s\" new \"%s\"", oldpath, newpath);
1341 /* this will fail if 'newpath' exists */
1342 r = symlink(oldpath, newpath);
1343 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1344 send_status(id, status);
1345 free(oldpath);
1346 free(newpath);
1347 }
1348
1349 static void
process_extended_posix_rename(u_int32_t id)1350 process_extended_posix_rename(u_int32_t id)
1351 {
1352 char *oldpath, *newpath;
1353 int r, status;
1354
1355 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1356 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1357 fatal_fr(r, "parse");
1358
1359 debug3("request %u: posix-rename", id);
1360 logit("posix-rename old \"%s\" new \"%s\"", oldpath, newpath);
1361 r = rename(oldpath, newpath);
1362 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1363 send_status(id, status);
1364 free(oldpath);
1365 free(newpath);
1366 }
1367
1368 static void
process_extended_statvfs(u_int32_t id)1369 process_extended_statvfs(u_int32_t id)
1370 {
1371 char *path;
1372 struct statvfs st;
1373 int r;
1374
1375 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1376 fatal_fr(r, "parse");
1377 debug3("request %u: statvfs", id);
1378 logit("statvfs \"%s\"", path);
1379
1380 if (statvfs(path, &st) != 0)
1381 send_status(id, errno_to_portable(errno));
1382 else
1383 send_statvfs(id, &st);
1384 free(path);
1385 }
1386
1387 static void
process_extended_fstatvfs(u_int32_t id)1388 process_extended_fstatvfs(u_int32_t id)
1389 {
1390 int r, handle, fd;
1391 struct statvfs st;
1392
1393 if ((r = get_handle(iqueue, &handle)) != 0)
1394 fatal_fr(r, "parse");
1395 debug("request %u: fstatvfs \"%s\" (handle %u)",
1396 id, handle_to_name(handle), handle);
1397 if ((fd = handle_to_fd(handle)) < 0) {
1398 send_status(id, SSH2_FX_FAILURE);
1399 return;
1400 }
1401 if (fstatvfs(fd, &st) != 0)
1402 send_status(id, errno_to_portable(errno));
1403 else
1404 send_statvfs(id, &st);
1405 }
1406
1407 static void
process_extended_hardlink(u_int32_t id)1408 process_extended_hardlink(u_int32_t id)
1409 {
1410 char *oldpath, *newpath;
1411 int r, status;
1412
1413 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1414 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1415 fatal_fr(r, "parse");
1416
1417 debug3("request %u: hardlink", id);
1418 logit("hardlink old \"%s\" new \"%s\"", oldpath, newpath);
1419 r = link(oldpath, newpath);
1420 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1421 send_status(id, status);
1422 free(oldpath);
1423 free(newpath);
1424 }
1425
1426 static void
process_extended_fsync(u_int32_t id)1427 process_extended_fsync(u_int32_t id)
1428 {
1429 int handle, fd, r, status = SSH2_FX_OP_UNSUPPORTED;
1430
1431 if ((r = get_handle(iqueue, &handle)) != 0)
1432 fatal_fr(r, "parse");
1433 debug3("request %u: fsync (handle %u)", id, handle);
1434 verbose("fsync \"%s\"", handle_to_name(handle));
1435 if ((fd = handle_to_fd(handle)) < 0)
1436 status = SSH2_FX_NO_SUCH_FILE;
1437 else if (handle_is_ok(handle, HANDLE_FILE)) {
1438 r = fsync(fd);
1439 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1440 }
1441 send_status(id, status);
1442 }
1443
1444 static void
process_extended_lsetstat(u_int32_t id)1445 process_extended_lsetstat(u_int32_t id)
1446 {
1447 Attrib a;
1448 char *name;
1449 int r, status = SSH2_FX_OK;
1450
1451 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
1452 (r = decode_attrib(iqueue, &a)) != 0)
1453 fatal_fr(r, "parse");
1454
1455 debug("request %u: lsetstat name \"%s\"", id, name);
1456 if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
1457 /* nonsensical for links */
1458 status = SSH2_FX_BAD_MESSAGE;
1459 goto out;
1460 }
1461 if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1462 logit("set \"%s\" mode %04o", name, a.perm);
1463 r = fchmodat(AT_FDCWD, name,
1464 a.perm & 07777, AT_SYMLINK_NOFOLLOW);
1465 if (r == -1)
1466 status = errno_to_portable(errno);
1467 }
1468 if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1469 char buf[64];
1470 time_t t = a.mtime;
1471
1472 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1473 localtime(&t));
1474 logit("set \"%s\" modtime %s", name, buf);
1475 r = utimensat(AT_FDCWD, name,
1476 attrib_to_ts(&a), AT_SYMLINK_NOFOLLOW);
1477 if (r == -1)
1478 status = errno_to_portable(errno);
1479 }
1480 if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1481 logit("set \"%s\" owner %lu group %lu", name,
1482 (u_long)a.uid, (u_long)a.gid);
1483 r = fchownat(AT_FDCWD, name, a.uid, a.gid,
1484 AT_SYMLINK_NOFOLLOW);
1485 if (r == -1)
1486 status = errno_to_portable(errno);
1487 }
1488 out:
1489 send_status(id, status);
1490 free(name);
1491 }
1492
1493 static void
process_extended_limits(u_int32_t id)1494 process_extended_limits(u_int32_t id)
1495 {
1496 struct sshbuf *msg;
1497 int r;
1498 uint64_t nfiles = 0;
1499 struct rlimit rlim;
1500
1501 debug("request %u: limits", id);
1502
1503 if (getrlimit(RLIMIT_NOFILE, &rlim) != -1 && rlim.rlim_cur > 5)
1504 nfiles = rlim.rlim_cur - 5; /* stdio(3) + syslog + spare */
1505
1506 if ((msg = sshbuf_new()) == NULL)
1507 fatal_f("sshbuf_new failed");
1508 if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
1509 (r = sshbuf_put_u32(msg, id)) != 0 ||
1510 /* max-packet-length */
1511 (r = sshbuf_put_u64(msg, SFTP_MAX_MSG_LENGTH)) != 0 ||
1512 /* max-read-length */
1513 (r = sshbuf_put_u64(msg, SFTP_MAX_READ_LENGTH)) != 0 ||
1514 /* max-write-length */
1515 (r = sshbuf_put_u64(msg, SFTP_MAX_MSG_LENGTH - 1024)) != 0 ||
1516 /* max-open-handles */
1517 (r = sshbuf_put_u64(msg, nfiles)) != 0)
1518 fatal_fr(r, "compose");
1519 send_msg(msg);
1520 sshbuf_free(msg);
1521 }
1522
1523 static void
process_extended_expand(u_int32_t id)1524 process_extended_expand(u_int32_t id)
1525 {
1526 char cwd[PATH_MAX], resolvedname[PATH_MAX];
1527 char *path, *npath;
1528 int r;
1529 Stat s;
1530
1531 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1532 fatal_fr(r, "parse");
1533 if (getcwd(cwd, sizeof(cwd)) == NULL) {
1534 send_status(id, errno_to_portable(errno));
1535 goto out;
1536 }
1537
1538 debug3("request %u: expand, original \"%s\"", id, path);
1539 if (path[0] == '\0') {
1540 /* empty path */
1541 free(path);
1542 path = xstrdup(".");
1543 } else if (*path == '~') {
1544 /* ~ expand path */
1545 /* Special-case for "~" and "~/" to respect homedir flag */
1546 if (strcmp(path, "~") == 0) {
1547 free(path);
1548 path = xstrdup(cwd);
1549 } else if (strncmp(path, "~/", 2) == 0) {
1550 npath = xstrdup(path + 2);
1551 free(path);
1552 xasprintf(&path, "%s/%s", cwd, npath);
1553 free(npath);
1554 } else {
1555 /* ~user expansions */
1556 if (tilde_expand(path, pw->pw_uid, &npath) != 0) {
1557 send_status_errmsg(id,
1558 errno_to_portable(ENOENT), "no such user");
1559 goto out;
1560 }
1561 free(path);
1562 path = npath;
1563 }
1564 } else if (*path != '/') {
1565 /* relative path */
1566 xasprintf(&npath, "%s/%s", cwd, path);
1567 free(path);
1568 path = npath;
1569 }
1570 verbose("expand \"%s\"", path);
1571 if (sftp_realpath(path, resolvedname) == NULL) {
1572 send_status(id, errno_to_portable(errno));
1573 goto out;
1574 }
1575 attrib_clear(&s.attrib);
1576 s.name = s.long_name = resolvedname;
1577 send_names(id, 1, &s);
1578 out:
1579 free(path);
1580 }
1581
1582 static void
process_extended_copy_data(u_int32_t id)1583 process_extended_copy_data(u_int32_t id)
1584 {
1585 u_char buf[64*1024];
1586 int read_handle, read_fd, write_handle, write_fd;
1587 u_int64_t len, read_off, read_len, write_off;
1588 int r, copy_until_eof, status = SSH2_FX_OP_UNSUPPORTED;
1589 size_t ret;
1590
1591 if ((r = get_handle(iqueue, &read_handle)) != 0 ||
1592 (r = sshbuf_get_u64(iqueue, &read_off)) != 0 ||
1593 (r = sshbuf_get_u64(iqueue, &read_len)) != 0 ||
1594 (r = get_handle(iqueue, &write_handle)) != 0 ||
1595 (r = sshbuf_get_u64(iqueue, &write_off)) != 0)
1596 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1597
1598 debug("request %u: copy-data from \"%s\" (handle %d) off %llu len %llu "
1599 "to \"%s\" (handle %d) off %llu",
1600 id, handle_to_name(read_handle), read_handle,
1601 (unsigned long long)read_off, (unsigned long long)read_len,
1602 handle_to_name(write_handle), write_handle,
1603 (unsigned long long)write_off);
1604
1605 /* For read length of 0, we read until EOF. */
1606 if (read_len == 0) {
1607 read_len = (u_int64_t)-1 - read_off;
1608 copy_until_eof = 1;
1609 } else
1610 copy_until_eof = 0;
1611
1612 read_fd = handle_to_fd(read_handle);
1613 write_fd = handle_to_fd(write_handle);
1614
1615 /* Disallow reading & writing to the same handle or same path or dirs */
1616 if (read_handle == write_handle || read_fd < 0 || write_fd < 0 ||
1617 !strcmp(handle_to_name(read_handle), handle_to_name(write_handle))) {
1618 status = SSH2_FX_FAILURE;
1619 goto out;
1620 }
1621
1622 if (lseek(read_fd, read_off, SEEK_SET) < 0) {
1623 status = errno_to_portable(errno);
1624 error("%s: read_seek failed", __func__);
1625 goto out;
1626 }
1627
1628 if ((handle_to_flags(write_handle) & O_APPEND) == 0 &&
1629 lseek(write_fd, write_off, SEEK_SET) < 0) {
1630 status = errno_to_portable(errno);
1631 error("%s: write_seek failed", __func__);
1632 goto out;
1633 }
1634
1635 /* Process the request in chunks. */
1636 while (read_len > 0 || copy_until_eof) {
1637 len = MINIMUM(sizeof(buf), read_len);
1638 read_len -= len;
1639
1640 ret = atomicio(read, read_fd, buf, len);
1641 if (ret == 0 && errno == EPIPE) {
1642 status = copy_until_eof ? SSH2_FX_OK : SSH2_FX_EOF;
1643 break;
1644 } else if (ret == 0) {
1645 status = errno_to_portable(errno);
1646 error("%s: read failed: %s", __func__, strerror(errno));
1647 break;
1648 }
1649 len = ret;
1650 handle_update_read(read_handle, len);
1651
1652 ret = atomicio(vwrite, write_fd, buf, len);
1653 if (ret != len) {
1654 status = errno_to_portable(errno);
1655 error("%s: write failed: %llu != %llu: %s", __func__,
1656 (unsigned long long)ret, (unsigned long long)len,
1657 strerror(errno));
1658 break;
1659 }
1660 handle_update_write(write_handle, len);
1661 }
1662
1663 if (read_len == 0)
1664 status = SSH2_FX_OK;
1665
1666 out:
1667 send_status(id, status);
1668 }
1669
1670 static void
process_extended_home_directory(u_int32_t id)1671 process_extended_home_directory(u_int32_t id)
1672 {
1673 char *username;
1674 struct passwd *user_pw;
1675 int r;
1676 Stat s;
1677
1678 if ((r = sshbuf_get_cstring(iqueue, &username, NULL)) != 0)
1679 fatal_fr(r, "parse");
1680
1681 debug3("request %u: home-directory \"%s\"", id, username);
1682 if (username[0] == '\0') {
1683 user_pw = pw;
1684 } else if ((user_pw = getpwnam(username)) == NULL) {
1685 send_status(id, SSH2_FX_FAILURE);
1686 goto out;
1687 }
1688
1689 verbose("home-directory \"%s\"", user_pw->pw_dir);
1690 attrib_clear(&s.attrib);
1691 s.name = s.long_name = user_pw->pw_dir;
1692 send_names(id, 1, &s);
1693 out:
1694 free(username);
1695 }
1696
1697 static void
process_extended_get_users_groups_by_id(u_int32_t id)1698 process_extended_get_users_groups_by_id(u_int32_t id)
1699 {
1700 struct passwd *user_pw;
1701 struct group *gr;
1702 struct sshbuf *uids, *gids, *usernames, *groupnames, *msg;
1703 int r;
1704 u_int n, nusers = 0, ngroups = 0;
1705 const char *name;
1706
1707 if ((usernames = sshbuf_new()) == NULL ||
1708 (groupnames = sshbuf_new()) == NULL ||
1709 (msg = sshbuf_new()) == NULL)
1710 fatal_f("sshbuf_new failed");
1711 if ((r = sshbuf_froms(iqueue, &uids)) != 0 ||
1712 (r = sshbuf_froms(iqueue, &gids)) != 0)
1713 fatal_fr(r, "parse");
1714 debug_f("uids len = %zu, gids len = %zu",
1715 sshbuf_len(uids), sshbuf_len(gids));
1716 while (sshbuf_len(uids) != 0) {
1717 if ((r = sshbuf_get_u32(uids, &n)) != 0)
1718 fatal_fr(r, "parse inner uid");
1719 user_pw = getpwuid((uid_t)n);
1720 name = user_pw == NULL ? "" : user_pw->pw_name;
1721 debug3_f("uid %u => \"%s\"", n, name);
1722 if ((r = sshbuf_put_cstring(usernames, name)) != 0)
1723 fatal_fr(r, "assemble uid reply");
1724 nusers++;
1725 }
1726 while (sshbuf_len(gids) != 0) {
1727 if ((r = sshbuf_get_u32(gids, &n)) != 0)
1728 fatal_fr(r, "parse inner gid");
1729 gr = getgrgid((gid_t)n);
1730 name = gr == NULL ? "" : gr->gr_name;
1731 debug3_f("gid %u => \"%s\"", n, name);
1732 if ((r = sshbuf_put_cstring(groupnames, name)) != 0)
1733 fatal_fr(r, "assemble gid reply");
1734 nusers++;
1735 }
1736 verbose("users-groups-by-id: %u users, %u groups", nusers, ngroups);
1737
1738 if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
1739 (r = sshbuf_put_u32(msg, id)) != 0 ||
1740 (r = sshbuf_put_stringb(msg, usernames)) != 0 ||
1741 (r = sshbuf_put_stringb(msg, groupnames)) != 0)
1742 fatal_fr(r, "compose");
1743 send_msg(msg);
1744
1745 sshbuf_free(uids);
1746 sshbuf_free(gids);
1747 sshbuf_free(usernames);
1748 sshbuf_free(groupnames);
1749 sshbuf_free(msg);
1750 }
1751
1752 static void
process_extended(u_int32_t id)1753 process_extended(u_int32_t id)
1754 {
1755 char *request;
1756 int r;
1757 const struct sftp_handler *exthand;
1758
1759 if ((r = sshbuf_get_cstring(iqueue, &request, NULL)) != 0)
1760 fatal_fr(r, "parse");
1761 if ((exthand = extended_handler_byname(request)) == NULL) {
1762 error("Unknown extended request \"%.100s\"", request);
1763 send_status(id, SSH2_FX_OP_UNSUPPORTED); /* MUST */
1764 } else {
1765 if (!request_permitted(exthand))
1766 send_status(id, SSH2_FX_PERMISSION_DENIED);
1767 else
1768 exthand->handler(id);
1769 }
1770 free(request);
1771 }
1772
1773 /* stolen from ssh-agent */
1774
1775 static void
process(void)1776 process(void)
1777 {
1778 u_int msg_len;
1779 u_int buf_len;
1780 u_int consumed;
1781 u_char type;
1782 const u_char *cp;
1783 int i, r;
1784 u_int32_t id;
1785
1786 buf_len = sshbuf_len(iqueue);
1787 if (buf_len < 5)
1788 return; /* Incomplete message. */
1789 cp = sshbuf_ptr(iqueue);
1790 msg_len = get_u32(cp);
1791 if (msg_len > SFTP_MAX_MSG_LENGTH) {
1792 error("bad message from %s local user %s",
1793 client_addr, pw->pw_name);
1794 sftp_server_cleanup_exit(11);
1795 }
1796 if (buf_len < msg_len + 4)
1797 return;
1798 if ((r = sshbuf_consume(iqueue, 4)) != 0)
1799 fatal_fr(r, "consume");
1800 buf_len -= 4;
1801 if ((r = sshbuf_get_u8(iqueue, &type)) != 0)
1802 fatal_fr(r, "parse type");
1803
1804 switch (type) {
1805 case SSH2_FXP_INIT:
1806 process_init();
1807 init_done = 1;
1808 break;
1809 case SSH2_FXP_EXTENDED:
1810 if (!init_done)
1811 fatal("Received extended request before init");
1812 if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
1813 fatal_fr(r, "parse extended ID");
1814 process_extended(id);
1815 break;
1816 default:
1817 if (!init_done)
1818 fatal("Received %u request before init", type);
1819 if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
1820 fatal_fr(r, "parse ID");
1821 for (i = 0; handlers[i].handler != NULL; i++) {
1822 if (type == handlers[i].type) {
1823 if (!request_permitted(&handlers[i])) {
1824 send_status(id,
1825 SSH2_FX_PERMISSION_DENIED);
1826 } else {
1827 handlers[i].handler(id);
1828 }
1829 break;
1830 }
1831 }
1832 if (handlers[i].handler == NULL)
1833 error("Unknown message %u", type);
1834 }
1835 /* discard the remaining bytes from the current packet */
1836 if (buf_len < sshbuf_len(iqueue)) {
1837 error("iqueue grew unexpectedly");
1838 sftp_server_cleanup_exit(255);
1839 }
1840 consumed = buf_len - sshbuf_len(iqueue);
1841 if (msg_len < consumed) {
1842 error("msg_len %u < consumed %u", msg_len, consumed);
1843 sftp_server_cleanup_exit(255);
1844 }
1845 if (msg_len > consumed &&
1846 (r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
1847 fatal_fr(r, "consume");
1848 }
1849
1850 /* Cleanup handler that logs active handles upon normal exit */
1851 void
sftp_server_cleanup_exit(int i)1852 sftp_server_cleanup_exit(int i)
1853 {
1854 if (pw != NULL && client_addr != NULL) {
1855 handle_log_exit();
1856 logit("session closed for local user %s from [%s]",
1857 pw->pw_name, client_addr);
1858 }
1859 _exit(i);
1860 }
1861
1862 __dead static void
sftp_server_usage(void)1863 sftp_server_usage(void)
1864 {
1865 extern char *__progname;
1866
1867 fprintf(stderr,
1868 "usage: %s [-ehR] [-d start_directory] [-f log_facility] "
1869 "[-l log_level]\n\t[-P denied_requests] "
1870 "[-p allowed_requests] [-u umask]\n"
1871 " %s -Q protocol_feature\n",
1872 __progname, __progname);
1873 exit(1);
1874 }
1875
1876 int
sftp_server_main(int argc,char ** argv,struct passwd * user_pw)1877 sftp_server_main(int argc, char **argv, struct passwd *user_pw)
1878 {
1879 int i, r, in, out, ch, skipargs = 0, log_stderr = 0;
1880 ssize_t len, olen;
1881 SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
1882 char *cp, *homedir = NULL, uidstr[32], buf[4*4096];
1883 long mask;
1884
1885 extern char *optarg;
1886 extern char *__progname;
1887
1888 log_init(__progname, log_level, log_facility, log_stderr);
1889
1890 pw = pwcopy(user_pw);
1891
1892 while (!skipargs && (ch = getopt(argc, argv,
1893 "d:f:l:P:p:Q:u:cehR")) != -1) {
1894 switch (ch) {
1895 case 'Q':
1896 if (strcasecmp(optarg, "requests") != 0) {
1897 fprintf(stderr, "Invalid query type\n");
1898 exit(1);
1899 }
1900 for (i = 0; handlers[i].handler != NULL; i++)
1901 printf("%s\n", handlers[i].name);
1902 for (i = 0; extended_handlers[i].handler != NULL; i++)
1903 printf("%s\n", extended_handlers[i].name);
1904 exit(0);
1905 break;
1906 case 'R':
1907 readonly = 1;
1908 break;
1909 case 'c':
1910 /*
1911 * Ignore all arguments if we are invoked as a
1912 * shell using "sftp-server -c command"
1913 */
1914 skipargs = 1;
1915 break;
1916 case 'e':
1917 log_stderr = 1;
1918 break;
1919 case 'l':
1920 log_level = log_level_number(optarg);
1921 if (log_level == SYSLOG_LEVEL_NOT_SET)
1922 error("Invalid log level \"%s\"", optarg);
1923 break;
1924 case 'f':
1925 log_facility = log_facility_number(optarg);
1926 if (log_facility == SYSLOG_FACILITY_NOT_SET)
1927 error("Invalid log facility \"%s\"", optarg);
1928 break;
1929 case 'd':
1930 cp = tilde_expand_filename(optarg, user_pw->pw_uid);
1931 snprintf(uidstr, sizeof(uidstr), "%llu",
1932 (unsigned long long)pw->pw_uid);
1933 homedir = percent_expand(cp, "d", user_pw->pw_dir,
1934 "u", user_pw->pw_name, "U", uidstr, (char *)NULL);
1935 free(cp);
1936 break;
1937 case 'p':
1938 if (request_allowlist != NULL)
1939 fatal("Permitted requests already set");
1940 request_allowlist = xstrdup(optarg);
1941 break;
1942 case 'P':
1943 if (request_denylist != NULL)
1944 fatal("Refused requests already set");
1945 request_denylist = xstrdup(optarg);
1946 break;
1947 case 'u':
1948 errno = 0;
1949 mask = strtol(optarg, &cp, 8);
1950 if (mask < 0 || mask > 0777 || *cp != '\0' ||
1951 cp == optarg || (mask == 0 && errno != 0))
1952 fatal("Invalid umask \"%s\"", optarg);
1953 (void)umask((mode_t)mask);
1954 break;
1955 case 'h':
1956 default:
1957 sftp_server_usage();
1958 }
1959 }
1960
1961 log_init(__progname, log_level, log_facility, log_stderr);
1962
1963 if ((cp = getenv("SSH_CONNECTION")) != NULL) {
1964 client_addr = xstrdup(cp);
1965 if ((cp = strchr(client_addr, ' ')) == NULL) {
1966 error("Malformed SSH_CONNECTION variable: \"%s\"",
1967 getenv("SSH_CONNECTION"));
1968 sftp_server_cleanup_exit(255);
1969 }
1970 *cp = '\0';
1971 } else
1972 client_addr = xstrdup("UNKNOWN");
1973
1974 logit("session opened for local user %s from [%s]",
1975 pw->pw_name, client_addr);
1976
1977 in = STDIN_FILENO;
1978 out = STDOUT_FILENO;
1979
1980 if ((iqueue = sshbuf_new()) == NULL)
1981 fatal_f("sshbuf_new failed");
1982 if ((oqueue = sshbuf_new()) == NULL)
1983 fatal_f("sshbuf_new failed");
1984
1985 if (homedir != NULL) {
1986 if (chdir(homedir) != 0) {
1987 error("chdir to \"%s\" failed: %s", homedir,
1988 strerror(errno));
1989 }
1990 }
1991
1992 for (;;) {
1993 struct pollfd pfd[2];
1994
1995 memset(pfd, 0, sizeof pfd);
1996 pfd[0].fd = pfd[1].fd = -1;
1997
1998 /*
1999 * Ensure that we can read a full buffer and handle
2000 * the worst-case length packet it can generate,
2001 * otherwise apply backpressure by stopping reads.
2002 */
2003 if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
2004 (r = sshbuf_check_reserve(oqueue,
2005 SFTP_MAX_MSG_LENGTH)) == 0) {
2006 pfd[0].fd = in;
2007 pfd[0].events = POLLIN;
2008 }
2009 else if (r != SSH_ERR_NO_BUFFER_SPACE)
2010 fatal_fr(r, "reserve");
2011
2012 olen = sshbuf_len(oqueue);
2013 if (olen > 0) {
2014 pfd[1].fd = out;
2015 pfd[1].events = POLLOUT;
2016 }
2017
2018 if (poll(pfd, 2, -1) == -1) {
2019 if (errno == EINTR)
2020 continue;
2021 error("poll: %s", strerror(errno));
2022 sftp_server_cleanup_exit(2);
2023 }
2024
2025 /* copy stdin to iqueue */
2026 if (pfd[0].revents & (POLLIN|POLLHUP)) {
2027 len = read(in, buf, sizeof buf);
2028 if (len == 0) {
2029 debug("read eof");
2030 sftp_server_cleanup_exit(0);
2031 } else if (len == -1) {
2032 if (errno != EAGAIN && errno != EINTR) {
2033 error("read: %s", strerror(errno));
2034 sftp_server_cleanup_exit(1);
2035 }
2036 } else if ((r = sshbuf_put(iqueue, buf, len)) != 0)
2037 fatal_fr(r, "sshbuf_put");
2038 }
2039 /* send oqueue to stdout */
2040 if (pfd[1].revents & (POLLOUT|POLLHUP)) {
2041 len = write(out, sshbuf_ptr(oqueue), olen);
2042 if (len == 0 || (len == -1 && errno == EPIPE)) {
2043 debug("write eof");
2044 sftp_server_cleanup_exit(0);
2045 } else if (len == -1) {
2046 sftp_server_cleanup_exit(1);
2047 if (errno != EAGAIN && errno != EINTR) {
2048 error("write: %s", strerror(errno));
2049 sftp_server_cleanup_exit(1);
2050 }
2051 } else if ((r = sshbuf_consume(oqueue, len)) != 0)
2052 fatal_fr(r, "consume");
2053 }
2054
2055 /*
2056 * Process requests from client if we can fit the results
2057 * into the output buffer, otherwise stop processing input
2058 * and let the output queue drain.
2059 */
2060 r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH);
2061 if (r == 0)
2062 process();
2063 else if (r != SSH_ERR_NO_BUFFER_SPACE)
2064 fatal_fr(r, "reserve");
2065 }
2066 }
2067