1 /* $NetBSD: sftp-server.c,v 1.29 2023/07/26 17:58:15 christos Exp $ */
2 /* $OpenBSD: sftp-server.c,v 1.146 2023/03/07 05:37:26 djm Exp $ */
3 /*
4 * Copyright (c) 2000-2004 Markus Friedl. All rights reserved.
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include "includes.h"
20 __RCSID("$NetBSD: sftp-server.c,v 1.29 2023/07/26 17:58:15 christos Exp $");
21
22 #include <sys/param.h> /* MIN */
23 #include <sys/types.h>
24 #include <sys/resource.h>
25 #include <sys/stat.h>
26 #include <sys/time.h>
27 #include <sys/mount.h>
28 #include <sys/statvfs.h>
29
30 #include <dirent.h>
31 #include <errno.h>
32 #include <fcntl.h>
33 #include <poll.h>
34 #include <stdlib.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <pwd.h>
38 #include <grp.h>
39 #include <time.h>
40 #include <unistd.h>
41 #include <stdarg.h>
42
43 #include "atomicio.h"
44 #include "xmalloc.h"
45 #include "sshbuf.h"
46 #include "ssherr.h"
47 #include "log.h"
48 #include "misc.h"
49 #include "match.h"
50 #include "uidswap.h"
51
52 #include "sftp.h"
53 #include "sftp-common.h"
54
55 char *sftp_realpath(const char *, char *); /* sftp-realpath.c */
56
57 /* Maximum data read that we are willing to accept */
58 #define SFTP_MAX_READ_LENGTH (SFTP_MAX_MSG_LENGTH - 1024)
59
60 /* Our verbosity */
61 static LogLevel log_level = SYSLOG_LEVEL_ERROR;
62
63 /* Our client */
64 static struct passwd *pw = NULL;
65 static char *client_addr = NULL;
66
67 /* input and output queue */
68 struct sshbuf *iqueue;
69 struct sshbuf *oqueue;
70
71 /* Version of client */
72 static u_int version;
73
74 /* SSH2_FXP_INIT received */
75 static int init_done;
76
77 /* Disable writes */
78 static int readonly;
79
80 /* Requests that are allowed/denied */
81 static char *request_allowlist, *request_denylist;
82
83 /* portable attributes, etc. */
84 typedef struct Stat Stat;
85
86 struct Stat {
87 char *name;
88 char *long_name;
89 Attrib attrib;
90 };
91
92 /* Packet handlers */
93 static void process_open(u_int32_t id);
94 static void process_close(u_int32_t id);
95 static void process_read(u_int32_t id);
96 static void process_write(u_int32_t id);
97 static void process_stat(u_int32_t id);
98 static void process_lstat(u_int32_t id);
99 static void process_fstat(u_int32_t id);
100 static void process_setstat(u_int32_t id);
101 static void process_fsetstat(u_int32_t id);
102 static void process_opendir(u_int32_t id);
103 static void process_readdir(u_int32_t id);
104 static void process_remove(u_int32_t id);
105 static void process_mkdir(u_int32_t id);
106 static void process_rmdir(u_int32_t id);
107 static void process_realpath(u_int32_t id);
108 static void process_rename(u_int32_t id);
109 static void process_readlink(u_int32_t id);
110 static void process_symlink(u_int32_t id);
111 static void process_extended_posix_rename(u_int32_t id);
112 static void process_extended_statvfs(u_int32_t id);
113 static void process_extended_fstatvfs(u_int32_t id);
114 static void process_extended_hardlink(u_int32_t id);
115 static void process_extended_fsync(u_int32_t id);
116 static void process_extended_lsetstat(u_int32_t id);
117 static void process_extended_limits(u_int32_t id);
118 static void process_extended_expand(u_int32_t id);
119 static void process_extended_copy_data(u_int32_t id);
120 static void process_extended_home_directory(u_int32_t id);
121 static void process_extended_get_users_groups_by_id(u_int32_t id);
122 static void process_extended(u_int32_t id);
123
124 struct sftp_handler {
125 const char *name; /* user-visible name for fine-grained perms */
126 const char *ext_name; /* extended request name */
127 u_int type; /* packet type, for non extended packets */
128 void (*handler)(u_int32_t);
129 int does_write; /* if nonzero, banned for readonly mode */
130 };
131
132 static const struct sftp_handler handlers[] = {
133 /* NB. SSH2_FXP_OPEN does the readonly check in the handler itself */
134 { "open", NULL, SSH2_FXP_OPEN, process_open, 0 },
135 { "close", NULL, SSH2_FXP_CLOSE, process_close, 0 },
136 { "read", NULL, SSH2_FXP_READ, process_read, 0 },
137 { "write", NULL, SSH2_FXP_WRITE, process_write, 1 },
138 { "lstat", NULL, SSH2_FXP_LSTAT, process_lstat, 0 },
139 { "fstat", NULL, SSH2_FXP_FSTAT, process_fstat, 0 },
140 { "setstat", NULL, SSH2_FXP_SETSTAT, process_setstat, 1 },
141 { "fsetstat", NULL, SSH2_FXP_FSETSTAT, process_fsetstat, 1 },
142 { "opendir", NULL, SSH2_FXP_OPENDIR, process_opendir, 0 },
143 { "readdir", NULL, SSH2_FXP_READDIR, process_readdir, 0 },
144 { "remove", NULL, SSH2_FXP_REMOVE, process_remove, 1 },
145 { "mkdir", NULL, SSH2_FXP_MKDIR, process_mkdir, 1 },
146 { "rmdir", NULL, SSH2_FXP_RMDIR, process_rmdir, 1 },
147 { "realpath", NULL, SSH2_FXP_REALPATH, process_realpath, 0 },
148 { "stat", NULL, SSH2_FXP_STAT, process_stat, 0 },
149 { "rename", NULL, SSH2_FXP_RENAME, process_rename, 1 },
150 { "readlink", NULL, SSH2_FXP_READLINK, process_readlink, 0 },
151 { "symlink", NULL, SSH2_FXP_SYMLINK, process_symlink, 1 },
152 { NULL, NULL, 0, NULL, 0 }
153 };
154
155 /* SSH2_FXP_EXTENDED submessages */
156 static const struct sftp_handler extended_handlers[] = {
157 { "posix-rename", "posix-rename@openssh.com", 0,
158 process_extended_posix_rename, 1 },
159 { "statvfs", "statvfs@openssh.com", 0, process_extended_statvfs, 0 },
160 { "fstatvfs", "fstatvfs@openssh.com", 0, process_extended_fstatvfs, 0 },
161 { "hardlink", "hardlink@openssh.com", 0, process_extended_hardlink, 1 },
162 { "fsync", "fsync@openssh.com", 0, process_extended_fsync, 1 },
163 { "lsetstat", "lsetstat@openssh.com", 0, process_extended_lsetstat, 1 },
164 { "limits", "limits@openssh.com", 0, process_extended_limits, 0 },
165 { "expand-path", "expand-path@openssh.com", 0,
166 process_extended_expand, 0 },
167 { "copy-data", "copy-data", 0, process_extended_copy_data, 1 },
168 { "home-directory", "home-directory", 0,
169 process_extended_home_directory, 0 },
170 { "users-groups-by-id", "users-groups-by-id@openssh.com", 0,
171 process_extended_get_users_groups_by_id, 0 },
172 { NULL, NULL, 0, NULL, 0 }
173 };
174
175 static const struct sftp_handler *
extended_handler_byname(const char * name)176 extended_handler_byname(const char *name)
177 {
178 int i;
179
180 for (i = 0; extended_handlers[i].handler != NULL; i++) {
181 if (strcmp(name, extended_handlers[i].ext_name) == 0)
182 return &extended_handlers[i];
183 }
184 return NULL;
185 }
186
187 static int
request_permitted(const struct sftp_handler * h)188 request_permitted(const struct sftp_handler *h)
189 {
190 char *result;
191
192 if (readonly && h->does_write) {
193 verbose("Refusing %s request in read-only mode", h->name);
194 return 0;
195 }
196 if (request_denylist != NULL &&
197 ((result = match_list(h->name, request_denylist, NULL))) != NULL) {
198 free(result);
199 verbose("Refusing denylisted %s request", h->name);
200 return 0;
201 }
202 if (request_allowlist != NULL &&
203 ((result = match_list(h->name, request_allowlist, NULL))) != NULL) {
204 free(result);
205 debug2("Permitting allowlisted %s request", h->name);
206 return 1;
207 }
208 if (request_allowlist != NULL) {
209 verbose("Refusing non-allowlisted %s request", h->name);
210 return 0;
211 }
212 return 1;
213 }
214
215 static int
errno_to_portable(int unixerrno)216 errno_to_portable(int unixerrno)
217 {
218 int ret = 0;
219
220 switch (unixerrno) {
221 case 0:
222 ret = SSH2_FX_OK;
223 break;
224 case ENOENT:
225 case ENOTDIR:
226 case EBADF:
227 case ELOOP:
228 ret = SSH2_FX_NO_SUCH_FILE;
229 break;
230 case EPERM:
231 case EACCES:
232 case EFAULT:
233 ret = SSH2_FX_PERMISSION_DENIED;
234 break;
235 case ENAMETOOLONG:
236 case EINVAL:
237 ret = SSH2_FX_BAD_MESSAGE;
238 break;
239 case ENOSYS:
240 ret = SSH2_FX_OP_UNSUPPORTED;
241 break;
242 default:
243 ret = SSH2_FX_FAILURE;
244 break;
245 }
246 return ret;
247 }
248
249 static int
flags_from_portable(int pflags)250 flags_from_portable(int pflags)
251 {
252 int flags = 0;
253
254 if ((pflags & SSH2_FXF_READ) &&
255 (pflags & SSH2_FXF_WRITE)) {
256 flags = O_RDWR;
257 } else if (pflags & SSH2_FXF_READ) {
258 flags = O_RDONLY;
259 } else if (pflags & SSH2_FXF_WRITE) {
260 flags = O_WRONLY;
261 }
262 if (pflags & SSH2_FXF_APPEND)
263 flags |= O_APPEND;
264 if (pflags & SSH2_FXF_CREAT)
265 flags |= O_CREAT;
266 if (pflags & SSH2_FXF_TRUNC)
267 flags |= O_TRUNC;
268 if (pflags & SSH2_FXF_EXCL)
269 flags |= O_EXCL;
270 return flags;
271 }
272
273 static const char *
string_from_portable(int pflags)274 string_from_portable(int pflags)
275 {
276 static char ret[128];
277
278 *ret = '\0';
279
280 #define PAPPEND(str) { \
281 if (*ret != '\0') \
282 strlcat(ret, ",", sizeof(ret)); \
283 strlcat(ret, str, sizeof(ret)); \
284 }
285
286 if (pflags & SSH2_FXF_READ)
287 PAPPEND("READ")
288 if (pflags & SSH2_FXF_WRITE)
289 PAPPEND("WRITE")
290 if (pflags & SSH2_FXF_APPEND)
291 PAPPEND("APPEND")
292 if (pflags & SSH2_FXF_CREAT)
293 PAPPEND("CREATE")
294 if (pflags & SSH2_FXF_TRUNC)
295 PAPPEND("TRUNCATE")
296 if (pflags & SSH2_FXF_EXCL)
297 PAPPEND("EXCL")
298
299 return ret;
300 }
301
302 /* handle handles */
303
304 typedef struct Handle Handle;
305 struct Handle {
306 int use;
307 DIR *dirp;
308 int fd;
309 int flags;
310 char *name;
311 u_int64_t bytes_read, bytes_write;
312 int next_unused;
313 };
314
315 enum {
316 HANDLE_UNUSED,
317 HANDLE_DIR,
318 HANDLE_FILE
319 };
320
321 static Handle *handles = NULL;
322 static u_int num_handles = 0;
323 static int first_unused_handle = -1;
324
handle_unused(int i)325 static void handle_unused(int i)
326 {
327 handles[i].use = HANDLE_UNUSED;
328 handles[i].next_unused = first_unused_handle;
329 first_unused_handle = i;
330 }
331
332 static int
handle_new(int use,const char * name,int fd,int flags,DIR * dirp)333 handle_new(int use, const char *name, int fd, int flags, DIR *dirp)
334 {
335 int i;
336
337 if (first_unused_handle == -1) {
338 if (num_handles + 1 <= num_handles)
339 return -1;
340 num_handles++;
341 handles = xreallocarray(handles, num_handles, sizeof(Handle));
342 handle_unused(num_handles - 1);
343 }
344
345 i = first_unused_handle;
346 first_unused_handle = handles[i].next_unused;
347
348 handles[i].use = use;
349 handles[i].dirp = dirp;
350 handles[i].fd = fd;
351 handles[i].flags = flags;
352 handles[i].name = xstrdup(name);
353 handles[i].bytes_read = handles[i].bytes_write = 0;
354
355 return i;
356 }
357
358 static int
handle_is_ok(int i,int type)359 handle_is_ok(int i, int type)
360 {
361 return i >= 0 && (u_int)i < num_handles && handles[i].use == type;
362 }
363
364 static int
handle_to_string(int handle,u_char ** stringp,int * hlenp)365 handle_to_string(int handle, u_char **stringp, int *hlenp)
366 {
367 if (stringp == NULL || hlenp == NULL)
368 return -1;
369 *stringp = xmalloc(sizeof(int32_t));
370 put_u32(*stringp, handle);
371 *hlenp = sizeof(int32_t);
372 return 0;
373 }
374
375 static int
handle_from_string(const u_char * handle,u_int hlen)376 handle_from_string(const u_char *handle, u_int hlen)
377 {
378 int val;
379
380 if (hlen != sizeof(int32_t))
381 return -1;
382 val = get_u32(handle);
383 if (handle_is_ok(val, HANDLE_FILE) ||
384 handle_is_ok(val, HANDLE_DIR))
385 return val;
386 return -1;
387 }
388
389 static char *
handle_to_name(int handle)390 handle_to_name(int handle)
391 {
392 if (handle_is_ok(handle, HANDLE_DIR)||
393 handle_is_ok(handle, HANDLE_FILE))
394 return handles[handle].name;
395 return NULL;
396 }
397
398 static DIR *
handle_to_dir(int handle)399 handle_to_dir(int handle)
400 {
401 if (handle_is_ok(handle, HANDLE_DIR))
402 return handles[handle].dirp;
403 return NULL;
404 }
405
406 static int
handle_to_fd(int handle)407 handle_to_fd(int handle)
408 {
409 if (handle_is_ok(handle, HANDLE_FILE))
410 return handles[handle].fd;
411 return -1;
412 }
413
414 static int
handle_to_flags(int handle)415 handle_to_flags(int handle)
416 {
417 if (handle_is_ok(handle, HANDLE_FILE))
418 return handles[handle].flags;
419 return 0;
420 }
421
422 static void
handle_update_read(int handle,ssize_t bytes)423 handle_update_read(int handle, ssize_t bytes)
424 {
425 if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
426 handles[handle].bytes_read += bytes;
427 }
428
429 static void
handle_update_write(int handle,ssize_t bytes)430 handle_update_write(int handle, ssize_t bytes)
431 {
432 if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0)
433 handles[handle].bytes_write += bytes;
434 }
435
436 static u_int64_t
handle_bytes_read(int handle)437 handle_bytes_read(int handle)
438 {
439 if (handle_is_ok(handle, HANDLE_FILE))
440 return (handles[handle].bytes_read);
441 return 0;
442 }
443
444 static u_int64_t
handle_bytes_write(int handle)445 handle_bytes_write(int handle)
446 {
447 if (handle_is_ok(handle, HANDLE_FILE))
448 return (handles[handle].bytes_write);
449 return 0;
450 }
451
452 static int
handle_close(int handle)453 handle_close(int handle)
454 {
455 int ret = -1;
456
457 if (handle_is_ok(handle, HANDLE_FILE)) {
458 ret = close(handles[handle].fd);
459 free(handles[handle].name);
460 handle_unused(handle);
461 } else if (handle_is_ok(handle, HANDLE_DIR)) {
462 ret = closedir(handles[handle].dirp);
463 free(handles[handle].name);
464 handle_unused(handle);
465 } else {
466 errno = ENOENT;
467 }
468 return ret;
469 }
470
471 static void
handle_log_close(int handle,const char * emsg)472 handle_log_close(int handle, const char *emsg)
473 {
474 if (handle_is_ok(handle, HANDLE_FILE)) {
475 logit("%s%sclose \"%s\" bytes read %llu written %llu",
476 emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
477 handle_to_name(handle),
478 (unsigned long long)handle_bytes_read(handle),
479 (unsigned long long)handle_bytes_write(handle));
480 } else {
481 logit("%s%sclosedir \"%s\"",
482 emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ",
483 handle_to_name(handle));
484 }
485 }
486
487 static void
handle_log_exit(void)488 handle_log_exit(void)
489 {
490 u_int i;
491
492 for (i = 0; i < num_handles; i++)
493 if (handles[i].use != HANDLE_UNUSED)
494 handle_log_close(i, "forced");
495 }
496
497 static int
get_handle(struct sshbuf * queue,int * hp)498 get_handle(struct sshbuf *queue, int *hp)
499 {
500 u_char *handle;
501 int r;
502 size_t hlen;
503
504 *hp = -1;
505 if ((r = sshbuf_get_string(queue, &handle, &hlen)) != 0)
506 return r;
507 if (hlen < 256)
508 *hp = handle_from_string(handle, hlen);
509 free(handle);
510 return 0;
511 }
512
513 /* send replies */
514
515 static void
send_msg(struct sshbuf * m)516 send_msg(struct sshbuf *m)
517 {
518 int r;
519
520 if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
521 fatal_fr(r, "enqueue");
522 sshbuf_reset(m);
523 }
524
525 static const char *
status_to_message(u_int32_t status)526 status_to_message(u_int32_t status)
527 {
528 static const char * const status_messages[] = {
529 "Success", /* SSH_FX_OK */
530 "End of file", /* SSH_FX_EOF */
531 "No such file", /* SSH_FX_NO_SUCH_FILE */
532 "Permission denied", /* SSH_FX_PERMISSION_DENIED */
533 "Failure", /* SSH_FX_FAILURE */
534 "Bad message", /* SSH_FX_BAD_MESSAGE */
535 "No connection", /* SSH_FX_NO_CONNECTION */
536 "Connection lost", /* SSH_FX_CONNECTION_LOST */
537 "Operation unsupported", /* SSH_FX_OP_UNSUPPORTED */
538 "Unknown error" /* Others */
539 };
540 return (status_messages[MINIMUM(status,SSH2_FX_MAX)]);
541 }
542
543 static void
send_status_errmsg(u_int32_t id,u_int32_t status,const char * errmsg)544 send_status_errmsg(u_int32_t id, u_int32_t status, const char *errmsg)
545 {
546 struct sshbuf *msg;
547 int r;
548
549 debug3("request %u: sent status %u", id, status);
550 if (log_level > SYSLOG_LEVEL_VERBOSE ||
551 (status != SSH2_FX_OK && status != SSH2_FX_EOF))
552 logit("sent status %s", status_to_message(status));
553 if ((msg = sshbuf_new()) == NULL)
554 fatal_f("sshbuf_new failed");
555 if ((r = sshbuf_put_u8(msg, SSH2_FXP_STATUS)) != 0 ||
556 (r = sshbuf_put_u32(msg, id)) != 0 ||
557 (r = sshbuf_put_u32(msg, status)) != 0)
558 fatal_fr(r, "compose");
559 if (version >= 3) {
560 if ((r = sshbuf_put_cstring(msg, errmsg == NULL ?
561 status_to_message(status) : errmsg)) != 0 ||
562 (r = sshbuf_put_cstring(msg, "")) != 0)
563 fatal_fr(r, "compose message");
564 }
565 send_msg(msg);
566 sshbuf_free(msg);
567 }
568
569 static void
send_status(u_int32_t id,u_int32_t status)570 send_status(u_int32_t id, u_int32_t status)
571 {
572 send_status_errmsg(id, status, NULL);
573 }
574
575 static void
send_data_or_handle(char type,u_int32_t id,const u_char * data,int dlen)576 send_data_or_handle(char type, u_int32_t id, const u_char *data, int dlen)
577 {
578 struct sshbuf *msg;
579 int r;
580
581 if ((msg = sshbuf_new()) == NULL)
582 fatal_f("sshbuf_new failed");
583 if ((r = sshbuf_put_u8(msg, type)) != 0 ||
584 (r = sshbuf_put_u32(msg, id)) != 0 ||
585 (r = sshbuf_put_string(msg, data, dlen)) != 0)
586 fatal_fr(r, "compose");
587 send_msg(msg);
588 sshbuf_free(msg);
589 }
590
591 static void
send_data(u_int32_t id,const u_char * data,int dlen)592 send_data(u_int32_t id, const u_char *data, int dlen)
593 {
594 debug("request %u: sent data len %d", id, dlen);
595 send_data_or_handle(SSH2_FXP_DATA, id, data, dlen);
596 }
597
598 static void
send_handle(u_int32_t id,int handle)599 send_handle(u_int32_t id, int handle)
600 {
601 u_char *string;
602 int hlen;
603
604 handle_to_string(handle, &string, &hlen);
605 debug("request %u: sent handle handle %d", id, handle);
606 send_data_or_handle(SSH2_FXP_HANDLE, id, string, hlen);
607 free(string);
608 }
609
610 static void
send_names(u_int32_t id,int count,const Stat * stats)611 send_names(u_int32_t id, int count, const Stat *stats)
612 {
613 struct sshbuf *msg;
614 int i, r;
615
616 if ((msg = sshbuf_new()) == NULL)
617 fatal_f("sshbuf_new failed");
618 if ((r = sshbuf_put_u8(msg, SSH2_FXP_NAME)) != 0 ||
619 (r = sshbuf_put_u32(msg, id)) != 0 ||
620 (r = sshbuf_put_u32(msg, count)) != 0)
621 fatal_fr(r, "compose");
622 debug("request %u: sent names count %d", id, count);
623 for (i = 0; i < count; i++) {
624 if ((r = sshbuf_put_cstring(msg, stats[i].name)) != 0 ||
625 (r = sshbuf_put_cstring(msg, stats[i].long_name)) != 0 ||
626 (r = encode_attrib(msg, &stats[i].attrib)) != 0)
627 fatal_fr(r, "compose filenames/attrib");
628 }
629 send_msg(msg);
630 sshbuf_free(msg);
631 }
632
633 static void
send_attrib(u_int32_t id,const Attrib * a)634 send_attrib(u_int32_t id, const Attrib *a)
635 {
636 struct sshbuf *msg;
637 int r;
638
639 debug("request %u: sent attrib have 0x%x", id, a->flags);
640 if ((msg = sshbuf_new()) == NULL)
641 fatal_f("sshbuf_new failed");
642 if ((r = sshbuf_put_u8(msg, SSH2_FXP_ATTRS)) != 0 ||
643 (r = sshbuf_put_u32(msg, id)) != 0 ||
644 (r = encode_attrib(msg, a)) != 0)
645 fatal_fr(r, "compose");
646 send_msg(msg);
647 sshbuf_free(msg);
648 }
649
650 static void
send_statvfs(u_int32_t id,struct statvfs * st)651 send_statvfs(u_int32_t id, struct statvfs *st)
652 {
653 struct sshbuf *msg;
654 u_int64_t flag;
655 int r;
656
657 flag = (st->f_flag & ST_RDONLY) ? SSH2_FXE_STATVFS_ST_RDONLY : 0;
658 flag |= (st->f_flag & ST_NOSUID) ? SSH2_FXE_STATVFS_ST_NOSUID : 0;
659
660 if ((msg = sshbuf_new()) == NULL)
661 fatal_f("sshbuf_new failed");
662 if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
663 (r = sshbuf_put_u32(msg, id)) != 0 ||
664 (r = sshbuf_put_u64(msg, st->f_bsize)) != 0 ||
665 (r = sshbuf_put_u64(msg, st->f_frsize)) != 0 ||
666 (r = sshbuf_put_u64(msg, st->f_blocks)) != 0 ||
667 (r = sshbuf_put_u64(msg, st->f_bfree)) != 0 ||
668 (r = sshbuf_put_u64(msg, st->f_bavail)) != 0 ||
669 (r = sshbuf_put_u64(msg, st->f_files)) != 0 ||
670 (r = sshbuf_put_u64(msg, st->f_ffree)) != 0 ||
671 (r = sshbuf_put_u64(msg, st->f_favail)) != 0 ||
672 (r = sshbuf_put_u64(msg, st->f_fsid)) != 0 ||
673 (r = sshbuf_put_u64(msg, flag)) != 0 ||
674 (r = sshbuf_put_u64(msg, st->f_namemax)) != 0)
675 fatal_fr(r, "compose");
676 send_msg(msg);
677 sshbuf_free(msg);
678 }
679
680 /*
681 * Prepare SSH2_FXP_VERSION extension advertisement for a single extension.
682 * The extension is checked for permission prior to advertisement.
683 */
684 static int
compose_extension(struct sshbuf * msg,const char * name,const char * ver)685 compose_extension(struct sshbuf *msg, const char *name, const char *ver)
686 {
687 int r;
688 const struct sftp_handler *exthnd;
689
690 if ((exthnd = extended_handler_byname(name)) == NULL)
691 fatal_f("internal error: no handler for %s", name);
692 if (!request_permitted(exthnd)) {
693 debug2_f("refusing to advertise disallowed extension %s", name);
694 return 0;
695 }
696 if ((r = sshbuf_put_cstring(msg, name)) != 0 ||
697 (r = sshbuf_put_cstring(msg, ver)) != 0)
698 fatal_fr(r, "compose %s", name);
699 return 0;
700 }
701
702 /* parse incoming */
703
704 static void
process_init(void)705 process_init(void)
706 {
707 struct sshbuf *msg;
708 int r;
709
710 if ((r = sshbuf_get_u32(iqueue, &version)) != 0)
711 fatal_fr(r, "parse");
712 verbose("received client version %u", version);
713 if ((msg = sshbuf_new()) == NULL)
714 fatal_f("sshbuf_new failed");
715 if ((r = sshbuf_put_u8(msg, SSH2_FXP_VERSION)) != 0 ||
716 (r = sshbuf_put_u32(msg, SSH2_FILEXFER_VERSION)) != 0)
717 fatal_fr(r, "compose");
718
719 /* extension advertisements */
720 compose_extension(msg, "posix-rename@openssh.com", "1");
721 compose_extension(msg, "statvfs@openssh.com", "2");
722 compose_extension(msg, "fstatvfs@openssh.com", "2");
723 compose_extension(msg, "hardlink@openssh.com", "1");
724 compose_extension(msg, "fsync@openssh.com", "1");
725 compose_extension(msg, "lsetstat@openssh.com", "1");
726 compose_extension(msg, "limits@openssh.com", "1");
727 compose_extension(msg, "expand-path@openssh.com", "1");
728 compose_extension(msg, "copy-data", "1");
729 compose_extension(msg, "home-directory", "1");
730 compose_extension(msg, "users-groups-by-id@openssh.com", "1");
731
732 send_msg(msg);
733 sshbuf_free(msg);
734 }
735
736 static void
process_open(u_int32_t id)737 process_open(u_int32_t id)
738 {
739 u_int32_t pflags;
740 Attrib a;
741 char *name;
742 int r, handle, fd, flags, mode, status = SSH2_FX_FAILURE;
743
744 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
745 (r = sshbuf_get_u32(iqueue, &pflags)) != 0 || /* portable flags */
746 (r = decode_attrib(iqueue, &a)) != 0)
747 fatal_fr(r, "parse");
748
749 debug3("request %u: open flags %d", id, pflags);
750 flags = flags_from_portable(pflags);
751 mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm : 0666;
752 logit("open \"%s\" flags %s mode 0%o",
753 name, string_from_portable(pflags), mode);
754 if (readonly &&
755 ((flags & O_ACCMODE) != O_RDONLY ||
756 (flags & (O_CREAT|O_TRUNC)) != 0)) {
757 verbose("Refusing open request in read-only mode");
758 status = SSH2_FX_PERMISSION_DENIED;
759 } else {
760 fd = open(name, flags, mode);
761 if (fd == -1) {
762 status = errno_to_portable(errno);
763 } else {
764 handle = handle_new(HANDLE_FILE, name, fd, flags, NULL);
765 if (handle < 0) {
766 close(fd);
767 } else {
768 send_handle(id, handle);
769 status = SSH2_FX_OK;
770 }
771 }
772 }
773 if (status != SSH2_FX_OK)
774 send_status(id, status);
775 free(name);
776 }
777
778 static void
process_close(u_int32_t id)779 process_close(u_int32_t id)
780 {
781 int r, handle, ret, status = SSH2_FX_FAILURE;
782
783 if ((r = get_handle(iqueue, &handle)) != 0)
784 fatal_fr(r, "parse");
785
786 debug3("request %u: close handle %u", id, handle);
787 handle_log_close(handle, NULL);
788 ret = handle_close(handle);
789 status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
790 send_status(id, status);
791 }
792
793 static void
process_read(u_int32_t id)794 process_read(u_int32_t id)
795 {
796 static u_char *buf;
797 static size_t buflen;
798 u_int32_t len;
799 int r, handle, fd, ret, status = SSH2_FX_FAILURE;
800 u_int64_t off;
801
802 if ((r = get_handle(iqueue, &handle)) != 0 ||
803 (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
804 (r = sshbuf_get_u32(iqueue, &len)) != 0)
805 fatal_fr(r, "parse");
806
807 debug("request %u: read \"%s\" (handle %d) off %llu len %u",
808 id, handle_to_name(handle), handle, (unsigned long long)off, len);
809 if ((fd = handle_to_fd(handle)) == -1)
810 goto out;
811 if (len > SFTP_MAX_READ_LENGTH) {
812 debug2("read change len %u to %u", len, SFTP_MAX_READ_LENGTH);
813 len = SFTP_MAX_READ_LENGTH;
814 }
815 if (len > buflen) {
816 debug3_f("allocate %zu => %u", buflen, len);
817 if ((buf = realloc(buf, len)) == NULL)
818 fatal_f("realloc failed");
819 buflen = len;
820 }
821 if (lseek(fd, off, SEEK_SET) == -1) {
822 status = errno_to_portable(errno);
823 error_f("seek \"%.100s\": %s", handle_to_name(handle),
824 strerror(errno));
825 goto out;
826 }
827 if (len == 0) {
828 /* weird, but not strictly disallowed */
829 ret = 0;
830 } else if ((ret = read(fd, buf, len)) == -1) {
831 status = errno_to_portable(errno);
832 error_f("read \"%.100s\": %s", handle_to_name(handle),
833 strerror(errno));
834 goto out;
835 } else if (ret == 0) {
836 status = SSH2_FX_EOF;
837 goto out;
838 }
839 send_data(id, buf, ret);
840 handle_update_read(handle, ret);
841 /* success */
842 status = SSH2_FX_OK;
843 out:
844 if (status != SSH2_FX_OK)
845 send_status(id, status);
846 }
847
848 static void
process_write(u_int32_t id)849 process_write(u_int32_t id)
850 {
851 u_int64_t off;
852 size_t len;
853 int r, handle, fd, ret, status;
854 u_char *data;
855
856 if ((r = get_handle(iqueue, &handle)) != 0 ||
857 (r = sshbuf_get_u64(iqueue, &off)) != 0 ||
858 (r = sshbuf_get_string(iqueue, &data, &len)) != 0)
859 fatal_fr(r, "parse");
860
861 debug("request %u: write \"%s\" (handle %d) off %llu len %zu",
862 id, handle_to_name(handle), handle, (unsigned long long)off, len);
863 fd = handle_to_fd(handle);
864
865 if (fd < 0)
866 status = SSH2_FX_FAILURE;
867 else {
868 if (!(handle_to_flags(handle) & O_APPEND) &&
869 lseek(fd, off, SEEK_SET) == -1) {
870 status = errno_to_portable(errno);
871 error_f("seek \"%.100s\": %s", handle_to_name(handle),
872 strerror(errno));
873 } else {
874 /* XXX ATOMICIO ? */
875 ret = write(fd, data, len);
876 if (ret == -1) {
877 status = errno_to_portable(errno);
878 error_f("write \"%.100s\": %s",
879 handle_to_name(handle), strerror(errno));
880 } else if ((size_t)ret == len) {
881 status = SSH2_FX_OK;
882 handle_update_write(handle, ret);
883 } else {
884 debug2_f("nothing at all written");
885 status = SSH2_FX_FAILURE;
886 }
887 }
888 }
889 send_status(id, status);
890 free(data);
891 }
892
893 static void
process_do_stat(u_int32_t id,int do_lstat)894 process_do_stat(u_int32_t id, int do_lstat)
895 {
896 Attrib a;
897 struct stat st;
898 char *name;
899 int r, status = SSH2_FX_FAILURE;
900
901 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
902 fatal_fr(r, "parse");
903
904 debug3("request %u: %sstat", id, do_lstat ? "l" : "");
905 verbose("%sstat name \"%s\"", do_lstat ? "l" : "", name);
906 r = do_lstat ? lstat(name, &st) : stat(name, &st);
907 if (r == -1) {
908 status = errno_to_portable(errno);
909 } else {
910 stat_to_attrib(&st, &a);
911 send_attrib(id, &a);
912 status = SSH2_FX_OK;
913 }
914 if (status != SSH2_FX_OK)
915 send_status(id, status);
916 free(name);
917 }
918
919 static void
process_stat(u_int32_t id)920 process_stat(u_int32_t id)
921 {
922 process_do_stat(id, 0);
923 }
924
925 static void
process_lstat(u_int32_t id)926 process_lstat(u_int32_t id)
927 {
928 process_do_stat(id, 1);
929 }
930
931 static void
process_fstat(u_int32_t id)932 process_fstat(u_int32_t id)
933 {
934 Attrib a;
935 struct stat st;
936 int fd, r, handle, status = SSH2_FX_FAILURE;
937
938 if ((r = get_handle(iqueue, &handle)) != 0)
939 fatal_fr(r, "parse");
940 debug("request %u: fstat \"%s\" (handle %u)",
941 id, handle_to_name(handle), handle);
942 fd = handle_to_fd(handle);
943 if (fd >= 0) {
944 r = fstat(fd, &st);
945 if (r == -1) {
946 status = errno_to_portable(errno);
947 } else {
948 stat_to_attrib(&st, &a);
949 send_attrib(id, &a);
950 status = SSH2_FX_OK;
951 }
952 }
953 if (status != SSH2_FX_OK)
954 send_status(id, status);
955 }
956
957 static struct timeval *
attrib_to_tv(const Attrib * a)958 attrib_to_tv(const Attrib *a)
959 {
960 static struct timeval tv[2];
961
962 tv[0].tv_sec = a->atime;
963 tv[0].tv_usec = 0;
964 tv[1].tv_sec = a->mtime;
965 tv[1].tv_usec = 0;
966 return tv;
967 }
968
969 static struct timespec *
attrib_to_ts(const Attrib * a)970 attrib_to_ts(const Attrib *a)
971 {
972 static struct timespec ts[2];
973
974 ts[0].tv_sec = a->atime;
975 ts[0].tv_nsec = 0;
976 ts[1].tv_sec = a->mtime;
977 ts[1].tv_nsec = 0;
978 return ts;
979 }
980
981 static void
process_setstat(u_int32_t id)982 process_setstat(u_int32_t id)
983 {
984 Attrib a;
985 char *name;
986 int r, status = SSH2_FX_OK;
987
988 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
989 (r = decode_attrib(iqueue, &a)) != 0)
990 fatal_fr(r, "parse");
991
992 debug("request %u: setstat name \"%s\"", id, name);
993 if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
994 logit("set \"%s\" size %llu",
995 name, (unsigned long long)a.size);
996 r = truncate(name, a.size);
997 if (r == -1)
998 status = errno_to_portable(errno);
999 }
1000 if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1001 logit("set \"%s\" mode %04o", name, a.perm);
1002 r = chmod(name, a.perm & 07777);
1003 if (r == -1)
1004 status = errno_to_portable(errno);
1005 }
1006 if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1007 char buf[64];
1008 time_t t = a.mtime;
1009
1010 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1011 localtime(&t));
1012 logit("set \"%s\" modtime %s", name, buf);
1013 r = utimes(name, attrib_to_tv(&a));
1014 if (r == -1)
1015 status = errno_to_portable(errno);
1016 }
1017 if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1018 logit("set \"%s\" owner %lu group %lu", name,
1019 (u_long)a.uid, (u_long)a.gid);
1020 r = chown(name, a.uid, a.gid);
1021 if (r == -1)
1022 status = errno_to_portable(errno);
1023 }
1024 send_status(id, status);
1025 free(name);
1026 }
1027
1028 static void
process_fsetstat(u_int32_t id)1029 process_fsetstat(u_int32_t id)
1030 {
1031 Attrib a;
1032 int handle, fd, r;
1033 int status = SSH2_FX_OK;
1034
1035 if ((r = get_handle(iqueue, &handle)) != 0 ||
1036 (r = decode_attrib(iqueue, &a)) != 0)
1037 fatal_fr(r, "parse");
1038
1039 debug("request %u: fsetstat handle %d", id, handle);
1040 fd = handle_to_fd(handle);
1041 if (fd < 0)
1042 status = SSH2_FX_FAILURE;
1043 else {
1044 char *name = handle_to_name(handle);
1045
1046 if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
1047 logit("set \"%s\" size %llu",
1048 name, (unsigned long long)a.size);
1049 r = ftruncate(fd, a.size);
1050 if (r == -1)
1051 status = errno_to_portable(errno);
1052 }
1053 if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1054 logit("set \"%s\" mode %04o", name, a.perm);
1055 r = fchmod(fd, a.perm & 07777);
1056 if (r == -1)
1057 status = errno_to_portable(errno);
1058 }
1059 if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1060 char buf[64];
1061 time_t t = a.mtime;
1062
1063 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1064 localtime(&t));
1065 logit("set \"%s\" modtime %s", name, buf);
1066 r = futimes(fd, attrib_to_tv(&a));
1067 if (r == -1)
1068 status = errno_to_portable(errno);
1069 }
1070 if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1071 logit("set \"%s\" owner %lu group %lu", name,
1072 (u_long)a.uid, (u_long)a.gid);
1073 r = fchown(fd, a.uid, a.gid);
1074 if (r == -1)
1075 status = errno_to_portable(errno);
1076 }
1077 }
1078 send_status(id, status);
1079 }
1080
1081 static void
process_opendir(u_int32_t id)1082 process_opendir(u_int32_t id)
1083 {
1084 DIR *dirp = NULL;
1085 char *path;
1086 int r, handle, status = SSH2_FX_FAILURE;
1087
1088 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1089 fatal_fr(r, "parse");
1090
1091 debug3("request %u: opendir", id);
1092 logit("opendir \"%s\"", path);
1093 dirp = opendir(path);
1094 if (dirp == NULL) {
1095 status = errno_to_portable(errno);
1096 } else {
1097 handle = handle_new(HANDLE_DIR, path, 0, 0, dirp);
1098 if (handle < 0) {
1099 closedir(dirp);
1100 } else {
1101 send_handle(id, handle);
1102 status = SSH2_FX_OK;
1103 }
1104
1105 }
1106 if (status != SSH2_FX_OK)
1107 send_status(id, status);
1108 free(path);
1109 }
1110
1111 static void
process_readdir(u_int32_t id)1112 process_readdir(u_int32_t id)
1113 {
1114 DIR *dirp;
1115 struct dirent *dp;
1116 char *path;
1117 int r, handle;
1118
1119 if ((r = get_handle(iqueue, &handle)) != 0)
1120 fatal_fr(r, "parse");
1121
1122 debug("request %u: readdir \"%s\" (handle %d)", id,
1123 handle_to_name(handle), handle);
1124 dirp = handle_to_dir(handle);
1125 path = handle_to_name(handle);
1126 if (dirp == NULL || path == NULL) {
1127 send_status(id, SSH2_FX_FAILURE);
1128 } else {
1129 struct stat st;
1130 char pathname[PATH_MAX];
1131 Stat *stats;
1132 int nstats = 10, count = 0, i;
1133
1134 stats = xcalloc(nstats, sizeof(Stat));
1135 while ((dp = readdir(dirp)) != NULL) {
1136 if (count >= nstats) {
1137 nstats *= 2;
1138 stats = xreallocarray(stats, nstats, sizeof(Stat));
1139 }
1140 /* XXX OVERFLOW ? */
1141 snprintf(pathname, sizeof pathname, "%s%s%s", path,
1142 strcmp(path, "/") ? "/" : "", dp->d_name);
1143 if (lstat(pathname, &st) == -1)
1144 continue;
1145 stat_to_attrib(&st, &(stats[count].attrib));
1146 stats[count].name = xstrdup(dp->d_name);
1147 stats[count].long_name = ls_file(dp->d_name, &st,
1148 0, 0, NULL, NULL);
1149 count++;
1150 /* send up to 100 entries in one message */
1151 /* XXX check packet size instead */
1152 if (count == 100)
1153 break;
1154 }
1155 if (count > 0) {
1156 send_names(id, count, stats);
1157 for (i = 0; i < count; i++) {
1158 free(stats[i].name);
1159 free(stats[i].long_name);
1160 }
1161 } else {
1162 send_status(id, SSH2_FX_EOF);
1163 }
1164 free(stats);
1165 }
1166 }
1167
1168 static void
process_remove(u_int32_t id)1169 process_remove(u_int32_t id)
1170 {
1171 char *name;
1172 int r, status = SSH2_FX_FAILURE;
1173
1174 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
1175 fatal_fr(r, "parse");
1176
1177 debug3("request %u: remove", id);
1178 logit("remove name \"%s\"", name);
1179 r = unlink(name);
1180 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1181 send_status(id, status);
1182 free(name);
1183 }
1184
1185 static void
process_mkdir(u_int32_t id)1186 process_mkdir(u_int32_t id)
1187 {
1188 Attrib a;
1189 char *name;
1190 int r, mode, status = SSH2_FX_FAILURE;
1191
1192 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
1193 (r = decode_attrib(iqueue, &a)) != 0)
1194 fatal_fr(r, "parse");
1195
1196 mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
1197 a.perm & 07777 : 0777;
1198 debug3("request %u: mkdir", id);
1199 logit("mkdir name \"%s\" mode 0%o", name, mode);
1200 r = mkdir(name, mode);
1201 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1202 send_status(id, status);
1203 free(name);
1204 }
1205
1206 static void
process_rmdir(u_int32_t id)1207 process_rmdir(u_int32_t id)
1208 {
1209 char *name;
1210 int r, status;
1211
1212 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0)
1213 fatal_fr(r, "parse");
1214
1215 debug3("request %u: rmdir", id);
1216 logit("rmdir name \"%s\"", name);
1217 r = rmdir(name);
1218 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1219 send_status(id, status);
1220 free(name);
1221 }
1222
1223 static void
process_realpath(u_int32_t id)1224 process_realpath(u_int32_t id)
1225 {
1226 char resolvedname[PATH_MAX];
1227 char *path;
1228 int r;
1229
1230 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1231 fatal_fr(r, "parse");
1232
1233 if (path[0] == '\0') {
1234 free(path);
1235 path = xstrdup(".");
1236 }
1237 debug3("request %u: realpath", id);
1238 verbose("realpath \"%s\"", path);
1239 if (sftp_realpath(path, resolvedname) == NULL) {
1240 send_status(id, errno_to_portable(errno));
1241 } else {
1242 Stat s;
1243 attrib_clear(&s.attrib);
1244 s.name = s.long_name = resolvedname;
1245 send_names(id, 1, &s);
1246 }
1247 free(path);
1248 }
1249
1250 static void
process_rename(u_int32_t id)1251 process_rename(u_int32_t id)
1252 {
1253 char *oldpath, *newpath;
1254 int r, status;
1255 struct stat sb;
1256
1257 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1258 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1259 fatal_fr(r, "parse");
1260
1261 debug3("request %u: rename", id);
1262 logit("rename old \"%s\" new \"%s\"", oldpath, newpath);
1263 status = SSH2_FX_FAILURE;
1264 if (lstat(oldpath, &sb) == -1)
1265 status = errno_to_portable(errno);
1266 else if (S_ISREG(sb.st_mode)) {
1267 /* Race-free rename of regular files */
1268 if (link(oldpath, newpath) == -1) {
1269 if (errno == EOPNOTSUPP) {
1270 struct stat st;
1271
1272 /*
1273 * fs doesn't support links, so fall back to
1274 * stat+rename. This is racy.
1275 */
1276 if (stat(newpath, &st) == -1) {
1277 if (rename(oldpath, newpath) == -1)
1278 status =
1279 errno_to_portable(errno);
1280 else
1281 status = SSH2_FX_OK;
1282 }
1283 } else {
1284 status = errno_to_portable(errno);
1285 }
1286 } else if (unlink(oldpath) == -1) {
1287 status = errno_to_portable(errno);
1288 /* clean spare link */
1289 unlink(newpath);
1290 } else
1291 status = SSH2_FX_OK;
1292 } else if (stat(newpath, &sb) == -1) {
1293 if (rename(oldpath, newpath) == -1)
1294 status = errno_to_portable(errno);
1295 else
1296 status = SSH2_FX_OK;
1297 }
1298 send_status(id, status);
1299 free(oldpath);
1300 free(newpath);
1301 }
1302
1303 static void
process_readlink(u_int32_t id)1304 process_readlink(u_int32_t id)
1305 {
1306 int r, len;
1307 char buf[PATH_MAX];
1308 char *path;
1309
1310 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1311 fatal_fr(r, "parse");
1312
1313 debug3("request %u: readlink", id);
1314 verbose("readlink \"%s\"", path);
1315 if ((len = readlink(path, buf, sizeof(buf) - 1)) == -1)
1316 send_status(id, errno_to_portable(errno));
1317 else {
1318 Stat s;
1319
1320 buf[len] = '\0';
1321 attrib_clear(&s.attrib);
1322 s.name = s.long_name = buf;
1323 send_names(id, 1, &s);
1324 }
1325 free(path);
1326 }
1327
1328 static void
process_symlink(u_int32_t id)1329 process_symlink(u_int32_t id)
1330 {
1331 char *oldpath, *newpath;
1332 int r, status;
1333
1334 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1335 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1336 fatal_fr(r, "parse");
1337
1338 debug3("request %u: symlink", id);
1339 logit("symlink old \"%s\" new \"%s\"", oldpath, newpath);
1340 /* this will fail if 'newpath' exists */
1341 r = symlink(oldpath, newpath);
1342 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1343 send_status(id, status);
1344 free(oldpath);
1345 free(newpath);
1346 }
1347
1348 static void
process_extended_posix_rename(u_int32_t id)1349 process_extended_posix_rename(u_int32_t id)
1350 {
1351 char *oldpath, *newpath;
1352 int r, status;
1353
1354 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1355 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1356 fatal_fr(r, "parse");
1357
1358 debug3("request %u: posix-rename", id);
1359 logit("posix-rename old \"%s\" new \"%s\"", oldpath, newpath);
1360 r = rename(oldpath, newpath);
1361 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1362 send_status(id, status);
1363 free(oldpath);
1364 free(newpath);
1365 }
1366
1367 static void
process_extended_statvfs(u_int32_t id)1368 process_extended_statvfs(u_int32_t id)
1369 {
1370 char *path;
1371 struct statvfs st;
1372 int r;
1373
1374 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1375 fatal_fr(r, "parse");
1376 debug3("request %u: statvfs", id);
1377 logit("statvfs \"%s\"", path);
1378
1379 if (statvfs(path, &st) != 0)
1380 send_status(id, errno_to_portable(errno));
1381 else
1382 send_statvfs(id, &st);
1383 free(path);
1384 }
1385
1386 static void
process_extended_fstatvfs(u_int32_t id)1387 process_extended_fstatvfs(u_int32_t id)
1388 {
1389 int r, handle, fd;
1390 struct statvfs st;
1391
1392 if ((r = get_handle(iqueue, &handle)) != 0)
1393 fatal_fr(r, "parse");
1394 debug("request %u: fstatvfs \"%s\" (handle %u)",
1395 id, handle_to_name(handle), handle);
1396 if ((fd = handle_to_fd(handle)) < 0) {
1397 send_status(id, SSH2_FX_FAILURE);
1398 return;
1399 }
1400 if (fstatvfs(fd, &st) != 0)
1401 send_status(id, errno_to_portable(errno));
1402 else
1403 send_statvfs(id, &st);
1404 }
1405
1406 static void
process_extended_hardlink(u_int32_t id)1407 process_extended_hardlink(u_int32_t id)
1408 {
1409 char *oldpath, *newpath;
1410 int r, status;
1411
1412 if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 ||
1413 (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0)
1414 fatal_fr(r, "parse");
1415
1416 debug3("request %u: hardlink", id);
1417 logit("hardlink old \"%s\" new \"%s\"", oldpath, newpath);
1418 r = link(oldpath, newpath);
1419 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1420 send_status(id, status);
1421 free(oldpath);
1422 free(newpath);
1423 }
1424
1425 static void
process_extended_fsync(u_int32_t id)1426 process_extended_fsync(u_int32_t id)
1427 {
1428 int handle, fd, r, status = SSH2_FX_OP_UNSUPPORTED;
1429
1430 if ((r = get_handle(iqueue, &handle)) != 0)
1431 fatal_fr(r, "parse");
1432 debug3("request %u: fsync (handle %u)", id, handle);
1433 verbose("fsync \"%s\"", handle_to_name(handle));
1434 if ((fd = handle_to_fd(handle)) < 0)
1435 status = SSH2_FX_NO_SUCH_FILE;
1436 else if (handle_is_ok(handle, HANDLE_FILE)) {
1437 r = fsync(fd);
1438 status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
1439 }
1440 send_status(id, status);
1441 }
1442
1443 static void
process_extended_lsetstat(u_int32_t id)1444 process_extended_lsetstat(u_int32_t id)
1445 {
1446 Attrib a;
1447 char *name;
1448 int r, status = SSH2_FX_OK;
1449
1450 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
1451 (r = decode_attrib(iqueue, &a)) != 0)
1452 fatal_fr(r, "parse");
1453
1454 debug("request %u: lsetstat name \"%s\"", id, name);
1455 if (a.flags & SSH2_FILEXFER_ATTR_SIZE) {
1456 /* nonsensical for links */
1457 status = SSH2_FX_BAD_MESSAGE;
1458 goto out;
1459 }
1460 if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) {
1461 logit("set \"%s\" mode %04o", name, a.perm);
1462 r = fchmodat(AT_FDCWD, name,
1463 a.perm & 07777, AT_SYMLINK_NOFOLLOW);
1464 if (r == -1)
1465 status = errno_to_portable(errno);
1466 }
1467 if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) {
1468 char buf[64];
1469 time_t t = a.mtime;
1470
1471 strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S",
1472 localtime(&t));
1473 logit("set \"%s\" modtime %s", name, buf);
1474 r = utimensat(AT_FDCWD, name,
1475 attrib_to_ts(&a), AT_SYMLINK_NOFOLLOW);
1476 if (r == -1)
1477 status = errno_to_portable(errno);
1478 }
1479 if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) {
1480 logit("set \"%s\" owner %lu group %lu", name,
1481 (u_long)a.uid, (u_long)a.gid);
1482 r = fchownat(AT_FDCWD, name, a.uid, a.gid,
1483 AT_SYMLINK_NOFOLLOW);
1484 if (r == -1)
1485 status = errno_to_portable(errno);
1486 }
1487 out:
1488 send_status(id, status);
1489 free(name);
1490 }
1491
1492 static void
process_extended_limits(u_int32_t id)1493 process_extended_limits(u_int32_t id)
1494 {
1495 struct sshbuf *msg;
1496 int r;
1497 uint64_t nfiles = 0;
1498 struct rlimit rlim;
1499
1500 debug("request %u: limits", id);
1501
1502 if (getrlimit(RLIMIT_NOFILE, &rlim) != -1 && rlim.rlim_cur > 5)
1503 nfiles = rlim.rlim_cur - 5; /* stdio(3) + syslog + spare */
1504
1505 if ((msg = sshbuf_new()) == NULL)
1506 fatal_f("sshbuf_new failed");
1507 if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
1508 (r = sshbuf_put_u32(msg, id)) != 0 ||
1509 /* max-packet-length */
1510 (r = sshbuf_put_u64(msg, SFTP_MAX_MSG_LENGTH)) != 0 ||
1511 /* max-read-length */
1512 (r = sshbuf_put_u64(msg, SFTP_MAX_READ_LENGTH)) != 0 ||
1513 /* max-write-length */
1514 (r = sshbuf_put_u64(msg, SFTP_MAX_MSG_LENGTH - 1024)) != 0 ||
1515 /* max-open-handles */
1516 (r = sshbuf_put_u64(msg, nfiles)) != 0)
1517 fatal_fr(r, "compose");
1518 send_msg(msg);
1519 sshbuf_free(msg);
1520 }
1521
1522 static void
process_extended_expand(u_int32_t id)1523 process_extended_expand(u_int32_t id)
1524 {
1525 char cwd[PATH_MAX], resolvedname[PATH_MAX];
1526 char *path, *npath;
1527 int r;
1528 Stat s;
1529
1530 if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0)
1531 fatal_fr(r, "parse");
1532 if (getcwd(cwd, sizeof(cwd)) == NULL) {
1533 send_status(id, errno_to_portable(errno));
1534 goto out;
1535 }
1536
1537 debug3("request %u: expand, original \"%s\"", id, path);
1538 if (path[0] == '\0') {
1539 /* empty path */
1540 free(path);
1541 path = xstrdup(".");
1542 } else if (*path == '~') {
1543 /* ~ expand path */
1544 /* Special-case for "~" and "~/" to respect homedir flag */
1545 if (strcmp(path, "~") == 0) {
1546 free(path);
1547 path = xstrdup(cwd);
1548 } else if (strncmp(path, "~/", 2) == 0) {
1549 npath = xstrdup(path + 2);
1550 free(path);
1551 xasprintf(&path, "%s/%s", cwd, npath);
1552 free(npath);
1553 } else {
1554 /* ~user expansions */
1555 if (tilde_expand(path, pw->pw_uid, &npath) != 0) {
1556 send_status_errmsg(id,
1557 errno_to_portable(ENOENT), "no such user");
1558 goto out;
1559 }
1560 free(path);
1561 path = npath;
1562 }
1563 } else if (*path != '/') {
1564 /* relative path */
1565 xasprintf(&npath, "%s/%s", cwd, path);
1566 free(path);
1567 path = npath;
1568 }
1569 verbose("expand \"%s\"", path);
1570 if (sftp_realpath(path, resolvedname) == NULL) {
1571 send_status(id, errno_to_portable(errno));
1572 goto out;
1573 }
1574 attrib_clear(&s.attrib);
1575 s.name = s.long_name = resolvedname;
1576 send_names(id, 1, &s);
1577 out:
1578 free(path);
1579 }
1580
1581 static void
process_extended_copy_data(u_int32_t id)1582 process_extended_copy_data(u_int32_t id)
1583 {
1584 u_char buf[64*1024];
1585 int read_handle, read_fd, write_handle, write_fd;
1586 u_int64_t len, read_off, read_len, write_off;
1587 int r, copy_until_eof, status = SSH2_FX_OP_UNSUPPORTED;
1588 size_t ret;
1589
1590 if ((r = get_handle(iqueue, &read_handle)) != 0 ||
1591 (r = sshbuf_get_u64(iqueue, &read_off)) != 0 ||
1592 (r = sshbuf_get_u64(iqueue, &read_len)) != 0 ||
1593 (r = get_handle(iqueue, &write_handle)) != 0 ||
1594 (r = sshbuf_get_u64(iqueue, &write_off)) != 0)
1595 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1596
1597 debug("request %u: copy-data from \"%s\" (handle %d) off %llu len %llu "
1598 "to \"%s\" (handle %d) off %llu",
1599 id, handle_to_name(read_handle), read_handle,
1600 (unsigned long long)read_off, (unsigned long long)read_len,
1601 handle_to_name(write_handle), write_handle,
1602 (unsigned long long)write_off);
1603
1604 /* For read length of 0, we read until EOF. */
1605 if (read_len == 0) {
1606 read_len = (u_int64_t)-1 - read_off;
1607 copy_until_eof = 1;
1608 } else
1609 copy_until_eof = 0;
1610
1611 read_fd = handle_to_fd(read_handle);
1612 write_fd = handle_to_fd(write_handle);
1613
1614 /* Disallow reading & writing to the same handle or same path or dirs */
1615 if (read_handle == write_handle || read_fd < 0 || write_fd < 0 ||
1616 !strcmp(handle_to_name(read_handle), handle_to_name(write_handle))) {
1617 status = SSH2_FX_FAILURE;
1618 goto out;
1619 }
1620
1621 if (lseek(read_fd, read_off, SEEK_SET) < 0) {
1622 status = errno_to_portable(errno);
1623 error("%s: read_seek failed", __func__);
1624 goto out;
1625 }
1626
1627 if ((handle_to_flags(write_handle) & O_APPEND) == 0 &&
1628 lseek(write_fd, write_off, SEEK_SET) < 0) {
1629 status = errno_to_portable(errno);
1630 error("%s: write_seek failed", __func__);
1631 goto out;
1632 }
1633
1634 /* Process the request in chunks. */
1635 while (read_len > 0 || copy_until_eof) {
1636 len = MINIMUM(sizeof(buf), read_len);
1637 read_len -= len;
1638
1639 ret = atomicio(read, read_fd, buf, len);
1640 if (ret == 0 && errno == EPIPE) {
1641 status = copy_until_eof ? SSH2_FX_OK : SSH2_FX_EOF;
1642 break;
1643 } else if (ret == 0) {
1644 status = errno_to_portable(errno);
1645 error("%s: read failed: %s", __func__, strerror(errno));
1646 break;
1647 }
1648 len = ret;
1649 handle_update_read(read_handle, len);
1650
1651 ret = atomicio(vwrite, write_fd, buf, len);
1652 if (ret != len) {
1653 status = errno_to_portable(errno);
1654 error("%s: write failed: %llu != %llu: %s", __func__,
1655 (unsigned long long)ret, (unsigned long long)len,
1656 strerror(errno));
1657 break;
1658 }
1659 handle_update_write(write_handle, len);
1660 }
1661
1662 if (read_len == 0)
1663 status = SSH2_FX_OK;
1664
1665 out:
1666 send_status(id, status);
1667 }
1668
1669 static void
process_extended_home_directory(u_int32_t id)1670 process_extended_home_directory(u_int32_t id)
1671 {
1672 char *username;
1673 struct passwd *user_pw;
1674 int r;
1675 Stat s;
1676
1677 if ((r = sshbuf_get_cstring(iqueue, &username, NULL)) != 0)
1678 fatal_fr(r, "parse");
1679
1680 debug3("request %u: home-directory \"%s\"", id, username);
1681 if ((user_pw = getpwnam(username)) == NULL) {
1682 send_status(id, SSH2_FX_FAILURE);
1683 goto out;
1684 }
1685
1686 verbose("home-directory \"%s\"", pw->pw_dir);
1687 attrib_clear(&s.attrib);
1688 s.name = s.long_name = pw->pw_dir;
1689 send_names(id, 1, &s);
1690 out:
1691 free(username);
1692 }
1693
1694 static void
process_extended_get_users_groups_by_id(u_int32_t id)1695 process_extended_get_users_groups_by_id(u_int32_t id)
1696 {
1697 struct passwd *user_pw;
1698 struct group *gr;
1699 struct sshbuf *uids, *gids, *usernames, *groupnames, *msg;
1700 int r;
1701 u_int n, nusers = 0, ngroups = 0;
1702 const char *name;
1703
1704 if ((usernames = sshbuf_new()) == NULL ||
1705 (groupnames = sshbuf_new()) == NULL ||
1706 (msg = sshbuf_new()) == NULL)
1707 fatal_f("sshbuf_new failed");
1708 if ((r = sshbuf_froms(iqueue, &uids)) != 0 ||
1709 (r = sshbuf_froms(iqueue, &gids)) != 0)
1710 fatal_fr(r, "parse");
1711 debug_f("uids len = %zu, gids len = %zu",
1712 sshbuf_len(uids), sshbuf_len(gids));
1713 while (sshbuf_len(uids) != 0) {
1714 if ((r = sshbuf_get_u32(uids, &n)) != 0)
1715 fatal_fr(r, "parse inner uid");
1716 user_pw = getpwuid((uid_t)n);
1717 name = user_pw == NULL ? "" : user_pw->pw_name;
1718 debug3_f("uid %u => \"%s\"", n, name);
1719 if ((r = sshbuf_put_cstring(usernames, name)) != 0)
1720 fatal_fr(r, "assemble uid reply");
1721 nusers++;
1722 }
1723 while (sshbuf_len(gids) != 0) {
1724 if ((r = sshbuf_get_u32(gids, &n)) != 0)
1725 fatal_fr(r, "parse inner gid");
1726 gr = getgrgid((gid_t)n);
1727 name = gr == NULL ? "" : gr->gr_name;
1728 debug3_f("gid %u => \"%s\"", n, name);
1729 if ((r = sshbuf_put_cstring(groupnames, name)) != 0)
1730 fatal_fr(r, "assemble gid reply");
1731 nusers++;
1732 }
1733 verbose("users-groups-by-id: %u users, %u groups", nusers, ngroups);
1734
1735 if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 ||
1736 (r = sshbuf_put_u32(msg, id)) != 0 ||
1737 (r = sshbuf_put_stringb(msg, usernames)) != 0 ||
1738 (r = sshbuf_put_stringb(msg, groupnames)) != 0)
1739 fatal_fr(r, "compose");
1740 send_msg(msg);
1741
1742 sshbuf_free(uids);
1743 sshbuf_free(gids);
1744 sshbuf_free(usernames);
1745 sshbuf_free(groupnames);
1746 sshbuf_free(msg);
1747 }
1748
1749 static void
process_extended(u_int32_t id)1750 process_extended(u_int32_t id)
1751 {
1752 char *request;
1753 int r;
1754 const struct sftp_handler *exthand;
1755
1756 if ((r = sshbuf_get_cstring(iqueue, &request, NULL)) != 0)
1757 fatal_fr(r, "parse");
1758 if ((exthand = extended_handler_byname(request)) == NULL) {
1759 error("Unknown extended request \"%.100s\"", request);
1760 send_status(id, SSH2_FX_OP_UNSUPPORTED); /* MUST */
1761 } else {
1762 if (!request_permitted(exthand))
1763 send_status(id, SSH2_FX_PERMISSION_DENIED);
1764 else
1765 exthand->handler(id);
1766 }
1767 free(request);
1768 }
1769
1770 /* stolen from ssh-agent */
1771
1772 static void
process(void)1773 process(void)
1774 {
1775 u_int msg_len;
1776 u_int buf_len;
1777 u_int consumed;
1778 u_char type;
1779 const u_char *cp;
1780 int i, r;
1781 u_int32_t id;
1782
1783 buf_len = sshbuf_len(iqueue);
1784 if (buf_len < 5)
1785 return; /* Incomplete message. */
1786 cp = sshbuf_ptr(iqueue);
1787 msg_len = get_u32(cp);
1788 if (msg_len > SFTP_MAX_MSG_LENGTH) {
1789 error("bad message from %s local user %s",
1790 client_addr, pw->pw_name);
1791 sftp_server_cleanup_exit(11);
1792 }
1793 if (buf_len < msg_len + 4)
1794 return;
1795 if ((r = sshbuf_consume(iqueue, 4)) != 0)
1796 fatal_fr(r, "consume");
1797 buf_len -= 4;
1798 if ((r = sshbuf_get_u8(iqueue, &type)) != 0)
1799 fatal_fr(r, "parse type");
1800
1801 switch (type) {
1802 case SSH2_FXP_INIT:
1803 process_init();
1804 init_done = 1;
1805 break;
1806 case SSH2_FXP_EXTENDED:
1807 if (!init_done)
1808 fatal("Received extended request before init");
1809 if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
1810 fatal_fr(r, "parse extended ID");
1811 process_extended(id);
1812 break;
1813 default:
1814 if (!init_done)
1815 fatal("Received %u request before init", type);
1816 if ((r = sshbuf_get_u32(iqueue, &id)) != 0)
1817 fatal_fr(r, "parse ID");
1818 for (i = 0; handlers[i].handler != NULL; i++) {
1819 if (type == handlers[i].type) {
1820 if (!request_permitted(&handlers[i])) {
1821 send_status(id,
1822 SSH2_FX_PERMISSION_DENIED);
1823 } else {
1824 handlers[i].handler(id);
1825 }
1826 break;
1827 }
1828 }
1829 if (handlers[i].handler == NULL)
1830 error("Unknown message %u", type);
1831 }
1832 /* discard the remaining bytes from the current packet */
1833 if (buf_len < sshbuf_len(iqueue)) {
1834 error("iqueue grew unexpectedly");
1835 sftp_server_cleanup_exit(255);
1836 }
1837 consumed = buf_len - sshbuf_len(iqueue);
1838 if (msg_len < consumed) {
1839 error("msg_len %u < consumed %u", msg_len, consumed);
1840 sftp_server_cleanup_exit(255);
1841 }
1842 if (msg_len > consumed &&
1843 (r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
1844 fatal_fr(r, "consume");
1845 }
1846
1847 /* Cleanup handler that logs active handles upon normal exit */
1848 void
sftp_server_cleanup_exit(int i)1849 sftp_server_cleanup_exit(int i)
1850 {
1851 if (pw != NULL && client_addr != NULL) {
1852 handle_log_exit();
1853 logit("session closed for local user %s from [%s]",
1854 pw->pw_name, client_addr);
1855 }
1856 _exit(i);
1857 }
1858
1859 __dead static void
sftp_server_usage(void)1860 sftp_server_usage(void)
1861 {
1862 extern char *__progname;
1863
1864 fprintf(stderr,
1865 "usage: %s [-ehR] [-d start_directory] [-f log_facility] "
1866 "[-l log_level]\n\t[-P denied_requests] "
1867 "[-p allowed_requests] [-u umask]\n"
1868 " %s -Q protocol_feature\n",
1869 __progname, __progname);
1870 exit(1);
1871 }
1872
1873 int
sftp_server_main(int argc,char ** argv,struct passwd * user_pw)1874 sftp_server_main(int argc, char **argv, struct passwd *user_pw)
1875 {
1876 int i, r, in, out, ch, skipargs = 0, log_stderr = 0;
1877 ssize_t len, olen;
1878 SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
1879 char *cp, *homedir = NULL, uidstr[32], buf[4*4096];
1880 long mask;
1881
1882 extern char *optarg;
1883 extern char *__progname;
1884
1885 log_init(__progname, log_level, log_facility, log_stderr);
1886
1887 pw = pwcopy(user_pw);
1888
1889 while (!skipargs && (ch = getopt(argc, argv,
1890 "d:f:l:P:p:Q:u:cehR")) != -1) {
1891 switch (ch) {
1892 case 'Q':
1893 if (strcasecmp(optarg, "requests") != 0) {
1894 fprintf(stderr, "Invalid query type\n");
1895 exit(1);
1896 }
1897 for (i = 0; handlers[i].handler != NULL; i++)
1898 printf("%s\n", handlers[i].name);
1899 for (i = 0; extended_handlers[i].handler != NULL; i++)
1900 printf("%s\n", extended_handlers[i].name);
1901 exit(0);
1902 break;
1903 case 'R':
1904 readonly = 1;
1905 break;
1906 case 'c':
1907 /*
1908 * Ignore all arguments if we are invoked as a
1909 * shell using "sftp-server -c command"
1910 */
1911 skipargs = 1;
1912 break;
1913 case 'e':
1914 log_stderr = 1;
1915 break;
1916 case 'l':
1917 log_level = log_level_number(optarg);
1918 if (log_level == SYSLOG_LEVEL_NOT_SET)
1919 error("Invalid log level \"%s\"", optarg);
1920 break;
1921 case 'f':
1922 log_facility = log_facility_number(optarg);
1923 if (log_facility == SYSLOG_FACILITY_NOT_SET)
1924 error("Invalid log facility \"%s\"", optarg);
1925 break;
1926 case 'd':
1927 cp = tilde_expand_filename(optarg, user_pw->pw_uid);
1928 snprintf(uidstr, sizeof(uidstr), "%llu",
1929 (unsigned long long)pw->pw_uid);
1930 homedir = percent_expand(cp, "d", user_pw->pw_dir,
1931 "u", user_pw->pw_name, "U", uidstr, (char *)NULL);
1932 free(cp);
1933 break;
1934 case 'p':
1935 if (request_allowlist != NULL)
1936 fatal("Permitted requests already set");
1937 request_allowlist = xstrdup(optarg);
1938 break;
1939 case 'P':
1940 if (request_denylist != NULL)
1941 fatal("Refused requests already set");
1942 request_denylist = xstrdup(optarg);
1943 break;
1944 case 'u':
1945 errno = 0;
1946 mask = strtol(optarg, &cp, 8);
1947 if (mask < 0 || mask > 0777 || *cp != '\0' ||
1948 cp == optarg || (mask == 0 && errno != 0))
1949 fatal("Invalid umask \"%s\"", optarg);
1950 (void)umask((mode_t)mask);
1951 break;
1952 case 'h':
1953 default:
1954 sftp_server_usage();
1955 }
1956 }
1957
1958 log_init(__progname, log_level, log_facility, log_stderr);
1959
1960 if ((cp = getenv("SSH_CONNECTION")) != NULL) {
1961 client_addr = xstrdup(cp);
1962 if ((cp = strchr(client_addr, ' ')) == NULL) {
1963 error("Malformed SSH_CONNECTION variable: \"%s\"",
1964 getenv("SSH_CONNECTION"));
1965 sftp_server_cleanup_exit(255);
1966 }
1967 *cp = '\0';
1968 } else
1969 client_addr = xstrdup("UNKNOWN");
1970
1971 logit("session opened for local user %s from [%s]",
1972 pw->pw_name, client_addr);
1973
1974 in = STDIN_FILENO;
1975 out = STDOUT_FILENO;
1976
1977 if ((iqueue = sshbuf_new()) == NULL)
1978 fatal_f("sshbuf_new failed");
1979 if ((oqueue = sshbuf_new()) == NULL)
1980 fatal_f("sshbuf_new failed");
1981
1982 if (homedir != NULL) {
1983 if (chdir(homedir) != 0) {
1984 error("chdir to \"%s\" failed: %s", homedir,
1985 strerror(errno));
1986 }
1987 }
1988
1989 for (;;) {
1990 struct pollfd pfd[2];
1991
1992 memset(pfd, 0, sizeof pfd);
1993 pfd[0].fd = pfd[1].fd = -1;
1994
1995 /*
1996 * Ensure that we can read a full buffer and handle
1997 * the worst-case length packet it can generate,
1998 * otherwise apply backpressure by stopping reads.
1999 */
2000 if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
2001 (r = sshbuf_check_reserve(oqueue,
2002 SFTP_MAX_MSG_LENGTH)) == 0) {
2003 pfd[0].fd = in;
2004 pfd[0].events = POLLIN;
2005 }
2006 else if (r != SSH_ERR_NO_BUFFER_SPACE)
2007 fatal_fr(r, "reserve");
2008
2009 olen = sshbuf_len(oqueue);
2010 if (olen > 0) {
2011 pfd[1].fd = out;
2012 pfd[1].events = POLLOUT;
2013 }
2014
2015 if (poll(pfd, 2, -1) == -1) {
2016 if (errno == EINTR)
2017 continue;
2018 error("poll: %s", strerror(errno));
2019 sftp_server_cleanup_exit(2);
2020 }
2021
2022 /* copy stdin to iqueue */
2023 if (pfd[0].revents & (POLLIN|POLLHUP)) {
2024 len = read(in, buf, sizeof buf);
2025 if (len == 0) {
2026 debug("read eof");
2027 sftp_server_cleanup_exit(0);
2028 } else if (len == -1) {
2029 if (errno != EAGAIN && errno != EINTR) {
2030 error("read: %s", strerror(errno));
2031 sftp_server_cleanup_exit(1);
2032 }
2033 } else if ((r = sshbuf_put(iqueue, buf, len)) != 0)
2034 fatal_fr(r, "sshbuf_put");
2035 }
2036 /* send oqueue to stdout */
2037 if (pfd[1].revents & (POLLOUT|POLLHUP)) {
2038 len = write(out, sshbuf_ptr(oqueue), olen);
2039 if (len == 0 || (len == -1 && errno == EPIPE)) {
2040 debug("write eof");
2041 sftp_server_cleanup_exit(0);
2042 } else if (len == -1) {
2043 sftp_server_cleanup_exit(1);
2044 if (errno != EAGAIN && errno != EINTR) {
2045 error("write: %s", strerror(errno));
2046 sftp_server_cleanup_exit(1);
2047 }
2048 } else if ((r = sshbuf_consume(oqueue, len)) != 0)
2049 fatal_fr(r, "consume");
2050 }
2051
2052 /*
2053 * Process requests from client if we can fit the results
2054 * into the output buffer, otherwise stop processing input
2055 * and let the output queue drain.
2056 */
2057 r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH);
2058 if (r == 0)
2059 process();
2060 else if (r != SSH_ERR_NO_BUFFER_SPACE)
2061 fatal_fr(r, "reserve");
2062 }
2063 }
2064