1 /* $OpenBSD: sshbuf-getput-basic.c,v 1.7 2017/06/01 04:51:58 djm Exp $ */
2 /*
3 * Copyright (c) 2011 Damien Miller
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #define SSHBUF_INTERNAL
19 #include "includes.h"
20
21 #include <sys/types.h>
22
23 #include <stdarg.h>
24 #include <stdlib.h>
25 #include <stdio.h>
26 #include <string.h>
27
28 #include "xmalloc.h"
29 #include "ssherr.h"
30 #include "sshbuf.h"
31
32 int
sshbuf_get(struct sshbuf * buf,void * v,size_t len)33 sshbuf_get(struct sshbuf *buf, void *v, size_t len)
34 {
35 const u_char *p = sshbuf_ptr(buf);
36 int r;
37
38 if ((r = sshbuf_consume(buf, len)) < 0)
39 return r;
40 if (v != NULL && len != 0)
41 memcpy(v, p, len);
42 return 0;
43 }
44
45 int
sshbuf_get_u64(struct sshbuf * buf,u_int64_t * valp)46 sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp)
47 {
48 const u_char *p = sshbuf_ptr(buf);
49 int r;
50
51 if ((r = sshbuf_consume(buf, 8)) < 0)
52 return r;
53 if (valp != NULL)
54 *valp = PEEK_U64(p);
55 return 0;
56 }
57
58 int
sshbuf_get_u32(struct sshbuf * buf,u_int32_t * valp)59 sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp)
60 {
61 const u_char *p = sshbuf_ptr(buf);
62 int r;
63
64 if ((r = sshbuf_consume(buf, 4)) < 0)
65 return r;
66 if (valp != NULL)
67 *valp = PEEK_U32(p);
68 return 0;
69 }
70
71 int
sshbuf_get_u16(struct sshbuf * buf,u_int16_t * valp)72 sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp)
73 {
74 const u_char *p = sshbuf_ptr(buf);
75 int r;
76
77 if ((r = sshbuf_consume(buf, 2)) < 0)
78 return r;
79 if (valp != NULL)
80 *valp = PEEK_U16(p);
81 return 0;
82 }
83
84 int
sshbuf_get_u8(struct sshbuf * buf,u_char * valp)85 sshbuf_get_u8(struct sshbuf *buf, u_char *valp)
86 {
87 const u_char *p = sshbuf_ptr(buf);
88 int r;
89
90 if ((r = sshbuf_consume(buf, 1)) < 0)
91 return r;
92 if (valp != NULL)
93 *valp = (u_int8_t)*p;
94 return 0;
95 }
96
97 int
sshbuf_get_string(struct sshbuf * buf,u_char ** valp,size_t * lenp)98 sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp)
99 {
100 const u_char *val;
101 size_t len;
102 int r;
103
104 if (valp != NULL)
105 *valp = NULL;
106 if (lenp != NULL)
107 *lenp = 0;
108 if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0)
109 return r;
110 if (valp != NULL) {
111 if ((*valp = malloc(len + 1)) == NULL) {
112 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
113 return SSH_ERR_ALLOC_FAIL;
114 }
115 if (len != 0)
116 memcpy(*valp, val, len);
117 (*valp)[len] = '\0';
118 }
119 if (lenp != NULL)
120 *lenp = len;
121 return 0;
122 }
123
124 int
sshbuf_get_string_direct(struct sshbuf * buf,const u_char ** valp,size_t * lenp)125 sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp)
126 {
127 size_t len;
128 const u_char *p;
129 int r;
130
131 if (valp != NULL)
132 *valp = NULL;
133 if (lenp != NULL)
134 *lenp = 0;
135 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0)
136 return r;
137 if (valp != NULL)
138 *valp = p;
139 if (lenp != NULL)
140 *lenp = len;
141 if (sshbuf_consume(buf, len + 4) != 0) {
142 /* Shouldn't happen */
143 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
144 SSHBUF_ABORT();
145 return SSH_ERR_INTERNAL_ERROR;
146 }
147 return 0;
148 }
149
150 int
sshbuf_peek_string_direct(const struct sshbuf * buf,const u_char ** valp,size_t * lenp)151 sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
152 size_t *lenp)
153 {
154 u_int32_t len;
155 const u_char *p = sshbuf_ptr(buf);
156
157 if (valp != NULL)
158 *valp = NULL;
159 if (lenp != NULL)
160 *lenp = 0;
161 if (sshbuf_len(buf) < 4) {
162 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
163 return SSH_ERR_MESSAGE_INCOMPLETE;
164 }
165 len = PEEK_U32(p);
166 if (len > SSHBUF_SIZE_MAX - 4) {
167 SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE"));
168 return SSH_ERR_STRING_TOO_LARGE;
169 }
170 if (sshbuf_len(buf) - 4 < len) {
171 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
172 return SSH_ERR_MESSAGE_INCOMPLETE;
173 }
174 if (valp != NULL)
175 *valp = p + 4;
176 if (lenp != NULL)
177 *lenp = len;
178 return 0;
179 }
180
181 int
sshbuf_get_cstring(struct sshbuf * buf,char ** valp,size_t * lenp)182 sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp)
183 {
184 size_t len;
185 const u_char *p, *z;
186 int r;
187
188 if (valp != NULL)
189 *valp = NULL;
190 if (lenp != NULL)
191 *lenp = 0;
192 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
193 return r;
194 /* Allow a \0 only at the end of the string */
195 if (len > 0 &&
196 (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) {
197 SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT"));
198 return SSH_ERR_INVALID_FORMAT;
199 }
200 if ((r = sshbuf_skip_string(buf)) != 0)
201 return -1;
202 if (valp != NULL) {
203 if ((*valp = malloc(len + 1)) == NULL) {
204 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
205 return SSH_ERR_ALLOC_FAIL;
206 }
207 if (len != 0)
208 memcpy(*valp, p, len);
209 (*valp)[len] = '\0';
210 }
211 if (lenp != NULL)
212 *lenp = (size_t)len;
213 return 0;
214 }
215
216 int
sshbuf_get_stringb(struct sshbuf * buf,struct sshbuf * v)217 sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v)
218 {
219 u_int32_t len;
220 u_char *p;
221 int r;
222
223 /*
224 * Use sshbuf_peek_string_direct() to figure out if there is
225 * a complete string in 'buf' and copy the string directly
226 * into 'v'.
227 */
228 if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 ||
229 (r = sshbuf_get_u32(buf, &len)) != 0 ||
230 (r = sshbuf_reserve(v, len, &p)) != 0 ||
231 (r = sshbuf_get(buf, p, len)) != 0)
232 return r;
233 return 0;
234 }
235
236 int
sshbuf_put(struct sshbuf * buf,const void * v,size_t len)237 sshbuf_put(struct sshbuf *buf, const void *v, size_t len)
238 {
239 u_char *p;
240 int r;
241
242 if ((r = sshbuf_reserve(buf, len, &p)) < 0)
243 return r;
244 if (len != 0)
245 memcpy(p, v, len);
246 return 0;
247 }
248
249 int
sshbuf_putb(struct sshbuf * buf,const struct sshbuf * v)250 sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v)
251 {
252 return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v));
253 }
254
255 int
sshbuf_putf(struct sshbuf * buf,const char * fmt,...)256 sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
257 {
258 va_list ap;
259 int r;
260
261 va_start(ap, fmt);
262 r = sshbuf_putfv(buf, fmt, ap);
263 va_end(ap);
264 return r;
265 }
266
267 int
sshbuf_putfv(struct sshbuf * buf,const char * fmt,va_list ap)268 sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)
269 {
270 va_list ap2;
271 int r, len;
272 u_char *p;
273
274 VA_COPY(ap2, ap);
275 if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) {
276 r = SSH_ERR_INVALID_ARGUMENT;
277 goto out;
278 }
279 if (len == 0) {
280 r = 0;
281 goto out; /* Nothing to do */
282 }
283 va_end(ap2);
284 VA_COPY(ap2, ap);
285 if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0)
286 goto out;
287 if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) {
288 r = SSH_ERR_INTERNAL_ERROR;
289 goto out; /* Shouldn't happen */
290 }
291 /* Consume terminating \0 */
292 if ((r = sshbuf_consume_end(buf, 1)) != 0)
293 goto out;
294 r = 0;
295 out:
296 va_end(ap2);
297 return r;
298 }
299
300 int
sshbuf_put_u64(struct sshbuf * buf,u_int64_t val)301 sshbuf_put_u64(struct sshbuf *buf, u_int64_t val)
302 {
303 u_char *p;
304 int r;
305
306 if ((r = sshbuf_reserve(buf, 8, &p)) < 0)
307 return r;
308 POKE_U64(p, val);
309 return 0;
310 }
311
312 int
sshbuf_put_u32(struct sshbuf * buf,u_int32_t val)313 sshbuf_put_u32(struct sshbuf *buf, u_int32_t val)
314 {
315 u_char *p;
316 int r;
317
318 if ((r = sshbuf_reserve(buf, 4, &p)) < 0)
319 return r;
320 POKE_U32(p, val);
321 return 0;
322 }
323
324 int
sshbuf_put_u16(struct sshbuf * buf,u_int16_t val)325 sshbuf_put_u16(struct sshbuf *buf, u_int16_t val)
326 {
327 u_char *p;
328 int r;
329
330 if ((r = sshbuf_reserve(buf, 2, &p)) < 0)
331 return r;
332 POKE_U16(p, val);
333 return 0;
334 }
335
336 int
sshbuf_put_u8(struct sshbuf * buf,u_char val)337 sshbuf_put_u8(struct sshbuf *buf, u_char val)
338 {
339 u_char *p;
340 int r;
341
342 if ((r = sshbuf_reserve(buf, 1, &p)) < 0)
343 return r;
344 p[0] = val;
345 return 0;
346 }
347
348 int
sshbuf_put_string(struct sshbuf * buf,const void * v,size_t len)349 sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)
350 {
351 u_char *d;
352 int r;
353
354 if (len > SSHBUF_SIZE_MAX - 4) {
355 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
356 return SSH_ERR_NO_BUFFER_SPACE;
357 }
358 if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)
359 return r;
360 POKE_U32(d, len);
361 if (len != 0)
362 memcpy(d + 4, v, len);
363 return 0;
364 }
365
366 int
sshbuf_put_cstring(struct sshbuf * buf,const char * v)367 sshbuf_put_cstring(struct sshbuf *buf, const char *v)
368 {
369 return sshbuf_put_string(buf, v, v == NULL ? 0 : strlen(v));
370 }
371
372 int
sshbuf_put_stringb(struct sshbuf * buf,const struct sshbuf * v)373 sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v)
374 {
375 return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v));
376 }
377
378 int
sshbuf_froms(struct sshbuf * buf,struct sshbuf ** bufp)379 sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp)
380 {
381 const u_char *p;
382 size_t len;
383 struct sshbuf *ret;
384 int r;
385
386 if (buf == NULL || bufp == NULL)
387 return SSH_ERR_INVALID_ARGUMENT;
388 *bufp = NULL;
389 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
390 return r;
391 if ((ret = sshbuf_from(p, len)) == NULL)
392 return SSH_ERR_ALLOC_FAIL;
393 if ((r = sshbuf_consume(buf, len + 4)) != 0 || /* Shouldn't happen */
394 (r = sshbuf_set_parent(ret, buf)) != 0) {
395 sshbuf_free(ret);
396 return r;
397 }
398 *bufp = ret;
399 return 0;
400 }
401
402 int
sshbuf_put_bignum2_bytes(struct sshbuf * buf,const void * v,size_t len)403 sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
404 {
405 u_char *d;
406 const u_char *s = (const u_char *)v;
407 int r, prepend;
408
409 if (len > SSHBUF_SIZE_MAX - 5) {
410 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
411 return SSH_ERR_NO_BUFFER_SPACE;
412 }
413 /* Skip leading zero bytes */
414 for (; len > 0 && *s == 0; len--, s++)
415 ;
416 /*
417 * If most significant bit is set then prepend a zero byte to
418 * avoid interpretation as a negative number.
419 */
420 prepend = len > 0 && (s[0] & 0x80) != 0;
421 if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0)
422 return r;
423 POKE_U32(d, len + prepend);
424 if (prepend)
425 d[4] = 0;
426 if (len != 0)
427 memcpy(d + 4 + prepend, s, len);
428 return 0;
429 }
430
431 int
sshbuf_get_bignum2_bytes_direct(struct sshbuf * buf,const u_char ** valp,size_t * lenp)432 sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
433 const u_char **valp, size_t *lenp)
434 {
435 const u_char *d;
436 size_t len, olen;
437 int r;
438
439 if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0)
440 return r;
441 len = olen;
442 /* Refuse negative (MSB set) bignums */
443 if ((len != 0 && (*d & 0x80) != 0))
444 return SSH_ERR_BIGNUM_IS_NEGATIVE;
445 /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
446 if (len > SSHBUF_MAX_BIGNUM + 1 ||
447 (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
448 return SSH_ERR_BIGNUM_TOO_LARGE;
449 /* Trim leading zeros */
450 while (len > 0 && *d == 0x00) {
451 d++;
452 len--;
453 }
454 if (valp != NULL)
455 *valp = d;
456 if (lenp != NULL)
457 *lenp = len;
458 if (sshbuf_consume(buf, olen + 4) != 0) {
459 /* Shouldn't happen */
460 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
461 SSHBUF_ABORT();
462 return SSH_ERR_INTERNAL_ERROR;
463 }
464 return 0;
465 }
466
467 /*
468 * store struct pwd
469 */
470 int
sshbuf_put_passwd(struct sshbuf * buf,const struct passwd * pwent)471 sshbuf_put_passwd(struct sshbuf *buf, const struct passwd *pwent)
472 {
473 int r;
474
475 /*
476 * We never send pointer values of struct passwd.
477 * It is safe from wild pointer even if a new pointer member is added.
478 */
479
480 if ((r = sshbuf_put_u64(buf, sizeof(*pwent)) != 0) ||
481 (r = sshbuf_put_cstring(buf, pwent->pw_name)) != 0 ||
482 (r = sshbuf_put_cstring(buf, "*")) != 0 ||
483 (r = sshbuf_put_u32(buf, pwent->pw_uid)) != 0 ||
484 (r = sshbuf_put_u32(buf, pwent->pw_gid)) != 0 ||
485 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
486 (r = sshbuf_put_time(buf, pwent->pw_change)) != 0 ||
487 #endif
488 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
489 (r = sshbuf_put_cstring(buf, pwent->pw_gecos)) != 0 ||
490 #endif
491 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
492 (r = sshbuf_put_cstring(buf, pwent->pw_class)) != 0 ||
493 #endif
494 (r = sshbuf_put_cstring(buf, pwent->pw_dir)) != 0 ||
495 (r = sshbuf_put_cstring(buf, pwent->pw_shell)) != 0 ||
496 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
497 (r = sshbuf_put_time(buf, pwent->pw_expire)) != 0 ||
498 #endif
499 (r = sshbuf_put_u32(buf, pwent->pw_fields)) != 0) {
500 return r;
501 }
502 return 0;
503 }
504
505 /*
506 * extract struct pwd
507 */
508 struct passwd *
sshbuf_get_passwd(struct sshbuf * buf)509 sshbuf_get_passwd(struct sshbuf *buf)
510 {
511 struct passwd *pw;
512 u_int64_t len;
513 int r;
514
515 /* check if size of struct passwd is as same as sender's size */
516 r = sshbuf_get_u64(buf, &len);
517 if (r != 0 || len != sizeof(*pw))
518 return NULL;
519
520 pw = xcalloc(1, sizeof(*pw));
521 if (sshbuf_get_cstring(buf, &pw->pw_name, NULL) != 0 ||
522 sshbuf_get_cstring(buf, &pw->pw_passwd, NULL) != 0 ||
523 sshbuf_get_u32(buf, &pw->pw_uid) != 0 ||
524 sshbuf_get_u32(buf, &pw->pw_gid) != 0 ||
525 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
526 sshbuf_get_time(buf, &pw->pw_change) != 0 ||
527 #endif
528 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
529 sshbuf_get_cstring(buf, &pw->pw_gecos, NULL) != 0 ||
530 #endif
531 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
532 sshbuf_get_cstring(buf, &pw->pw_class, NULL) != 0 ||
533 #endif
534 sshbuf_get_cstring(buf, &pw->pw_dir, NULL) != 0 ||
535 sshbuf_get_cstring(buf, &pw->pw_shell, NULL) != 0 ||
536 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
537 sshbuf_get_time(buf, &pw->pw_expire) != 0 ||
538 #endif
539 sshbuf_get_u32(buf, &pw->pw_fields) != 0) {
540 sshbuf_free_passwd(pw);
541 return NULL;
542 }
543 return pw;
544 }
545
546 /*
547 * free struct passwd obtained from sshbuf_get_passwd.
548 */
549 void
sshbuf_free_passwd(struct passwd * pwent)550 sshbuf_free_passwd(struct passwd *pwent)
551 {
552 if (pwent == NULL)
553 return;
554 free(pwent->pw_shell);
555 free(pwent->pw_dir);
556 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
557 free(pwent->pw_class);
558 #endif
559 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
560 free(pwent->pw_gecos);
561 #endif
562 free(pwent->pw_passwd);
563 free(pwent->pw_name);
564 free(pwent);
565 }
566