1 /* $OpenBSD: sshbuf-getput-basic.c,v 1.4 2015/01/14 15:02:39 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 #include <stdlib.h>
23 #include <stdio.h>
24 #include <string.h>
25
26 #include "ssherr.h"
27 #include "sshbuf.h"
28
29 int
sshbuf_get(struct sshbuf * buf,void * v,size_t len)30 sshbuf_get(struct sshbuf *buf, void *v, size_t len)
31 {
32 const u_char *p = sshbuf_ptr(buf);
33 int r;
34
35 if ((r = sshbuf_consume(buf, len)) < 0)
36 return r;
37 if (v != NULL && len != 0)
38 memcpy(v, p, len);
39 return 0;
40 }
41
42 int
sshbuf_get_u64(struct sshbuf * buf,u_int64_t * valp)43 sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp)
44 {
45 const u_char *p = sshbuf_ptr(buf);
46 int r;
47
48 if ((r = sshbuf_consume(buf, 8)) < 0)
49 return r;
50 if (valp != NULL)
51 *valp = PEEK_U64(p);
52 return 0;
53 }
54
55 int
sshbuf_get_u32(struct sshbuf * buf,u_int32_t * valp)56 sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp)
57 {
58 const u_char *p = sshbuf_ptr(buf);
59 int r;
60
61 if ((r = sshbuf_consume(buf, 4)) < 0)
62 return r;
63 if (valp != NULL)
64 *valp = PEEK_U32(p);
65 return 0;
66 }
67
68 int
sshbuf_get_u16(struct sshbuf * buf,u_int16_t * valp)69 sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp)
70 {
71 const u_char *p = sshbuf_ptr(buf);
72 int r;
73
74 if ((r = sshbuf_consume(buf, 2)) < 0)
75 return r;
76 if (valp != NULL)
77 *valp = PEEK_U16(p);
78 return 0;
79 }
80
81 int
sshbuf_get_u8(struct sshbuf * buf,u_char * valp)82 sshbuf_get_u8(struct sshbuf *buf, u_char *valp)
83 {
84 const u_char *p = sshbuf_ptr(buf);
85 int r;
86
87 if ((r = sshbuf_consume(buf, 1)) < 0)
88 return r;
89 if (valp != NULL)
90 *valp = (u_int8_t)*p;
91 return 0;
92 }
93
94 int
sshbuf_get_string(struct sshbuf * buf,u_char ** valp,size_t * lenp)95 sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp)
96 {
97 const u_char *val;
98 size_t len;
99 int r;
100
101 if (valp != NULL)
102 *valp = NULL;
103 if (lenp != NULL)
104 *lenp = 0;
105 if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0)
106 return r;
107 if (valp != NULL) {
108 if ((*valp = malloc(len + 1)) == NULL) {
109 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
110 return SSH_ERR_ALLOC_FAIL;
111 }
112 if (len != 0)
113 memcpy(*valp, val, len);
114 (*valp)[len] = '\0';
115 }
116 if (lenp != NULL)
117 *lenp = len;
118 return 0;
119 }
120
121 int
sshbuf_get_string_direct(struct sshbuf * buf,const u_char ** valp,size_t * lenp)122 sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp)
123 {
124 size_t len;
125 const u_char *p;
126 int r;
127
128 if (valp != NULL)
129 *valp = NULL;
130 if (lenp != NULL)
131 *lenp = 0;
132 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0)
133 return r;
134 if (valp != 0)
135 *valp = p;
136 if (lenp != NULL)
137 *lenp = len;
138 if (sshbuf_consume(buf, len + 4) != 0) {
139 /* Shouldn't happen */
140 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
141 SSHBUF_ABORT();
142 return SSH_ERR_INTERNAL_ERROR;
143 }
144 return 0;
145 }
146
147 int
sshbuf_peek_string_direct(const struct sshbuf * buf,const u_char ** valp,size_t * lenp)148 sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
149 size_t *lenp)
150 {
151 u_int32_t len;
152 const u_char *p = sshbuf_ptr(buf);
153
154 if (valp != NULL)
155 *valp = NULL;
156 if (lenp != NULL)
157 *lenp = 0;
158 if (sshbuf_len(buf) < 4) {
159 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
160 return SSH_ERR_MESSAGE_INCOMPLETE;
161 }
162 len = PEEK_U32(p);
163 if (len > SSHBUF_SIZE_MAX - 4) {
164 SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE"));
165 return SSH_ERR_STRING_TOO_LARGE;
166 }
167 if (sshbuf_len(buf) - 4 < len) {
168 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
169 return SSH_ERR_MESSAGE_INCOMPLETE;
170 }
171 if (valp != 0)
172 *valp = p + 4;
173 if (lenp != NULL)
174 *lenp = len;
175 return 0;
176 }
177
178 int
sshbuf_get_cstring(struct sshbuf * buf,char ** valp,size_t * lenp)179 sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp)
180 {
181 size_t len;
182 const u_char *p, *z;
183 int r;
184
185 if (valp != NULL)
186 *valp = NULL;
187 if (lenp != NULL)
188 *lenp = 0;
189 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
190 return r;
191 /* Allow a \0 only at the end of the string */
192 if (len > 0 &&
193 (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) {
194 SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT"));
195 return SSH_ERR_INVALID_FORMAT;
196 }
197 if ((r = sshbuf_skip_string(buf)) != 0)
198 return -1;
199 if (valp != NULL) {
200 if ((*valp = malloc(len + 1)) == NULL) {
201 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
202 return SSH_ERR_ALLOC_FAIL;
203 }
204 if (len != 0)
205 memcpy(*valp, p, len);
206 (*valp)[len] = '\0';
207 }
208 if (lenp != NULL)
209 *lenp = (size_t)len;
210 return 0;
211 }
212
213 int
sshbuf_get_stringb(struct sshbuf * buf,struct sshbuf * v)214 sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v)
215 {
216 u_int32_t len;
217 u_char *p;
218 int r;
219
220 /*
221 * Use sshbuf_peek_string_direct() to figure out if there is
222 * a complete string in 'buf' and copy the string directly
223 * into 'v'.
224 */
225 if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 ||
226 (r = sshbuf_get_u32(buf, &len)) != 0 ||
227 (r = sshbuf_reserve(v, len, &p)) != 0 ||
228 (r = sshbuf_get(buf, p, len)) != 0)
229 return r;
230 return 0;
231 }
232
233 int
sshbuf_put(struct sshbuf * buf,const void * v,size_t len)234 sshbuf_put(struct sshbuf *buf, const void *v, size_t len)
235 {
236 u_char *p;
237 int r;
238
239 if ((r = sshbuf_reserve(buf, len, &p)) < 0)
240 return r;
241 if (len != 0)
242 memcpy(p, v, len);
243 return 0;
244 }
245
246 int
sshbuf_putb(struct sshbuf * buf,const struct sshbuf * v)247 sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v)
248 {
249 return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v));
250 }
251
252 int
sshbuf_putf(struct sshbuf * buf,const char * fmt,...)253 sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
254 {
255 va_list ap;
256 int r;
257
258 va_start(ap, fmt);
259 r = sshbuf_putfv(buf, fmt, ap);
260 va_end(ap);
261 return r;
262 }
263
264 int
sshbuf_putfv(struct sshbuf * buf,const char * fmt,va_list ap)265 sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)
266 {
267 va_list ap2;
268 int r, len;
269 u_char *p;
270
271 va_copy(ap2, ap);
272 if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) {
273 r = SSH_ERR_INVALID_ARGUMENT;
274 goto out;
275 }
276 if (len == 0) {
277 r = 0;
278 goto out; /* Nothing to do */
279 }
280 va_end(ap2);
281 va_copy(ap2, ap);
282 if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0)
283 goto out;
284 if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) {
285 r = SSH_ERR_INTERNAL_ERROR;
286 goto out; /* Shouldn't happen */
287 }
288 /* Consume terminating \0 */
289 if ((r = sshbuf_consume_end(buf, 1)) != 0)
290 goto out;
291 r = 0;
292 out:
293 va_end(ap2);
294 return r;
295 }
296
297 int
sshbuf_put_u64(struct sshbuf * buf,u_int64_t val)298 sshbuf_put_u64(struct sshbuf *buf, u_int64_t val)
299 {
300 u_char *p;
301 int r;
302
303 if ((r = sshbuf_reserve(buf, 8, &p)) < 0)
304 return r;
305 POKE_U64(p, val);
306 return 0;
307 }
308
309 int
sshbuf_put_u32(struct sshbuf * buf,u_int32_t val)310 sshbuf_put_u32(struct sshbuf *buf, u_int32_t val)
311 {
312 u_char *p;
313 int r;
314
315 if ((r = sshbuf_reserve(buf, 4, &p)) < 0)
316 return r;
317 POKE_U32(p, val);
318 return 0;
319 }
320
321 int
sshbuf_put_u16(struct sshbuf * buf,u_int16_t val)322 sshbuf_put_u16(struct sshbuf *buf, u_int16_t val)
323 {
324 u_char *p;
325 int r;
326
327 if ((r = sshbuf_reserve(buf, 2, &p)) < 0)
328 return r;
329 POKE_U16(p, val);
330 return 0;
331 }
332
333 int
sshbuf_put_u8(struct sshbuf * buf,u_char val)334 sshbuf_put_u8(struct sshbuf *buf, u_char val)
335 {
336 u_char *p;
337 int r;
338
339 if ((r = sshbuf_reserve(buf, 1, &p)) < 0)
340 return r;
341 p[0] = val;
342 return 0;
343 }
344
345 int
sshbuf_put_string(struct sshbuf * buf,const void * v,size_t len)346 sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)
347 {
348 u_char *d;
349 int r;
350
351 if (len > SSHBUF_SIZE_MAX - 4) {
352 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
353 return SSH_ERR_NO_BUFFER_SPACE;
354 }
355 if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)
356 return r;
357 POKE_U32(d, len);
358 if (len != 0)
359 memcpy(d + 4, v, len);
360 return 0;
361 }
362
363 int
sshbuf_put_cstring(struct sshbuf * buf,const char * v)364 sshbuf_put_cstring(struct sshbuf *buf, const char *v)
365 {
366 return sshbuf_put_string(buf, (u_char *)v, v == NULL ? 0 : strlen(v));
367 }
368
369 int
sshbuf_put_stringb(struct sshbuf * buf,const struct sshbuf * v)370 sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v)
371 {
372 return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v));
373 }
374
375 int
sshbuf_froms(struct sshbuf * buf,struct sshbuf ** bufp)376 sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp)
377 {
378 const u_char *p;
379 size_t len;
380 struct sshbuf *ret;
381 int r;
382
383 if (buf == NULL || bufp == NULL)
384 return SSH_ERR_INVALID_ARGUMENT;
385 *bufp = NULL;
386 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
387 return r;
388 if ((ret = sshbuf_from(p, len)) == NULL)
389 return SSH_ERR_ALLOC_FAIL;
390 if ((r = sshbuf_consume(buf, len + 4)) != 0 || /* Shouldn't happen */
391 (r = sshbuf_set_parent(ret, buf)) != 0) {
392 sshbuf_free(ret);
393 return r;
394 }
395 *bufp = ret;
396 return 0;
397 }
398
399 int
sshbuf_put_bignum2_bytes(struct sshbuf * buf,const void * v,size_t len)400 sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
401 {
402 u_char *d;
403 const u_char *s = (const u_char *)v;
404 int r, prepend;
405
406 if (len > SSHBUF_SIZE_MAX - 5) {
407 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
408 return SSH_ERR_NO_BUFFER_SPACE;
409 }
410 /* Skip leading zero bytes */
411 for (; len > 0 && *s == 0; len--, s++)
412 ;
413 /*
414 * If most significant bit is set then prepend a zero byte to
415 * avoid interpretation as a negative number.
416 */
417 prepend = len > 0 && (s[0] & 0x80) != 0;
418 if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0)
419 return r;
420 POKE_U32(d, len + prepend);
421 if (prepend)
422 d[4] = 0;
423 if (len != 0)
424 memcpy(d + 4 + prepend, s, len);
425 return 0;
426 }
427
428 int
sshbuf_get_bignum2_bytes_direct(struct sshbuf * buf,const u_char ** valp,size_t * lenp)429 sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
430 const u_char **valp, size_t *lenp)
431 {
432 const u_char *d;
433 size_t len, olen;
434 int r;
435
436 if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0)
437 return r;
438 len = olen;
439 /* Refuse negative (MSB set) bignums */
440 if ((len != 0 && (*d & 0x80) != 0))
441 return SSH_ERR_BIGNUM_IS_NEGATIVE;
442 /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
443 if (len > SSHBUF_MAX_BIGNUM + 1 ||
444 (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
445 return SSH_ERR_BIGNUM_TOO_LARGE;
446 /* Trim leading zeros */
447 while (len > 0 && *d == 0x00) {
448 d++;
449 len--;
450 }
451 if (valp != 0)
452 *valp = d;
453 if (lenp != NULL)
454 *lenp = len;
455 if (sshbuf_consume(buf, olen + 4) != 0) {
456 /* Shouldn't happen */
457 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
458 SSHBUF_ABORT();
459 return SSH_ERR_INTERNAL_ERROR;
460 }
461 return 0;
462 }
463