1 /* $OpenBSD: sshbuf-getput-basic.c,v 1.10 2019/12/13 19:09:37 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 #ifdef HAVE_STDINT_H 28 # include <stdint.h> 29 #endif 30 31 #include "ssherr.h" 32 #include "sshbuf.h" 33 34 int 35 sshbuf_get(struct sshbuf *buf, void *v, size_t len) 36 { 37 const u_char *p = sshbuf_ptr(buf); 38 int r; 39 40 if ((r = sshbuf_consume(buf, len)) < 0) 41 return r; 42 if (v != NULL && len != 0) 43 memcpy(v, p, len); 44 return 0; 45 } 46 47 int 48 sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp) 49 { 50 const u_char *p = sshbuf_ptr(buf); 51 int r; 52 53 if ((r = sshbuf_consume(buf, 8)) < 0) 54 return r; 55 if (valp != NULL) 56 *valp = PEEK_U64(p); 57 return 0; 58 } 59 60 int 61 sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp) 62 { 63 const u_char *p = sshbuf_ptr(buf); 64 int r; 65 66 if ((r = sshbuf_consume(buf, 4)) < 0) 67 return r; 68 if (valp != NULL) 69 *valp = PEEK_U32(p); 70 return 0; 71 } 72 73 int 74 sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp) 75 { 76 const u_char *p = sshbuf_ptr(buf); 77 int r; 78 79 if ((r = sshbuf_consume(buf, 2)) < 0) 80 return r; 81 if (valp != NULL) 82 *valp = PEEK_U16(p); 83 return 0; 84 } 85 86 int 87 sshbuf_get_u8(struct sshbuf *buf, u_char *valp) 88 { 89 const u_char *p = sshbuf_ptr(buf); 90 int r; 91 92 if ((r = sshbuf_consume(buf, 1)) < 0) 93 return r; 94 if (valp != NULL) 95 *valp = (u_int8_t)*p; 96 return 0; 97 } 98 99 static int 100 check_offset(const struct sshbuf *buf, int wr, size_t offset, size_t len) 101 { 102 if (sshbuf_ptr(buf) == NULL) /* calls sshbuf_check_sanity() */ 103 return SSH_ERR_INTERNAL_ERROR; 104 if (offset >= SIZE_MAX - len) 105 return SSH_ERR_INVALID_ARGUMENT; 106 if (offset + len > sshbuf_len(buf)) { 107 return wr ? 108 SSH_ERR_NO_BUFFER_SPACE : SSH_ERR_MESSAGE_INCOMPLETE; 109 } 110 return 0; 111 } 112 113 static int 114 check_roffset(const struct sshbuf *buf, size_t offset, size_t len, 115 const u_char **p) 116 { 117 int r; 118 119 *p = NULL; 120 if ((r = check_offset(buf, 0, offset, len)) != 0) 121 return r; 122 *p = sshbuf_ptr(buf) + offset; 123 return 0; 124 } 125 126 int 127 sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, u_int64_t *valp) 128 { 129 const u_char *p = NULL; 130 int r; 131 132 if (valp != NULL) 133 *valp = 0; 134 if ((r = check_roffset(buf, offset, 8, &p)) != 0) 135 return r; 136 if (valp != NULL) 137 *valp = PEEK_U64(p); 138 return 0; 139 } 140 141 int 142 sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, u_int32_t *valp) 143 { 144 const u_char *p = NULL; 145 int r; 146 147 if (valp != NULL) 148 *valp = 0; 149 if ((r = check_roffset(buf, offset, 4, &p)) != 0) 150 return r; 151 if (valp != NULL) 152 *valp = PEEK_U32(p); 153 return 0; 154 } 155 156 int 157 sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, u_int16_t *valp) 158 { 159 const u_char *p = NULL; 160 int r; 161 162 if (valp != NULL) 163 *valp = 0; 164 if ((r = check_roffset(buf, offset, 2, &p)) != 0) 165 return r; 166 if (valp != NULL) 167 *valp = PEEK_U16(p); 168 return 0; 169 } 170 171 int 172 sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, u_char *valp) 173 { 174 const u_char *p = NULL; 175 int r; 176 177 if (valp != NULL) 178 *valp = 0; 179 if ((r = check_roffset(buf, offset, 1, &p)) != 0) 180 return r; 181 if (valp != NULL) 182 *valp = *p; 183 return 0; 184 } 185 186 int 187 sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp) 188 { 189 const u_char *val; 190 size_t len; 191 int r; 192 193 if (valp != NULL) 194 *valp = NULL; 195 if (lenp != NULL) 196 *lenp = 0; 197 if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0) 198 return r; 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, val, len); 206 (*valp)[len] = '\0'; 207 } 208 if (lenp != NULL) 209 *lenp = len; 210 return 0; 211 } 212 213 int 214 sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp) 215 { 216 size_t len; 217 const u_char *p; 218 int r; 219 220 if (valp != NULL) 221 *valp = NULL; 222 if (lenp != NULL) 223 *lenp = 0; 224 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0) 225 return r; 226 if (valp != NULL) 227 *valp = p; 228 if (lenp != NULL) 229 *lenp = len; 230 if (sshbuf_consume(buf, len + 4) != 0) { 231 /* Shouldn't happen */ 232 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); 233 SSHBUF_ABORT(); 234 return SSH_ERR_INTERNAL_ERROR; 235 } 236 return 0; 237 } 238 239 int 240 sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 241 size_t *lenp) 242 { 243 u_int32_t len; 244 const u_char *p = sshbuf_ptr(buf); 245 246 if (valp != NULL) 247 *valp = NULL; 248 if (lenp != NULL) 249 *lenp = 0; 250 if (sshbuf_len(buf) < 4) { 251 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE")); 252 return SSH_ERR_MESSAGE_INCOMPLETE; 253 } 254 len = PEEK_U32(p); 255 if (len > SSHBUF_SIZE_MAX - 4) { 256 SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE")); 257 return SSH_ERR_STRING_TOO_LARGE; 258 } 259 if (sshbuf_len(buf) - 4 < len) { 260 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE")); 261 return SSH_ERR_MESSAGE_INCOMPLETE; 262 } 263 if (valp != NULL) 264 *valp = p + 4; 265 if (lenp != NULL) 266 *lenp = len; 267 return 0; 268 } 269 270 int 271 sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp) 272 { 273 size_t len; 274 const u_char *p, *z; 275 int r; 276 277 if (valp != NULL) 278 *valp = NULL; 279 if (lenp != NULL) 280 *lenp = 0; 281 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0) 282 return r; 283 /* Allow a \0 only at the end of the string */ 284 if (len > 0 && 285 (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) { 286 SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT")); 287 return SSH_ERR_INVALID_FORMAT; 288 } 289 if ((r = sshbuf_skip_string(buf)) != 0) 290 return -1; 291 if (valp != NULL) { 292 if ((*valp = malloc(len + 1)) == NULL) { 293 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL")); 294 return SSH_ERR_ALLOC_FAIL; 295 } 296 if (len != 0) 297 memcpy(*valp, p, len); 298 (*valp)[len] = '\0'; 299 } 300 if (lenp != NULL) 301 *lenp = (size_t)len; 302 return 0; 303 } 304 305 int 306 sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v) 307 { 308 u_int32_t len; 309 u_char *p; 310 int r; 311 312 /* 313 * Use sshbuf_peek_string_direct() to figure out if there is 314 * a complete string in 'buf' and copy the string directly 315 * into 'v'. 316 */ 317 if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 || 318 (r = sshbuf_get_u32(buf, &len)) != 0 || 319 (r = sshbuf_reserve(v, len, &p)) != 0 || 320 (r = sshbuf_get(buf, p, len)) != 0) 321 return r; 322 return 0; 323 } 324 325 int 326 sshbuf_put(struct sshbuf *buf, const void *v, size_t len) 327 { 328 u_char *p; 329 int r; 330 331 if ((r = sshbuf_reserve(buf, len, &p)) < 0) 332 return r; 333 if (len != 0) 334 memcpy(p, v, len); 335 return 0; 336 } 337 338 int 339 sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v) 340 { 341 return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v)); 342 } 343 344 int 345 sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 346 { 347 va_list ap; 348 int r; 349 350 va_start(ap, fmt); 351 r = sshbuf_putfv(buf, fmt, ap); 352 va_end(ap); 353 return r; 354 } 355 356 int 357 sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap) 358 { 359 va_list ap2; 360 int r, len; 361 u_char *p; 362 363 VA_COPY(ap2, ap); 364 if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) { 365 r = SSH_ERR_INVALID_ARGUMENT; 366 goto out; 367 } 368 if (len == 0) { 369 r = 0; 370 goto out; /* Nothing to do */ 371 } 372 va_end(ap2); 373 VA_COPY(ap2, ap); 374 if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0) 375 goto out; 376 if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) { 377 r = SSH_ERR_INTERNAL_ERROR; 378 goto out; /* Shouldn't happen */ 379 } 380 /* Consume terminating \0 */ 381 if ((r = sshbuf_consume_end(buf, 1)) != 0) 382 goto out; 383 r = 0; 384 out: 385 va_end(ap2); 386 return r; 387 } 388 389 int 390 sshbuf_put_u64(struct sshbuf *buf, u_int64_t val) 391 { 392 u_char *p; 393 int r; 394 395 if ((r = sshbuf_reserve(buf, 8, &p)) < 0) 396 return r; 397 POKE_U64(p, val); 398 return 0; 399 } 400 401 int 402 sshbuf_put_u32(struct sshbuf *buf, u_int32_t val) 403 { 404 u_char *p; 405 int r; 406 407 if ((r = sshbuf_reserve(buf, 4, &p)) < 0) 408 return r; 409 POKE_U32(p, val); 410 return 0; 411 } 412 413 int 414 sshbuf_put_u16(struct sshbuf *buf, u_int16_t val) 415 { 416 u_char *p; 417 int r; 418 419 if ((r = sshbuf_reserve(buf, 2, &p)) < 0) 420 return r; 421 POKE_U16(p, val); 422 return 0; 423 } 424 425 int 426 sshbuf_put_u8(struct sshbuf *buf, u_char val) 427 { 428 u_char *p; 429 int r; 430 431 if ((r = sshbuf_reserve(buf, 1, &p)) < 0) 432 return r; 433 p[0] = val; 434 return 0; 435 } 436 437 static int 438 check_woffset(struct sshbuf *buf, size_t offset, size_t len, u_char **p) 439 { 440 int r; 441 442 *p = NULL; 443 if ((r = check_offset(buf, 1, offset, len)) != 0) 444 return r; 445 if (sshbuf_mutable_ptr(buf) == NULL) 446 return SSH_ERR_BUFFER_READ_ONLY; 447 *p = sshbuf_mutable_ptr(buf) + offset; 448 return 0; 449 } 450 451 int 452 sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val) 453 { 454 u_char *p = NULL; 455 int r; 456 457 if ((r = check_woffset(buf, offset, 8, &p)) != 0) 458 return r; 459 POKE_U64(p, val); 460 return 0; 461 } 462 463 int 464 sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val) 465 { 466 u_char *p = NULL; 467 int r; 468 469 if ((r = check_woffset(buf, offset, 4, &p)) != 0) 470 return r; 471 POKE_U32(p, val); 472 return 0; 473 } 474 475 int 476 sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val) 477 { 478 u_char *p = NULL; 479 int r; 480 481 if ((r = check_woffset(buf, offset, 2, &p)) != 0) 482 return r; 483 POKE_U16(p, val); 484 return 0; 485 } 486 487 int 488 sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val) 489 { 490 u_char *p = NULL; 491 int r; 492 493 if ((r = check_woffset(buf, offset, 1, &p)) != 0) 494 return r; 495 *p = val; 496 return 0; 497 } 498 499 int 500 sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len) 501 { 502 u_char *p = NULL; 503 int r; 504 505 if ((r = check_woffset(buf, offset, len, &p)) != 0) 506 return r; 507 memcpy(p, v, len); 508 return 0; 509 } 510 511 int 512 sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len) 513 { 514 u_char *d; 515 int r; 516 517 if (len > SSHBUF_SIZE_MAX - 4) { 518 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE")); 519 return SSH_ERR_NO_BUFFER_SPACE; 520 } 521 if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0) 522 return r; 523 POKE_U32(d, len); 524 if (len != 0) 525 memcpy(d + 4, v, len); 526 return 0; 527 } 528 529 int 530 sshbuf_put_cstring(struct sshbuf *buf, const char *v) 531 { 532 return sshbuf_put_string(buf, v, v == NULL ? 0 : strlen(v)); 533 } 534 535 int 536 sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v) 537 { 538 if (v == NULL) 539 return sshbuf_put_string(buf, NULL, 0); 540 541 return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v)); 542 } 543 544 int 545 sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp) 546 { 547 const u_char *p; 548 size_t len; 549 struct sshbuf *ret; 550 int r; 551 552 if (buf == NULL || bufp == NULL) 553 return SSH_ERR_INVALID_ARGUMENT; 554 *bufp = NULL; 555 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0) 556 return r; 557 if ((ret = sshbuf_from(p, len)) == NULL) 558 return SSH_ERR_ALLOC_FAIL; 559 if ((r = sshbuf_consume(buf, len + 4)) != 0 || /* Shouldn't happen */ 560 (r = sshbuf_set_parent(ret, buf)) != 0) { 561 sshbuf_free(ret); 562 return r; 563 } 564 *bufp = ret; 565 return 0; 566 } 567 568 int 569 sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len) 570 { 571 u_char *d; 572 const u_char *s = (const u_char *)v; 573 int r, prepend; 574 575 if (len > SSHBUF_SIZE_MAX - 5) { 576 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE")); 577 return SSH_ERR_NO_BUFFER_SPACE; 578 } 579 /* Skip leading zero bytes */ 580 for (; len > 0 && *s == 0; len--, s++) 581 ; 582 /* 583 * If most significant bit is set then prepend a zero byte to 584 * avoid interpretation as a negative number. 585 */ 586 prepend = len > 0 && (s[0] & 0x80) != 0; 587 if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0) 588 return r; 589 POKE_U32(d, len + prepend); 590 if (prepend) 591 d[4] = 0; 592 if (len != 0) 593 memcpy(d + 4 + prepend, s, len); 594 return 0; 595 } 596 597 int 598 sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 599 const u_char **valp, size_t *lenp) 600 { 601 const u_char *d; 602 size_t len, olen; 603 int r; 604 605 if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0) 606 return r; 607 len = olen; 608 /* Refuse negative (MSB set) bignums */ 609 if ((len != 0 && (*d & 0x80) != 0)) 610 return SSH_ERR_BIGNUM_IS_NEGATIVE; 611 /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */ 612 if (len > SSHBUF_MAX_BIGNUM + 1 || 613 (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0)) 614 return SSH_ERR_BIGNUM_TOO_LARGE; 615 /* Trim leading zeros */ 616 while (len > 0 && *d == 0x00) { 617 d++; 618 len--; 619 } 620 if (valp != NULL) 621 *valp = d; 622 if (lenp != NULL) 623 *lenp = len; 624 if (sshbuf_consume(buf, olen + 4) != 0) { 625 /* Shouldn't happen */ 626 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); 627 SSHBUF_ABORT(); 628 return SSH_ERR_INTERNAL_ERROR; 629 } 630 return 0; 631 } 632