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 #include "includes.h" 18 __RCSID("$NetBSD: sshbuf-getput-basic.c,v 1.10 2020/02/27 00:24:40 christos Exp $"); 19 20 #include <sys/types.h> 21 22 #include <stdarg.h> 23 #include <stdlib.h> 24 #include <stdio.h> 25 #include <string.h> 26 #include <stdint.h> 27 28 #include "ssherr.h" 29 #define SSHBUF_INTERNAL 30 #include "sshbuf.h" 31 32 int 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 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 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 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 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 static int 98 check_offset(const struct sshbuf *buf, int wr, size_t offset, size_t len) 99 { 100 if (sshbuf_ptr(buf) == NULL) /* calls sshbuf_check_sanity() */ 101 return SSH_ERR_INTERNAL_ERROR; 102 if (offset >= SIZE_MAX - len) 103 return SSH_ERR_INVALID_ARGUMENT; 104 if (offset + len > sshbuf_len(buf)) { 105 return wr ? 106 SSH_ERR_NO_BUFFER_SPACE : SSH_ERR_MESSAGE_INCOMPLETE; 107 } 108 return 0; 109 } 110 111 static int 112 check_roffset(const struct sshbuf *buf, size_t offset, size_t len, 113 const u_char **p) 114 { 115 int r; 116 117 *p = NULL; 118 if ((r = check_offset(buf, 0, offset, len)) != 0) 119 return r; 120 *p = sshbuf_ptr(buf) + offset; 121 return 0; 122 } 123 124 int 125 sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, u_int64_t *valp) 126 { 127 const u_char *p = NULL; 128 int r; 129 130 if (valp != NULL) 131 *valp = 0; 132 if ((r = check_roffset(buf, offset, 8, &p)) != 0) 133 return r; 134 if (valp != NULL) 135 *valp = PEEK_U64(p); 136 return 0; 137 } 138 139 int 140 sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, u_int32_t *valp) 141 { 142 const u_char *p = NULL; 143 int r; 144 145 if (valp != NULL) 146 *valp = 0; 147 if ((r = check_roffset(buf, offset, 4, &p)) != 0) 148 return r; 149 if (valp != NULL) 150 *valp = PEEK_U32(p); 151 return 0; 152 } 153 154 int 155 sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, u_int16_t *valp) 156 { 157 const u_char *p = NULL; 158 int r; 159 160 if (valp != NULL) 161 *valp = 0; 162 if ((r = check_roffset(buf, offset, 2, &p)) != 0) 163 return r; 164 if (valp != NULL) 165 *valp = PEEK_U16(p); 166 return 0; 167 } 168 169 int 170 sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, u_char *valp) 171 { 172 const u_char *p = NULL; 173 int r; 174 175 if (valp != NULL) 176 *valp = 0; 177 if ((r = check_roffset(buf, offset, 1, &p)) != 0) 178 return r; 179 if (valp != NULL) 180 *valp = *p; 181 return 0; 182 } 183 184 int 185 sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp) 186 { 187 const u_char *val; 188 size_t len; 189 int r; 190 191 if (valp != NULL) 192 *valp = NULL; 193 if (lenp != NULL) 194 *lenp = 0; 195 if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0) 196 return r; 197 if (valp != NULL) { 198 if ((*valp = malloc(len + 1)) == NULL) { 199 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL")); 200 return SSH_ERR_ALLOC_FAIL; 201 } 202 if (len != 0) 203 memcpy(*valp, val, len); 204 (*valp)[len] = '\0'; 205 } 206 if (lenp != NULL) 207 *lenp = len; 208 return 0; 209 } 210 211 int 212 sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp) 213 { 214 size_t len; 215 const u_char *p; 216 int r; 217 218 if (valp != NULL) 219 *valp = NULL; 220 if (lenp != NULL) 221 *lenp = 0; 222 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0) 223 return r; 224 if (valp != NULL) 225 *valp = p; 226 if (lenp != NULL) 227 *lenp = len; 228 if (sshbuf_consume(buf, len + 4) != 0) { 229 /* Shouldn't happen */ 230 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); 231 SSHBUF_ABORT(); 232 return SSH_ERR_INTERNAL_ERROR; 233 } 234 return 0; 235 } 236 237 int 238 sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 239 size_t *lenp) 240 { 241 u_int32_t len; 242 const u_char *p = sshbuf_ptr(buf); 243 244 if (valp != NULL) 245 *valp = NULL; 246 if (lenp != NULL) 247 *lenp = 0; 248 if (sshbuf_len(buf) < 4) { 249 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE")); 250 return SSH_ERR_MESSAGE_INCOMPLETE; 251 } 252 len = PEEK_U32(p); 253 if (len > SSHBUF_SIZE_MAX - 4) { 254 SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE")); 255 return SSH_ERR_STRING_TOO_LARGE; 256 } 257 if (sshbuf_len(buf) - 4 < len) { 258 SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE")); 259 return SSH_ERR_MESSAGE_INCOMPLETE; 260 } 261 if (valp != NULL) 262 *valp = p + 4; 263 if (lenp != NULL) 264 *lenp = len; 265 return 0; 266 } 267 268 int 269 sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp) 270 { 271 size_t len; 272 const u_char *p, *z; 273 int r; 274 275 if (valp != NULL) 276 *valp = NULL; 277 if (lenp != NULL) 278 *lenp = 0; 279 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0) 280 return r; 281 /* Allow a \0 only at the end of the string */ 282 if (len > 0 && 283 (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) { 284 SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT")); 285 return SSH_ERR_INVALID_FORMAT; 286 } 287 if ((r = sshbuf_skip_string(buf)) != 0) 288 return -1; 289 if (valp != NULL) { 290 if ((*valp = malloc(len + 1)) == NULL) { 291 SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL")); 292 return SSH_ERR_ALLOC_FAIL; 293 } 294 if (len != 0) 295 memcpy(*valp, p, len); 296 (*valp)[len] = '\0'; 297 } 298 if (lenp != NULL) 299 *lenp = (size_t)len; 300 return 0; 301 } 302 303 int 304 sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v) 305 { 306 u_int32_t len; 307 u_char *p; 308 int r; 309 310 /* 311 * Use sshbuf_peek_string_direct() to figure out if there is 312 * a complete string in 'buf' and copy the string directly 313 * into 'v'. 314 */ 315 if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 || 316 (r = sshbuf_get_u32(buf, &len)) != 0 || 317 (r = sshbuf_reserve(v, len, &p)) != 0 || 318 (r = sshbuf_get(buf, p, len)) != 0) 319 return r; 320 return 0; 321 } 322 323 int 324 sshbuf_put(struct sshbuf *buf, const void *v, size_t len) 325 { 326 u_char *p; 327 int r; 328 329 if ((r = sshbuf_reserve(buf, len, &p)) < 0) 330 return r; 331 if (len != 0) 332 memcpy(p, v, len); 333 return 0; 334 } 335 336 int 337 sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v) 338 { 339 return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v)); 340 } 341 342 int 343 sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 344 { 345 va_list ap; 346 int r; 347 348 va_start(ap, fmt); 349 r = sshbuf_putfv(buf, fmt, ap); 350 va_end(ap); 351 return r; 352 } 353 354 int 355 sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap) 356 { 357 va_list ap2; 358 int r, len; 359 u_char *p; 360 361 va_copy(ap2, ap); 362 if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) { 363 r = SSH_ERR_INVALID_ARGUMENT; 364 goto out; 365 } 366 if (len == 0) { 367 r = 0; 368 goto out; /* Nothing to do */ 369 } 370 va_end(ap2); 371 va_copy(ap2, ap); 372 if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0) 373 goto out; 374 if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) { 375 r = SSH_ERR_INTERNAL_ERROR; 376 goto out; /* Shouldn't happen */ 377 } 378 /* Consume terminating \0 */ 379 if ((r = sshbuf_consume_end(buf, 1)) != 0) 380 goto out; 381 r = 0; 382 out: 383 va_end(ap2); 384 return r; 385 } 386 387 int 388 sshbuf_put_u64(struct sshbuf *buf, u_int64_t val) 389 { 390 u_char *p; 391 int r; 392 393 if ((r = sshbuf_reserve(buf, 8, &p)) < 0) 394 return r; 395 POKE_U64(p, val); 396 return 0; 397 } 398 399 int 400 sshbuf_put_u32(struct sshbuf *buf, u_int32_t val) 401 { 402 u_char *p; 403 int r; 404 405 if ((r = sshbuf_reserve(buf, 4, &p)) < 0) 406 return r; 407 POKE_U32(p, val); 408 return 0; 409 } 410 411 int 412 sshbuf_put_u16(struct sshbuf *buf, u_int16_t val) 413 { 414 u_char *p; 415 int r; 416 417 if ((r = sshbuf_reserve(buf, 2, &p)) < 0) 418 return r; 419 POKE_U16(p, val); 420 return 0; 421 } 422 423 int 424 sshbuf_put_u8(struct sshbuf *buf, u_char val) 425 { 426 u_char *p; 427 int r; 428 429 if ((r = sshbuf_reserve(buf, 1, &p)) < 0) 430 return r; 431 p[0] = val; 432 return 0; 433 } 434 435 static int 436 check_woffset(struct sshbuf *buf, size_t offset, size_t len, u_char **p) 437 { 438 int r; 439 440 *p = NULL; 441 if ((r = check_offset(buf, 1, offset, len)) != 0) 442 return r; 443 if (sshbuf_mutable_ptr(buf) == NULL) 444 return SSH_ERR_BUFFER_READ_ONLY; 445 *p = sshbuf_mutable_ptr(buf) + offset; 446 return 0; 447 } 448 449 int 450 sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val) 451 { 452 u_char *p = NULL; 453 int r; 454 455 if ((r = check_woffset(buf, offset, 8, &p)) != 0) 456 return r; 457 POKE_U64(p, val); 458 return 0; 459 } 460 461 int 462 sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val) 463 { 464 u_char *p = NULL; 465 int r; 466 467 if ((r = check_woffset(buf, offset, 4, &p)) != 0) 468 return r; 469 POKE_U32(p, val); 470 return 0; 471 } 472 473 int 474 sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val) 475 { 476 u_char *p = NULL; 477 int r; 478 479 if ((r = check_woffset(buf, offset, 2, &p)) != 0) 480 return r; 481 POKE_U16(p, val); 482 return 0; 483 } 484 485 int 486 sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val) 487 { 488 u_char *p = NULL; 489 int r; 490 491 if ((r = check_woffset(buf, offset, 1, &p)) != 0) 492 return r; 493 *p = val; 494 return 0; 495 } 496 497 int 498 sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len) 499 { 500 u_char *p = NULL; 501 int r; 502 503 if ((r = check_woffset(buf, offset, len, &p)) != 0) 504 return r; 505 memcpy(p, v, len); 506 return 0; 507 } 508 509 int 510 sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len) 511 { 512 u_char *d; 513 int r; 514 515 if (len > SSHBUF_SIZE_MAX - 4) { 516 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE")); 517 return SSH_ERR_NO_BUFFER_SPACE; 518 } 519 if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0) 520 return r; 521 POKE_U32(d, len); 522 if (len != 0) 523 memcpy(d + 4, v, len); 524 return 0; 525 } 526 527 int 528 sshbuf_put_cstring(struct sshbuf *buf, const char *v) 529 { 530 return sshbuf_put_string(buf, __UNCONST(v), v == NULL ? 0 : strlen(v)); 531 } 532 533 int 534 sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v) 535 { 536 if (v == NULL) 537 return sshbuf_put_string(buf, NULL, 0); 538 539 return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v)); 540 } 541 542 int 543 sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp) 544 { 545 const u_char *p; 546 size_t len; 547 struct sshbuf *ret; 548 int r; 549 550 if (buf == NULL || bufp == NULL) 551 return SSH_ERR_INVALID_ARGUMENT; 552 *bufp = NULL; 553 if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0) 554 return r; 555 if ((ret = sshbuf_from(p, len)) == NULL) 556 return SSH_ERR_ALLOC_FAIL; 557 if ((r = sshbuf_consume(buf, len + 4)) != 0 || /* Shouldn't happen */ 558 (r = sshbuf_set_parent(ret, buf)) != 0) { 559 sshbuf_free(ret); 560 return r; 561 } 562 *bufp = ret; 563 return 0; 564 } 565 566 int 567 sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len) 568 { 569 u_char *d; 570 const u_char *s = (const u_char *)v; 571 int r, prepend; 572 573 if (len > SSHBUF_SIZE_MAX - 5) { 574 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE")); 575 return SSH_ERR_NO_BUFFER_SPACE; 576 } 577 /* Skip leading zero bytes */ 578 for (; len > 0 && *s == 0; len--, s++) 579 ; 580 /* 581 * If most significant bit is set then prepend a zero byte to 582 * avoid interpretation as a negative number. 583 */ 584 prepend = len > 0 && (s[0] & 0x80) != 0; 585 if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0) 586 return r; 587 POKE_U32(d, len + prepend); 588 if (prepend) 589 d[4] = 0; 590 if (len != 0) 591 memcpy(d + 4 + prepend, s, len); 592 return 0; 593 } 594 595 int 596 sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 597 const u_char **valp, size_t *lenp) 598 { 599 const u_char *d; 600 size_t len, olen; 601 int r; 602 603 if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0) 604 return r; 605 len = olen; 606 /* Refuse negative (MSB set) bignums */ 607 if ((len != 0 && (*d & 0x80) != 0)) 608 return SSH_ERR_BIGNUM_IS_NEGATIVE; 609 /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */ 610 if (len > SSHBUF_MAX_BIGNUM + 1 || 611 (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0)) 612 return SSH_ERR_BIGNUM_TOO_LARGE; 613 /* Trim leading zeros */ 614 while (len > 0 && *d == 0x00) { 615 d++; 616 len--; 617 } 618 if (valp != NULL) 619 *valp = d; 620 if (lenp != NULL) 621 *lenp = len; 622 if (sshbuf_consume(buf, olen + 4) != 0) { 623 /* Shouldn't happen */ 624 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); 625 SSHBUF_ABORT(); 626 return SSH_ERR_INTERNAL_ERROR; 627 } 628 return 0; 629 } 630