sshbuf-getput-basic.c

   1 /*      $OpenBSD: sshbuf-getput-basic.c,v 1.13 2022/05/25 06:03:44 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         if (v == NULL)
 342                 return 0;
 343         return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v));
 344 }
 345
 346 int
 347 sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
 348 {
 349         va_list ap;
 350         int r;
 351
 352         va_start(ap, fmt);
 353         r = sshbuf_putfv(buf, fmt, ap);
 354         va_end(ap);
 355         return r;
 356 }
 357
 358 int
 359 sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)
 360 {
 361         va_list ap2;
 362         int r, len;
 363         u_char *p;
 364
 365         VA_COPY(ap2, ap);
 366         if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) {
 367                 r = SSH_ERR_INVALID_ARGUMENT;
 368                 goto out;
 369         }
 370         if (len == 0) {
 371                 r = 0;
 372                 goto out; /* Nothing to do */
 373         }
 374         va_end(ap2);
 375         VA_COPY(ap2, ap);
 376         if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0)
 377                 goto out;
 378         if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) {
 379                 r = SSH_ERR_INTERNAL_ERROR;
 380                 goto out; /* Shouldn't happen */
 381         }
 382         /* Consume terminating \0 */
 383         if ((r = sshbuf_consume_end(buf, 1)) != 0)
 384                 goto out;
 385         r = 0;
 386  out:
 387         va_end(ap2);
 388         return r;
 389 }
 390
 391 int
 392 sshbuf_put_u64(struct sshbuf *buf, u_int64_t val)
 393 {
 394         u_char *p;
 395         int r;
 396
 397         if ((r = sshbuf_reserve(buf, 8, &p)) < 0)
 398                 return r;
 399         POKE_U64(p, val);
 400         return 0;
 401 }
 402
 403 int
 404 sshbuf_put_u32(struct sshbuf *buf, u_int32_t val)
 405 {
 406         u_char *p;
 407         int r;
 408
 409         if ((r = sshbuf_reserve(buf, 4, &p)) < 0)
 410                 return r;
 411         POKE_U32(p, val);
 412         return 0;
 413 }
 414
 415 int
 416 sshbuf_put_u16(struct sshbuf *buf, u_int16_t val)
 417 {
 418         u_char *p;
 419         int r;
 420
 421         if ((r = sshbuf_reserve(buf, 2, &p)) < 0)
 422                 return r;
 423         POKE_U16(p, val);
 424         return 0;
 425 }
 426
 427 int
 428 sshbuf_put_u8(struct sshbuf *buf, u_char val)
 429 {
 430         u_char *p;
 431         int r;
 432
 433         if ((r = sshbuf_reserve(buf, 1, &p)) < 0)
 434                 return r;
 435         p[0] = val;
 436         return 0;
 437 }
 438
 439 static int
 440 check_woffset(struct sshbuf *buf, size_t offset, size_t len, u_char **p)
 441 {
 442         int r;
 443
 444         *p = NULL;
 445         if ((r = check_offset(buf, 1, offset, len)) != 0)
 446                 return r;
 447         if (sshbuf_mutable_ptr(buf) == NULL)
 448                 return SSH_ERR_BUFFER_READ_ONLY;
 449         *p = sshbuf_mutable_ptr(buf) + offset;
 450         return 0;
 451 }
 452
 453 int
 454 sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val)
 455 {
 456         u_char *p = NULL;
 457         int r;
 458
 459         if ((r = check_woffset(buf, offset, 8, &p)) != 0)
 460                 return r;
 461         POKE_U64(p, val);
 462         return 0;
 463 }
 464
 465 int
 466 sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val)
 467 {
 468         u_char *p = NULL;
 469         int r;
 470
 471         if ((r = check_woffset(buf, offset, 4, &p)) != 0)
 472                 return r;
 473         POKE_U32(p, val);
 474         return 0;
 475 }
 476
 477 int
 478 sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val)
 479 {
 480         u_char *p = NULL;
 481         int r;
 482
 483         if ((r = check_woffset(buf, offset, 2, &p)) != 0)
 484                 return r;
 485         POKE_U16(p, val);
 486         return 0;
 487 }
 488
 489 int
 490 sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val)
 491 {
 492         u_char *p = NULL;
 493         int r;
 494
 495         if ((r = check_woffset(buf, offset, 1, &p)) != 0)
 496                 return r;
 497         *p = val;
 498         return 0;
 499 }
 500
 501 int
 502 sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len)
 503 {
 504         u_char *p = NULL;
 505         int r;
 506
 507         if ((r = check_woffset(buf, offset, len, &p)) != 0)
 508                 return r;
 509         memcpy(p, v, len);
 510         return 0;
 511 }
 512
 513 int
 514 sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)
 515 {
 516         u_char *d;
 517         int r;
 518
 519         if (len > SSHBUF_SIZE_MAX - 4) {
 520                 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
 521                 return SSH_ERR_NO_BUFFER_SPACE;
 522         }
 523         if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)
 524                 return r;
 525         POKE_U32(d, len);
 526         if (len != 0)
 527                 memcpy(d + 4, v, len);
 528         return 0;
 529 }
 530
 531 int
 532 sshbuf_put_cstring(struct sshbuf *buf, const char *v)
 533 {
 534         return sshbuf_put_string(buf, v, v == NULL ? 0 : strlen(v));
 535 }
 536
 537 int
 538 sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v)
 539 {
 540         if (v == NULL)
 541                 return sshbuf_put_string(buf, NULL, 0);
 542
 543         return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v));
 544 }
 545
 546 int
 547 sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp)
 548 {
 549         const u_char *p;
 550         size_t len;
 551         struct sshbuf *ret;
 552         int r;
 553
 554         if (buf == NULL || bufp == NULL)
 555                 return SSH_ERR_INVALID_ARGUMENT;
 556         *bufp = NULL;
 557         if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
 558                 return r;
 559         if ((ret = sshbuf_from(p, len)) == NULL)
 560                 return SSH_ERR_ALLOC_FAIL;
 561         if ((r = sshbuf_consume(buf, len + 4)) != 0 ||  /* Shouldn't happen */
 562             (r = sshbuf_set_parent(ret, buf)) != 0) {
 563                 sshbuf_free(ret);
 564                 return r;
 565         }
 566         *bufp = ret;
 567         return 0;
 568 }
 569
 570 int
 571 sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
 572 {
 573         u_char *d;
 574         const u_char *s = (const u_char *)v;
 575         int r, prepend;
 576
 577         if (len > SSHBUF_SIZE_MAX - 5) {
 578                 SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
 579                 return SSH_ERR_NO_BUFFER_SPACE;
 580         }
 581         /* Skip leading zero bytes */
 582         for (; len > 0 && *s == 0; len--, s++)
 583                 ;
 584         /*
 585          * If most significant bit is set then prepend a zero byte to
 586          * avoid interpretation as a negative number.
 587          */
 588         prepend = len > 0 && (s[0] & 0x80) != 0;
 589         if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0)
 590                 return r;
 591         POKE_U32(d, len + prepend);
 592         if (prepend)
 593                 d[4] = 0;
 594         if (len != 0)
 595                 memcpy(d + 4 + prepend, s, len);
 596         return 0;
 597 }
 598
 599 int
 600 sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
 601     const u_char **valp, size_t *lenp)
 602 {
 603         const u_char *d;
 604         size_t len, olen;
 605         int r;
 606
 607         if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0)
 608                 return r;
 609         len = olen;
 610         /* Refuse negative (MSB set) bignums */
 611         if ((len != 0 && (*d & 0x80) != 0))
 612                 return SSH_ERR_BIGNUM_IS_NEGATIVE;
 613         /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
 614         if (len > SSHBUF_MAX_BIGNUM + 1 ||
 615             (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
 616                 return SSH_ERR_BIGNUM_TOO_LARGE;
 617         /* Trim leading zeros */
 618         while (len > 0 && *d == 0x00) {
 619                 d++;
 620                 len--;
 621         }
 622         if (valp != NULL)
 623                 *valp = d;
 624         if (lenp != NULL)
 625                 *lenp = len;
 626         if (sshbuf_consume(buf, olen + 4) != 0) {
 627                 /* Shouldn't happen */
 628                 SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
 629                 SSHBUF_ABORT();
 630                 return SSH_ERR_INTERNAL_ERROR;
 631         }
 632         return 0;
 633 }