1 /* $OpenBSD: sshbuf.h,v 1.36 2026/04/07 07:40:40 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 #ifndef _SSHBUF_H 19 #define _SSHBUF_H 20 21 #include <sys/types.h> 22 #include <stdarg.h> 23 #include <stdio.h> 24 #include <stdint.h> 25 26 #ifdef WITH_OPENSSL 27 # include <openssl/bn.h> 28 # include <openssl/evp.h> 29 # ifdef OPENSSL_HAS_ECC 30 # include <openssl/ec.h> 31 # endif /* OPENSSL_HAS_ECC */ 32 #endif /* WITH_OPENSSL */ 33 34 #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ 35 #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 36 #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 37 #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 38 39 struct sshbuf; 40 41 /* 42 * Create a new sshbuf buffer. 43 * Returns pointer to buffer on success, or NULL on allocation failure. 44 */ 45 struct sshbuf *sshbuf_new(void); 46 47 /* 48 * Create a new, read-only sshbuf buffer from existing data. 49 * Returns pointer to buffer on success, or NULL on allocation failure. 50 */ 51 struct sshbuf *sshbuf_from(const void *blob, size_t len); 52 53 /* 54 * Create a new, read-only sshbuf buffer from the contents of an existing 55 * buffer. The contents of "buf" must not change in the lifetime of the 56 * resultant buffer. 57 * Returns pointer to buffer on success, or NULL on allocation failure. 58 */ 59 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 60 61 /* 62 * Create a new, read-only sshbuf buffer from the contents of a string in 63 * an existing buffer (the string is consumed in the process). 64 * The contents of "buf" must not change in the lifetime of the resultant 65 * buffer. 66 * On success, a pointer to the newly allocated buffer is placed in *bufp. 67 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 68 */ 69 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 70 71 /* 72 * Clear and free buf 73 */ 74 void sshbuf_free(struct sshbuf *buf); 75 76 /* 77 * Reset buf, clearing its contents. NB. max_size is preserved. 78 */ 79 void sshbuf_reset(struct sshbuf *buf); 80 81 /* 82 * Return the maximum size of buf 83 */ 84 size_t sshbuf_max_size(const struct sshbuf *buf); 85 86 /* 87 * Set the maximum size of buf 88 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 89 */ 90 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 91 92 /* 93 * Returns the length of data in buf 94 */ 95 size_t sshbuf_len(const struct sshbuf *buf); 96 97 /* 98 * Returns number of bytes left in buffer before hitting max_size. 99 */ 100 size_t sshbuf_avail(const struct sshbuf *buf); 101 102 /* 103 * Returns a read-only pointer to the start of the data in buf 104 */ 105 const u_char *sshbuf_ptr(const struct sshbuf *buf); 106 107 /* 108 * Returns a mutable pointer to the start of the data in buf, or 109 * NULL if the buffer is read-only. 110 */ 111 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 112 113 /* 114 * Check whether a reservation of size len will succeed in buf 115 * Safer to use than direct comparisons again sshbuf_avail as it copes 116 * with unsigned overflows correctly. 117 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 118 */ 119 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 120 121 /* 122 * Preallocates len additional bytes in buf. 123 * Useful for cases where the caller knows how many bytes will ultimately be 124 * required to avoid realloc in the buffer code. 125 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 126 */ 127 int sshbuf_allocate(struct sshbuf *buf, size_t len); 128 129 /* 130 * Reserve len bytes in buf. 131 * Returns 0 on success and a pointer to the first reserved byte via the 132 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 133 */ 134 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 135 136 /* 137 * Consume len bytes from the start of buf 138 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 139 */ 140 int sshbuf_consume(struct sshbuf *buf, size_t len); 141 142 /* 143 * Consume len bytes from the end of buf 144 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 145 */ 146 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 147 148 /* 149 * Consume data from a parent buffer up to that of a child buffer (i.e. 150 * one created by sshbuf_fromb()). 151 * 152 * Intended to be used in a pattern like: 153 * 154 * b = sshbuf_fromb(parent); 155 * sshbuf_get_string(b, &foo, &foostr); 156 * sshbuf_get_u32(b, &bar); 157 * sshbuf_consume_upto_child(parent, b); 158 * 159 * After which, both "b" and "parent" will point to the same data. 160 * 161 * "child" must be a direct child of "buf" (i.e. neither an unrelated buffer 162 * nor a grandchild) which has consumed data past that of "buf". 163 */ 164 int sshbuf_consume_upto_child(struct sshbuf *buf, const struct sshbuf *child); 165 166 /* Extract or deposit some bytes */ 167 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 168 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 169 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 170 171 /* Append using a printf(3) format */ 172 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 173 __attribute__((format(printf, 2, 3))); 174 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 175 176 /* Functions to extract or store big-endian words of various sizes */ 177 int sshbuf_get_u64(struct sshbuf *buf, uint64_t *valp); 178 int sshbuf_get_u32(struct sshbuf *buf, uint32_t *valp); 179 int sshbuf_get_u16(struct sshbuf *buf, uint16_t *valp); 180 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 181 int sshbuf_put_u64(struct sshbuf *buf, uint64_t val); 182 int sshbuf_put_u32(struct sshbuf *buf, uint32_t val); 183 int sshbuf_put_u16(struct sshbuf *buf, uint16_t val); 184 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 185 186 /* Functions to peek at the contents of a buffer without modifying it. */ 187 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 188 uint64_t *valp); 189 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 190 uint32_t *valp); 191 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 192 uint16_t *valp); 193 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 194 u_char *valp); 195 196 /* 197 * Functions to poke values into an existing buffer (e.g. a length header 198 * to a packet). The destination bytes must already exist in the buffer. 199 */ 200 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, uint64_t val); 201 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, uint32_t val); 202 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, uint16_t val); 203 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 204 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 205 206 /* 207 * Functions to extract or store SSH wire encoded strings (u32 len || data) 208 * The "cstring" variants admit no \0 characters in the string contents. 209 * Caller must free *valp. 210 */ 211 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 212 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 213 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 214 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 215 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 216 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 217 218 /* 219 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 220 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 221 * next sshbuf-modifying function call. Caller does not free. 222 */ 223 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 224 size_t *lenp); 225 226 /* Skip past a string */ 227 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 228 229 /* Another variant: "peeks" into the buffer without modifying it */ 230 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 231 size_t *lenp); 232 233 /* 234 * Functions to extract or store SSH wire encoded bignums and elliptic 235 * curve points. 236 */ 237 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 238 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 239 const u_char **valp, size_t *lenp); 240 #ifdef WITH_OPENSSL 241 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 242 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 243 # ifdef OPENSSL_HAS_ECC 244 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 245 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 246 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 247 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 248 int sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey); 249 # endif /* OPENSSL_HAS_ECC */ 250 #endif /* WITH_OPENSSL */ 251 252 /* Functions to extract or store various non-SSH wire encoded values */ 253 int sshbuf_get_nulterminated_string(struct sshbuf *buf, size_t maxlen, 254 char **valp, size_t *lenp); 255 256 /* Dump the contents of the buffer in a human-readable format */ 257 void sshbuf_dump(const struct sshbuf *buf, FILE *f); 258 259 /* Dump specified memory in a human-readable format */ 260 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 261 262 /* Return the hexadecimal representation of the contents of the buffer */ 263 char *sshbuf_dtob16(const struct sshbuf *buf); 264 /* Make a sshbuf from a hex string */ 265 struct sshbuf *sshbuf_b16tod(const char *b16); 266 267 /* Encode the contents of the buffer as base64 */ 268 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 269 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 270 /* RFC4648 "base64url" encoding variant */ 271 int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 272 273 /* Decode base64 data and append it to the buffer */ 274 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 275 276 /* 277 * Tests whether the buffer contains the specified byte sequence at the 278 * specified offset. Returns 0 on successful match, or a ssherr.h code 279 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 280 * present but the buffer contents did not match those supplied. Zero- 281 * length comparisons are not allowed. 282 * 283 * If sufficient data is present to make a comparison, then it is 284 * performed with timing independent of the value of the data. If 285 * insufficient data is present then the comparison is not attempted at 286 * all. 287 */ 288 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 289 const void *s, size_t len); 290 291 /* 292 * Test whether two buffers have identical contents. 293 * SSH_ERR_MESSAGE_INCOMPLETE indicates the buffers had differing size. 294 * SSH_ERR_INVALID_FORMAT indicates the buffers were the same size but 295 * had differing contents. 296 * Returns 0 on successful compare (comparing two empty buffers returns 0). 297 */ 298 int sshbuf_equals(const struct sshbuf *a, const struct sshbuf *b); 299 300 /* 301 * Searches the buffer for the specified string. Returns 0 on success 302 * and updates *offsetp with the offset of the first match, relative to 303 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 304 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 305 * present in the buffer for a match to be possible but none was found. 306 * Searches for zero-length data are not allowed. 307 */ 308 int 309 sshbuf_find(const struct sshbuf *b, size_t start_offset, 310 const void *s, size_t len, size_t *offsetp); 311 312 /* 313 * Duplicate the contents of a buffer to a string (caller to free). 314 * Returns NULL on buffer error, or if the buffer contains a premature 315 * nul character. 316 */ 317 char *sshbuf_dup_string(struct sshbuf *buf); 318 319 /* 320 * Fill a buffer from a file descriptor or filename. Both allocate the 321 * buffer for the caller. 322 */ 323 int sshbuf_load_fd(int, struct sshbuf **) 324 __attribute__((__nonnull__ (2))); 325 int sshbuf_load_file(const char *, struct sshbuf **) 326 __attribute__((__nonnull__ (2))); 327 328 /* 329 * Write a buffer to a path, creating/truncating as needed (mode 0644, 330 * subject to umask). The buffer contents are not modified. 331 */ 332 int sshbuf_write_file(const char *path, struct sshbuf *buf) 333 __attribute__((__nonnull__ (2))); 334 335 /* Read up to maxlen bytes from a fd directly to a buffer */ 336 int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 337 __attribute__((__nonnull__ (2))); 338 339 /* Macros for decoding/encoding integers */ 340 #define PEEK_U64(p) \ 341 (((uint64_t)(((const u_char *)(p))[0]) << 56) | \ 342 ((uint64_t)(((const u_char *)(p))[1]) << 48) | \ 343 ((uint64_t)(((const u_char *)(p))[2]) << 40) | \ 344 ((uint64_t)(((const u_char *)(p))[3]) << 32) | \ 345 ((uint64_t)(((const u_char *)(p))[4]) << 24) | \ 346 ((uint64_t)(((const u_char *)(p))[5]) << 16) | \ 347 ((uint64_t)(((const u_char *)(p))[6]) << 8) | \ 348 (uint64_t)(((const u_char *)(p))[7])) 349 #define PEEK_U32(p) \ 350 (((uint32_t)(((const u_char *)(p))[0]) << 24) | \ 351 ((uint32_t)(((const u_char *)(p))[1]) << 16) | \ 352 ((uint32_t)(((const u_char *)(p))[2]) << 8) | \ 353 (uint32_t)(((const u_char *)(p))[3])) 354 #define PEEK_U16(p) \ 355 (((uint16_t)(((const u_char *)(p))[0]) << 8) | \ 356 (uint16_t)(((const u_char *)(p))[1])) 357 358 #define POKE_U64(p, v) \ 359 do { \ 360 const uint64_t __v = (v); \ 361 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 362 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 363 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 364 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 365 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 366 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 367 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 368 ((u_char *)(p))[7] = __v & 0xff; \ 369 } while (0) 370 #define POKE_U32(p, v) \ 371 do { \ 372 const uint32_t __v = (v); \ 373 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 374 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 375 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 376 ((u_char *)(p))[3] = __v & 0xff; \ 377 } while (0) 378 #define POKE_U16(p, v) \ 379 do { \ 380 const uint16_t __v = (v); \ 381 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 382 ((u_char *)(p))[1] = __v & 0xff; \ 383 } while (0) 384 385 /* Internal definitions follow. Exposed for regress tests */ 386 #ifdef SSHBUF_INTERNAL 387 388 /* 389 * Return the allocation size of buf 390 */ 391 size_t sshbuf_alloc(const struct sshbuf *buf); 392 393 /* 394 * Increment the reference count of buf. 395 */ 396 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 397 398 /* 399 * Return the parent buffer of buf, or NULL if it has no parent. 400 */ 401 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 402 403 /* 404 * Return the reference count of buf 405 */ 406 u_int sshbuf_refcount(const struct sshbuf *buf); 407 408 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 409 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 410 # define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 411 412 /* # define SSHBUF_ABORT abort */ 413 /* # define SSHBUF_DEBUG */ 414 415 # ifndef SSHBUF_ABORT 416 # define SSHBUF_ABORT() 417 # endif 418 419 # ifdef SSHBUF_DEBUG 420 # define SSHBUF_DBG(x) do { \ 421 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 422 printf x; \ 423 printf("\n"); \ 424 fflush(stdout); \ 425 } while (0) 426 # else 427 # define SSHBUF_DBG(x) 428 # endif 429 #endif /* SSHBUF_INTERNAL */ 430 431 #endif /* _SSHBUF_H */ 432