1 /* $OpenBSD: sshbuf.h,v 1.35 2026/03/03 09:57:25 dtucker 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 25 #ifdef WITH_OPENSSL 26 # include <openssl/bn.h> 27 # include <openssl/evp.h> 28 # ifdef OPENSSL_HAS_ECC 29 # include <openssl/ec.h> 30 # endif /* OPENSSL_HAS_ECC */ 31 #endif /* WITH_OPENSSL */ 32 33 #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ 34 #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 35 #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 36 #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 37 38 struct sshbuf; 39 40 /* 41 * Create a new sshbuf buffer. 42 * Returns pointer to buffer on success, or NULL on allocation failure. 43 */ 44 struct sshbuf *sshbuf_new(void); 45 46 /* 47 * Create a new, read-only sshbuf buffer from existing data. 48 * Returns pointer to buffer on success, or NULL on allocation failure. 49 */ 50 struct sshbuf *sshbuf_from(const void *blob, size_t len); 51 52 /* 53 * Create a new, read-only sshbuf buffer from the contents of an existing 54 * buffer. The contents of "buf" must not change in the lifetime of the 55 * resultant buffer. 56 * Returns pointer to buffer on success, or NULL on allocation failure. 57 */ 58 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 59 60 /* 61 * Create a new, read-only sshbuf buffer from the contents of a string in 62 * an existing buffer (the string is consumed in the process). 63 * The contents of "buf" must not change in the lifetime of the resultant 64 * buffer. 65 * On success, a pointer to the newly allocated buffer is placed in *bufp. 66 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 67 */ 68 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 69 70 /* 71 * Clear and free buf 72 */ 73 void sshbuf_free(struct sshbuf *buf); 74 75 /* 76 * Reset buf, clearing its contents. NB. max_size is preserved. 77 */ 78 void sshbuf_reset(struct sshbuf *buf); 79 80 /* 81 * Return the maximum size of buf 82 */ 83 size_t sshbuf_max_size(const struct sshbuf *buf); 84 85 /* 86 * Set the maximum size of buf 87 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 88 */ 89 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 90 91 /* 92 * Returns the length of data in buf 93 */ 94 size_t sshbuf_len(const struct sshbuf *buf); 95 96 /* 97 * Returns number of bytes left in buffer before hitting max_size. 98 */ 99 size_t sshbuf_avail(const struct sshbuf *buf); 100 101 /* 102 * Returns a read-only pointer to the start of the data in buf 103 */ 104 const u_char *sshbuf_ptr(const struct sshbuf *buf); 105 106 /* 107 * Returns a mutable pointer to the start of the data in buf, or 108 * NULL if the buffer is read-only. 109 */ 110 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 111 112 /* 113 * Check whether a reservation of size len will succeed in buf 114 * Safer to use than direct comparisons again sshbuf_avail as it copes 115 * with unsigned overflows correctly. 116 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 117 */ 118 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 119 120 /* 121 * Preallocates len additional bytes in buf. 122 * Useful for cases where the caller knows how many bytes will ultimately be 123 * required to avoid realloc in the buffer code. 124 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 125 */ 126 int sshbuf_allocate(struct sshbuf *buf, size_t len); 127 128 /* 129 * Reserve len bytes in buf. 130 * Returns 0 on success and a pointer to the first reserved byte via the 131 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 132 */ 133 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 134 135 /* 136 * Consume len bytes from the start of buf 137 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 138 */ 139 int sshbuf_consume(struct sshbuf *buf, size_t len); 140 141 /* 142 * Consume len bytes from the end of buf 143 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 144 */ 145 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 146 147 /* 148 * Consume data from a parent buffer up to that of a child buffer (i.e. 149 * one created by sshbuf_fromb()). 150 * 151 * Intended to be used in a pattern like: 152 * 153 * b = sshbuf_fromb(parent); 154 * sshbuf_get_string(b, &foo, &foostr); 155 * sshbuf_get_u32(b, &bar); 156 * sshbuf_consume_upto_child(parent, b); 157 * 158 * After which, both "b" and "parent" will point to the same data. 159 * 160 * "child" must be a direct child of "buf" (i.e. neither an unrelated buffer 161 * nor a grandchild) which has consumed data past that of "buf". 162 */ 163 int sshbuf_consume_upto_child(struct sshbuf *buf, const struct sshbuf *child); 164 165 /* Extract or deposit some bytes */ 166 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 167 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 168 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 169 170 /* Append using a printf(3) format */ 171 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 172 __attribute__((format(printf, 2, 3))); 173 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 174 175 /* Functions to extract or store big-endian words of various sizes */ 176 int sshbuf_get_u64(struct sshbuf *buf, uint64_t *valp); 177 int sshbuf_get_u32(struct sshbuf *buf, uint32_t *valp); 178 int sshbuf_get_u16(struct sshbuf *buf, uint16_t *valp); 179 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 180 int sshbuf_put_u64(struct sshbuf *buf, uint64_t val); 181 int sshbuf_put_u32(struct sshbuf *buf, uint32_t val); 182 int sshbuf_put_u16(struct sshbuf *buf, uint16_t val); 183 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 184 185 /* Functions to peek at the contents of a buffer without modifying it. */ 186 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 187 uint64_t *valp); 188 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 189 uint32_t *valp); 190 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 191 uint16_t *valp); 192 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 193 u_char *valp); 194 195 /* 196 * Functions to poke values into an existing buffer (e.g. a length header 197 * to a packet). The destination bytes must already exist in the buffer. 198 */ 199 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, uint64_t val); 200 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, uint32_t val); 201 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, uint16_t val); 202 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 203 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 204 205 /* 206 * Functions to extract or store SSH wire encoded strings (u32 len || data) 207 * The "cstring" variants admit no \0 characters in the string contents. 208 * Caller must free *valp. 209 */ 210 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 211 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 212 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 213 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 214 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 215 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 216 217 /* 218 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 219 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 220 * next sshbuf-modifying function call. Caller does not free. 221 */ 222 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 223 size_t *lenp); 224 225 /* Skip past a string */ 226 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 227 228 /* Another variant: "peeks" into the buffer without modifying it */ 229 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 230 size_t *lenp); 231 232 /* 233 * Functions to extract or store SSH wire encoded bignums and elliptic 234 * curve points. 235 */ 236 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 237 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 238 const u_char **valp, size_t *lenp); 239 #ifdef WITH_OPENSSL 240 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 241 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 242 # ifdef OPENSSL_HAS_ECC 243 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 244 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 245 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 246 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 247 int sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey); 248 # endif /* OPENSSL_HAS_ECC */ 249 #endif /* WITH_OPENSSL */ 250 251 /* Functions to extract or store various non-SSH wire encoded values */ 252 int sshbuf_get_nulterminated_string(struct sshbuf *buf, size_t maxlen, 253 char **valp, size_t *lenp); 254 255 /* Dump the contents of the buffer in a human-readable format */ 256 void sshbuf_dump(const struct sshbuf *buf, FILE *f); 257 258 /* Dump specified memory in a human-readable format */ 259 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 260 261 /* Return the hexadecimal representation of the contents of the buffer */ 262 char *sshbuf_dtob16(const struct sshbuf *buf); 263 /* Make a sshbuf from a hex string */ 264 struct sshbuf *sshbuf_b16tod(const char *b16); 265 266 /* Encode the contents of the buffer as base64 */ 267 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 268 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 269 /* RFC4648 "base64url" encoding variant */ 270 int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 271 272 /* Decode base64 data and append it to the buffer */ 273 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 274 275 /* 276 * Tests whether the buffer contains the specified byte sequence at the 277 * specified offset. Returns 0 on successful match, or a ssherr.h code 278 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 279 * present but the buffer contents did not match those supplied. Zero- 280 * length comparisons are not allowed. 281 * 282 * If sufficient data is present to make a comparison, then it is 283 * performed with timing independent of the value of the data. If 284 * insufficient data is present then the comparison is not attempted at 285 * all. 286 */ 287 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 288 const void *s, size_t len); 289 290 /* 291 * Test whether two buffers have identical contents. 292 * SSH_ERR_MESSAGE_INCOMPLETE indicates the buffers had differing size. 293 * SSH_ERR_INVALID_FORMAT indicates the buffers were the same size but 294 * had differing contents. 295 * Returns 0 on successful compare (comparing two empty buffers returns 0). 296 */ 297 int sshbuf_equals(const struct sshbuf *a, const struct sshbuf *b); 298 299 /* 300 * Searches the buffer for the specified string. Returns 0 on success 301 * and updates *offsetp with the offset of the first match, relative to 302 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 303 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 304 * present in the buffer for a match to be possible but none was found. 305 * Searches for zero-length data are not allowed. 306 */ 307 int 308 sshbuf_find(const struct sshbuf *b, size_t start_offset, 309 const void *s, size_t len, size_t *offsetp); 310 311 /* 312 * Duplicate the contents of a buffer to a string (caller to free). 313 * Returns NULL on buffer error, or if the buffer contains a premature 314 * nul character. 315 */ 316 char *sshbuf_dup_string(struct sshbuf *buf); 317 318 /* 319 * Fill a buffer from a file descriptor or filename. Both allocate the 320 * buffer for the caller. 321 */ 322 int sshbuf_load_fd(int, struct sshbuf **) 323 __attribute__((__nonnull__ (2))); 324 int sshbuf_load_file(const char *, struct sshbuf **) 325 __attribute__((__nonnull__ (2))); 326 327 /* 328 * Write a buffer to a path, creating/truncating as needed (mode 0644, 329 * subject to umask). The buffer contents are not modified. 330 */ 331 int sshbuf_write_file(const char *path, struct sshbuf *buf) 332 __attribute__((__nonnull__ (2))); 333 334 /* Read up to maxlen bytes from a fd directly to a buffer */ 335 int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 336 __attribute__((__nonnull__ (2))); 337 338 /* Macros for decoding/encoding integers */ 339 #define PEEK_U64(p) \ 340 (((uint64_t)(((const u_char *)(p))[0]) << 56) | \ 341 ((uint64_t)(((const u_char *)(p))[1]) << 48) | \ 342 ((uint64_t)(((const u_char *)(p))[2]) << 40) | \ 343 ((uint64_t)(((const u_char *)(p))[3]) << 32) | \ 344 ((uint64_t)(((const u_char *)(p))[4]) << 24) | \ 345 ((uint64_t)(((const u_char *)(p))[5]) << 16) | \ 346 ((uint64_t)(((const u_char *)(p))[6]) << 8) | \ 347 (uint64_t)(((const u_char *)(p))[7])) 348 #define PEEK_U32(p) \ 349 (((uint32_t)(((const u_char *)(p))[0]) << 24) | \ 350 ((uint32_t)(((const u_char *)(p))[1]) << 16) | \ 351 ((uint32_t)(((const u_char *)(p))[2]) << 8) | \ 352 (uint32_t)(((const u_char *)(p))[3])) 353 #define PEEK_U16(p) \ 354 (((uint16_t)(((const u_char *)(p))[0]) << 8) | \ 355 (uint16_t)(((const u_char *)(p))[1])) 356 357 #define POKE_U64(p, v) \ 358 do { \ 359 const uint64_t __v = (v); \ 360 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 361 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 362 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 363 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 364 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 365 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 366 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 367 ((u_char *)(p))[7] = __v & 0xff; \ 368 } while (0) 369 #define POKE_U32(p, v) \ 370 do { \ 371 const uint32_t __v = (v); \ 372 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 373 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 374 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 375 ((u_char *)(p))[3] = __v & 0xff; \ 376 } while (0) 377 #define POKE_U16(p, v) \ 378 do { \ 379 const uint16_t __v = (v); \ 380 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 381 ((u_char *)(p))[1] = __v & 0xff; \ 382 } while (0) 383 384 /* Internal definitions follow. Exposed for regress tests */ 385 #ifdef SSHBUF_INTERNAL 386 387 /* 388 * Return the allocation size of buf 389 */ 390 size_t sshbuf_alloc(const struct sshbuf *buf); 391 392 /* 393 * Increment the reference count of buf. 394 */ 395 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 396 397 /* 398 * Return the parent buffer of buf, or NULL if it has no parent. 399 */ 400 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 401 402 /* 403 * Return the reference count of buf 404 */ 405 u_int sshbuf_refcount(const struct sshbuf *buf); 406 407 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 408 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 409 # define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 410 411 /* # define SSHBUF_ABORT abort */ 412 /* # define SSHBUF_DEBUG */ 413 414 # ifndef SSHBUF_ABORT 415 # define SSHBUF_ABORT() 416 # endif 417 418 # ifdef SSHBUF_DEBUG 419 # define SSHBUF_DBG(x) do { \ 420 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 421 printf x; \ 422 printf("\n"); \ 423 fflush(stdout); \ 424 } while (0) 425 # else 426 # define SSHBUF_DBG(x) 427 # endif 428 #endif /* SSHBUF_INTERNAL */ 429 430 #endif /* _SSHBUF_H */ 431