1 /* $OpenBSD: sshbuf.h,v 1.32 2025/09/02 09:41:23 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 #ifdef WITH_OPENSSL 25 # include <openssl/bn.h> 26 # include <openssl/evp.h> 27 # ifdef OPENSSL_HAS_ECC 28 # include <openssl/ec.h> 29 # endif /* OPENSSL_HAS_ECC */ 30 #endif /* WITH_OPENSSL */ 31 32 #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ 33 #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 34 #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 35 #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 36 37 struct sshbuf; 38 39 /* 40 * Create a new sshbuf buffer. 41 * Returns pointer to buffer on success, or NULL on allocation failure. 42 */ 43 struct sshbuf *sshbuf_new(void); 44 45 /* 46 * Create a new, read-only sshbuf buffer from existing data. 47 * Returns pointer to buffer on success, or NULL on allocation failure. 48 */ 49 struct sshbuf *sshbuf_from(const void *blob, size_t len); 50 51 /* 52 * Create a new, read-only sshbuf buffer from the contents of an existing 53 * buffer. The contents of "buf" must not change in the lifetime of the 54 * resultant buffer. 55 * Returns pointer to buffer on success, or NULL on allocation failure. 56 */ 57 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 58 59 /* 60 * Create a new, read-only sshbuf buffer from the contents of a string in 61 * an existing buffer (the string is consumed in the process). 62 * The contents of "buf" must not change in the lifetime of the resultant 63 * buffer. 64 * On success, a pointer to the newly allocated buffer is placed in *bufp. 65 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 66 */ 67 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 68 69 /* 70 * Clear and free buf 71 */ 72 void sshbuf_free(struct sshbuf *buf); 73 74 /* 75 * Reset buf, clearing its contents. NB. max_size is preserved. 76 */ 77 void sshbuf_reset(struct sshbuf *buf); 78 79 /* 80 * Return the maximum size of buf 81 */ 82 size_t sshbuf_max_size(const struct sshbuf *buf); 83 84 /* 85 * Set the maximum size of buf 86 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 87 */ 88 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 89 90 /* 91 * Returns the length of data in buf 92 */ 93 size_t sshbuf_len(const struct sshbuf *buf); 94 95 /* 96 * Returns number of bytes left in buffer before hitting max_size. 97 */ 98 size_t sshbuf_avail(const struct sshbuf *buf); 99 100 /* 101 * Returns a read-only pointer to the start of the data in buf 102 */ 103 const u_char *sshbuf_ptr(const struct sshbuf *buf); 104 105 /* 106 * Returns a mutable pointer to the start of the data in buf, or 107 * NULL if the buffer is read-only. 108 */ 109 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 110 111 /* 112 * Check whether a reservation of size len will succeed in buf 113 * Safer to use than direct comparisons again sshbuf_avail as it copes 114 * with unsigned overflows correctly. 115 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 116 */ 117 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 118 119 /* 120 * Preallocates len additional bytes in buf. 121 * Useful for cases where the caller knows how many bytes will ultimately be 122 * required to avoid realloc in the buffer code. 123 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 124 */ 125 int sshbuf_allocate(struct sshbuf *buf, size_t len); 126 127 /* 128 * Reserve len bytes in buf. 129 * Returns 0 on success and a pointer to the first reserved byte via the 130 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 131 */ 132 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 133 134 /* 135 * Consume len bytes from the start of buf 136 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 137 */ 138 int sshbuf_consume(struct sshbuf *buf, size_t len); 139 140 /* 141 * Consume len bytes from the end of buf 142 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 143 */ 144 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 145 146 /* Extract or deposit some bytes */ 147 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 148 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 149 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 150 151 /* Append using a printf(3) format */ 152 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 153 __attribute__((format(printf, 2, 3))); 154 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 155 156 /* Functions to extract or store big-endian words of various sizes */ 157 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 158 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 159 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 160 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 161 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 162 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 163 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 164 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 165 166 /* Functions to peek at the contents of a buffer without modifying it. */ 167 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 168 u_int64_t *valp); 169 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 170 u_int32_t *valp); 171 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 172 u_int16_t *valp); 173 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 174 u_char *valp); 175 176 /* 177 * Functions to poke values into an existing buffer (e.g. a length header 178 * to a packet). The destination bytes must already exist in the buffer. 179 */ 180 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 181 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 182 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 183 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 184 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 185 186 /* 187 * Functions to extract or store SSH wire encoded strings (u32 len || data) 188 * The "cstring" variants admit no \0 characters in the string contents. 189 * Caller must free *valp. 190 */ 191 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 192 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 193 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 194 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 195 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 196 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 197 198 /* 199 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 200 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 201 * next sshbuf-modifying function call. Caller does not free. 202 */ 203 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 204 size_t *lenp); 205 206 /* Skip past a string */ 207 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 208 209 /* Another variant: "peeks" into the buffer without modifying it */ 210 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 211 size_t *lenp); 212 213 /* 214 * Functions to extract or store SSH wire encoded bignums and elliptic 215 * curve points. 216 */ 217 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 218 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 219 const u_char **valp, size_t *lenp); 220 #ifdef WITH_OPENSSL 221 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 222 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 223 # ifdef OPENSSL_HAS_ECC 224 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 225 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 226 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 227 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 228 int sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey); 229 # endif /* OPENSSL_HAS_ECC */ 230 #endif /* WITH_OPENSSL */ 231 232 /* Dump the contents of the buffer in a human-readable format */ 233 void sshbuf_dump(const struct sshbuf *buf, FILE *f); 234 235 /* Dump specified memory in a human-readable format */ 236 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 237 238 /* Return the hexadecimal representation of the contents of the buffer */ 239 char *sshbuf_dtob16(const struct sshbuf *buf); 240 /* Make a sshbuf from a hex string */ 241 struct sshbuf *sshbuf_b16tod(const char *b16); 242 243 /* Encode the contents of the buffer as base64 */ 244 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 245 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 246 /* RFC4648 "base64url" encoding variant */ 247 int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 248 249 /* Decode base64 data and append it to the buffer */ 250 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 251 252 /* 253 * Tests whether the buffer contains the specified byte sequence at the 254 * specified offset. Returns 0 on successful match, or a ssherr.h code 255 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 256 * present but the buffer contents did not match those supplied. Zero- 257 * length comparisons are not allowed. 258 * 259 * If sufficient data is present to make a comparison, then it is 260 * performed with timing independent of the value of the data. If 261 * insufficient data is present then the comparison is not attempted at 262 * all. 263 */ 264 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 265 const void *s, size_t len); 266 267 /* 268 * Test whether two buffers have identical contents. 269 * SSH_ERR_MESSAGE_INCOMPLETE indicates the buffers had differing size. 270 * SSH_ERR_INVALID_FORMAT indicates the buffers were the same size but 271 * had differing contents. 272 * Returns 0 on successful compare (comparing two empty buffers returns 0). 273 */ 274 int sshbuf_equals(const struct sshbuf *a, const struct sshbuf *b); 275 276 /* 277 * Searches the buffer for the specified string. Returns 0 on success 278 * and updates *offsetp with the offset of the first match, relative to 279 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 280 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 281 * present in the buffer for a match to be possible but none was found. 282 * Searches for zero-length data are not allowed. 283 */ 284 int 285 sshbuf_find(const struct sshbuf *b, size_t start_offset, 286 const void *s, size_t len, size_t *offsetp); 287 288 /* 289 * Duplicate the contents of a buffer to a string (caller to free). 290 * Returns NULL on buffer error, or if the buffer contains a premature 291 * nul character. 292 */ 293 char *sshbuf_dup_string(struct sshbuf *buf); 294 295 /* 296 * Fill a buffer from a file descriptor or filename. Both allocate the 297 * buffer for the caller. 298 */ 299 int sshbuf_load_fd(int, struct sshbuf **) 300 __attribute__((__nonnull__ (2))); 301 int sshbuf_load_file(const char *, struct sshbuf **) 302 __attribute__((__nonnull__ (2))); 303 304 /* 305 * Write a buffer to a path, creating/truncating as needed (mode 0644, 306 * subject to umask). The buffer contents are not modified. 307 */ 308 int sshbuf_write_file(const char *path, struct sshbuf *buf) 309 __attribute__((__nonnull__ (2))); 310 311 /* Read up to maxlen bytes from a fd directly to a buffer */ 312 int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 313 __attribute__((__nonnull__ (2))); 314 315 /* Macros for decoding/encoding integers */ 316 #define PEEK_U64(p) \ 317 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 318 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 319 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 320 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 321 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 322 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 323 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 324 (u_int64_t)(((const u_char *)(p))[7])) 325 #define PEEK_U32(p) \ 326 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 327 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 328 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 329 (u_int32_t)(((const u_char *)(p))[3])) 330 #define PEEK_U16(p) \ 331 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 332 (u_int16_t)(((const u_char *)(p))[1])) 333 334 #define POKE_U64(p, v) \ 335 do { \ 336 const u_int64_t __v = (v); \ 337 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 338 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 339 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 340 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 341 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 342 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 343 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 344 ((u_char *)(p))[7] = __v & 0xff; \ 345 } while (0) 346 #define POKE_U32(p, v) \ 347 do { \ 348 const u_int32_t __v = (v); \ 349 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 350 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 351 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 352 ((u_char *)(p))[3] = __v & 0xff; \ 353 } while (0) 354 #define POKE_U16(p, v) \ 355 do { \ 356 const u_int16_t __v = (v); \ 357 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 358 ((u_char *)(p))[1] = __v & 0xff; \ 359 } while (0) 360 361 /* Internal definitions follow. Exposed for regress tests */ 362 #ifdef SSHBUF_INTERNAL 363 364 /* 365 * Return the allocation size of buf 366 */ 367 size_t sshbuf_alloc(const struct sshbuf *buf); 368 369 /* 370 * Increment the reference count of buf. 371 */ 372 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 373 374 /* 375 * Return the parent buffer of buf, or NULL if it has no parent. 376 */ 377 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 378 379 /* 380 * Return the reference count of buf 381 */ 382 u_int sshbuf_refcount(const struct sshbuf *buf); 383 384 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 385 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 386 # define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 387 388 /* # define SSHBUF_ABORT abort */ 389 /* # define SSHBUF_DEBUG */ 390 391 # ifndef SSHBUF_ABORT 392 # define SSHBUF_ABORT() 393 # endif 394 395 # ifdef SSHBUF_DEBUG 396 # define SSHBUF_DBG(x) do { \ 397 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 398 printf x; \ 399 printf("\n"); \ 400 fflush(stdout); \ 401 } while (0) 402 # else 403 # define SSHBUF_DBG(x) 404 # endif 405 #endif /* SSHBUF_INTERNAL */ 406 407 #endif /* _SSHBUF_H */ 408