1 /* $OpenBSD: sshbuf.h,v 1.29 2024/08/15 00:51:51 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 * Returns pointer to buffer on success, or NULL on allocation failure. 65 */ 66 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 67 68 /* 69 * Clear and free buf 70 */ 71 void sshbuf_free(struct sshbuf *buf); 72 73 /* 74 * Reset buf, clearing its contents. NB. max_size is preserved. 75 */ 76 void sshbuf_reset(struct sshbuf *buf); 77 78 /* 79 * Return the maximum size of buf 80 */ 81 size_t sshbuf_max_size(const struct sshbuf *buf); 82 83 /* 84 * Set the maximum size of buf 85 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 86 */ 87 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 88 89 /* 90 * Returns the length of data in buf 91 */ 92 size_t sshbuf_len(const struct sshbuf *buf); 93 94 /* 95 * Returns number of bytes left in buffer before hitting max_size. 96 */ 97 size_t sshbuf_avail(const struct sshbuf *buf); 98 99 /* 100 * Returns a read-only pointer to the start of the data in buf 101 */ 102 const u_char *sshbuf_ptr(const struct sshbuf *buf); 103 104 /* 105 * Returns a mutable pointer to the start of the data in buf, or 106 * NULL if the buffer is read-only. 107 */ 108 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 109 110 /* 111 * Check whether a reservation of size len will succeed in buf 112 * Safer to use than direct comparisons again sshbuf_avail as it copes 113 * with unsigned overflows correctly. 114 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 115 */ 116 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 117 118 /* 119 * Preallocates len additional bytes in buf. 120 * Useful for cases where the caller knows how many bytes will ultimately be 121 * required to avoid realloc in the buffer code. 122 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 123 */ 124 int sshbuf_allocate(struct sshbuf *buf, size_t len); 125 126 /* 127 * Reserve len bytes in buf. 128 * Returns 0 on success and a pointer to the first reserved byte via the 129 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 130 */ 131 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 132 133 /* 134 * Consume len bytes from the start of buf 135 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 136 */ 137 int sshbuf_consume(struct sshbuf *buf, size_t len); 138 139 /* 140 * Consume len bytes from the end of buf 141 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 142 */ 143 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 144 145 /* Extract or deposit some bytes */ 146 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 147 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 148 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 149 150 /* Append using a printf(3) format */ 151 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 152 __attribute__((format(printf, 2, 3))); 153 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 154 155 /* Functions to extract or store big-endian words of various sizes */ 156 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 157 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 158 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 159 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 160 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 161 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 162 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 163 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 164 165 /* Functions to peek at the contents of a buffer without modifying it. */ 166 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 167 u_int64_t *valp); 168 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 169 u_int32_t *valp); 170 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 171 u_int16_t *valp); 172 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 173 u_char *valp); 174 175 /* 176 * Functions to poke values into an existing buffer (e.g. a length header 177 * to a packet). The destination bytes must already exist in the buffer. 178 */ 179 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 180 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 181 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 182 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 183 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 184 185 /* 186 * Functions to extract or store SSH wire encoded strings (u32 len || data) 187 * The "cstring" variants admit no \0 characters in the string contents. 188 * Caller must free *valp. 189 */ 190 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 191 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 192 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 193 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 194 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 195 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 196 197 /* 198 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 199 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 200 * next sshbuf-modifying function call. Caller does not free. 201 */ 202 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 203 size_t *lenp); 204 205 /* Skip past a string */ 206 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 207 208 /* Another variant: "peeks" into the buffer without modifying it */ 209 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 210 size_t *lenp); 211 212 /* 213 * Functions to extract or store SSH wire encoded bignums and elliptic 214 * curve points. 215 */ 216 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 217 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 218 const u_char **valp, size_t *lenp); 219 #ifdef WITH_OPENSSL 220 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 221 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 222 # ifdef OPENSSL_HAS_ECC 223 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 224 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 225 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 226 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 227 int sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey); 228 # endif /* OPENSSL_HAS_ECC */ 229 #endif /* WITH_OPENSSL */ 230 231 /* Dump the contents of the buffer in a human-readable format */ 232 void sshbuf_dump(const struct sshbuf *buf, FILE *f); 233 234 /* Dump specified memory in a human-readable format */ 235 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 236 237 /* Return the hexadecimal representation of the contents of the buffer */ 238 char *sshbuf_dtob16(struct sshbuf *buf); 239 240 /* Encode the contents of the buffer as base64 */ 241 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 242 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 243 /* RFC4648 "base64url" encoding variant */ 244 int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 245 246 /* Decode base64 data and append it to the buffer */ 247 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 248 249 /* 250 * Tests whether the buffer contains the specified byte sequence at the 251 * specified offset. Returns 0 on successful match, or a ssherr.h code 252 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 253 * present but the buffer contents did not match those supplied. Zero- 254 * length comparisons are not allowed. 255 * 256 * If sufficient data is present to make a comparison, then it is 257 * performed with timing independent of the value of the data. If 258 * insufficient data is present then the comparison is not attempted at 259 * all. 260 */ 261 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 262 const void *s, size_t len); 263 264 /* 265 * Searches the buffer for the specified string. Returns 0 on success 266 * and updates *offsetp with the offset of the first match, relative to 267 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 268 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 269 * present in the buffer for a match to be possible but none was found. 270 * Searches for zero-length data are not allowed. 271 */ 272 int 273 sshbuf_find(const struct sshbuf *b, size_t start_offset, 274 const void *s, size_t len, size_t *offsetp); 275 276 /* 277 * Duplicate the contents of a buffer to a string (caller to free). 278 * Returns NULL on buffer error, or if the buffer contains a premature 279 * nul character. 280 */ 281 char *sshbuf_dup_string(struct sshbuf *buf); 282 283 /* 284 * Fill a buffer from a file descriptor or filename. Both allocate the 285 * buffer for the caller. 286 */ 287 int sshbuf_load_fd(int, struct sshbuf **) 288 __attribute__((__nonnull__ (2))); 289 int sshbuf_load_file(const char *, struct sshbuf **) 290 __attribute__((__nonnull__ (2))); 291 292 /* 293 * Write a buffer to a path, creating/truncating as needed (mode 0644, 294 * subject to umask). The buffer contents are not modified. 295 */ 296 int sshbuf_write_file(const char *path, struct sshbuf *buf) 297 __attribute__((__nonnull__ (2))); 298 299 /* Read up to maxlen bytes from a fd directly to a buffer */ 300 int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 301 __attribute__((__nonnull__ (2))); 302 303 /* Macros for decoding/encoding integers */ 304 #define PEEK_U64(p) \ 305 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 306 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 307 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 308 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 309 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 310 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 311 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 312 (u_int64_t)(((const u_char *)(p))[7])) 313 #define PEEK_U32(p) \ 314 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 315 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 316 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 317 (u_int32_t)(((const u_char *)(p))[3])) 318 #define PEEK_U16(p) \ 319 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 320 (u_int16_t)(((const u_char *)(p))[1])) 321 322 #define POKE_U64(p, v) \ 323 do { \ 324 const u_int64_t __v = (v); \ 325 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 326 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 327 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 328 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 329 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 330 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 331 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 332 ((u_char *)(p))[7] = __v & 0xff; \ 333 } while (0) 334 #define POKE_U32(p, v) \ 335 do { \ 336 const u_int32_t __v = (v); \ 337 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 338 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 339 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 340 ((u_char *)(p))[3] = __v & 0xff; \ 341 } while (0) 342 #define POKE_U16(p, v) \ 343 do { \ 344 const u_int16_t __v = (v); \ 345 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 346 ((u_char *)(p))[1] = __v & 0xff; \ 347 } while (0) 348 349 /* Internal definitions follow. Exposed for regress tests */ 350 #ifdef SSHBUF_INTERNAL 351 352 /* 353 * Return the allocation size of buf 354 */ 355 size_t sshbuf_alloc(const struct sshbuf *buf); 356 357 /* 358 * Increment the reference count of buf. 359 */ 360 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 361 362 /* 363 * Return the parent buffer of buf, or NULL if it has no parent. 364 */ 365 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 366 367 /* 368 * Return the reference count of buf 369 */ 370 u_int sshbuf_refcount(const struct sshbuf *buf); 371 372 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 373 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 374 # define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 375 376 /* # define SSHBUF_ABORT abort */ 377 /* # define SSHBUF_DEBUG */ 378 379 # ifndef SSHBUF_ABORT 380 # define SSHBUF_ABORT() 381 # endif 382 383 # ifdef SSHBUF_DEBUG 384 # define SSHBUF_DBG(x) do { \ 385 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 386 printf x; \ 387 printf("\n"); \ 388 fflush(stdout); \ 389 } while (0) 390 # else 391 # define SSHBUF_DBG(x) 392 # endif 393 #endif /* SSHBUF_INTERNAL */ 394 395 #endif /* _SSHBUF_H */ 396