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