1 /* $OpenBSD: sshbuf.h,v 1.28 2022/12/02 04:40:27 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 #else /* OPENSSL */ 30 #define BIGNUM void 31 #define EC_KEY void 32 #define EC_GROUP void 33 #define EC_POINT void 34 #endif /* WITH_OPENSSL */ 35 36 #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ 37 #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 38 #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 39 #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 40 41 struct sshbuf; 42 43 /* 44 * Create a new sshbuf buffer. 45 * Returns pointer to buffer on success, or NULL on allocation failure. 46 */ 47 struct sshbuf *sshbuf_new(void); 48 49 /* 50 * Create a new, read-only sshbuf buffer from existing data. 51 * Returns pointer to buffer on success, or NULL on allocation failure. 52 */ 53 struct sshbuf *sshbuf_from(const void *blob, size_t len); 54 55 /* 56 * Create a new, read-only sshbuf buffer from the contents of an existing 57 * buffer. The contents of "buf" must not change in the lifetime of the 58 * resultant buffer. 59 * Returns pointer to buffer on success, or NULL on allocation failure. 60 */ 61 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 62 63 /* 64 * Create a new, read-only sshbuf buffer from the contents of a string in 65 * an existing buffer (the string is consumed in the process). 66 * The contents of "buf" must not change in the lifetime of the resultant 67 * buffer. 68 * Returns pointer to buffer on success, or NULL on allocation failure. 69 */ 70 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 71 72 /* 73 * Clear and free buf 74 */ 75 void sshbuf_free(struct sshbuf *buf); 76 77 /* 78 * Reset buf, clearing its contents. NB. max_size is preserved. 79 */ 80 void sshbuf_reset(struct sshbuf *buf); 81 82 /* 83 * Return the maximum size of buf 84 */ 85 size_t sshbuf_max_size(const struct sshbuf *buf); 86 87 /* 88 * Set the maximum size of buf 89 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 90 */ 91 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 92 93 /* 94 * Returns the length of data in buf 95 */ 96 size_t sshbuf_len(const struct sshbuf *buf); 97 98 /* 99 * Returns number of bytes left in buffer before hitting max_size. 100 */ 101 size_t sshbuf_avail(const struct sshbuf *buf); 102 103 /* 104 * Returns a read-only pointer to the start of the data in buf 105 */ 106 const u_char *sshbuf_ptr(const struct sshbuf *buf); 107 108 /* 109 * Returns a mutable pointer to the start of the data in buf, or 110 * NULL if the buffer is read-only. 111 */ 112 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 113 114 /* 115 * Check whether a reservation of size len will succeed in buf 116 * Safer to use than direct comparisons again sshbuf_avail as it copes 117 * with unsigned overflows correctly. 118 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 119 */ 120 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 121 122 /* 123 * Preallocates len additional bytes in buf. 124 * Useful for cases where the caller knows how many bytes will ultimately be 125 * required to avoid realloc in the buffer code. 126 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 127 */ 128 int sshbuf_allocate(struct sshbuf *buf, size_t len); 129 130 /* 131 * Reserve len bytes in buf. 132 * Returns 0 on success and a pointer to the first reserved byte via the 133 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 134 */ 135 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 136 137 /* 138 * Consume len bytes from the start of buf 139 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 140 */ 141 int sshbuf_consume(struct sshbuf *buf, size_t len); 142 143 /* 144 * Consume len bytes from the end of buf 145 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 146 */ 147 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 148 149 /* Extract or deposit some bytes */ 150 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 151 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 152 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 153 154 /* Append using a printf(3) format */ 155 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 156 __attribute__((format(printf, 2, 3))); 157 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 158 159 /* Functions to extract or store big-endian words of various sizes */ 160 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 161 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 162 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 163 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 164 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 165 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 166 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 167 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 168 169 /* Functions to peek at the contents of a buffer without modifying it. */ 170 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 171 u_int64_t *valp); 172 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 173 u_int32_t *valp); 174 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 175 u_int16_t *valp); 176 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 177 u_char *valp); 178 179 /* 180 * Functions to poke values into an existing buffer (e.g. a length header 181 * to a packet). The destination bytes must already exist in the buffer. 182 */ 183 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 184 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 185 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 186 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 187 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 188 189 /* 190 * Functions to extract or store SSH wire encoded strings (u32 len || data) 191 * The "cstring" variants admit no \0 characters in the string contents. 192 * Caller must free *valp. 193 */ 194 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 195 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 196 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 197 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 198 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 199 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 200 201 /* 202 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 203 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 204 * next sshbuf-modifying function call. Caller does not free. 205 */ 206 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 207 size_t *lenp); 208 209 /* Skip past a string */ 210 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 211 212 /* Another variant: "peeks" into the buffer without modifying it */ 213 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 214 size_t *lenp); 215 216 /* 217 * Functions to extract or store SSH wire encoded bignums and elliptic 218 * curve points. 219 */ 220 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 221 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 222 const u_char **valp, size_t *lenp); 223 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 224 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 225 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 226 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 227 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 228 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 229 230 /* Dump the contents of the buffer in a human-readable format */ 231 void sshbuf_dump(const struct sshbuf *buf, FILE *f); 232 233 /* Dump specified memory in a human-readable format */ 234 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 235 236 /* Return the hexadecimal representation of the contents of the buffer */ 237 char *sshbuf_dtob16(struct sshbuf *buf); 238 239 /* Encode the contents of the buffer as base64 */ 240 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 241 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 242 /* RFC4648 "base64url" encoding variant */ 243 int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 244 245 /* Decode base64 data and append it to the buffer */ 246 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 247 248 /* 249 * Tests whether the buffer contains the specified byte sequence at the 250 * specified offset. Returns 0 on successful match, or a ssherr.h code 251 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 252 * present but the buffer contents did not match those supplied. Zero- 253 * length comparisons are not allowed. 254 * 255 * If sufficient data is present to make a comparison, then it is 256 * performed with timing independent of the value of the data. If 257 * insufficient data is present then the comparison is not attempted at 258 * all. 259 */ 260 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 261 const void *s, size_t len); 262 263 /* 264 * Searches the buffer for the specified string. Returns 0 on success 265 * and updates *offsetp with the offset of the first match, relative to 266 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 267 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 268 * present in the buffer for a match to be possible but none was found. 269 * Searches for zero-length data are not allowed. 270 */ 271 int 272 sshbuf_find(const struct sshbuf *b, size_t start_offset, 273 const void *s, size_t len, size_t *offsetp); 274 275 /* 276 * Duplicate the contents of a buffer to a string (caller to free). 277 * Returns NULL on buffer error, or if the buffer contains a premature 278 * nul character. 279 */ 280 char *sshbuf_dup_string(struct sshbuf *buf); 281 282 /* 283 * Fill a buffer from a file descriptor or filename. Both allocate the 284 * buffer for the caller. 285 */ 286 int sshbuf_load_fd(int, struct sshbuf **) 287 __attribute__((__nonnull__ (2))); 288 int sshbuf_load_file(const char *, struct sshbuf **) 289 __attribute__((__nonnull__ (2))); 290 291 /* 292 * Write a buffer to a path, creating/truncating as needed (mode 0644, 293 * subject to umask). The buffer contents are not modified. 294 */ 295 int sshbuf_write_file(const char *path, struct sshbuf *buf) 296 __attribute__((__nonnull__ (2))); 297 298 /* Read up to maxlen bytes from a fd directly to a buffer */ 299 int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 300 __attribute__((__nonnull__ (2))); 301 302 /* Macros for decoding/encoding integers */ 303 #define PEEK_U64(p) \ 304 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 305 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 306 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 307 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 308 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 309 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 310 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 311 (u_int64_t)(((const u_char *)(p))[7])) 312 #define PEEK_U32(p) \ 313 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 314 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 315 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 316 (u_int32_t)(((const u_char *)(p))[3])) 317 #define PEEK_U16(p) \ 318 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 319 (u_int16_t)(((const u_char *)(p))[1])) 320 321 #define POKE_U64(p, v) \ 322 do { \ 323 const u_int64_t __v = (v); \ 324 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 325 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 326 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 327 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 328 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 329 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 330 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 331 ((u_char *)(p))[7] = __v & 0xff; \ 332 } while (0) 333 #define POKE_U32(p, v) \ 334 do { \ 335 const u_int32_t __v = (v); \ 336 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 337 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 338 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 339 ((u_char *)(p))[3] = __v & 0xff; \ 340 } while (0) 341 #define POKE_U16(p, v) \ 342 do { \ 343 const u_int16_t __v = (v); \ 344 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 345 ((u_char *)(p))[1] = __v & 0xff; \ 346 } while (0) 347 348 /* Internal definitions follow. Exposed for regress tests */ 349 #ifdef SSHBUF_INTERNAL 350 351 /* 352 * Return the allocation size of buf 353 */ 354 size_t sshbuf_alloc(const struct sshbuf *buf); 355 356 /* 357 * Increment the reference count of buf. 358 */ 359 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 360 361 /* 362 * Return the parent buffer of buf, or NULL if it has no parent. 363 */ 364 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 365 366 /* 367 * Return the reference count of buf 368 */ 369 u_int sshbuf_refcount(const struct sshbuf *buf); 370 371 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 372 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 373 # define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 374 375 /* # define SSHBUF_ABORT abort */ 376 /* # define SSHBUF_DEBUG */ 377 378 # ifndef SSHBUF_ABORT 379 # define SSHBUF_ABORT() 380 # endif 381 382 # ifdef SSHBUF_DEBUG 383 # define SSHBUF_DBG(x) do { \ 384 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 385 printf x; \ 386 printf("\n"); \ 387 fflush(stdout); \ 388 } while (0) 389 # else 390 # define SSHBUF_DBG(x) 391 # endif 392 #endif /* SSHBUF_INTERNAL */ 393 394 #endif /* _SSHBUF_H */ 395