1 /* $NetBSD: sshbuf.h,v 1.21 2024/09/24 21:32:19 christos Exp $ */ 2 /* $OpenBSD: sshbuf.h,v 1.29 2024/08/15 00:51:51 djm Exp $ */ 3 4 /* 5 * Copyright (c) 2011 Damien Miller 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #ifndef _SSHBUF_H 21 #define _SSHBUF_H 22 23 #include <sys/types.h> 24 #include <stdarg.h> 25 #include <stdio.h> 26 27 #ifdef WITH_OPENSSL 28 #include <openssl/bn.h> 29 #include <openssl/ec.h> 30 #include <openssl/ecdsa.h> 31 #include <openssl/evp.h> 32 #else /* OPENSSL */ 33 #define BIGNUM void 34 #define EC_KEY void 35 #define EC_GROUP void 36 #define EC_POINT void 37 #define EVP_PKEY void 38 #endif /* WITH_OPENSSL */ 39 40 #define SSHBUF_SIZE_MAX 0x10000000 /* Hard maximum size 256MB */ 41 #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 42 #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 43 #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 44 45 struct sshbuf; 46 47 /* 48 * Create a new sshbuf buffer. 49 * Returns pointer to buffer on success, or NULL on allocation failure. 50 */ 51 struct sshbuf *sshbuf_new(void); 52 53 /* 54 * Create a new, read-only sshbuf buffer from existing data. 55 * Returns pointer to buffer on success, or NULL on allocation failure. 56 */ 57 struct sshbuf *sshbuf_from(const void *blob, size_t len); 58 59 /* 60 * Create a new, read-only sshbuf buffer from the contents of an existing 61 * buffer. The contents of "buf" must not change in the lifetime of the 62 * resultant buffer. 63 * Returns pointer to buffer on success, or NULL on allocation failure. 64 */ 65 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 66 67 /* 68 * Create a new, read-only sshbuf buffer from the contents of a string in 69 * an existing buffer (the string is consumed in the process). 70 * The contents of "buf" must not change in the lifetime of the resultant 71 * buffer. 72 * Returns pointer to buffer on success, or NULL on allocation failure. 73 */ 74 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 75 76 /* 77 * Clear and free buf 78 */ 79 void sshbuf_free(struct sshbuf *buf); 80 81 /* 82 * Reset buf, clearing its contents. NB. max_size is preserved. 83 */ 84 void sshbuf_reset(struct sshbuf *buf); 85 86 /* 87 * Return the maximum size of buf 88 */ 89 size_t sshbuf_max_size(const struct sshbuf *buf); 90 91 /* 92 * Set the maximum size of buf 93 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 94 */ 95 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 96 97 /* 98 * Returns the length of data in buf 99 */ 100 size_t sshbuf_len(const struct sshbuf *buf); 101 102 /* 103 * Returns number of bytes left in buffer before hitting max_size. 104 */ 105 size_t sshbuf_avail(const struct sshbuf *buf); 106 107 /* 108 * Returns a read-only pointer to the start of the data in buf 109 */ 110 const u_char *sshbuf_ptr(const struct sshbuf *buf); 111 112 /* 113 * Returns a mutable pointer to the start of the data in buf, or 114 * NULL if the buffer is read-only. 115 */ 116 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 117 118 /* 119 * Check whether a reservation of size len will succeed in buf 120 * Safer to use than direct comparisons again sshbuf_avail as it copes 121 * with unsigned overflows correctly. 122 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 123 */ 124 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 125 126 /* 127 * Preallocates len additional bytes in buf. 128 * Useful for cases where the caller knows how many bytes will ultimately be 129 * required to avoid realloc in the buffer code. 130 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 131 */ 132 int sshbuf_allocate(struct sshbuf *buf, size_t len); 133 134 /* 135 * Reserve len bytes in buf. 136 * Returns 0 on success and a pointer to the first reserved byte via the 137 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 138 */ 139 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 140 141 /* 142 * Consume len bytes from the start of buf 143 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 144 */ 145 int sshbuf_consume(struct sshbuf *buf, size_t len); 146 147 /* 148 * Consume len bytes from the end of buf 149 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 150 */ 151 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 152 153 /* Extract or deposit some bytes */ 154 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 155 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 156 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 157 158 /* Append using a printf(3) format */ 159 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 160 __attribute__((format(printf, 2, 3))); 161 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap) 162 __printflike(2, 0); 163 164 /* Functions to extract or store big-endian words of various sizes */ 165 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 166 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 167 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 168 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 169 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 170 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 171 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 172 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 173 174 /* Functions to peek at the contents of a buffer without modifying it. */ 175 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 176 u_int64_t *valp); 177 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 178 u_int32_t *valp); 179 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 180 u_int16_t *valp); 181 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 182 u_char *valp); 183 184 /* 185 * Functions to poke values into an existing buffer (e.g. a length header 186 * to a packet). The destination bytes must already exist in the buffer. 187 */ 188 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 189 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 190 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 191 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 192 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 193 194 /* 195 * Functions to extract or store SSH wire encoded strings (u32 len || data) 196 * The "cstring" variants admit no \0 characters in the string contents. 197 * Caller must free *valp. 198 */ 199 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 200 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 201 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 202 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 203 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 204 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 205 206 /* 207 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 208 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 209 * next sshbuf-modifying function call. Caller does not free. 210 */ 211 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 212 size_t *lenp); 213 214 /* Skip past a string */ 215 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 216 217 /* Another variant: "peeks" into the buffer without modifying it */ 218 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 219 size_t *lenp); 220 221 /* 222 * Functions to extract or store SSH wire encoded bignums and elliptic 223 * curve points. 224 */ 225 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 226 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 227 const u_char **valp, size_t *lenp); 228 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 229 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 230 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 231 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 232 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 233 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 234 int sshbuf_put_ec_pkey(struct sshbuf *buf, EVP_PKEY *pkey); 235 236 /* Dump the contents of the buffer in a human-readable format */ 237 void sshbuf_dump(const struct sshbuf *buf, FILE *f); 238 239 /* Dump specified memory in a human-readable format */ 240 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 241 242 /* Return the hexadecimal representation of the contents of the buffer */ 243 char *sshbuf_dtob16(struct sshbuf *buf); 244 245 /* Encode the contents of the buffer as base64 */ 246 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 247 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 248 /* RFC4648 "base64url" encoding variant */ 249 int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 250 251 /* Decode base64 data and append it to the buffer */ 252 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 253 254 /* 255 * Tests whether the buffer contains the specified byte sequence at the 256 * specified offset. Returns 0 on successful match, or a ssherr.h code 257 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 258 * present but the buffer contents did not match those supplied. Zero- 259 * length comparisons are not allowed. 260 * 261 * If sufficient data is present to make a comparison, then it is 262 * performed with timing independent of the value of the data. If 263 * insufficient data is present then the comparison is not attempted at 264 * all. 265 */ 266 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 267 const void *s, size_t len); 268 269 /* 270 * Searches the buffer for the specified string. Returns 0 on success 271 * and updates *offsetp with the offset of the first match, relative to 272 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 273 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 274 * present in the buffer for a match to be possible but none was found. 275 * Searches for zero-length data are not allowed. 276 */ 277 int 278 sshbuf_find(const struct sshbuf *b, size_t start_offset, 279 const void *s, size_t len, size_t *offsetp); 280 281 /* 282 * Duplicate the contents of a buffer to a string (caller to free). 283 * Returns NULL on buffer error, or if the buffer contains a premature 284 * nul character. 285 */ 286 char *sshbuf_dup_string(struct sshbuf *buf); 287 288 /* 289 * Fill a buffer from a file descriptor or filename. Both allocate the 290 * buffer for the caller. 291 */ 292 int sshbuf_load_fd(int, struct sshbuf **) 293 __attribute__((__nonnull__ (2))); 294 int sshbuf_load_file(const char *, struct sshbuf **) 295 __attribute__((__nonnull__ (2))); 296 297 /* 298 * Write a buffer to a path, creating/truncating as needed (mode 0644, 299 * subject to umask). The buffer contents are not modified. 300 */ 301 int sshbuf_write_file(const char *path, struct sshbuf *buf) 302 __attribute__((__nonnull__ (2))); 303 304 /* Read up to maxlen bytes from a fd directly to a buffer */ 305 int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 306 __attribute__((__nonnull__ (2))); 307 308 /* Macros for decoding/encoding integers */ 309 #define PEEK_U64(p) \ 310 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 311 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 312 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 313 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 314 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 315 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 316 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 317 (u_int64_t)(((const u_char *)(p))[7])) 318 #define PEEK_U32(p) \ 319 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 320 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 321 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 322 (u_int32_t)(((const u_char *)(p))[3])) 323 #define PEEK_U16(p) \ 324 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 325 (u_int16_t)(((const u_char *)(p))[1])) 326 327 #define POKE_U64(p, v) \ 328 do { \ 329 const u_int64_t __v = (v); \ 330 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 331 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 332 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 333 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 334 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 335 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 336 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 337 ((u_char *)(p))[7] = __v & 0xff; \ 338 } while (0) 339 #define POKE_U32(p, v) \ 340 do { \ 341 const u_int32_t __v = (v); \ 342 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 343 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 344 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 345 ((u_char *)(p))[3] = __v & 0xff; \ 346 } while (0) 347 #define POKE_U16(p, v) \ 348 do { \ 349 const u_int16_t __v = (v); \ 350 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 351 ((u_char *)(p))[1] = __v & 0xff; \ 352 } while (0) 353 354 /* Internal definitions follow. Exposed for regress tests */ 355 #ifdef SSHBUF_INTERNAL 356 357 /* 358 * Return the allocation size of buf 359 */ 360 size_t sshbuf_alloc(const struct sshbuf *buf); 361 362 /* 363 * Increment the reference count of buf. 364 */ 365 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 366 367 /* 368 * Return the parent buffer of buf, or NULL if it has no parent. 369 */ 370 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 371 372 /* 373 * Return the reference count of buf 374 */ 375 u_int sshbuf_refcount(const struct sshbuf *buf); 376 377 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 378 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 379 # define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 380 381 /* # define SSHBUF_ABORT abort */ 382 /* # define SSHBUF_DEBUG */ 383 384 # ifndef SSHBUF_ABORT 385 # define SSHBUF_ABORT() 386 # endif 387 388 # ifdef SSHBUF_DEBUG 389 # define SSHBUF_DBG(x) do { \ 390 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 391 printf x; \ 392 printf("\n"); \ 393 fflush(stdout); \ 394 } while (0) 395 # else 396 # define SSHBUF_DBG(x) 397 # endif 398 #endif /* SSHBUF_INTERNAL */ 399 400 #endif /* _SSHBUF_H */ 401