1 /* $OpenBSD: sshbuf.h,v 1.19 2020/01/25 23:02:14 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 /* 42 * NB. do not depend on the internals of this. It will be made opaque 43 * one day. 44 */ 45 struct sshbuf { 46 u_char *d; /* Data */ 47 const u_char *cd; /* Const data */ 48 size_t off; /* First available byte is buf->d + buf->off */ 49 size_t size; /* Last byte is buf->d + buf->size - 1 */ 50 size_t max_size; /* Maximum size of buffer */ 51 size_t alloc; /* Total bytes allocated to buf->d */ 52 int readonly; /* Refers to external, const data */ 53 int dont_free; /* Kludge to support sshbuf_init */ 54 u_int refcount; /* Tracks self and number of child buffers */ 55 struct sshbuf *parent; /* If child, pointer to parent */ 56 }; 57 58 /* 59 * Create a new sshbuf buffer. 60 * Returns pointer to buffer on success, or NULL on allocation failure. 61 */ 62 struct sshbuf *sshbuf_new(void); 63 64 /* 65 * Create a new, read-only sshbuf buffer from existing data. 66 * Returns pointer to buffer on success, or NULL on allocation failure. 67 */ 68 struct sshbuf *sshbuf_from(const void *blob, size_t len); 69 70 /* 71 * Create a new, read-only sshbuf buffer from the contents of an existing 72 * buffer. The contents of "buf" must not change in the lifetime of the 73 * resultant buffer. 74 * Returns pointer to buffer on success, or NULL on allocation failure. 75 */ 76 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 77 78 /* 79 * Create a new, read-only sshbuf buffer from the contents of a string in 80 * an existing buffer (the string is consumed in the process). 81 * The contents of "buf" must not change in the lifetime of the resultant 82 * buffer. 83 * Returns pointer to buffer on success, or NULL on allocation failure. 84 */ 85 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 86 87 /* 88 * Clear and free buf 89 */ 90 void sshbuf_free(struct sshbuf *buf); 91 92 /* 93 * Reset buf, clearing its contents. NB. max_size is preserved. 94 */ 95 void sshbuf_reset(struct sshbuf *buf); 96 97 /* 98 * Return the maximum size of buf 99 */ 100 size_t sshbuf_max_size(const struct sshbuf *buf); 101 102 /* 103 * Set the maximum size of buf 104 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 105 */ 106 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 107 108 /* 109 * Returns the length of data in buf 110 */ 111 size_t sshbuf_len(const struct sshbuf *buf); 112 113 /* 114 * Returns number of bytes left in buffer before hitting max_size. 115 */ 116 size_t sshbuf_avail(const struct sshbuf *buf); 117 118 /* 119 * Returns a read-only pointer to the start of the data in buf 120 */ 121 const u_char *sshbuf_ptr(const struct sshbuf *buf); 122 123 /* 124 * Returns a mutable pointer to the start of the data in buf, or 125 * NULL if the buffer is read-only. 126 */ 127 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 128 129 /* 130 * Check whether a reservation of size len will succeed in buf 131 * Safer to use than direct comparisons again sshbuf_avail as it copes 132 * with unsigned overflows correctly. 133 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 134 */ 135 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 136 137 /* 138 * Preallocates len additional bytes in buf. 139 * Useful for cases where the caller knows how many bytes will ultimately be 140 * required to avoid realloc in the buffer code. 141 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 142 */ 143 int sshbuf_allocate(struct sshbuf *buf, size_t len); 144 145 /* 146 * Reserve len bytes in buf. 147 * Returns 0 on success and a pointer to the first reserved byte via the 148 * optional dpp parameter or a negative * SSH_ERR_* error code on failure. 149 */ 150 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 151 152 /* 153 * Consume len bytes from the start of buf 154 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 155 */ 156 int sshbuf_consume(struct sshbuf *buf, size_t len); 157 158 /* 159 * Consume len bytes from the end of buf 160 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 161 */ 162 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 163 164 /* Extract or deposit some bytes */ 165 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 166 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 167 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 168 169 /* Append using a printf(3) format */ 170 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 171 __attribute__((format(printf, 2, 3))); 172 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 173 174 /* Functions to extract or store big-endian words of various sizes */ 175 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 176 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 177 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 178 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 179 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 180 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 181 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 182 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 183 184 /* Functions to peek at the contents of a buffer without modifying it. */ 185 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 186 u_int64_t *valp); 187 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 188 u_int32_t *valp); 189 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 190 u_int16_t *valp); 191 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 192 u_char *valp); 193 194 /* 195 * Functions to poke values into an exisiting buffer (e.g. a length header 196 * to a packet). The destination bytes must already exist in the buffer. 197 */ 198 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 199 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 200 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 201 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 202 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 203 204 /* 205 * Functions to extract or store SSH wire encoded strings (u32 len || data) 206 * The "cstring" variants admit no \0 characters in the string contents. 207 * Caller must free *valp. 208 */ 209 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 210 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 211 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 212 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 213 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 214 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 215 216 /* 217 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 218 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 219 * next sshbuf-modifying function call. Caller does not free. 220 */ 221 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 222 size_t *lenp); 223 224 /* Skip past a string */ 225 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 226 227 /* Another variant: "peeks" into the buffer without modifying it */ 228 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 229 size_t *lenp); 230 231 /* 232 * Functions to extract or store SSH wire encoded bignums and elliptic 233 * curve points. 234 */ 235 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 236 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 237 const u_char **valp, size_t *lenp); 238 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 239 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 240 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 241 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 242 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 243 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 244 245 /* Dump the contents of the buffer in a human-readable format */ 246 void sshbuf_dump(struct sshbuf *buf, FILE *f); 247 248 /* Dump specified memory in a human-readable format */ 249 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 250 251 /* Return the hexadecimal representation of the contents of the buffer */ 252 char *sshbuf_dtob16(struct sshbuf *buf); 253 254 /* Encode the contents of the buffer as base64 */ 255 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 256 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 257 258 /* Decode base64 data and append it to the buffer */ 259 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 260 261 /* 262 * Tests whether the buffer contains the specified byte sequence at the 263 * specified offset. Returns 0 on successful match, or a ssherr.h code 264 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 265 * present but the buffer contents did not match those supplied. Zero- 266 * length comparisons are not allowed. 267 * 268 * If sufficient data is present to make a comparison, then it is 269 * performed with timing independent of the value of the data. If 270 * insufficient data is present then the comparison is not attempted at 271 * all. 272 */ 273 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 274 const void *s, size_t len); 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 /* Macros for decoding/encoding integers */ 312 #define PEEK_U64(p) \ 313 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 314 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 315 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 316 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 317 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 318 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 319 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 320 (u_int64_t)(((const u_char *)(p))[7])) 321 #define PEEK_U32(p) \ 322 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 323 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 324 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 325 (u_int32_t)(((const u_char *)(p))[3])) 326 #define PEEK_U16(p) \ 327 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 328 (u_int16_t)(((const u_char *)(p))[1])) 329 330 #define POKE_U64(p, v) \ 331 do { \ 332 const u_int64_t __v = (v); \ 333 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 334 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 335 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 336 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 337 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 338 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 339 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 340 ((u_char *)(p))[7] = __v & 0xff; \ 341 } while (0) 342 #define POKE_U32(p, v) \ 343 do { \ 344 const u_int32_t __v = (v); \ 345 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 346 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 347 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 348 ((u_char *)(p))[3] = __v & 0xff; \ 349 } while (0) 350 #define POKE_U16(p, v) \ 351 do { \ 352 const u_int16_t __v = (v); \ 353 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 354 ((u_char *)(p))[1] = __v & 0xff; \ 355 } while (0) 356 357 /* Internal definitions follow. Exposed for regress tests */ 358 #ifdef SSHBUF_INTERNAL 359 360 /* 361 * Return the allocation size of buf 362 */ 363 size_t sshbuf_alloc(const struct sshbuf *buf); 364 365 /* 366 * Increment the reference count of buf. 367 */ 368 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 369 370 /* 371 * Return the parent buffer of buf, or NULL if it has no parent. 372 */ 373 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 374 375 /* 376 * Return the reference count of buf 377 */ 378 u_int sshbuf_refcount(const struct sshbuf *buf); 379 380 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 381 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 382 # define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */ 383 384 /* # define SSHBUF_ABORT abort */ 385 /* # define SSHBUF_DEBUG */ 386 387 # ifndef SSHBUF_ABORT 388 # define SSHBUF_ABORT() 389 # endif 390 391 # ifdef SSHBUF_DEBUG 392 # define SSHBUF_TELL(what) do { \ 393 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \ 394 __FILE__, __LINE__, __func__, what, \ 395 buf->size, buf->alloc, buf->off, buf->max_size); \ 396 fflush(stdout); \ 397 } while (0) 398 # define SSHBUF_DBG(x) do { \ 399 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 400 printf x; \ 401 printf("\n"); \ 402 fflush(stdout); \ 403 } while (0) 404 # else 405 # define SSHBUF_TELL(what) 406 # define SSHBUF_DBG(x) 407 # endif 408 #endif /* SSHBUF_INTERNAL */ 409 410 #endif /* _SSHBUF_H */ 411