1 /* $NetBSD: sshbuf.h,v 1.14 2020/05/28 17:05:49 christos Exp $ */ 2 /* $OpenBSD: sshbuf.h,v 1.21 2020/04/26 09:38:14 dtucker Exp $ */ 3 /* 4 * Copyright (c) 2011 Damien Miller 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #ifndef _SSHBUF_H 20 #define _SSHBUF_H 21 22 #include <sys/types.h> 23 #include <stdarg.h> 24 #include <stdio.h> 25 26 #ifdef WITH_OPENSSL 27 #include <openssl/bn.h> 28 #include <openssl/ec.h> 29 #include <openssl/ecdsa.h> 30 #else /* OPENSSL */ 31 #define BIGNUM void 32 #define EC_KEY void 33 #define EC_GROUP void 34 #define EC_POINT void 35 #endif /* WITH_OPENSSL */ 36 37 /* move the following to a more appropriate place and name */ 38 #define BUFFER_MAX_LEN_HPN 0x4000000 /* 64MB */ 39 40 #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ 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 /* 46 * NB. do not depend on the internals of this. It will be made opaque 47 * one day. 48 */ 49 struct sshbuf { 50 u_char *d; /* Data */ 51 const u_char *cd; /* Const data */ 52 size_t off; /* First available byte is buf->d + buf->off */ 53 size_t size; /* Last byte is buf->d + buf->size - 1 */ 54 size_t max_size; /* Maximum size of buffer */ 55 size_t alloc; /* Total bytes allocated to buf->d */ 56 int readonly; /* Refers to external, const data */ 57 int dont_free; /* Kludge to support sshbuf_init */ 58 u_int refcount; /* Tracks self and number of child buffers */ 59 struct sshbuf *parent; /* If child, pointer to parent */ 60 }; 61 62 /* 63 * Create a new sshbuf buffer. 64 * Returns pointer to buffer on success, or NULL on allocation failure. 65 */ 66 struct sshbuf *sshbuf_new(void); 67 68 /* 69 * Create a new, read-only sshbuf buffer from existing data. 70 * Returns pointer to buffer on success, or NULL on allocation failure. 71 */ 72 struct sshbuf *sshbuf_from(const void *blob, size_t len); 73 74 /* 75 * Create a new, read-only sshbuf buffer from the contents of an existing 76 * buffer. The contents of "buf" must not change in the lifetime of the 77 * resultant buffer. 78 * Returns pointer to buffer on success, or NULL on allocation failure. 79 */ 80 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 81 82 /* 83 * Create a new, read-only sshbuf buffer from the contents of a string in 84 * an existing buffer (the string is consumed in the process). 85 * The contents of "buf" must not change in the lifetime of the resultant 86 * buffer. 87 * Returns pointer to buffer on success, or NULL on allocation failure. 88 */ 89 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 90 91 /* 92 * Clear and free buf 93 */ 94 void sshbuf_free(struct sshbuf *buf); 95 96 /* 97 * Reset buf, clearing its contents. NB. max_size is preserved. 98 */ 99 void sshbuf_reset(struct sshbuf *buf); 100 101 /* 102 * Return the maximum size of buf 103 */ 104 size_t sshbuf_max_size(const struct sshbuf *buf); 105 106 /* 107 * Set the maximum size of buf 108 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 109 */ 110 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 111 112 /* 113 * Returns the length of data in buf 114 */ 115 size_t sshbuf_len(const struct sshbuf *buf); 116 117 /* 118 * Returns number of bytes left in buffer before hitting max_size. 119 */ 120 size_t sshbuf_avail(const struct sshbuf *buf); 121 122 /* 123 * Returns a read-only pointer to the start of the data in buf 124 */ 125 const u_char *sshbuf_ptr(const struct sshbuf *buf); 126 127 /* 128 * Returns a mutable pointer to the start of the data in buf, or 129 * NULL if the buffer is read-only. 130 */ 131 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 132 133 /* 134 * Check whether a reservation of size len will succeed in buf 135 * Safer to use than direct comparisons again sshbuf_avail as it copes 136 * with unsigned overflows correctly. 137 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 138 */ 139 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 140 141 /* 142 * Preallocates len additional bytes in buf. 143 * Useful for cases where the caller knows how many bytes will ultimately be 144 * required to avoid realloc in the buffer code. 145 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 146 */ 147 int sshbuf_allocate(struct sshbuf *buf, size_t len); 148 149 /* 150 * Reserve len bytes in buf. 151 * Returns 0 on success and a pointer to the first reserved byte via the 152 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 153 */ 154 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 155 156 /* 157 * Consume len bytes from the start of buf 158 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 159 */ 160 int sshbuf_consume(struct sshbuf *buf, size_t len); 161 162 /* 163 * Consume len bytes from the end of buf 164 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 165 */ 166 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 167 168 /* Extract or deposit some bytes */ 169 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 170 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 171 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 172 173 /* Append using a printf(3) format */ 174 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 175 __attribute__((format(printf, 2, 3))); 176 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap) 177 __printflike(2, 0); 178 179 /* Functions to extract or store big-endian words of various sizes */ 180 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 181 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 182 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 183 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 184 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 185 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 186 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 187 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 188 189 /* Functions to peek at the contents of a buffer without modifying it. */ 190 int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 191 u_int64_t *valp); 192 int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 193 u_int32_t *valp); 194 int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 195 u_int16_t *valp); 196 int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, 197 u_char *valp); 198 199 /* 200 * Functions to poke values into an existing buffer (e.g. a length header 201 * to a packet). The destination bytes must already exist in the buffer. 202 */ 203 int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 204 int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 205 int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 206 int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 207 int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); 208 209 /* 210 * Functions to extract or store SSH wire encoded strings (u32 len || data) 211 * The "cstring" variants admit no \0 characters in the string contents. 212 * Caller must free *valp. 213 */ 214 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 215 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 216 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 217 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 218 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 219 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 220 221 /* 222 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 223 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 224 * next sshbuf-modifying function call. Caller does not free. 225 */ 226 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 227 size_t *lenp); 228 229 /* Skip past a string */ 230 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 231 232 /* Another variant: "peeks" into the buffer without modifying it */ 233 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 234 size_t *lenp); 235 236 /* 237 * Functions to extract or store SSH wire encoded bignums and elliptic 238 * curve points. 239 */ 240 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 241 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 242 const u_char **valp, size_t *lenp); 243 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 244 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 245 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 246 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 247 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 248 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 249 250 /* Dump the contents of the buffer in a human-readable format */ 251 void sshbuf_dump(struct sshbuf *buf, FILE *f); 252 253 /* Dump specified memory in a human-readable format */ 254 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 255 256 /* Return the hexadecimal representation of the contents of the buffer */ 257 char *sshbuf_dtob16(struct sshbuf *buf); 258 259 /* Encode the contents of the buffer as base64 */ 260 char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 261 int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 262 263 /* Decode base64 data and append it to the buffer */ 264 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 265 266 /* 267 * Tests whether the buffer contains the specified byte sequence at the 268 * specified offset. Returns 0 on successful match, or a ssherr.h code 269 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 270 * present but the buffer contents did not match those supplied. Zero- 271 * length comparisons are not allowed. 272 * 273 * If sufficient data is present to make a comparison, then it is 274 * performed with timing independent of the value of the data. If 275 * insufficient data is present then the comparison is not attempted at 276 * all. 277 */ 278 int sshbuf_cmp(const struct sshbuf *b, size_t offset, 279 const void *s, size_t len); 280 281 /* 282 * Searches the buffer for the specified string. Returns 0 on success 283 * and updates *offsetp with the offset of the first match, relative to 284 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 285 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 286 * present in the buffer for a match to be possible but none was found. 287 * Searches for zero-length data are not allowed. 288 */ 289 int 290 sshbuf_find(const struct sshbuf *b, size_t start_offset, 291 const void *s, size_t len, size_t *offsetp); 292 293 /* 294 * Duplicate the contents of a buffer to a string (caller to free). 295 * Returns NULL on buffer error, or if the buffer contains a premature 296 * nul character. 297 */ 298 char *sshbuf_dup_string(struct sshbuf *buf); 299 300 /* 301 * Fill a buffer from a file descriptor or filename. Both allocate the 302 * buffer for the caller. 303 */ 304 int sshbuf_load_fd(int, struct sshbuf **) 305 __attribute__((__nonnull__ (2))); 306 int sshbuf_load_file(const char *, struct sshbuf **) 307 __attribute__((__nonnull__ (2))); 308 309 /* 310 * Write a buffer to a path, creating/truncating as needed (mode 0644, 311 * subject to umask). The buffer contents are not modified. 312 */ 313 int sshbuf_write_file(const char *path, struct sshbuf *buf) 314 __attribute__((__nonnull__ (2))); 315 316 /* Macros for decoding/encoding integers */ 317 #define PEEK_U64(p) \ 318 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 319 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 320 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 321 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 322 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 323 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 324 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 325 (u_int64_t)(((const u_char *)(p))[7])) 326 #define PEEK_U32(p) \ 327 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 328 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 329 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 330 (u_int32_t)(((const u_char *)(p))[3])) 331 #define PEEK_U16(p) \ 332 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 333 (u_int16_t)(((const u_char *)(p))[1])) 334 335 #define POKE_U64(p, v) \ 336 do { \ 337 const u_int64_t __v = (v); \ 338 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 339 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 340 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 341 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 342 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 343 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 344 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 345 ((u_char *)(p))[7] = __v & 0xff; \ 346 } while (0) 347 #define POKE_U32(p, v) \ 348 do { \ 349 const u_int32_t __v = (v); \ 350 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 351 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 352 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 353 ((u_char *)(p))[3] = __v & 0xff; \ 354 } while (0) 355 #define POKE_U16(p, v) \ 356 do { \ 357 const u_int16_t __v = (v); \ 358 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 359 ((u_char *)(p))[1] = __v & 0xff; \ 360 } while (0) 361 362 /* Internal definitions follow. Exposed for regress tests */ 363 #ifdef SSHBUF_INTERNAL 364 365 /* 366 * Return the allocation size of buf 367 */ 368 size_t sshbuf_alloc(const struct sshbuf *buf); 369 370 /* 371 * Increment the reference count of buf. 372 */ 373 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 374 375 /* 376 * Return the parent buffer of buf, or NULL if it has no parent. 377 */ 378 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 379 380 /* 381 * Return the reference count of buf 382 */ 383 u_int sshbuf_refcount(const struct sshbuf *buf); 384 385 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 386 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 387 # define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */ 388 389 /* # define SSHBUF_ABORT abort */ 390 /* # define SSHBUF_DEBUG */ 391 392 # ifndef SSHBUF_ABORT 393 # define SSHBUF_ABORT() 394 # endif 395 396 # ifdef SSHBUF_DEBUG 397 # define SSHBUF_TELL(what) do { \ 398 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \ 399 __FILE__, __LINE__, __func__, what, \ 400 buf->size, buf->alloc, buf->off, buf->max_size); \ 401 fflush(stdout); \ 402 } while (0) 403 # define SSHBUF_DBG(x) do { \ 404 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 405 printf x; \ 406 printf("\n"); \ 407 fflush(stdout); \ 408 } while (0) 409 # else 410 # define SSHBUF_TELL(what) 411 # define SSHBUF_DBG(x) 412 # endif 413 #endif /* SSHBUF_INTERNAL */ 414 415 #endif /* _SSHBUF_H */ 416