1/* $NetBSD: sshbuf.h,v 1.19 2023/07/26 17:58:16 christos Exp $ */ 2/* $OpenBSD: sshbuf.h,v 1.28 2022/12/02 04:40:27 djm 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#define SSHBUF_SIZE_MAX 0x10000000 /* Hard maximum size 256MB */ 38#define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 39#define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 40#define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 41 42struct sshbuf; 43 44/* 45 * Create a new sshbuf buffer. 46 * Returns pointer to buffer on success, or NULL on allocation failure. 47 */ 48struct sshbuf *sshbuf_new(void); 49 50/* 51 * Create a new, read-only sshbuf buffer from existing data. 52 * Returns pointer to buffer on success, or NULL on allocation failure. 53 */ 54struct sshbuf *sshbuf_from(const void *blob, size_t len); 55 56/* 57 * Create a new, read-only sshbuf buffer from the contents of an existing 58 * buffer. The contents of "buf" must not change in the lifetime of the 59 * resultant buffer. 60 * Returns pointer to buffer on success, or NULL on allocation failure. 61 */ 62struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 63 64/* 65 * Create a new, read-only sshbuf buffer from the contents of a string in 66 * an existing buffer (the string is consumed in the process). 67 * The contents of "buf" must not change in the lifetime of the resultant 68 * buffer. 69 * Returns pointer to buffer on success, or NULL on allocation failure. 70 */ 71int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 72 73/* 74 * Clear and free buf 75 */ 76void sshbuf_free(struct sshbuf *buf); 77 78/* 79 * Reset buf, clearing its contents. NB. max_size is preserved. 80 */ 81void sshbuf_reset(struct sshbuf *buf); 82 83/* 84 * Return the maximum size of buf 85 */ 86size_t sshbuf_max_size(const struct sshbuf *buf); 87 88/* 89 * Set the maximum size of buf 90 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 91 */ 92int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 93 94/* 95 * Returns the length of data in buf 96 */ 97size_t sshbuf_len(const struct sshbuf *buf); 98 99/* 100 * Returns number of bytes left in buffer before hitting max_size. 101 */ 102size_t sshbuf_avail(const struct sshbuf *buf); 103 104/* 105 * Returns a read-only pointer to the start of the data in buf 106 */ 107const u_char *sshbuf_ptr(const struct sshbuf *buf); 108 109/* 110 * Returns a mutable pointer to the start of the data in buf, or 111 * NULL if the buffer is read-only. 112 */ 113u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 114 115/* 116 * Check whether a reservation of size len will succeed in buf 117 * Safer to use than direct comparisons again sshbuf_avail as it copes 118 * with unsigned overflows correctly. 119 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 120 */ 121int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 122 123/* 124 * Preallocates len additional bytes in buf. 125 * Useful for cases where the caller knows how many bytes will ultimately be 126 * required to avoid realloc in the buffer code. 127 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 128 */ 129int sshbuf_allocate(struct sshbuf *buf, size_t len); 130 131/* 132 * Reserve len bytes in buf. 133 * Returns 0 on success and a pointer to the first reserved byte via the 134 * optional dpp parameter or a negative SSH_ERR_* error code on failure. 135 */ 136int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 137 138/* 139 * Consume len bytes from the start of buf 140 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 141 */ 142int sshbuf_consume(struct sshbuf *buf, size_t len); 143 144/* 145 * Consume len bytes from the end of buf 146 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 147 */ 148int sshbuf_consume_end(struct sshbuf *buf, size_t len); 149 150/* Extract or deposit some bytes */ 151int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 152int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 153int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 154 155/* Append using a printf(3) format */ 156int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 157 __attribute__((format(printf, 2, 3))); 158int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap) 159 __printflike(2, 0); 160 161/* Functions to extract or store big-endian words of various sizes */ 162int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 163int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 164int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 165int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 166int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 167int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 168int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 169int sshbuf_put_u8(struct sshbuf *buf, u_char val); 170 171/* Functions to peek at the contents of a buffer without modifying it. */ 172int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, 173 u_int64_t *valp); 174int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, 175 u_int32_t *valp); 176int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, 177 u_int16_t *valp); 178int 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 */ 185int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); 186int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); 187int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); 188int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); 189int 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 */ 196int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 197int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 198int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 199int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 200int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 201int 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 */ 208int 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 */ 215int 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 */ 222int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 223int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 224 const u_char **valp, size_t *lenp); 225int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 226int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 227int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 228int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 229int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 230int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 231 232/* Dump the contents of the buffer in a human-readable format */ 233void sshbuf_dump(const struct sshbuf *buf, FILE *f); 234 235/* Dump specified memory in a human-readable format */ 236void sshbuf_dump_data(const void *s, size_t len, FILE *f); 237 238/* Return the hexadecimal representation of the contents of the buffer */ 239char *sshbuf_dtob16(struct sshbuf *buf); 240 241/* Encode the contents of the buffer as base64 */ 242char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); 243int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 244/* RFC4648 "base64url" encoding variant */ 245int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap); 246 247/* Decode base64 data and append it to the buffer */ 248int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 249 250/* 251 * Tests whether the buffer contains the specified byte sequence at the 252 * specified offset. Returns 0 on successful match, or a ssherr.h code 253 * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 254 * present but the buffer contents did not match those supplied. Zero- 255 * length comparisons are not allowed. 256 * 257 * If sufficient data is present to make a comparison, then it is 258 * performed with timing independent of the value of the data. If 259 * insufficient data is present then the comparison is not attempted at 260 * all. 261 */ 262int sshbuf_cmp(const struct sshbuf *b, size_t offset, 263 const void *s, size_t len); 264 265/* 266 * Searches the buffer for the specified string. Returns 0 on success 267 * and updates *offsetp with the offset of the first match, relative to 268 * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h 269 * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were 270 * present in the buffer for a match to be possible but none was found. 271 * Searches for zero-length data are not allowed. 272 */ 273int 274sshbuf_find(const struct sshbuf *b, size_t start_offset, 275 const void *s, size_t len, size_t *offsetp); 276 277/* 278 * Duplicate the contents of a buffer to a string (caller to free). 279 * Returns NULL on buffer error, or if the buffer contains a premature 280 * nul character. 281 */ 282char *sshbuf_dup_string(struct sshbuf *buf); 283 284/* 285 * Fill a buffer from a file descriptor or filename. Both allocate the 286 * buffer for the caller. 287 */ 288int sshbuf_load_fd(int, struct sshbuf **) 289 __attribute__((__nonnull__ (2))); 290int sshbuf_load_file(const char *, struct sshbuf **) 291 __attribute__((__nonnull__ (2))); 292 293/* 294 * Write a buffer to a path, creating/truncating as needed (mode 0644, 295 * subject to umask). The buffer contents are not modified. 296 */ 297int sshbuf_write_file(const char *path, struct sshbuf *buf) 298 __attribute__((__nonnull__ (2))); 299 300/* Read up to maxlen bytes from a fd directly to a buffer */ 301int sshbuf_read(int, struct sshbuf *, size_t, size_t *) 302 __attribute__((__nonnull__ (2))); 303 304/* Macros for decoding/encoding integers */ 305#define PEEK_U64(p) \ 306 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 307 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 308 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 309 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 310 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 311 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 312 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 313 (u_int64_t)(((const u_char *)(p))[7])) 314#define PEEK_U32(p) \ 315 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 316 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 317 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 318 (u_int32_t)(((const u_char *)(p))[3])) 319#define PEEK_U16(p) \ 320 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 321 (u_int16_t)(((const u_char *)(p))[1])) 322 323#define POKE_U64(p, v) \ 324 do { \ 325 const u_int64_t __v = (v); \ 326 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 327 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 328 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 329 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 330 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 331 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 332 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 333 ((u_char *)(p))[7] = __v & 0xff; \ 334 } while (0) 335#define POKE_U32(p, v) \ 336 do { \ 337 const u_int32_t __v = (v); \ 338 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 339 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 340 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 341 ((u_char *)(p))[3] = __v & 0xff; \ 342 } while (0) 343#define POKE_U16(p, v) \ 344 do { \ 345 const u_int16_t __v = (v); \ 346 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 347 ((u_char *)(p))[1] = __v & 0xff; \ 348 } while (0) 349 350/* Internal definitions follow. Exposed for regress tests */ 351#ifdef SSHBUF_INTERNAL 352 353/* 354 * Return the allocation size of buf 355 */ 356size_t sshbuf_alloc(const struct sshbuf *buf); 357 358/* 359 * Increment the reference count of buf. 360 */ 361int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 362 363/* 364 * Return the parent buffer of buf, or NULL if it has no parent. 365 */ 366const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 367 368/* 369 * Return the reference count of buf 370 */ 371u_int sshbuf_refcount(const struct sshbuf *buf); 372 373# define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 374# define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 375# define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */ 376 377/* # define SSHBUF_ABORT abort */ 378/* # define SSHBUF_DEBUG */ 379 380# ifndef SSHBUF_ABORT 381# define SSHBUF_ABORT() 382# endif 383 384# ifdef SSHBUF_DEBUG 385# define SSHBUF_DBG(x) do { \ 386 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 387 printf x; \ 388 printf("\n"); \ 389 fflush(stdout); \ 390 } while (0) 391# else 392# define SSHBUF_DBG(x) 393# endif 394#endif /* SSHBUF_INTERNAL */ 395 396#endif /* _SSHBUF_H */ 397