1 /* $OpenBSD: sshbuf.h,v 1.10 2018/04/10 00:10:49 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 #include <openssl/bn.h> 25 #include <openssl/ec.h> 26 27 #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ 28 #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ 29 #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ 30 #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ 31 32 /* 33 * NB. do not depend on the internals of this. It will be made opaque 34 * one day. 35 */ 36 struct sshbuf { 37 u_char *d; /* Data */ 38 const u_char *cd; /* Const data */ 39 size_t off; /* First available byte is buf->d + buf->off */ 40 size_t size; /* Last byte is buf->d + buf->size - 1 */ 41 size_t max_size; /* Maximum size of buffer */ 42 size_t alloc; /* Total bytes allocated to buf->d */ 43 int readonly; /* Refers to external, const data */ 44 int dont_free; /* Kludge to support sshbuf_init */ 45 u_int refcount; /* Tracks self and number of child buffers */ 46 struct sshbuf *parent; /* If child, pointer to parent */ 47 }; 48 49 #ifndef SSHBUF_NO_DEPREACTED 50 /* 51 * NB. Please do not use sshbuf_init() in new code. Please use sshbuf_new() 52 * instead. sshbuf_init() is deprecated and will go away soon (it is 53 * only included to allow compat with buffer_* in OpenSSH) 54 */ 55 void sshbuf_init(struct sshbuf *buf); 56 #endif 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 /* 185 * Functions to extract or store SSH wire encoded strings (u32 len || data) 186 * The "cstring" variants admit no \0 characters in the string contents. 187 * Caller must free *valp. 188 */ 189 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 190 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 191 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 192 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 193 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 194 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 195 196 /* 197 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 198 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 199 * next sshbuf-modifying function call. Caller does not free. 200 */ 201 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 202 size_t *lenp); 203 204 /* Skip past a string */ 205 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 206 207 /* Another variant: "peeks" into the buffer without modifying it */ 208 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 209 size_t *lenp); 210 /* XXX peek_u8 / peek_u32 */ 211 212 /* 213 * Functions to extract or store SSH wire encoded bignums and elliptic 214 * curve points. 215 */ 216 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v); 217 int sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v); 218 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 219 const u_char **valp, size_t *lenp); 220 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 221 int sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v); 222 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 223 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 224 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 225 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 226 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 227 228 /* Dump the contents of the buffer in a human-readable format */ 229 void sshbuf_dump(struct sshbuf *buf, FILE *f); 230 231 /* Dump specified memory in a human-readable format */ 232 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 233 234 /* Return the hexadecimal representation of the contents of the buffer */ 235 char *sshbuf_dtob16(struct sshbuf *buf); 236 237 /* Encode the contents of the buffer as base64 */ 238 char *sshbuf_dtob64(struct sshbuf *buf); 239 240 /* Decode base64 data and append it to the buffer */ 241 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 242 243 /* 244 * Duplicate the contents of a buffer to a string (caller to free). 245 * Returns NULL on buffer error, or if the buffer contains a premature 246 * nul character. 247 */ 248 char *sshbuf_dup_string(struct sshbuf *buf); 249 250 /* Macros for decoding/encoding integers */ 251 #define PEEK_U64(p) \ 252 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 253 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 254 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 255 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 256 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 257 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 258 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 259 (u_int64_t)(((const u_char *)(p))[7])) 260 #define PEEK_U32(p) \ 261 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 262 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 263 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 264 (u_int32_t)(((const u_char *)(p))[3])) 265 #define PEEK_U16(p) \ 266 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 267 (u_int16_t)(((const u_char *)(p))[1])) 268 269 #define POKE_U64(p, v) \ 270 do { \ 271 const u_int64_t __v = (v); \ 272 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 273 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 274 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 275 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 276 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 277 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 278 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 279 ((u_char *)(p))[7] = __v & 0xff; \ 280 } while (0) 281 #define POKE_U32(p, v) \ 282 do { \ 283 const u_int32_t __v = (v); \ 284 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 285 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 286 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 287 ((u_char *)(p))[3] = __v & 0xff; \ 288 } while (0) 289 #define POKE_U16(p, v) \ 290 do { \ 291 const u_int16_t __v = (v); \ 292 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 293 ((u_char *)(p))[1] = __v & 0xff; \ 294 } while (0) 295 296 /* Internal definitions follow. Exposed for regress tests */ 297 #ifdef SSHBUF_INTERNAL 298 299 /* 300 * Return the allocation size of buf 301 */ 302 size_t sshbuf_alloc(const struct sshbuf *buf); 303 304 /* 305 * Increment the reference count of buf. 306 */ 307 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 308 309 /* 310 * Return the parent buffer of buf, or NULL if it has no parent. 311 */ 312 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 313 314 /* 315 * Return the reference count of buf 316 */ 317 u_int sshbuf_refcount(const struct sshbuf *buf); 318 319 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 320 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 321 # define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */ 322 323 /* # define SSHBUF_ABORT abort */ 324 /* # define SSHBUF_DEBUG */ 325 326 # ifndef SSHBUF_ABORT 327 # define SSHBUF_ABORT() 328 # endif 329 330 # ifdef SSHBUF_DEBUG 331 # define SSHBUF_TELL(what) do { \ 332 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \ 333 __FILE__, __LINE__, __func__, what, \ 334 buf->size, buf->alloc, buf->off, buf->max_size); \ 335 fflush(stdout); \ 336 } while (0) 337 # define SSHBUF_DBG(x) do { \ 338 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 339 printf x; \ 340 printf("\n"); \ 341 fflush(stdout); \ 342 } while (0) 343 # else 344 # define SSHBUF_TELL(what) 345 # define SSHBUF_DBG(x) 346 # endif 347 #endif /* SSHBUF_INTERNAL */ 348 349 #endif /* _SSHBUF_H */ 350