1 /* $OpenBSD: sshbuf.h,v 1.13 2019/01/21 09:54:11 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 /* 50 * Create a new sshbuf buffer. 51 * Returns pointer to buffer on success, or NULL on allocation failure. 52 */ 53 struct sshbuf *sshbuf_new(void); 54 55 /* 56 * Create a new, read-only sshbuf buffer from existing data. 57 * Returns pointer to buffer on success, or NULL on allocation failure. 58 */ 59 struct sshbuf *sshbuf_from(const void *blob, size_t len); 60 61 /* 62 * Create a new, read-only sshbuf buffer from the contents of an existing 63 * buffer. The contents of "buf" must not change in the lifetime of the 64 * resultant buffer. 65 * Returns pointer to buffer on success, or NULL on allocation failure. 66 */ 67 struct sshbuf *sshbuf_fromb(struct sshbuf *buf); 68 69 /* 70 * Create a new, read-only sshbuf buffer from the contents of a string in 71 * an existing buffer (the string is consumed in the process). 72 * The contents of "buf" must not change in the lifetime of the resultant 73 * buffer. 74 * Returns pointer to buffer on success, or NULL on allocation failure. 75 */ 76 int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); 77 78 /* 79 * Clear and free buf 80 */ 81 void sshbuf_free(struct sshbuf *buf); 82 83 /* 84 * Reset buf, clearing its contents. NB. max_size is preserved. 85 */ 86 void sshbuf_reset(struct sshbuf *buf); 87 88 /* 89 * Return the maximum size of buf 90 */ 91 size_t sshbuf_max_size(const struct sshbuf *buf); 92 93 /* 94 * Set the maximum size of buf 95 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 96 */ 97 int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); 98 99 /* 100 * Returns the length of data in buf 101 */ 102 size_t sshbuf_len(const struct sshbuf *buf); 103 104 /* 105 * Returns number of bytes left in buffer before hitting max_size. 106 */ 107 size_t sshbuf_avail(const struct sshbuf *buf); 108 109 /* 110 * Returns a read-only pointer to the start of the data in buf 111 */ 112 const u_char *sshbuf_ptr(const struct sshbuf *buf); 113 114 /* 115 * Returns a mutable pointer to the start of the data in buf, or 116 * NULL if the buffer is read-only. 117 */ 118 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); 119 120 /* 121 * Check whether a reservation of size len will succeed in buf 122 * Safer to use than direct comparisons again sshbuf_avail as it copes 123 * with unsigned overflows correctly. 124 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 125 */ 126 int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); 127 128 /* 129 * Preallocates len additional bytes in buf. 130 * Useful for cases where the caller knows how many bytes will ultimately be 131 * required to avoid realloc in the buffer code. 132 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 133 */ 134 int sshbuf_allocate(struct sshbuf *buf, size_t len); 135 136 /* 137 * Reserve len bytes in buf. 138 * Returns 0 on success and a pointer to the first reserved byte via the 139 * optional dpp parameter or a negative * SSH_ERR_* error code on failure. 140 */ 141 int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); 142 143 /* 144 * Consume len bytes from the start of buf 145 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 146 */ 147 int sshbuf_consume(struct sshbuf *buf, size_t len); 148 149 /* 150 * Consume len bytes from the end of buf 151 * Returns 0 on success, or a negative SSH_ERR_* error code on failure. 152 */ 153 int sshbuf_consume_end(struct sshbuf *buf, size_t len); 154 155 /* Extract or deposit some bytes */ 156 int sshbuf_get(struct sshbuf *buf, void *v, size_t len); 157 int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); 158 int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); 159 160 /* Append using a printf(3) format */ 161 int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) 162 __attribute__((format(printf, 2, 3))); 163 int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); 164 165 /* Functions to extract or store big-endian words of various sizes */ 166 int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); 167 int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); 168 int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); 169 int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); 170 int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); 171 int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); 172 int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); 173 int sshbuf_put_u8(struct sshbuf *buf, u_char val); 174 175 /* 176 * Functions to extract or store SSH wire encoded strings (u32 len || data) 177 * The "cstring" variants admit no \0 characters in the string contents. 178 * Caller must free *valp. 179 */ 180 int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); 181 int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); 182 int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); 183 int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); 184 int sshbuf_put_cstring(struct sshbuf *buf, const char *v); 185 int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); 186 187 /* 188 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to 189 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the 190 * next sshbuf-modifying function call. Caller does not free. 191 */ 192 int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, 193 size_t *lenp); 194 195 /* Skip past a string */ 196 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) 197 198 /* Another variant: "peeks" into the buffer without modifying it */ 199 int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, 200 size_t *lenp); 201 /* XXX peek_u8 / peek_u32 */ 202 203 /* 204 * Functions to extract or store SSH wire encoded bignums and elliptic 205 * curve points. 206 */ 207 int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); 208 int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, 209 const u_char **valp, size_t *lenp); 210 int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); 211 int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); 212 int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); 213 int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); 214 int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); 215 int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); 216 217 /* Dump the contents of the buffer in a human-readable format */ 218 void sshbuf_dump(struct sshbuf *buf, FILE *f); 219 220 /* Dump specified memory in a human-readable format */ 221 void sshbuf_dump_data(const void *s, size_t len, FILE *f); 222 223 /* Return the hexadecimal representation of the contents of the buffer */ 224 char *sshbuf_dtob16(struct sshbuf *buf); 225 226 /* Encode the contents of the buffer as base64 */ 227 char *sshbuf_dtob64(struct sshbuf *buf); 228 229 /* Decode base64 data and append it to the buffer */ 230 int sshbuf_b64tod(struct sshbuf *buf, const char *b64); 231 232 /* 233 * Duplicate the contents of a buffer to a string (caller to free). 234 * Returns NULL on buffer error, or if the buffer contains a premature 235 * nul character. 236 */ 237 char *sshbuf_dup_string(struct sshbuf *buf); 238 239 /* Macros for decoding/encoding integers */ 240 #define PEEK_U64(p) \ 241 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ 242 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ 243 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ 244 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ 245 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ 246 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ 247 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ 248 (u_int64_t)(((const u_char *)(p))[7])) 249 #define PEEK_U32(p) \ 250 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ 251 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ 252 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ 253 (u_int32_t)(((const u_char *)(p))[3])) 254 #define PEEK_U16(p) \ 255 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ 256 (u_int16_t)(((const u_char *)(p))[1])) 257 258 #define POKE_U64(p, v) \ 259 do { \ 260 const u_int64_t __v = (v); \ 261 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ 262 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ 263 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ 264 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ 265 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ 266 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ 267 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ 268 ((u_char *)(p))[7] = __v & 0xff; \ 269 } while (0) 270 #define POKE_U32(p, v) \ 271 do { \ 272 const u_int32_t __v = (v); \ 273 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ 274 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ 275 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ 276 ((u_char *)(p))[3] = __v & 0xff; \ 277 } while (0) 278 #define POKE_U16(p, v) \ 279 do { \ 280 const u_int16_t __v = (v); \ 281 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ 282 ((u_char *)(p))[1] = __v & 0xff; \ 283 } while (0) 284 285 /* Internal definitions follow. Exposed for regress tests */ 286 #ifdef SSHBUF_INTERNAL 287 288 /* 289 * Return the allocation size of buf 290 */ 291 size_t sshbuf_alloc(const struct sshbuf *buf); 292 293 /* 294 * Increment the reference count of buf. 295 */ 296 int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); 297 298 /* 299 * Return the parent buffer of buf, or NULL if it has no parent. 300 */ 301 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); 302 303 /* 304 * Return the reference count of buf 305 */ 306 u_int sshbuf_refcount(const struct sshbuf *buf); 307 308 # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ 309 # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ 310 # define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */ 311 312 /* # define SSHBUF_ABORT abort */ 313 /* # define SSHBUF_DEBUG */ 314 315 # ifndef SSHBUF_ABORT 316 # define SSHBUF_ABORT() 317 # endif 318 319 # ifdef SSHBUF_DEBUG 320 # define SSHBUF_TELL(what) do { \ 321 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \ 322 __FILE__, __LINE__, __func__, what, \ 323 buf->size, buf->alloc, buf->off, buf->max_size); \ 324 fflush(stdout); \ 325 } while (0) 326 # define SSHBUF_DBG(x) do { \ 327 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ 328 printf x; \ 329 printf("\n"); \ 330 fflush(stdout); \ 331 } while (0) 332 # else 333 # define SSHBUF_TELL(what) 334 # define SSHBUF_DBG(x) 335 # endif 336 #endif /* SSHBUF_INTERNAL */ 337 338 #endif /* _SSHBUF_H */ 339