crypto/openssh/sshbuf.h

   1 /*      $OpenBSD: sshbuf.h,v 1.7 2016/05/02 08:49:03 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 #ifdef WITH_OPENSSL
  25 # include <openssl/bn.h>
  26 # ifdef OPENSSL_HAS_ECC
  27 #  include <openssl/ec.h>
  28 # endif /* OPENSSL_HAS_ECC */
  29 #endif /* WITH_OPENSSL */
  30
  31 #define SSHBUF_SIZE_MAX         0x8000000       /* Hard maximum size */
  32 #define SSHBUF_REFS_MAX         0x100000        /* Max child buffers */
  33 #define SSHBUF_MAX_BIGNUM       (16384 / 8)     /* Max bignum *bytes* */
  34 #define SSHBUF_MAX_ECPOINT      ((528 * 2 / 8) + 1) /* Max EC point *bytes* */
  35
  36 /*
  37  * NB. do not depend on the internals of this. It will be made opaque
  38  * one day.
  39  */
  40 struct sshbuf {
  41         u_char *d;              /* Data */
  42         const u_char *cd;       /* Const data */
  43         size_t off;             /* First available byte is buf->d + buf->off */
  44         size_t size;            /* Last byte is buf->d + buf->size - 1 */
  45         size_t max_size;        /* Maximum size of buffer */
  46         size_t alloc;           /* Total bytes allocated to buf->d */
  47         int readonly;           /* Refers to external, const data */
  48         int dont_free;          /* Kludge to support sshbuf_init */
  49         u_int refcount;         /* Tracks self and number of child buffers */
  50         struct sshbuf *parent;  /* If child, pointer to parent */
  51 };
  52
  53 #ifndef SSHBUF_NO_DEPREACTED
  54 /*
  55  * NB. Please do not use sshbuf_init() in new code. Please use sshbuf_new()
  56  * instead. sshbuf_init() is deprectated and will go away soon (it is
  57  * only included to allow compat with buffer_* in OpenSSH)
  58  */
  59 void sshbuf_init(struct sshbuf *buf);
  60 #endif
  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  * Reserve len bytes in buf.
 143  * Returns 0 on success and a pointer to the first reserved byte via the
 144  * optional dpp parameter or a negative * SSH_ERR_* error code on failure.
 145  */
 146 int     sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp);
 147
 148 /*
 149  * Consume len bytes from the start of buf
 150  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
 151  */
 152 int     sshbuf_consume(struct sshbuf *buf, size_t len);
 153
 154 /*
 155  * Consume len bytes from the end of buf
 156  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
 157  */
 158 int     sshbuf_consume_end(struct sshbuf *buf, size_t len);
 159
 160 /* Extract or deposit some bytes */
 161 int     sshbuf_get(struct sshbuf *buf, void *v, size_t len);
 162 int     sshbuf_put(struct sshbuf *buf, const void *v, size_t len);
 163 int     sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v);
 164
 165 /* Append using a printf(3) format */
 166 int     sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
 167             __attribute__((format(printf, 2, 3)));
 168 int     sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap);
 169
 170 /* Functions to extract or store big-endian words of various sizes */
 171 int     sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp);
 172 int     sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp);
 173 int     sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp);
 174 int     sshbuf_get_u8(struct sshbuf *buf, u_char *valp);
 175 int     sshbuf_put_u64(struct sshbuf *buf, u_int64_t val);
 176 int     sshbuf_put_u32(struct sshbuf *buf, u_int32_t val);
 177 int     sshbuf_put_u16(struct sshbuf *buf, u_int16_t val);
 178 int     sshbuf_put_u8(struct sshbuf *buf, u_char val);
 179
 180 /*
 181  * Functions to extract or store SSH wire encoded strings (u32 len || data)
 182  * The "cstring" variants admit no \0 characters in the string contents.
 183  * Caller must free *valp.
 184  */
 185 int     sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp);
 186 int     sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp);
 187 int     sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v);
 188 int     sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len);
 189 int     sshbuf_put_cstring(struct sshbuf *buf, const char *v);
 190 int     sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v);
 191
 192 /*
 193  * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to
 194  * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the
 195  * next sshbuf-modifying function call. Caller does not free.
 196  */
 197 int     sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp,
 198             size_t *lenp);
 199
 200 /* Skip past a string */
 201 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL)
 202
 203 /* Another variant: "peeks" into the buffer without modifying it */
 204 int     sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
 205             size_t *lenp);
 206
 207 /*
 208  * Functions to extract or store SSH wire encoded bignums and elliptic
 209  * curve points.
 210  */
 211 int     sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
 212 int     sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
 213             const u_char **valp, size_t *lenp);
 214 #ifdef WITH_OPENSSL
 215 int     sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v);
 216 int     sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v);
 217 int     sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v);
 218 int     sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v);
 219 # ifdef OPENSSL_HAS_ECC
 220 int     sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g);
 221 int     sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v);
 222 int     sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g);
 223 int     sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v);
 224 # endif /* OPENSSL_HAS_ECC */
 225 #endif /* WITH_OPENSSL */
 226
 227 /* Dump the contents of the buffer in a human-readable format */
 228 void    sshbuf_dump(struct sshbuf *buf, FILE *f);
 229
 230 /* Dump specified memory in a human-readable format */
 231 void    sshbuf_dump_data(const void *s, size_t len, FILE *f);
 232
 233 /* Return the hexadecimal representation of the contents of the buffer */
 234 char    *sshbuf_dtob16(struct sshbuf *buf);
 235
 236 /* Encode the contents of the buffer as base64 */
 237 char    *sshbuf_dtob64(struct sshbuf *buf);
 238
 239 /* Decode base64 data and append it to the buffer */
 240 int     sshbuf_b64tod(struct sshbuf *buf, const char *b64);
 241
 242 /*
 243  * Duplicate the contents of a buffer to a string (caller to free).
 244  * Returns NULL on buffer error, or if the buffer contains a premature
 245  * nul character.
 246  */
 247 char *sshbuf_dup_string(struct sshbuf *buf);
 248
 249 /* Macros for decoding/encoding integers */
 250 #define PEEK_U64(p) \
 251         (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \
 252          ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \
 253          ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \
 254          ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \
 255          ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \
 256          ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \
 257          ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \
 258           (u_int64_t)(((const u_char *)(p))[7]))
 259 #define PEEK_U32(p) \
 260         (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \
 261          ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \
 262          ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \
 263           (u_int32_t)(((const u_char *)(p))[3]))
 264 #define PEEK_U16(p) \
 265         (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \
 266           (u_int16_t)(((const u_char *)(p))[1]))
 267
 268 #define POKE_U64(p, v) \
 269         do { \
 270                 const u_int64_t __v = (v); \
 271                 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \
 272                 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \
 273                 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \
 274                 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \
 275                 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \
 276                 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \
 277                 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \
 278                 ((u_char *)(p))[7] = __v & 0xff; \
 279         } while (0)
 280 #define POKE_U32(p, v) \
 281         do { \
 282                 const u_int32_t __v = (v); \
 283                 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \
 284                 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \
 285                 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \
 286                 ((u_char *)(p))[3] = __v & 0xff; \
 287         } while (0)
 288 #define POKE_U16(p, v) \
 289         do { \
 290                 const u_int16_t __v = (v); \
 291                 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \
 292                 ((u_char *)(p))[1] = __v & 0xff; \
 293         } while (0)
 294
 295 /* Internal definitions follow. Exposed for regress tests */
 296 #ifdef SSHBUF_INTERNAL
 297
 298 /*
 299  * Return the allocation size of buf
 300  */
 301 size_t  sshbuf_alloc(const struct sshbuf *buf);
 302
 303 /*
 304  * Increment the reference count of buf.
 305  */
 306 int     sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent);
 307
 308 /*
 309  * Return the parent buffer of buf, or NULL if it has no parent.
 310  */
 311 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf);
 312
 313 /*
 314  * Return the reference count of buf
 315  */
 316 u_int   sshbuf_refcount(const struct sshbuf *buf);
 317
 318 # define SSHBUF_SIZE_INIT       256             /* Initial allocation */
 319 # define SSHBUF_SIZE_INC        256             /* Preferred increment length */
 320 # define SSHBUF_PACK_MIN        8192            /* Minimim packable offset */
 321
 322 /* # define SSHBUF_ABORT abort */
 323 /* # define SSHBUF_DEBUG */
 324
 325 # ifndef SSHBUF_ABORT
 326 #  define SSHBUF_ABORT()
 327 # endif
 328
 329 # ifdef SSHBUF_DEBUG
 330 #  define SSHBUF_TELL(what) do { \
 331                 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
 332                     __FILE__, __LINE__, __func__, what, \
 333                     buf->size, buf->alloc, buf->off, buf->max_size); \
 334                 fflush(stdout); \
 335         } while (0)
 336 #  define SSHBUF_DBG(x) do { \
 337                 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
 338                 printf x; \
 339                 printf("\n"); \
 340                 fflush(stdout); \
 341         } while (0)
 342 # else
 343 #  define SSHBUF_TELL(what)
 344 #  define SSHBUF_DBG(x)
 345 # endif
 346 #endif /* SSHBUF_INTERNAL */
 347
 348 #endif /* _SSHBUF_H */