/* $OpenBSD: sshbuf.h,v 1.18 2019/09/06 05:23:55 djm Exp $ */ /* * Copyright (c) 2011 Damien Miller * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #ifndef _SSHBUF_H #define _SSHBUF_H #include #include #include #ifdef WITH_OPENSSL #include #include #include #else /* OPENSSL */ #define BIGNUM void #define EC_KEY void #define EC_GROUP void #define EC_POINT void #endif /* WITH_OPENSSL */ #define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */ #define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */ #define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */ #define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */ /* * NB. do not depend on the internals of this. It will be made opaque * one day. */ struct sshbuf { u_char *d; /* Data */ const u_char *cd; /* Const data */ size_t off; /* First available byte is buf->d + buf->off */ size_t size; /* Last byte is buf->d + buf->size - 1 */ size_t max_size; /* Maximum size of buffer */ size_t alloc; /* Total bytes allocated to buf->d */ int readonly; /* Refers to external, const data */ int dont_free; /* Kludge to support sshbuf_init */ u_int refcount; /* Tracks self and number of child buffers */ struct sshbuf *parent; /* If child, pointer to parent */ }; /* * Create a new sshbuf buffer. * Returns pointer to buffer on success, or NULL on allocation failure. */ struct sshbuf *sshbuf_new(void); /* * Create a new, read-only sshbuf buffer from existing data. * Returns pointer to buffer on success, or NULL on allocation failure. */ struct sshbuf *sshbuf_from(const void *blob, size_t len); /* * Create a new, read-only sshbuf buffer from the contents of an existing * buffer. The contents of "buf" must not change in the lifetime of the * resultant buffer. * Returns pointer to buffer on success, or NULL on allocation failure. */ struct sshbuf *sshbuf_fromb(struct sshbuf *buf); /* * Create a new, read-only sshbuf buffer from the contents of a string in * an existing buffer (the string is consumed in the process). * The contents of "buf" must not change in the lifetime of the resultant * buffer. * Returns pointer to buffer on success, or NULL on allocation failure. */ int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp); /* * Clear and free buf */ void sshbuf_free(struct sshbuf *buf); /* * Reset buf, clearing its contents. NB. max_size is preserved. */ void sshbuf_reset(struct sshbuf *buf); /* * Return the maximum size of buf */ size_t sshbuf_max_size(const struct sshbuf *buf); /* * Set the maximum size of buf * Returns 0 on success, or a negative SSH_ERR_* error code on failure. */ int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size); /* * Returns the length of data in buf */ size_t sshbuf_len(const struct sshbuf *buf); /* * Returns number of bytes left in buffer before hitting max_size. */ size_t sshbuf_avail(const struct sshbuf *buf); /* * Returns a read-only pointer to the start of the data in buf */ const u_char *sshbuf_ptr(const struct sshbuf *buf); /* * Returns a mutable pointer to the start of the data in buf, or * NULL if the buffer is read-only. */ u_char *sshbuf_mutable_ptr(const struct sshbuf *buf); /* * Check whether a reservation of size len will succeed in buf * Safer to use than direct comparisons again sshbuf_avail as it copes * with unsigned overflows correctly. * Returns 0 on success, or a negative SSH_ERR_* error code on failure. */ int sshbuf_check_reserve(const struct sshbuf *buf, size_t len); /* * Preallocates len additional bytes in buf. * Useful for cases where the caller knows how many bytes will ultimately be * required to avoid realloc in the buffer code. * Returns 0 on success, or a negative SSH_ERR_* error code on failure. */ int sshbuf_allocate(struct sshbuf *buf, size_t len); /* * Reserve len bytes in buf. * Returns 0 on success and a pointer to the first reserved byte via the * optional dpp parameter or a negative * SSH_ERR_* error code on failure. */ int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp); /* * Consume len bytes from the start of buf * Returns 0 on success, or a negative SSH_ERR_* error code on failure. */ int sshbuf_consume(struct sshbuf *buf, size_t len); /* * Consume len bytes from the end of buf * Returns 0 on success, or a negative SSH_ERR_* error code on failure. */ int sshbuf_consume_end(struct sshbuf *buf, size_t len); /* Extract or deposit some bytes */ int sshbuf_get(struct sshbuf *buf, void *v, size_t len); int sshbuf_put(struct sshbuf *buf, const void *v, size_t len); int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v); /* Append using a printf(3) format */ int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) __attribute__((format(printf, 2, 3))); int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap); /* Functions to extract or store big-endian words of various sizes */ int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp); int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp); int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp); int sshbuf_get_u8(struct sshbuf *buf, u_char *valp); int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val); int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val); int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val); int sshbuf_put_u8(struct sshbuf *buf, u_char val); /* Functions to peek at the contents of a buffer without modifying it. */ int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, u_int64_t *valp); int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, u_int32_t *valp); int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, u_int16_t *valp); int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, u_char *valp); /* * Functions to poke values into an exisiting buffer (e.g. a length header * to a packet). The destination bytes must already exist in the buffer. */ int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val); int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val); int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val); int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val); int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len); /* * Functions to extract or store SSH wire encoded strings (u32 len || data) * The "cstring" variants admit no \0 characters in the string contents. * Caller must free *valp. */ int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp); int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp); int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v); int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len); int sshbuf_put_cstring(struct sshbuf *buf, const char *v); int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v); /* * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the * next sshbuf-modifying function call. Caller does not free. */ int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp); /* Skip past a string */ #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL) /* Another variant: "peeks" into the buffer without modifying it */ int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, size_t *lenp); /* * Functions to extract or store SSH wire encoded bignums and elliptic * curve points. */ int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp); int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g); int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v); int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g); int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v); /* Dump the contents of the buffer in a human-readable format */ void sshbuf_dump(struct sshbuf *buf, FILE *f); /* Dump specified memory in a human-readable format */ void sshbuf_dump_data(const void *s, size_t len, FILE *f); /* Return the hexadecimal representation of the contents of the buffer */ char *sshbuf_dtob16(struct sshbuf *buf); /* Encode the contents of the buffer as base64 */ char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap); int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap); /* Decode base64 data and append it to the buffer */ int sshbuf_b64tod(struct sshbuf *buf, const char *b64); /* * Tests whether the buffer contains the specified byte sequence at the * specified offset. Returns 0 on successful match, or a ssherr.h code * otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were * present but the buffer contents did not match those supplied. Zero- * length comparisons are not allowed. * * If sufficient data is present to make a comparison, then it is * performed with timing independent of the value of the data. If * insufficient data is present then the comparison is not attempted at * all. */ int sshbuf_cmp(const struct sshbuf *b, size_t offset, const void *s, size_t len); /* * Searches the buffer for the specified string. Returns 0 on success * and updates *offsetp with the offset of the first match, relative to * the start of the buffer. Otherwise sshbuf_find will return a ssherr.h * error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were * present in the buffer for a match to be possible but none was found. * Searches for zero-length data are not allowed. */ int sshbuf_find(const struct sshbuf *b, size_t start_offset, const void *s, size_t len, size_t *offsetp); /* * Duplicate the contents of a buffer to a string (caller to free). * Returns NULL on buffer error, or if the buffer contains a premature * nul character. */ char *sshbuf_dup_string(struct sshbuf *buf); /* Macros for decoding/encoding integers */ #define PEEK_U64(p) \ (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \ ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \ ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \ ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \ ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \ ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \ ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \ (u_int64_t)(((const u_char *)(p))[7])) #define PEEK_U32(p) \ (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \ ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \ ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \ (u_int32_t)(((const u_char *)(p))[3])) #define PEEK_U16(p) \ (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \ (u_int16_t)(((const u_char *)(p))[1])) #define POKE_U64(p, v) \ do { \ const u_int64_t __v = (v); \ ((u_char *)(p))[0] = (__v >> 56) & 0xff; \ ((u_char *)(p))[1] = (__v >> 48) & 0xff; \ ((u_char *)(p))[2] = (__v >> 40) & 0xff; \ ((u_char *)(p))[3] = (__v >> 32) & 0xff; \ ((u_char *)(p))[4] = (__v >> 24) & 0xff; \ ((u_char *)(p))[5] = (__v >> 16) & 0xff; \ ((u_char *)(p))[6] = (__v >> 8) & 0xff; \ ((u_char *)(p))[7] = __v & 0xff; \ } while (0) #define POKE_U32(p, v) \ do { \ const u_int32_t __v = (v); \ ((u_char *)(p))[0] = (__v >> 24) & 0xff; \ ((u_char *)(p))[1] = (__v >> 16) & 0xff; \ ((u_char *)(p))[2] = (__v >> 8) & 0xff; \ ((u_char *)(p))[3] = __v & 0xff; \ } while (0) #define POKE_U16(p, v) \ do { \ const u_int16_t __v = (v); \ ((u_char *)(p))[0] = (__v >> 8) & 0xff; \ ((u_char *)(p))[1] = __v & 0xff; \ } while (0) /* Internal definitions follow. Exposed for regress tests */ #ifdef SSHBUF_INTERNAL /* * Return the allocation size of buf */ size_t sshbuf_alloc(const struct sshbuf *buf); /* * Increment the reference count of buf. */ int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent); /* * Return the parent buffer of buf, or NULL if it has no parent. */ const struct sshbuf *sshbuf_parent(const struct sshbuf *buf); /* * Return the reference count of buf */ u_int sshbuf_refcount(const struct sshbuf *buf); # define SSHBUF_SIZE_INIT 256 /* Initial allocation */ # define SSHBUF_SIZE_INC 256 /* Preferred increment length */ # define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */ /* # define SSHBUF_ABORT abort */ /* # define SSHBUF_DEBUG */ # ifndef SSHBUF_ABORT # define SSHBUF_ABORT() # endif # ifdef SSHBUF_DEBUG # define SSHBUF_TELL(what) do { \ printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \ __FILE__, __LINE__, __func__, what, \ buf->size, buf->alloc, buf->off, buf->max_size); \ fflush(stdout); \ } while (0) # define SSHBUF_DBG(x) do { \ printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \ printf x; \ printf("\n"); \ fflush(stdout); \ } while (0) # else # define SSHBUF_TELL(what) # define SSHBUF_DBG(x) # endif #endif /* SSHBUF_INTERNAL */ #endif /* _SSHBUF_H */