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Diffstat (limited to '')
| -rw-r--r-- | sshbuf.h | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/sshbuf.h b/sshbuf.h new file mode 100644 index 0000000..2ad0e61 --- /dev/null +++ b/sshbuf.h @@ -0,0 +1,411 @@ +/* $OpenBSD: sshbuf.h,v 1.23 2020/06/22 05:54:10 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 <sys/types.h> +#include <stdarg.h> +#include <stdio.h> +#ifdef WITH_OPENSSL +# include <openssl/bn.h> +# ifdef OPENSSL_HAS_ECC +# include <openssl/ec.h> +# endif /* OPENSSL_HAS_ECC */ +#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 existing 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_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len); +int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, + const u_char **valp, size_t *lenp); +#ifdef WITH_OPENSSL +int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp); +int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v); +# ifdef OPENSSL_HAS_ECC +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); +# endif /* OPENSSL_HAS_ECC */ +#endif /* WITH_OPENSSL */ + +/* Dump the contents of the buffer in a human-readable format */ +void sshbuf_dump(const 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); +/* RFC4648 "base64url" encoding variant */ +int sshbuf_dtourlb64(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); + +/* + * Fill a buffer from a file descriptor or filename. Both allocate the + * buffer for the caller. + */ +int sshbuf_load_fd(int, struct sshbuf **) + __attribute__((__nonnull__ (2))); +int sshbuf_load_file(const char *, struct sshbuf **) + __attribute__((__nonnull__ (2))); + +/* + * Write a buffer to a path, creating/truncating as needed (mode 0644, + * subject to umask). The buffer contents are not modified. + */ +int sshbuf_write_file(const char *path, struct sshbuf *buf) + __attribute__((__nonnull__ (2))); + +/* 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 */ |