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-rw-r--r--sshbuf.h411
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+/* $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 */