New buffer API; the first installment of the conversion/replacement

of OpenSSH's internals to make them usable as a standalone library.

This includes a set of wrappers to make it compatible with the
existing buffer API so replacement can occur incrementally.

With and ok markus@

Thanks also to Ben Hawkes, David Tomaschik, Ivan Fratric, Matthew
Dempsky and Ron Bowes for a detailed review.

1 files changed, 325 insertions, 0 deletions

diff --git a/usr.bin/ssh/sshbuf.h b/usr.bin/ssh/sshbuf.h
new file mode 100644
index 00000000000..1d7da31c744
--- /dev/null
+++ b/usr.bin/ssh/sshbuf.h
@@ -0,0 +1,325 @@
+/*	$OpenBSD: sshbuf.h,v 1.1 2014/04/30 05:29:56 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>
+#include <openssl/bn.h>
+#include <openssl/ec.h>
+
+#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 */
+};
+
+#ifndef SSHBUF_NO_DEPREACTED
+/*
+ * NB. Please do not use sshbuf_init() in new code. Please use sshbuf_new()
+ * instead. sshbuf_init() is deprectated and will go away soon (it is
+ * only included to allow compat with buffer_* in OpenSSH)
+ */
+void sshbuf_init(struct sshbuf *buf);
+#endif
+
+/*
+ * 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 the data in buf
+ */
+const u_char *sshbuf_ptr(const struct sshbuf *buf);
+
+/*
+ * Returns a mutable pointer to the start of the 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);
+
+/*
+ * 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 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 *v);
+int	sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v);
+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_bignum2(struct sshbuf *buf, const BIGNUM *v);
+int	sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *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);
+int	sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
+
+/* Dump the contents of the buffer to stderr in a human-readable format */
+void	sshbuf_dump(struct sshbuf *buf, 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(struct sshbuf *buf);
+
+/* Decode base64 data and append it to the buffer */
+int	sshbuf_b64tod(struct sshbuf *buf, const char *b64);
+
+/* Macros for decoding/encoding integers */
+#define PEEK_U64(p) \
+	(((u_int64_t)(((u_char *)(p))[0]) << 56) | \
+	 ((u_int64_t)(((u_char *)(p))[1]) << 48) | \
+	 ((u_int64_t)(((u_char *)(p))[2]) << 40) | \
+	 ((u_int64_t)(((u_char *)(p))[3]) << 32) | \
+	 ((u_int64_t)(((u_char *)(p))[4]) << 24) | \
+	 ((u_int64_t)(((u_char *)(p))[5]) << 16) | \
+	 ((u_int64_t)(((u_char *)(p))[6]) << 8) | \
+	  (u_int64_t)(((u_char *)(p))[7]))
+#define PEEK_U32(p) \
+	(((u_int32_t)(((u_char *)(p))[0]) << 24) | \
+	 ((u_int32_t)(((u_char *)(p))[1]) << 16) | \
+	 ((u_int32_t)(((u_char *)(p))[2]) << 8) | \
+	  (u_int32_t)(((u_char *)(p))[3]))
+#define PEEK_U16(p) \
+	(((u_int16_t)(((u_char *)(p))[0]) << 8) | \
+	  (u_int16_t)(((u_char *)(p))[1]))
+
+#define POKE_U64(p, v) \
+	do { \
+		((u_char *)(p))[0] = (((u_int64_t)(v)) >> 56) & 0xff; \
+		((u_char *)(p))[1] = (((u_int64_t)(v)) >> 48) & 0xff; \
+		((u_char *)(p))[2] = (((u_int64_t)(v)) >> 40) & 0xff; \
+		((u_char *)(p))[3] = (((u_int64_t)(v)) >> 32) & 0xff; \
+		((u_char *)(p))[4] = (((u_int64_t)(v)) >> 24) & 0xff; \
+		((u_char *)(p))[5] = (((u_int64_t)(v)) >> 16) & 0xff; \
+		((u_char *)(p))[6] = (((u_int64_t)(v)) >> 8) & 0xff; \
+		((u_char *)(p))[7] = ((u_int64_t)(v)) & 0xff; \
+	} while (0)
+#define POKE_U32(p, v) \
+	do { \
+		((u_char *)(p))[0] = (((u_int64_t)(v)) >> 24) & 0xff; \
+		((u_char *)(p))[1] = (((u_int64_t)(v)) >> 16) & 0xff; \
+		((u_char *)(p))[2] = (((u_int64_t)(v)) >> 8) & 0xff; \
+		((u_char *)(p))[3] = ((u_int64_t)(v)) & 0xff; \
+	} while (0)
+#define POKE_U16(p, v) \
+	do { \
+		((u_char *)(p))[0] = (((u_int64_t)(v)) >> 8) & 0xff; \
+		((u_char *)(p))[1] = ((u_int64_t)(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 */