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, 42 insertions, 168 deletions

diff --git a/usr.bin/ssh/bufbn.c b/usr.bin/ssh/bufbn.c
index 301922a624b..0a519ed2d7b 100644
--- a/usr.bin/ssh/bufbn.c
+++ b/usr.bin/ssh/bufbn.c
@@ -1,227 +1,101 @@
-/* $OpenBSD: bufbn.c,v 1.11 2014/02/27 08:25:09 djm Exp $*/
+/* $OpenBSD: bufbn.c,v 1.12 2014/04/30 05:29:56 djm Exp $ */
+
 /*
- * Author: Tatu Ylonen <ylo@cs.hut.fi>
- * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- *                    All rights reserved
- * Auxiliary functions for storing and retrieving various data types to/from
- * Buffers.
- *
- * As far as I am concerned, the code I have written for this software
- * can be used freely for any purpose.  Any derived versions of this
- * software must be clearly marked as such, and if the derived work is
- * incompatible with the protocol description in the RFC file, it must be
- * called by a name other than "ssh" or "Secure Shell".
- *
- *
- * SSH2 packet format added by Markus Friedl
- * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2012 Damien Miller <djm@mindrot.org>
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
+ * 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.
  *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 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.
  */
 
-#include <sys/types.h>
-
-#include <openssl/bn.h>
+/* Emulation wrappers for legacy OpenSSH buffer API atop sshbuf */
 
-#include <string.h>
-#include <stdarg.h>
-#include <stdlib.h>
+#include <sys/types.h>
 
-#include "xmalloc.h"
 #include "buffer.h"
 #include "log.h"
-#include "misc.h"
+#include "ssherr.h"
 
-/*
- * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
- * by (bits+7)/8 bytes of binary data, msb first.
- */
 int
 buffer_put_bignum_ret(Buffer *buffer, const BIGNUM *value)
 {
-	int bits = BN_num_bits(value);
-	int bin_size = (bits + 7) / 8;
-	u_char *buf = xmalloc(bin_size);
-	int oi;
-	char msg[2];
-
-	/* Get the value of in binary */
-	oi = BN_bn2bin(value, buf);
-	if (oi != bin_size) {
-		error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d",
-		    oi, bin_size);
-		free(buf);
-		return (-1);
-	}
-
-	/* Store the number of bits in the buffer in two bytes, msb first. */
-	put_u16(msg, bits);
-	buffer_append(buffer, msg, 2);
-	/* Store the binary data. */
-	buffer_append(buffer, buf, oi);
-
-	explicit_bzero(buf, bin_size);
-	free(buf);
+	int ret;
 
-	return (0);
+	if ((ret = sshbuf_put_bignum1(buffer, value)) != 0) {
+		error("%s: %s", __func__, ssh_err(ret));
+		return -1;
+	}
+	return 0;
 }
 
 void
 buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
 {
 	if (buffer_put_bignum_ret(buffer, value) == -1)
-		fatal("buffer_put_bignum: buffer error");
+		fatal("%s: buffer error", __func__);
 }
 
-/*
- * Retrieves a BIGNUM from the buffer.
- */
 int
 buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value)
 {
-	u_int bits, bytes;
-	u_char buf[2], *bin;
+	int ret;
 
-	/* Get the number of bits. */
-	if (buffer_get_ret(buffer, (char *) buf, 2) == -1) {
-		error("buffer_get_bignum_ret: invalid length");
-		return (-1);
+	if ((ret = sshbuf_get_bignum1(buffer, value)) != 0) {
+		error("%s: %s", __func__, ssh_err(ret));
+		return -1;
 	}
-	bits = get_u16(buf);
-	if (bits > 65535-7) {
-		error("buffer_get_bignum_ret: cannot handle BN of size %d",
-		    bits);
-		return (-1);
-	}
-	/* Compute the number of binary bytes that follow. */
-	bytes = (bits + 7) / 8;
-	if (bytes > 8 * 1024) {
-		error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes);
-		return (-1);
-	}
-	if (buffer_len(buffer) < bytes) {
-		error("buffer_get_bignum_ret: input buffer too small");
-		return (-1);
-	}
-	bin = buffer_ptr(buffer);
-	if (BN_bin2bn(bin, bytes, value) == NULL) {
-		error("buffer_get_bignum_ret: BN_bin2bn failed");
-		return (-1);
-	}
-	if (buffer_consume_ret(buffer, bytes) == -1) {
-		error("buffer_get_bignum_ret: buffer_consume failed");
-		return (-1);
-	}
-	return (0);
+	return 0;
 }
 
 void
 buffer_get_bignum(Buffer *buffer, BIGNUM *value)
 {
 	if (buffer_get_bignum_ret(buffer, value) == -1)
-		fatal("buffer_get_bignum: buffer error");
+		fatal("%s: buffer error", __func__);
 }
 
-/*
- * Stores a BIGNUM in the buffer in SSH2 format.
- */
 int
 buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value)
 {
-	u_int bytes;
-	u_char *buf;
-	int oi;
-	u_int hasnohigh = 0;
-
-	if (BN_is_zero(value)) {
-		buffer_put_int(buffer, 0);
-		return 0;
-	}
-	if (value->neg) {
-		error("buffer_put_bignum2_ret: negative numbers not supported");
-		return (-1);
-	}
-	bytes = BN_num_bytes(value) + 1; /* extra padding byte */
-	if (bytes < 2) {
-		error("buffer_put_bignum2_ret: BN too small");
-		return (-1);
-	}
-	buf = xmalloc(bytes);
-	buf[0] = 0x00;
-	/* Get the value of in binary */
-	oi = BN_bn2bin(value, buf+1);
-	if (oi < 0 || (u_int)oi != bytes - 1) {
-		error("buffer_put_bignum2_ret: BN_bn2bin() failed: "
-		    "oi %d != bin_size %d", oi, bytes);
-		free(buf);
-		return (-1);
+	int ret;
+
+	if ((ret = sshbuf_put_bignum2(buffer, value)) != 0) {
+		error("%s: %s", __func__, ssh_err(ret));
+		return -1;
 	}
-	hasnohigh = (buf[1] & 0x80) ? 0 : 1;
-	buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
-	explicit_bzero(buf, bytes);
-	free(buf);
-	return (0);
+	return 0;
 }
 
 void
 buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
 {
 	if (buffer_put_bignum2_ret(buffer, value) == -1)
-		fatal("buffer_put_bignum2: buffer error");
+		fatal("%s: buffer error", __func__);
 }
 
 int
 buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value)
 {
-	u_int len;
-	u_char *bin;
+	int ret;
 
-	if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) {
-		error("buffer_get_bignum2_ret: invalid bignum");
-		return (-1);
-	}
-
-	if (len > 0 && (bin[0] & 0x80)) {
-		error("buffer_get_bignum2_ret: negative numbers not supported");
-		free(bin);
-		return (-1);
-	}
-	if (len > 8 * 1024) {
-		error("buffer_get_bignum2_ret: cannot handle BN of size %d",
-		    len);
-		free(bin);
-		return (-1);
-	}
-	if (BN_bin2bn(bin, len, value) == NULL) {
-		error("buffer_get_bignum2_ret: BN_bin2bn failed");
-		free(bin);
-		return (-1);
+	if ((ret = sshbuf_get_bignum2(buffer, value)) != 0) {
+		error("%s: %s", __func__, ssh_err(ret));
+		return -1;
 	}
-	free(bin);
-	return (0);
+	return 0;
 }
 
 void
 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
 {
 	if (buffer_get_bignum2_ret(buffer, value) == -1)
-		fatal("buffer_get_bignum2: buffer error");
+		fatal("%s: buffer error", __func__);
 }