зеркало из https://github.com/Azure/sonic-openssh.git
147 строки
3.9 KiB
C
147 строки
3.9 KiB
C
/* $OpenBSD: bufec.c,v 1.2 2013/05/17 00:13:13 djm Exp $ */
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/*
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* Copyright (c) 2010 Damien Miller <djm@mindrot.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#ifdef OPENSSL_HAS_ECC
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#include <sys/types.h>
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#include <openssl/bn.h>
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#include <openssl/ec.h>
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#include <string.h>
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#include <stdarg.h>
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#include "xmalloc.h"
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#include "buffer.h"
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#include "log.h"
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#include "misc.h"
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/*
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* Maximum supported EC GFp field length is 528 bits. SEC1 uncompressed
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* encoding represents this as two bitstring points that should each
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* be no longer than the field length, SEC1 specifies a 1 byte
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* point type header.
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* Being paranoid here may insulate us to parsing problems in
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* EC_POINT_oct2point.
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*/
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#define BUFFER_MAX_ECPOINT_LEN ((528*2 / 8) + 1)
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/*
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* Append an EC_POINT to the buffer as a string containing a SEC1 encoded
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* uncompressed point. Fortunately OpenSSL handles the gory details for us.
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*/
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int
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buffer_put_ecpoint_ret(Buffer *buffer, const EC_GROUP *curve,
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const EC_POINT *point)
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{
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u_char *buf = NULL;
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size_t len;
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BN_CTX *bnctx;
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int ret = -1;
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/* Determine length */
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if ((bnctx = BN_CTX_new()) == NULL)
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fatal("%s: BN_CTX_new failed", __func__);
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len = EC_POINT_point2oct(curve, point, POINT_CONVERSION_UNCOMPRESSED,
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NULL, 0, bnctx);
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if (len > BUFFER_MAX_ECPOINT_LEN) {
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error("%s: giant EC point: len = %lu (max %u)",
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__func__, (u_long)len, BUFFER_MAX_ECPOINT_LEN);
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goto out;
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}
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/* Convert */
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buf = xmalloc(len);
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if (EC_POINT_point2oct(curve, point, POINT_CONVERSION_UNCOMPRESSED,
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buf, len, bnctx) != len) {
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error("%s: EC_POINT_point2oct length mismatch", __func__);
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goto out;
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}
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/* Append */
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buffer_put_string(buffer, buf, len);
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ret = 0;
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out:
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if (buf != NULL) {
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bzero(buf, len);
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free(buf);
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}
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BN_CTX_free(bnctx);
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return ret;
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}
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void
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buffer_put_ecpoint(Buffer *buffer, const EC_GROUP *curve,
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const EC_POINT *point)
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{
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if (buffer_put_ecpoint_ret(buffer, curve, point) == -1)
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fatal("%s: buffer error", __func__);
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}
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int
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buffer_get_ecpoint_ret(Buffer *buffer, const EC_GROUP *curve,
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EC_POINT *point)
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{
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u_char *buf;
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u_int len;
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BN_CTX *bnctx;
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int ret = -1;
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if ((buf = buffer_get_string_ret(buffer, &len)) == NULL) {
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error("%s: invalid point", __func__);
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return -1;
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}
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if ((bnctx = BN_CTX_new()) == NULL)
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fatal("%s: BN_CTX_new failed", __func__);
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if (len > BUFFER_MAX_ECPOINT_LEN) {
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error("%s: EC_POINT too long: %u > max %u", __func__,
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len, BUFFER_MAX_ECPOINT_LEN);
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goto out;
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}
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if (len == 0) {
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error("%s: EC_POINT buffer is empty", __func__);
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goto out;
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}
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if (buf[0] != POINT_CONVERSION_UNCOMPRESSED) {
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error("%s: EC_POINT is in an incorrect form: "
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"0x%02x (want 0x%02x)", __func__, buf[0],
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POINT_CONVERSION_UNCOMPRESSED);
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goto out;
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}
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if (EC_POINT_oct2point(curve, point, buf, len, bnctx) != 1) {
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error("buffer_get_bignum2_ret: BN_bin2bn failed");
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goto out;
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}
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/* EC_POINT_oct2point verifies that the point is on the curve for us */
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ret = 0;
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out:
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BN_CTX_free(bnctx);
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bzero(buf, len);
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free(buf);
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return ret;
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}
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void
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buffer_get_ecpoint(Buffer *buffer, const EC_GROUP *curve,
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EC_POINT *point)
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{
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if (buffer_get_ecpoint_ret(buffer, curve, point) == -1)
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fatal("%s: buffer error", __func__);
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}
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#endif /* OPENSSL_HAS_ECC */
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