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/* $OpenBSD: sshbuf-getput-crypto.c,v 1.2 2014/06/18 15:42:09 naddy 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.
*/
#define SSHBUF_INTERNAL
#include "includes.h"
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <openssl/bn.h>
#include <openssl/ec.h>
#include "ssherr.h"
#include "sshbuf.h"
int
sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v)
{
const u_char *d;
size_t len;
int r;
if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
return r;
/* Refuse negative (MSB set) bignums */
if ((len != 0 && (*d & 0x80) != 0))
return SSH_ERR_BIGNUM_IS_NEGATIVE;
/* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
if (len > SSHBUF_MAX_BIGNUM + 1 ||
(len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
return SSH_ERR_BIGNUM_TOO_LARGE;
if (v != NULL && BN_bin2bn(d, len, v) == NULL)
return SSH_ERR_ALLOC_FAIL;
/* Consume the string */
if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
/* Shouldn't happen */
SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
int
sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v)
{
const u_char *d = sshbuf_ptr(buf);
u_int16_t len_bits;
size_t len_bytes;
/* Length in bits */
if (sshbuf_len(buf) < 2)
return SSH_ERR_MESSAGE_INCOMPLETE;
len_bits = PEEK_U16(d);
len_bytes = (len_bits + 7) >> 3;
if (len_bytes > SSHBUF_MAX_BIGNUM)
return SSH_ERR_BIGNUM_TOO_LARGE;
if (sshbuf_len(buf) < 2 + len_bytes)
return SSH_ERR_MESSAGE_INCOMPLETE;
if (v != NULL && BN_bin2bn(d + 2, len_bytes, v) == NULL)
return SSH_ERR_ALLOC_FAIL;
if (sshbuf_consume(buf, 2 + len_bytes) != 0) {
SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
#ifdef OPENSSL_HAS_ECC
static int
get_ec(const u_char *d, size_t len, EC_POINT *v, const EC_GROUP *g)
{
/* Refuse overlong bignums */
if (len == 0 || len > SSHBUF_MAX_ECPOINT)
return SSH_ERR_ECPOINT_TOO_LARGE;
/* Only handle uncompressed points */
if (*d != POINT_CONVERSION_UNCOMPRESSED)
return SSH_ERR_INVALID_FORMAT;
if (v != NULL && EC_POINT_oct2point(g, v, d, len, NULL) != 1)
return SSH_ERR_INVALID_FORMAT; /* XXX assumption */
return 0;
}
int
sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g)
{
const u_char *d;
size_t len;
int r;
if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
return r;
if ((r = get_ec(d, len, v, g)) != 0)
return r;
/* Skip string */
if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
/* Shouldn't happen */
SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
int
sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v)
{
EC_POINT *pt = EC_POINT_new(EC_KEY_get0_group(v));
int r;
const u_char *d;
size_t len;
if (pt == NULL) {
SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
return SSH_ERR_ALLOC_FAIL;
}
if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0) {
EC_POINT_free(pt);
return r;
}
if ((r = get_ec(d, len, pt, EC_KEY_get0_group(v))) != 0) {
EC_POINT_free(pt);
return r;
}
if (EC_KEY_set_public_key(v, pt) != 1) {
EC_POINT_free(pt);
return SSH_ERR_ALLOC_FAIL; /* XXX assumption */
}
EC_POINT_free(pt);
/* Skip string */
if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
/* Shouldn't happen */
SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
#endif /* OPENSSL_HAS_ECC */
int
sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v)
{
u_char d[SSHBUF_MAX_BIGNUM + 1];
int len = BN_num_bytes(v), prepend = 0, r;
if (len < 0 || len > SSHBUF_MAX_BIGNUM)
return SSH_ERR_INVALID_ARGUMENT;
*d = '\0';
if (BN_bn2bin(v, d + 1) != len)
return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
/* If MSB is set, prepend a \0 */
if (len > 0 && (d[1] & 0x80) != 0)
prepend = 1;
if ((r = sshbuf_put_string(buf, d + 1 - prepend, len + prepend)) < 0) {
bzero(d, sizeof(d));
return r;
}
bzero(d, sizeof(d));
return 0;
}
int
sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v)
{
int r, len_bits = BN_num_bits(v);
size_t len_bytes = (len_bits + 7) / 8;
u_char d[SSHBUF_MAX_BIGNUM], *dp;
if (len_bits < 0 || len_bytes > SSHBUF_MAX_BIGNUM)
return SSH_ERR_INVALID_ARGUMENT;
if (BN_bn2bin(v, d) != (int)len_bytes)
return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
if ((r = sshbuf_reserve(buf, len_bytes + 2, &dp)) < 0) {
bzero(d, sizeof(d));
return r;
}
POKE_U16(dp, len_bits);
memcpy(dp + 2, d, len_bytes);
bzero(d, sizeof(d));
return 0;
}
#ifdef OPENSSL_HAS_ECC
int
sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g)
{
u_char d[SSHBUF_MAX_ECPOINT];
BN_CTX *bn_ctx;
size_t len;
int ret;
if ((bn_ctx = BN_CTX_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((len = EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
NULL, 0, bn_ctx)) > SSHBUF_MAX_ECPOINT) {
BN_CTX_free(bn_ctx);
return SSH_ERR_INVALID_ARGUMENT;
}
if (EC_POINT_point2oct(g, v, POINT_CONVERSION_UNCOMPRESSED,
d, len, bn_ctx) != len) {
BN_CTX_free(bn_ctx);
return SSH_ERR_INTERNAL_ERROR; /* Shouldn't happen */
}
BN_CTX_free(bn_ctx);
ret = sshbuf_put_string(buf, d, len);
bzero(d, len);
return ret;
}
int
sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v)
{
return sshbuf_put_ec(buf, EC_KEY_get0_public_key(v),
EC_KEY_get0_group(v));
}
#endif /* OPENSSL_HAS_ECC */
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