upstream commit

fix ssh protocol 1, spotted by miod@
This commit is contained in:
djm@openbsd.org 2015-01-30 00:22:25 +00:00 committed by Damien Miller
parent 9ce86c926d
commit 25f5f78d8b
1 changed files with 20 additions and 9 deletions

29
kex.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: kex.c,v 1.104 2015/01/26 06:10:03 djm Exp $ */
/* $OpenBSD: kex.c,v 1.105 2015/01/30 00:22:25 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
*
@ -785,17 +785,27 @@ int
derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
u_int8_t cookie[8], u_int8_t id[16])
{
u_int8_t nbuf[2048], obuf[SSH_DIGEST_MAX_LENGTH];
u_int8_t hbuf[2048], sbuf[2048], obuf[SSH_DIGEST_MAX_LENGTH];
struct ssh_digest_ctx *hashctx = NULL;
size_t len;
size_t hlen, slen;
int r;
len = BN_num_bytes(host_modulus);
if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
hlen = BN_num_bytes(host_modulus);
slen = BN_num_bytes(server_modulus);
if (hlen < (512 / 8) || (u_int)hlen > sizeof(hbuf) ||
slen < (512 / 8) || (u_int)slen > sizeof(sbuf))
return SSH_ERR_KEY_BITS_MISMATCH;
if (BN_bn2bin(host_modulus, nbuf) <= 0 ||
(hashctx = ssh_digest_start(SSH_DIGEST_MD5)) == NULL ||
ssh_digest_update(hashctx, nbuf, len) != 0 ||
if (BN_bn2bin(host_modulus, hbuf) <= 0 ||
BN_bn2bin(server_modulus, sbuf) <= 0) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if ((hashctx = ssh_digest_start(SSH_DIGEST_MD5)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (ssh_digest_update(hashctx, hbuf, hlen) != 0 ||
ssh_digest_update(hashctx, sbuf, slen) != 0 ||
ssh_digest_update(hashctx, cookie, 8) != 0 ||
ssh_digest_final(hashctx, obuf, sizeof(obuf)) != 0) {
r = SSH_ERR_LIBCRYPTO_ERROR;
@ -805,7 +815,8 @@ derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
r = 0;
out:
ssh_digest_free(hashctx);
explicit_bzero(nbuf, sizeof(nbuf));
explicit_bzero(hbuf, sizeof(hbuf));
explicit_bzero(sbuf, sizeof(sbuf));
explicit_bzero(obuf, sizeof(obuf));
return r;
}