Release notes are available at https://www.openssh.com/txt/release-9.2 OpenSSH 9.2 contains fixes for two security problems and a memory safety problem. The memory safety problem is not believed to be exploitable. These fixes have already been committed to OpenSSH 9.1 in FreeBSD. Some other notable items from the release notes: * ssh(1): add a new EnableEscapeCommandline ssh_config(5) option that controls whether the client-side ~C escape sequence that provides a command-line is available. Among other things, the ~C command-line could be used to add additional port-forwards at runtime. * sshd(8): add support for channel inactivity timeouts via a new sshd_config(5) ChannelTimeout directive. This allows channels that have not seen traffic in a configurable interval to be automatically closed. Different timeouts may be applied to session, X11, agent and TCP forwarding channels. * sshd(8): add a sshd_config UnusedConnectionTimeout option to terminate client connections that have no open channels for a length of time. This complements the ChannelTimeout option above. * sshd(8): add a -V (version) option to sshd like the ssh client has. * scp(1), sftp(1): add a -X option to both scp(1) and sftp(1) to allow control over some SFTP protocol parameters: the copy buffer length and the number of in-flight requests, both of which are used during upload/download. Previously these could be controlled in sftp(1) only. This makes them available in both SFTP protocol clients using the same option character sequence. * ssh-keyscan(1): allow scanning of complete CIDR address ranges, e.g. "ssh-keyscan 192.168.0.0/24". If a CIDR range is passed, then it will be expanded to all possible addresses in the range including the all-0s and all-1s addresses. bz#976 * ssh(1): support dynamic remote port forwarding in escape command-line's -R processing. bz#3499 MFC after: 1 week Sponsored by: The FreeBSD Foundation
458 lines
12 KiB
C
458 lines
12 KiB
C
/* $OpenBSD: ssh-dss.c,v 1.48 2022/10/28 00:44:44 djm Exp $ */
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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#ifdef WITH_OPENSSL
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#include <sys/types.h>
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#include <openssl/bn.h>
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#include <openssl/dsa.h>
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#include <openssl/evp.h>
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#include <stdarg.h>
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#include <string.h>
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#include "sshbuf.h"
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#include "compat.h"
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#include "ssherr.h"
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#include "digest.h"
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#define SSHKEY_INTERNAL
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#include "sshkey.h"
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#include "openbsd-compat/openssl-compat.h"
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#define INTBLOB_LEN 20
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#define SIGBLOB_LEN (2*INTBLOB_LEN)
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static u_int
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ssh_dss_size(const struct sshkey *key)
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{
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const BIGNUM *dsa_p;
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if (key->dsa == NULL)
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return 0;
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DSA_get0_pqg(key->dsa, &dsa_p, NULL, NULL);
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return BN_num_bits(dsa_p);
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}
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static int
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ssh_dss_alloc(struct sshkey *k)
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{
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if ((k->dsa = DSA_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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return 0;
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}
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static void
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ssh_dss_cleanup(struct sshkey *k)
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{
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DSA_free(k->dsa);
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k->dsa = NULL;
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}
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static int
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ssh_dss_equal(const struct sshkey *a, const struct sshkey *b)
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{
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const BIGNUM *dsa_p_a, *dsa_q_a, *dsa_g_a, *dsa_pub_key_a;
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const BIGNUM *dsa_p_b, *dsa_q_b, *dsa_g_b, *dsa_pub_key_b;
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if (a->dsa == NULL || b->dsa == NULL)
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return 0;
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DSA_get0_pqg(a->dsa, &dsa_p_a, &dsa_q_a, &dsa_g_a);
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DSA_get0_pqg(b->dsa, &dsa_p_b, &dsa_q_b, &dsa_g_b);
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DSA_get0_key(a->dsa, &dsa_pub_key_a, NULL);
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DSA_get0_key(b->dsa, &dsa_pub_key_b, NULL);
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if (dsa_p_a == NULL || dsa_p_b == NULL ||
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dsa_q_a == NULL || dsa_q_b == NULL ||
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dsa_g_a == NULL || dsa_g_b == NULL ||
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dsa_pub_key_a == NULL || dsa_pub_key_b == NULL)
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return 0;
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if (BN_cmp(dsa_p_a, dsa_p_b) != 0)
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return 0;
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if (BN_cmp(dsa_q_a, dsa_q_b) != 0)
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return 0;
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if (BN_cmp(dsa_g_a, dsa_g_b) != 0)
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return 0;
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if (BN_cmp(dsa_pub_key_a, dsa_pub_key_b) != 0)
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return 0;
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return 1;
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}
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static int
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ssh_dss_serialize_public(const struct sshkey *key, struct sshbuf *b,
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enum sshkey_serialize_rep opts)
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{
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int r;
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const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
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if (key->dsa == NULL)
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return SSH_ERR_INVALID_ARGUMENT;
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DSA_get0_pqg(key->dsa, &dsa_p, &dsa_q, &dsa_g);
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DSA_get0_key(key->dsa, &dsa_pub_key, NULL);
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if (dsa_p == NULL || dsa_q == NULL ||
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dsa_g == NULL || dsa_pub_key == NULL)
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return SSH_ERR_INTERNAL_ERROR;
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if ((r = sshbuf_put_bignum2(b, dsa_p)) != 0 ||
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(r = sshbuf_put_bignum2(b, dsa_q)) != 0 ||
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(r = sshbuf_put_bignum2(b, dsa_g)) != 0 ||
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(r = sshbuf_put_bignum2(b, dsa_pub_key)) != 0)
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return r;
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return 0;
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}
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static int
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ssh_dss_serialize_private(const struct sshkey *key, struct sshbuf *b,
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enum sshkey_serialize_rep opts)
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{
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int r;
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const BIGNUM *dsa_priv_key;
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DSA_get0_key(key->dsa, NULL, &dsa_priv_key);
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if (!sshkey_is_cert(key)) {
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if ((r = ssh_dss_serialize_public(key, b, opts)) != 0)
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return r;
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}
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if ((r = sshbuf_put_bignum2(b, dsa_priv_key)) != 0)
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return r;
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return 0;
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}
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static int
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ssh_dss_generate(struct sshkey *k, int bits)
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{
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DSA *private;
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if (bits != 1024)
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return SSH_ERR_KEY_LENGTH;
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if ((private = DSA_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if (!DSA_generate_parameters_ex(private, bits, NULL, 0, NULL,
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NULL, NULL) || !DSA_generate_key(private)) {
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DSA_free(private);
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return SSH_ERR_LIBCRYPTO_ERROR;
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}
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k->dsa = private;
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return 0;
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}
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static int
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ssh_dss_copy_public(const struct sshkey *from, struct sshkey *to)
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{
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const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
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BIGNUM *dsa_p_dup = NULL, *dsa_q_dup = NULL, *dsa_g_dup = NULL;
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BIGNUM *dsa_pub_key_dup = NULL;
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int r = SSH_ERR_INTERNAL_ERROR;
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DSA_get0_pqg(from->dsa, &dsa_p, &dsa_q, &dsa_g);
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DSA_get0_key(from->dsa, &dsa_pub_key, NULL);
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if ((dsa_p_dup = BN_dup(dsa_p)) == NULL ||
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(dsa_q_dup = BN_dup(dsa_q)) == NULL ||
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(dsa_g_dup = BN_dup(dsa_g)) == NULL ||
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(dsa_pub_key_dup = BN_dup(dsa_pub_key)) == NULL) {
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r = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if (!DSA_set0_pqg(to->dsa, dsa_p_dup, dsa_q_dup, dsa_g_dup)) {
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r = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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dsa_p_dup = dsa_q_dup = dsa_g_dup = NULL; /* transferred */
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if (!DSA_set0_key(to->dsa, dsa_pub_key_dup, NULL)) {
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r = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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dsa_pub_key_dup = NULL; /* transferred */
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/* success */
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r = 0;
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out:
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BN_clear_free(dsa_p_dup);
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BN_clear_free(dsa_q_dup);
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BN_clear_free(dsa_g_dup);
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BN_clear_free(dsa_pub_key_dup);
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return r;
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}
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static int
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ssh_dss_deserialize_public(const char *ktype, struct sshbuf *b,
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struct sshkey *key)
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{
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int ret = SSH_ERR_INTERNAL_ERROR;
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BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL, *dsa_pub_key = NULL;
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if (sshbuf_get_bignum2(b, &dsa_p) != 0 ||
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sshbuf_get_bignum2(b, &dsa_q) != 0 ||
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sshbuf_get_bignum2(b, &dsa_g) != 0 ||
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sshbuf_get_bignum2(b, &dsa_pub_key) != 0) {
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ret = SSH_ERR_INVALID_FORMAT;
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goto out;
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}
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if (!DSA_set0_pqg(key->dsa, dsa_p, dsa_q, dsa_g)) {
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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dsa_p = dsa_q = dsa_g = NULL; /* transferred */
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if (!DSA_set0_key(key->dsa, dsa_pub_key, NULL)) {
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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dsa_pub_key = NULL; /* transferred */
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#ifdef DEBUG_PK
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DSA_print_fp(stderr, key->dsa, 8);
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#endif
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/* success */
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ret = 0;
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out:
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BN_clear_free(dsa_p);
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BN_clear_free(dsa_q);
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BN_clear_free(dsa_g);
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BN_clear_free(dsa_pub_key);
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return ret;
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}
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static int
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ssh_dss_deserialize_private(const char *ktype, struct sshbuf *b,
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struct sshkey *key)
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{
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int r;
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BIGNUM *dsa_priv_key = NULL;
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if (!sshkey_is_cert(key)) {
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if ((r = ssh_dss_deserialize_public(ktype, b, key)) != 0)
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return r;
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}
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if ((r = sshbuf_get_bignum2(b, &dsa_priv_key)) != 0)
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return r;
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if (!DSA_set0_key(key->dsa, NULL, dsa_priv_key)) {
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BN_clear_free(dsa_priv_key);
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return SSH_ERR_LIBCRYPTO_ERROR;
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}
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return 0;
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}
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static int
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ssh_dss_sign(struct sshkey *key,
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u_char **sigp, size_t *lenp,
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const u_char *data, size_t datalen,
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const char *alg, const char *sk_provider, const char *sk_pin, u_int compat)
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{
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DSA_SIG *sig = NULL;
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const BIGNUM *sig_r, *sig_s;
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u_char digest[SSH_DIGEST_MAX_LENGTH], sigblob[SIGBLOB_LEN];
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size_t rlen, slen, len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
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struct sshbuf *b = NULL;
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int ret = SSH_ERR_INVALID_ARGUMENT;
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if (lenp != NULL)
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*lenp = 0;
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if (sigp != NULL)
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*sigp = NULL;
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if (key == NULL || key->dsa == NULL ||
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sshkey_type_plain(key->type) != KEY_DSA)
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return SSH_ERR_INVALID_ARGUMENT;
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if (dlen == 0)
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return SSH_ERR_INTERNAL_ERROR;
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if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
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digest, sizeof(digest))) != 0)
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goto out;
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if ((sig = DSA_do_sign(digest, dlen, key->dsa)) == NULL) {
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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DSA_SIG_get0(sig, &sig_r, &sig_s);
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rlen = BN_num_bytes(sig_r);
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slen = BN_num_bytes(sig_s);
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if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
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ret = SSH_ERR_INTERNAL_ERROR;
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goto out;
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}
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explicit_bzero(sigblob, SIGBLOB_LEN);
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BN_bn2bin(sig_r, sigblob + SIGBLOB_LEN - INTBLOB_LEN - rlen);
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BN_bn2bin(sig_s, sigblob + SIGBLOB_LEN - slen);
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if ((b = sshbuf_new()) == NULL) {
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ret = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 ||
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(ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
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goto out;
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len = sshbuf_len(b);
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if (sigp != NULL) {
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if ((*sigp = malloc(len)) == NULL) {
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ret = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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memcpy(*sigp, sshbuf_ptr(b), len);
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}
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if (lenp != NULL)
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*lenp = len;
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ret = 0;
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out:
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explicit_bzero(digest, sizeof(digest));
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DSA_SIG_free(sig);
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sshbuf_free(b);
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return ret;
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}
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static int
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ssh_dss_verify(const struct sshkey *key,
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const u_char *sig, size_t siglen,
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const u_char *data, size_t dlen, const char *alg, u_int compat,
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struct sshkey_sig_details **detailsp)
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{
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DSA_SIG *dsig = NULL;
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BIGNUM *sig_r = NULL, *sig_s = NULL;
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u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob = NULL;
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size_t len, hlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
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int ret = SSH_ERR_INTERNAL_ERROR;
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struct sshbuf *b = NULL;
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char *ktype = NULL;
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if (key == NULL || key->dsa == NULL ||
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sshkey_type_plain(key->type) != KEY_DSA ||
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sig == NULL || siglen == 0)
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return SSH_ERR_INVALID_ARGUMENT;
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if (hlen == 0)
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return SSH_ERR_INTERNAL_ERROR;
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/* fetch signature */
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if ((b = sshbuf_from(sig, siglen)) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
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sshbuf_get_string(b, &sigblob, &len) != 0) {
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ret = SSH_ERR_INVALID_FORMAT;
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goto out;
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}
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if (strcmp("ssh-dss", ktype) != 0) {
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ret = SSH_ERR_KEY_TYPE_MISMATCH;
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goto out;
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}
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if (sshbuf_len(b) != 0) {
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ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
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goto out;
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}
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if (len != SIGBLOB_LEN) {
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ret = SSH_ERR_INVALID_FORMAT;
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goto out;
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}
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/* parse signature */
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if ((dsig = DSA_SIG_new()) == NULL ||
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(sig_r = BN_new()) == NULL ||
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(sig_s = BN_new()) == NULL) {
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ret = SSH_ERR_ALLOC_FAIL;
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goto out;
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}
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if ((BN_bin2bn(sigblob, INTBLOB_LEN, sig_r) == NULL) ||
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(BN_bin2bn(sigblob + INTBLOB_LEN, INTBLOB_LEN, sig_s) == NULL)) {
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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if (!DSA_SIG_set0(dsig, sig_r, sig_s)) {
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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sig_r = sig_s = NULL; /* transferred */
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/* sha1 the data */
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if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, dlen,
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digest, sizeof(digest))) != 0)
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goto out;
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switch (DSA_do_verify(digest, hlen, dsig, key->dsa)) {
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case 1:
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ret = 0;
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break;
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case 0:
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ret = SSH_ERR_SIGNATURE_INVALID;
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goto out;
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default:
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ret = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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out:
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explicit_bzero(digest, sizeof(digest));
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DSA_SIG_free(dsig);
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BN_clear_free(sig_r);
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BN_clear_free(sig_s);
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sshbuf_free(b);
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free(ktype);
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if (sigblob != NULL)
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freezero(sigblob, len);
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return ret;
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}
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static const struct sshkey_impl_funcs sshkey_dss_funcs = {
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/* .size = */ ssh_dss_size,
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/* .alloc = */ ssh_dss_alloc,
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/* .cleanup = */ ssh_dss_cleanup,
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/* .equal = */ ssh_dss_equal,
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/* .ssh_serialize_public = */ ssh_dss_serialize_public,
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/* .ssh_deserialize_public = */ ssh_dss_deserialize_public,
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/* .ssh_serialize_private = */ ssh_dss_serialize_private,
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/* .ssh_deserialize_private = */ ssh_dss_deserialize_private,
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/* .generate = */ ssh_dss_generate,
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/* .copy_public = */ ssh_dss_copy_public,
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/* .sign = */ ssh_dss_sign,
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/* .verify = */ ssh_dss_verify,
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};
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const struct sshkey_impl sshkey_dss_impl = {
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/* .name = */ "ssh-dss",
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/* .shortname = */ "DSA",
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/* .sigalg = */ NULL,
|
|
/* .type = */ KEY_DSA,
|
|
/* .nid = */ 0,
|
|
/* .cert = */ 0,
|
|
/* .sigonly = */ 0,
|
|
/* .keybits = */ 0,
|
|
/* .funcs = */ &sshkey_dss_funcs,
|
|
};
|
|
|
|
const struct sshkey_impl sshkey_dsa_cert_impl = {
|
|
/* .name = */ "ssh-dss-cert-v01@openssh.com",
|
|
/* .shortname = */ "DSA-CERT",
|
|
/* .sigalg = */ NULL,
|
|
/* .type = */ KEY_DSA_CERT,
|
|
/* .nid = */ 0,
|
|
/* .cert = */ 1,
|
|
/* .sigonly = */ 0,
|
|
/* .keybits = */ 0,
|
|
/* .funcs = */ &sshkey_dss_funcs,
|
|
};
|
|
#endif /* WITH_OPENSSL */
|