GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/ssh/lib/../ssh-dss.c Lines: 0 93 0.0 %
Date: 2017-11-13 Branches: 0 83 0.0 %

Line Branch Exec Source
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/* $OpenBSD: ssh-dss.c,v 1.35 2016/04/21 06:08:02 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 <sys/types.h>
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#include <openssl/bn.h>
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#include <openssl/evp.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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#define INTBLOB_LEN	20
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#define SIGBLOB_LEN	(2*INTBLOB_LEN)
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int
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ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
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    const u_char *data, size_t datalen, u_int compat)
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{
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	DSA_SIG *sig = NULL;
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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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	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 (compat & SSH_BUG_SIGBLOB) {
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		if (sigp != NULL) {
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			if ((*sigp = malloc(SIGBLOB_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, sigblob, SIGBLOB_LEN);
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		}
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		if (lenp != NULL)
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			*lenp = SIGBLOB_LEN;
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		ret = 0;
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	} else {
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		/* ietf-drafts */
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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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	}
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 out:
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	explicit_bzero(digest, sizeof(digest));
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	if (sig != NULL)
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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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int
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ssh_dss_verify(const struct sshkey *key,
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    const u_char *signature, size_t signaturelen,
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    const u_char *data, size_t datalen, u_int compat)
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{
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	DSA_SIG *sig = NULL;
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	u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob = NULL;
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	size_t len, dlen = 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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	    signature == NULL || signaturelen == 0)
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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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	/* fetch signature */
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	if (compat & SSH_BUG_SIGBLOB) {
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		if ((sigblob = malloc(signaturelen)) == NULL)
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			return SSH_ERR_ALLOC_FAIL;
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		memcpy(sigblob, signature, signaturelen);
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		len = signaturelen;
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	} else {
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		/* ietf-drafts */
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		if ((b = sshbuf_from(signature, signaturelen)) == 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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	}
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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 ((sig = 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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	/* sha1 the data */
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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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	switch (DSA_do_verify(digest, dlen, sig, 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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	if (sig != NULL)
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		DSA_SIG_free(sig);
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	sshbuf_free(b);
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	free(ktype);
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	if (sigblob != NULL) {
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		explicit_bzero(sigblob, len);
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		free(sigblob);
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	}
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	return ret;
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}