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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/ssh/lib/../ssh-dss.c	Lines:	69	98	70.4 %
Date:	2017-11-07	Branches:	37	83	44.6 %


/* $OpenBSD: ssh-dss.c,v 1.35 2016/04/21 06:08:02 djm Exp $ */
/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>

#include <openssl/bn.h>
#include <openssl/evp.h>

#include <string.h>

#include "sshbuf.h"
#include "compat.h"
#include "ssherr.h"
#include "digest.h"
#define SSHKEY_INTERNAL
#include "sshkey.h"

#define INTBLOB_LEN	20
#define SIGBLOB_LEN	(2*INTBLOB_LEN)

int
ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
    const u_char *data, size_t datalen, u_int compat)
{
	DSA_SIG *sig = NULL;
	u_char digest[SSH_DIGEST_MAX_LENGTH], sigblob[SIGBLOB_LEN];
	size_t rlen, slen, len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
	struct sshbuf *b = NULL;
	int ret = SSH_ERR_INVALID_ARGUMENT;

	if (lenp != NULL)
		*lenp = 0;
	if (sigp != NULL)
		*sigp = NULL;

	if (key == NULL || key->dsa == NULL ||
	    sshkey_type_plain(key->type) != KEY_DSA)
		return SSH_ERR_INVALID_ARGUMENT;
	if (dlen == 0)
		return SSH_ERR_INTERNAL_ERROR;

	if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
	    digest, sizeof(digest))) != 0)
		goto out;

	if ((sig = DSA_do_sign(digest, dlen, key->dsa)) == NULL) {
		ret = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}

	rlen = BN_num_bytes(sig->r);
	slen = BN_num_bytes(sig->s);
	if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
		ret = SSH_ERR_INTERNAL_ERROR;
		goto out;
	}
	explicit_bzero(sigblob, SIGBLOB_LEN);
	BN_bn2bin(sig->r, sigblob + SIGBLOB_LEN - INTBLOB_LEN - rlen);
	BN_bn2bin(sig->s, sigblob + SIGBLOB_LEN - slen);

	if (compat & SSH_BUG_SIGBLOB) {
		if (sigp != NULL) {
			if ((*sigp = malloc(SIGBLOB_LEN)) == NULL) {
				ret = SSH_ERR_ALLOC_FAIL;
				goto out;
			}
			memcpy(*sigp, sigblob, SIGBLOB_LEN);
		}
		if (lenp != NULL)
			*lenp = SIGBLOB_LEN;
		ret = 0;
	} else {
		/* ietf-drafts */
		if ((b = sshbuf_new()) == NULL) {
			ret = SSH_ERR_ALLOC_FAIL;
			goto out;
		}
		if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 ||
		    (ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
			goto out;
		len = sshbuf_len(b);
		if (sigp != NULL) {
			if ((*sigp = malloc(len)) == NULL) {
				ret = SSH_ERR_ALLOC_FAIL;
				goto out;
			}
			memcpy(*sigp, sshbuf_ptr(b), len);
		}
		if (lenp != NULL)
			*lenp = len;
		ret = 0;
	}
 out:
	explicit_bzero(digest, sizeof(digest));
	if (sig != NULL)
		DSA_SIG_free(sig);
	sshbuf_free(b);
	return ret;
}

int
ssh_dss_verify(const struct sshkey *key,
    const u_char *signature, size_t signaturelen,
    const u_char *data, size_t datalen, u_int compat)
{
	DSA_SIG *sig = NULL;
	u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob = NULL;
	size_t len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
	int ret = SSH_ERR_INTERNAL_ERROR;
	struct sshbuf *b = NULL;
	char *ktype = NULL;

	if (key == NULL || key->dsa == NULL ||
	    sshkey_type_plain(key->type) != KEY_DSA ||
	    signature == NULL || signaturelen == 0)
		return SSH_ERR_INVALID_ARGUMENT;
	if (dlen == 0)
		return SSH_ERR_INTERNAL_ERROR;

	/* fetch signature */
	if (compat & SSH_BUG_SIGBLOB) {
		if ((sigblob = malloc(signaturelen)) == NULL)
			return SSH_ERR_ALLOC_FAIL;
		memcpy(sigblob, signature, signaturelen);
		len = signaturelen;
	} else {
		/* ietf-drafts */
		if ((b = sshbuf_from(signature, signaturelen)) == NULL)
			return SSH_ERR_ALLOC_FAIL;
		if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
		    sshbuf_get_string(b, &sigblob, &len) != 0) {
			ret = SSH_ERR_INVALID_FORMAT;
			goto out;
		}
		if (strcmp("ssh-dss", ktype) != 0) {
			ret = SSH_ERR_KEY_TYPE_MISMATCH;
			goto out;
		}
		if (sshbuf_len(b) != 0) {
			ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
			goto out;
		}
	}

	if (len != SIGBLOB_LEN) {
		ret = SSH_ERR_INVALID_FORMAT;
		goto out;
	}

	/* parse signature */
	if ((sig = DSA_SIG_new()) == NULL ||
	    (sig->r = BN_new()) == NULL ||
	    (sig->s = BN_new()) == NULL) {
		ret = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((BN_bin2bn(sigblob, INTBLOB_LEN, sig->r) == NULL) ||
	    (BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s) == NULL)) {
		ret = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}

	/* sha1 the data */
	if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
	    digest, sizeof(digest))) != 0)
		goto out;

	switch (DSA_do_verify(digest, dlen, sig, key->dsa)) {
	case 1:
		ret = 0;
		break;
	case 0:
		ret = SSH_ERR_SIGNATURE_INVALID;
		goto out;
	default:
		ret = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}

 out:
	explicit_bzero(digest, sizeof(digest));
	if (sig != NULL)
		DSA_SIG_free(sig);
	sshbuf_free(b);
	free(ktype);
	if (sigblob != NULL) {
		explicit_bzero(sigblob, len);
		free(sigblob);
	}
	return ret;
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: ssh-dss.c,v 1.35 2016/04/21 06:08:02 djm Exp $ */
2			/*
3			* Copyright (c) 2000 Markus Friedl. All rights reserved.
4			*
5			* Redistribution and use in source and binary forms, with or without
6			* modification, are permitted provided that the following conditions
7			* are met:
8			* 1. Redistributions of source code must retain the above copyright
9			* notice, this list of conditions and the following disclaimer.
10			* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13			*
14			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15			* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17			* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24			*/
25
26			#include <sys/types.h>
27
28			#include <openssl/bn.h>
29			#include <openssl/evp.h>
30
31			#include <string.h>
32
33			#include "sshbuf.h"
34			#include "compat.h"
35			#include "ssherr.h"
36			#include "digest.h"
37			#define SSHKEY_INTERNAL
38			#include "sshkey.h"
39
40			#define INTBLOB_LEN 20
41			#define SIGBLOB_LEN (2*INTBLOB_LEN)
42
43			int
44			ssh_dss_sign(const struct sshkey key, u_char sigp, size_t lenp,
45			const u_char *data, size_t datalen, u_int compat)
46			{
47			DSA_SIG *sig = NULL;
48		8	u_char digest[SSH_DIGEST_MAX_LENGTH], sigblob[SIGBLOB_LEN];
49		4	size_t rlen, slen, len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
50			struct sshbuf *b = NULL;
51			int ret = SSH_ERR_INVALID_ARGUMENT;
52
53	✓✗	4	if (lenp != NULL)
54		4	*lenp = 0;
55	✓✗	4	if (sigp != NULL)
56		4	*sigp = NULL;
57
58	✓✗✓✗ ✗✓	12	if (key == NULL \|\| key->dsa == NULL \|\|
59		4	sshkey_type_plain(key->type) != KEY_DSA)
60			return SSH_ERR_INVALID_ARGUMENT;
61	✗✓	4	if (dlen == 0)
62			return SSH_ERR_INTERNAL_ERROR;
63
64	✓✗	8	if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
65		8	digest, sizeof(digest))) != 0)
66			goto out;
67
68	✗✓	4	if ((sig = DSA_do_sign(digest, dlen, key->dsa)) == NULL) {
69			ret = SSH_ERR_LIBCRYPTO_ERROR;
70			goto out;
71			}
72
73		4	rlen = BN_num_bytes(sig->r);
74		4	slen = BN_num_bytes(sig->s);
75	✗✓	4	if (rlen > INTBLOB_LEN \|\| slen > INTBLOB_LEN) {
76			ret = SSH_ERR_INTERNAL_ERROR;
77			goto out;
78			}
79		4	explicit_bzero(sigblob, SIGBLOB_LEN);
80		4	BN_bn2bin(sig->r, sigblob + SIGBLOB_LEN - INTBLOB_LEN - rlen);
81		4	BN_bn2bin(sig->s, sigblob + SIGBLOB_LEN - slen);
82
83	✗✓	4	if (compat & SSH_BUG_SIGBLOB) {
84			if (sigp != NULL) {
85			if ((*sigp = malloc(SIGBLOB_LEN)) == NULL) {
86			ret = SSH_ERR_ALLOC_FAIL;
87			goto out;
88			}
89			memcpy(*sigp, sigblob, SIGBLOB_LEN);
90			}
91			if (lenp != NULL)
92			*lenp = SIGBLOB_LEN;
93			ret = 0;
94			} else {
95			/* ietf-drafts */
96	✗✓	4	if ((b = sshbuf_new()) == NULL) {
97			ret = SSH_ERR_ALLOC_FAIL;
98			goto out;
99			}
100	✓✗✓✗	8	if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 \|\|
101		4	(ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
102			goto out;
103		4	len = sshbuf_len(b);
104	✓✗	4	if (sigp != NULL) {
105	✗✓	4	if ((*sigp = malloc(len)) == NULL) {
106			ret = SSH_ERR_ALLOC_FAIL;
107			goto out;
108			}
109		4	memcpy(*sigp, sshbuf_ptr(b), len);
110		4	}
111	✓✗	4	if (lenp != NULL)
112		4	*lenp = len;
113			ret = 0;
114			}
115			out:
116		4	explicit_bzero(digest, sizeof(digest));
117	✓✗	4	if (sig != NULL)
118		4	DSA_SIG_free(sig);
119		4	sshbuf_free(b);
120		4	return ret;
121		4	}
122
123			int
124			ssh_dss_verify(const struct sshkey *key,
125			const u_char *signature, size_t signaturelen,
126			const u_char *data, size_t datalen, u_int compat)
127			{
128			DSA_SIG *sig = NULL;
129		8	u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob = NULL;
130		4	size_t len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
131			int ret = SSH_ERR_INTERNAL_ERROR;
132			struct sshbuf *b = NULL;
133		4	char *ktype = NULL;
134
135	✓✗✓✗	8	if (key == NULL \|\| key->dsa == NULL \|\|
136	✗✓	12	sshkey_type_plain(key->type) != KEY_DSA \|\|
137		8	signature == NULL \|\| signaturelen == 0)
138			return SSH_ERR_INVALID_ARGUMENT;
139	✗✓	4	if (dlen == 0)
140			return SSH_ERR_INTERNAL_ERROR;
141
142			/* fetch signature */
143	✗✓	4	if (compat & SSH_BUG_SIGBLOB) {
144			if ((sigblob = malloc(signaturelen)) == NULL)
145			return SSH_ERR_ALLOC_FAIL;
146			memcpy(sigblob, signature, signaturelen);
147			len = signaturelen;
148			} else {
149			/* ietf-drafts */
150	✗✓	4	if ((b = sshbuf_from(signature, signaturelen)) == NULL)
151			return SSH_ERR_ALLOC_FAIL;
152	✓✗✗✓	8	if (sshbuf_get_cstring(b, &ktype, NULL) != 0 \|\|
153		4	sshbuf_get_string(b, &sigblob, &len) != 0) {
154			ret = SSH_ERR_INVALID_FORMAT;
155			goto out;
156			}
157	✗✓	4	if (strcmp("ssh-dss", ktype) != 0) {
158			ret = SSH_ERR_KEY_TYPE_MISMATCH;
159			goto out;
160			}
161	✗✓	4	if (sshbuf_len(b) != 0) {
162			ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
163			goto out;
164			}
165			}
166
167	✗✓	4	if (len != SIGBLOB_LEN) {
168			ret = SSH_ERR_INVALID_FORMAT;
169			goto out;
170			}
171
172			/* parse signature */
173	✓✗✗✓	8	if ((sig = DSA_SIG_new()) == NULL \|\|
174	✓✗	4	(sig->r = BN_new()) == NULL \|\|
175		4	(sig->s = BN_new()) == NULL) {
176			ret = SSH_ERR_ALLOC_FAIL;
177			goto out;
178			}
179	✓✗✗✓	8	if ((BN_bin2bn(sigblob, INTBLOB_LEN, sig->r) == NULL) \|\|
180		4	(BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s) == NULL)) {
181			ret = SSH_ERR_LIBCRYPTO_ERROR;
182			goto out;
183			}
184
185			/* sha1 the data */
186	✓✗	8	if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
187		8	digest, sizeof(digest))) != 0)
188			goto out;
189
190	✓✗✗	4	switch (DSA_do_verify(digest, dlen, sig, key->dsa)) {
191			case 1:
192			ret = 0;
193			break;
194			case 0:
195			ret = SSH_ERR_SIGNATURE_INVALID;
196			goto out;
197			default:
198			ret = SSH_ERR_LIBCRYPTO_ERROR;
199			goto out;
200		4	}
201
202			out:
203		4	explicit_bzero(digest, sizeof(digest));
204	✓✗	4	if (sig != NULL)
205		4	DSA_SIG_free(sig);
206		4	sshbuf_free(b);
207		4	free(ktype);
208	✓✗	4	if (sigblob != NULL) {
209		4	explicit_bzero(sigblob, len);
210		4	free(sigblob);
211		4	}
212		4	return ret;
213		4	}