[openssh.git] / ssh-rsa.c

/*
 * 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 "includes.h"
RCSID("$OpenBSD: ssh-rsa.c,v 1.1 2000/11/12 19:50:38 markus Exp $");

#include "ssh.h"
#include "xmalloc.h"
#include "buffer.h"
#include "bufaux.h"

#include <openssl/evp.h>
#include <openssl/dsa.h>
#include <openssl/rsa.h>
#include <openssl/err.h>

#include "key.h"

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

/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
int
ssh_rsa_sign(
    Key *key,
    unsigned char **sigp, int *lenp,
    unsigned char *data, int datalen)
{
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	unsigned char *digest, *sig, *ret;
	unsigned int slen, dlen, len;
	int ok;
	Buffer b;

	if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
		error("ssh_rsa_sign: no RSA key");
		return -1;
	}
	slen = RSA_size(key->rsa);
	sig = xmalloc(slen);

	dlen = evp_md->md_size;
	digest = xmalloc(dlen);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, NULL);

	ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
	memset(digest, 'd', dlen);
	xfree(digest);

	if (ok != 1) {
		int ecode = ERR_get_error();
		error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
		xfree(sig);
		return -1;
	}
	if (len < slen) {
		int diff = slen - len;
		debug("slen %d > len %d", slen, len);
		memmove(sig + diff, sig, len);
		memset(sig, 0, diff);
	} else if (len > slen) {
		error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
		xfree(sig);
		return -1;
	}
	/* encode signature */
	buffer_init(&b);
	buffer_put_cstring(&b, "ssh-rsa");
	buffer_put_string(&b, sig, slen);
	len = buffer_len(&b);
	ret = xmalloc(len);
	memcpy(ret, buffer_ptr(&b), len);
	buffer_free(&b);
	memset(sig, 's', slen);
	xfree(sig);

	if (lenp != NULL)
		*lenp = len;
	if (sigp != NULL)
		*sigp = ret;
	debug2("ssh_rsa_sign: done");
	return 0;
}

int
ssh_rsa_verify(
    Key *key,
    unsigned char *signature, int signaturelen,
    unsigned char *data, int datalen)
{
	Buffer b;
	EVP_MD *evp_md = EVP_sha1();
	EVP_MD_CTX md;
	char *ktype;
	unsigned char *sigblob, *digest;
	unsigned int len, dlen;
	int rlen;
	int ret;

	if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
		error("ssh_rsa_verify: no RSA key");
		return -1;
	}
	buffer_init(&b);
	buffer_append(&b, (char *) signature, signaturelen);
	ktype = buffer_get_string(&b, NULL);
	if (strcmp("ssh-rsa", ktype) != 0) {
		error("ssh_rsa_verify: cannot handle type %s", ktype);
		buffer_free(&b);
		xfree(ktype);
		return -1;
	}
	xfree(ktype);
	sigblob = (unsigned char *)buffer_get_string(&b, &len);
	rlen = buffer_len(&b);
	buffer_free(&b);
	if(rlen != 0) {
		error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
		return -1;
	}

	dlen = evp_md->md_size;
	digest = xmalloc(dlen);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, NULL);

	ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
	memset(digest, 'd', dlen);
	xfree(digest);
	memset(sigblob, 's', len);
	xfree(sigblob);
	if (ret == 0) {
		int ecode = ERR_get_error();
		error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
	}
	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
	return ret;
}
Commit	Line	Data
fa08c86b	1	/*
	2	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	*
	13	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	15	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	16	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	17	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	18	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	19	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	20	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	21	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	22	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	23	*/
	24
	25	#include "includes.h"
	26	RCSID("$OpenBSD: ssh-rsa.c,v 1.1 2000/11/12 19:50:38 markus Exp $");
	27
	28	#include "ssh.h"
	29	#include "xmalloc.h"
	30	#include "buffer.h"
	31	#include "bufaux.h"
	32
	33	#include <openssl/evp.h>
	34	#include <openssl/dsa.h>
	35	#include <openssl/rsa.h>
	36	#include <openssl/err.h>
	37
	38	#include "key.h"
	39
	40	#define INTBLOB_LEN 20
	41	#define SIGBLOB_LEN (2*INTBLOB_LEN)
	42
	43	/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
	44	int
	45	ssh_rsa_sign(
	46	Key *key,
	47	unsigned char *sigp, int lenp,
	48	unsigned char *data, int datalen)
	49	{
	50	EVP_MD *evp_md = EVP_sha1();
	51	EVP_MD_CTX md;
	52	unsigned char digest, sig, *ret;
	53	unsigned int slen, dlen, len;
	54	int ok;
	55	Buffer b;
	56
	57	if (key == NULL \|\| key->type != KEY_RSA \|\| key->rsa == NULL) {
	58	error("ssh_rsa_sign: no RSA key");
	59	return -1;
	60	}
	61	slen = RSA_size(key->rsa);
	62	sig = xmalloc(slen);
	63
	64	dlen = evp_md->md_size;
65	digest = xmalloc(dlen);
66	EVP_DigestInit(&md, evp_md);
67	EVP_DigestUpdate(&md, data, datalen);
68	EVP_DigestFinal(&md, digest, NULL);
69
70	ok = RSA_sign(NID_sha1, digest, dlen, sig, &len, key->rsa);
71	memset(digest, 'd', dlen);
72	xfree(digest);
73
74	if (ok != 1) {
75	int ecode = ERR_get_error();
76	error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL));
77	xfree(sig);
78	return -1;
79	}
80	if (len < slen) {
81	int diff = slen - len;
82	debug("slen %d > len %d", slen, len);
83	memmove(sig + diff, sig, len);
84	memset(sig, 0, diff);
85	} else if (len > slen) {
86	error("ssh_rsa_sign: slen %d slen2 %d", slen, len);
87	xfree(sig);
88	return -1;
89	}
90	/* encode signature */
91	buffer_init(&b);
92	buffer_put_cstring(&b, "ssh-rsa");
93	buffer_put_string(&b, sig, slen);
94	len = buffer_len(&b);
95	ret = xmalloc(len);
96	memcpy(ret, buffer_ptr(&b), len);
97	buffer_free(&b);
98	memset(sig, 's', slen);
99	xfree(sig);
100
101	if (lenp != NULL)
102	*lenp = len;
103	if (sigp != NULL)
104	*sigp = ret;
105	debug2("ssh_rsa_sign: done");
106	return 0;
107	}
108
109	int
110	ssh_rsa_verify(
111	Key *key,
112	unsigned char *signature, int signaturelen,
113	unsigned char *data, int datalen)
114	{
115	Buffer b;
116	EVP_MD *evp_md = EVP_sha1();
117	EVP_MD_CTX md;
118	char *ktype;
119	unsigned char sigblob, digest;
120	unsigned int len, dlen;
121	int rlen;
122	int ret;
123
124	if (key == NULL \|\| key->type != KEY_RSA \|\| key->rsa == NULL) {
125	error("ssh_rsa_verify: no RSA key");
126	return -1;
127	}
128	buffer_init(&b);
129	buffer_append(&b, (char *) signature, signaturelen);
130	ktype = buffer_get_string(&b, NULL);
131	if (strcmp("ssh-rsa", ktype) != 0) {
132	error("ssh_rsa_verify: cannot handle type %s", ktype);
133	buffer_free(&b);
134	xfree(ktype);
135	return -1;
136	}
137	xfree(ktype);
138	sigblob = (unsigned char *)buffer_get_string(&b, &len);
139	rlen = buffer_len(&b);
140	buffer_free(&b);
141	if(rlen != 0) {
142	error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
143	return -1;
144	}
145
146	dlen = evp_md->md_size;
147	digest = xmalloc(dlen);
148	EVP_DigestInit(&md, evp_md);
149	EVP_DigestUpdate(&md, data, datalen);
150	EVP_DigestFinal(&md, digest, NULL);
151
152	ret = RSA_verify(NID_sha1, digest, dlen, sigblob, len, key->rsa);
153	memset(digest, 'd', dlen);
154	xfree(digest);
155	memset(sigblob, 's', len);
156	xfree(sigblob);
157	if (ret == 0) {
158	int ecode = ERR_get_error();
159	error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL));
160	}
161	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
162	return ret;
163	}