xref: /openbsd-src/lib/libcrypto/rsa/rsa_sign.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /* crypto/rsa/rsa_sign.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  *
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  *
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  *
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  *
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58 
59 #include <stdio.h>
60 #include "cryptlib.h"
61 #include <openssl/bn.h>
62 #include <openssl/rsa.h>
63 #include <openssl/objects.h>
64 #include <openssl/x509.h>
65 #include <openssl/engine.h>
66 
67 /* Size of an SSL signature: MD5+SHA1 */
68 #define SSL_SIG_LENGTH	36
69 
70 int RSA_sign(int type, unsigned char *m, unsigned int m_len,
71 	     unsigned char *sigret, unsigned int *siglen, RSA *rsa)
72 	{
73 	X509_SIG sig;
74 	ASN1_TYPE parameter;
75 	int i,j,ret=1;
76 	unsigned char *p,*s = NULL;
77 	X509_ALGOR algor;
78 	ASN1_OCTET_STRING digest;
79 	if(rsa->flags & RSA_FLAG_SIGN_VER)
80 	      return ENGINE_get_RSA(rsa->engine)->rsa_sign(type,
81 			m, m_len, sigret, siglen, rsa);
82 	/* Special case: SSL signature, just check the length */
83 	if(type == NID_md5_sha1) {
84 		if(m_len != SSL_SIG_LENGTH) {
85 			RSAerr(RSA_F_RSA_SIGN,RSA_R_INVALID_MESSAGE_LENGTH);
86 			return(0);
87 		}
88 		i = SSL_SIG_LENGTH;
89 		s = m;
90 	} else {
91 		sig.algor= &algor;
92 		sig.algor->algorithm=OBJ_nid2obj(type);
93 		if (sig.algor->algorithm == NULL)
94 			{
95 			RSAerr(RSA_F_RSA_SIGN,RSA_R_UNKNOWN_ALGORITHM_TYPE);
96 			return(0);
97 			}
98 		if (sig.algor->algorithm->length == 0)
99 			{
100 			RSAerr(RSA_F_RSA_SIGN,RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
101 			return(0);
102 			}
103 		parameter.type=V_ASN1_NULL;
104 		parameter.value.ptr=NULL;
105 		sig.algor->parameter= &parameter;
106 
107 		sig.digest= &digest;
108 		sig.digest->data=m;
109 		sig.digest->length=m_len;
110 
111 		i=i2d_X509_SIG(&sig,NULL);
112 	}
113 	j=RSA_size(rsa);
114 	if ((i-RSA_PKCS1_PADDING) > j)
115 		{
116 		RSAerr(RSA_F_RSA_SIGN,RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
117 		return(0);
118 		}
119 	if(type != NID_md5_sha1) {
120 		s=(unsigned char *)OPENSSL_malloc((unsigned int)j+1);
121 		if (s == NULL)
122 			{
123 			RSAerr(RSA_F_RSA_SIGN,ERR_R_MALLOC_FAILURE);
124 			return(0);
125 			}
126 		p=s;
127 		i2d_X509_SIG(&sig,&p);
128 	}
129 	i=RSA_private_encrypt(i,s,sigret,rsa,RSA_PKCS1_PADDING);
130 	if (i <= 0)
131 		ret=0;
132 	else
133 		*siglen=i;
134 
135 	if(type != NID_md5_sha1) {
136 		memset(s,0,(unsigned int)j+1);
137 		OPENSSL_free(s);
138 	}
139 	return(ret);
140 	}
141 
142 int RSA_verify(int dtype, unsigned char *m, unsigned int m_len,
143 	     unsigned char *sigbuf, unsigned int siglen, RSA *rsa)
144 	{
145 	int i,ret=0,sigtype;
146 	unsigned char *p,*s;
147 	X509_SIG *sig=NULL;
148 
149 	if (siglen != (unsigned int)RSA_size(rsa))
150 		{
151 		RSAerr(RSA_F_RSA_VERIFY,RSA_R_WRONG_SIGNATURE_LENGTH);
152 		return(0);
153 		}
154 
155 	if(rsa->flags & RSA_FLAG_SIGN_VER)
156 	    return ENGINE_get_RSA(rsa->engine)->rsa_verify(dtype,
157 			m, m_len, sigbuf, siglen, rsa);
158 
159 	s=(unsigned char *)OPENSSL_malloc((unsigned int)siglen);
160 	if (s == NULL)
161 		{
162 		RSAerr(RSA_F_RSA_VERIFY,ERR_R_MALLOC_FAILURE);
163 		goto err;
164 		}
165 	if((dtype == NID_md5_sha1) && (m_len != SSL_SIG_LENGTH) ) {
166 			RSAerr(RSA_F_RSA_VERIFY,RSA_R_INVALID_MESSAGE_LENGTH);
167 			return(0);
168 	}
169 	i=RSA_public_decrypt((int)siglen,sigbuf,s,rsa,RSA_PKCS1_PADDING);
170 
171 	if (i <= 0) goto err;
172 
173 	/* Special case: SSL signature */
174 	if(dtype == NID_md5_sha1) {
175 		if((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH))
176 				RSAerr(RSA_F_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
177 		else ret = 1;
178 	} else {
179 		p=s;
180 		sig=d2i_X509_SIG(NULL,&p,(long)i);
181 
182 		if (sig == NULL) goto err;
183 		sigtype=OBJ_obj2nid(sig->algor->algorithm);
184 
185 
186 	#ifdef RSA_DEBUG
187 		/* put a backward compatibility flag in EAY */
188 		fprintf(stderr,"in(%s) expect(%s)\n",OBJ_nid2ln(sigtype),
189 			OBJ_nid2ln(dtype));
190 	#endif
191 		if (sigtype != dtype)
192 			{
193 			if (((dtype == NID_md5) &&
194 				(sigtype == NID_md5WithRSAEncryption)) ||
195 				((dtype == NID_md2) &&
196 				(sigtype == NID_md2WithRSAEncryption)))
197 				{
198 				/* ok, we will let it through */
199 	#if !defined(NO_STDIO) && !defined(WIN16)
200 				fprintf(stderr,"signature has problems, re-make with post SSLeay045\n");
201 	#endif
202 				}
203 			else
204 				{
205 				RSAerr(RSA_F_RSA_VERIFY,
206 						RSA_R_ALGORITHM_MISMATCH);
207 				goto err;
208 				}
209 			}
210 		if (	((unsigned int)sig->digest->length != m_len) ||
211 			(memcmp(m,sig->digest->data,m_len) != 0))
212 			{
213 			RSAerr(RSA_F_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
214 			}
215 		else
216 			ret=1;
217 	}
218 err:
219 	if (sig != NULL) X509_SIG_free(sig);
220 	memset(s,0,(unsigned int)siglen);
221 	OPENSSL_free(s);
222 	return(ret);
223 	}
224 
225