xref: /freebsd/crypto/openssl/crypto/rsa/rsa_sign.c (revision 3e11bd9e2a2b1cbd4283c87c93e3cc75e3f2dacb)
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 "rsa_locl.h"
66 
67 /* Size of an SSL signature: MD5+SHA1 */
68 #define SSL_SIG_LENGTH	36
69 
70 int RSA_sign(int type, const 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, *tmps = NULL;
77 	const unsigned char *s = NULL;
78 	X509_ALGOR algor;
79 	ASN1_OCTET_STRING digest;
80 #ifdef OPENSSL_FIPS
81 	if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
82 			&& !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
83 		{
84 		RSAerr(RSA_F_RSA_SIGN, RSA_R_NON_FIPS_RSA_METHOD);
85 		return 0;
86 		}
87 #endif
88 	if((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_sign)
89 		{
90 		return rsa->meth->rsa_sign(type, m, m_len,
91 			sigret, siglen, rsa);
92 		}
93 	/* Special case: SSL signature, just check the length */
94 	if(type == NID_md5_sha1) {
95 		if(m_len != SSL_SIG_LENGTH) {
96 			RSAerr(RSA_F_RSA_SIGN,RSA_R_INVALID_MESSAGE_LENGTH);
97 			return(0);
98 		}
99 		i = SSL_SIG_LENGTH;
100 		s = m;
101 	} else {
102 		sig.algor= &algor;
103 		sig.algor->algorithm=OBJ_nid2obj(type);
104 		if (sig.algor->algorithm == NULL)
105 			{
106 			RSAerr(RSA_F_RSA_SIGN,RSA_R_UNKNOWN_ALGORITHM_TYPE);
107 			return(0);
108 			}
109 		if (sig.algor->algorithm->length == 0)
110 			{
111 			RSAerr(RSA_F_RSA_SIGN,RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
112 			return(0);
113 			}
114 		parameter.type=V_ASN1_NULL;
115 		parameter.value.ptr=NULL;
116 		sig.algor->parameter= &parameter;
117 
118 		sig.digest= &digest;
119 		sig.digest->data=(unsigned char *)m; /* TMP UGLY CAST */
120 		sig.digest->length=m_len;
121 
122 		i=i2d_X509_SIG(&sig,NULL);
123 	}
124 	j=RSA_size(rsa);
125 	if (i > (j-RSA_PKCS1_PADDING_SIZE))
126 		{
127 		RSAerr(RSA_F_RSA_SIGN,RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
128 		return(0);
129 		}
130 	if(type != NID_md5_sha1) {
131 		tmps=(unsigned char *)OPENSSL_malloc((unsigned int)j+1);
132 		if (tmps == NULL)
133 			{
134 			RSAerr(RSA_F_RSA_SIGN,ERR_R_MALLOC_FAILURE);
135 			return(0);
136 			}
137 		p=tmps;
138 		i2d_X509_SIG(&sig,&p);
139 		s=tmps;
140 	}
141 	i=RSA_private_encrypt(i,s,sigret,rsa,RSA_PKCS1_PADDING);
142 	if (i <= 0)
143 		ret=0;
144 	else
145 		*siglen=i;
146 
147 	if(type != NID_md5_sha1) {
148 		OPENSSL_cleanse(tmps,(unsigned int)j+1);
149 		OPENSSL_free(tmps);
150 	}
151 	return(ret);
152 	}
153 
154 /*
155  * Check DigestInfo structure does not contain extraneous data by reencoding
156  * using DER and checking encoding against original.
157  */
158 static int rsa_check_digestinfo(X509_SIG *sig, const unsigned char *dinfo, int dinfolen)
159 	{
160 	unsigned char *der = NULL;
161 	int derlen;
162 	int ret = 0;
163 	derlen = i2d_X509_SIG(sig, &der);
164 	if (derlen <= 0)
165 		return 0;
166 	if (derlen == dinfolen && !memcmp(dinfo, der, derlen))
167 		ret = 1;
168 	OPENSSL_cleanse(der, derlen);
169 	OPENSSL_free(der);
170 	return ret;
171 	}
172 
173 int int_rsa_verify(int dtype, const unsigned char *m,
174 			  unsigned int m_len,
175 			  unsigned char *rm, size_t *prm_len,
176 			  const unsigned char *sigbuf, size_t siglen,
177 			  RSA *rsa)
178 	{
179 	int i,ret=0,sigtype;
180 	unsigned char *s;
181 	X509_SIG *sig=NULL;
182 
183 #ifdef OPENSSL_FIPS
184 	if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
185 			&& !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
186 		{
187 		RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_NON_FIPS_RSA_METHOD);
188 		return 0;
189 		}
190 #endif
191 
192 	if (siglen != (unsigned int)RSA_size(rsa))
193 		{
194 		RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_WRONG_SIGNATURE_LENGTH);
195 		return(0);
196 		}
197 
198 	if((dtype == NID_md5_sha1) && rm)
199 		{
200 		i = RSA_public_decrypt((int)siglen,
201 					sigbuf,rm,rsa,RSA_PKCS1_PADDING);
202 		if (i <= 0)
203 			return 0;
204 		*prm_len = i;
205 		return 1;
206 		}
207 
208 	s=(unsigned char *)OPENSSL_malloc((unsigned int)siglen);
209 	if (s == NULL)
210 		{
211 		RSAerr(RSA_F_INT_RSA_VERIFY,ERR_R_MALLOC_FAILURE);
212 		goto err;
213 		}
214 	if((dtype == NID_md5_sha1) && (m_len != SSL_SIG_LENGTH) ) {
215 			RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_INVALID_MESSAGE_LENGTH);
216 			goto err;
217 	}
218 	i=RSA_public_decrypt((int)siglen,sigbuf,s,rsa,RSA_PKCS1_PADDING);
219 
220 	if (i <= 0) goto err;
221 	/* Oddball MDC2 case: signature can be OCTET STRING.
222 	 * check for correct tag and length octets.
223 	 */
224 	if (dtype == NID_mdc2 && i == 18 && s[0] == 0x04 && s[1] == 0x10)
225 		{
226 		if (rm)
227 			{
228 			memcpy(rm, s + 2, 16);
229 			*prm_len = 16;
230 			ret = 1;
231 			}
232 		else if(memcmp(m, s + 2, 16))
233 			RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
234 		else
235 			ret = 1;
236 		}
237 
238 	/* Special case: SSL signature */
239 	if(dtype == NID_md5_sha1) {
240 		if((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH))
241 				RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
242 		else ret = 1;
243 	} else {
244 		const unsigned char *p=s;
245 		sig=d2i_X509_SIG(NULL,&p,(long)i);
246 
247 		if (sig == NULL) goto err;
248 
249 		/* Excess data can be used to create forgeries */
250 		if(p != s+i || !rsa_check_digestinfo(sig, s, i))
251 			{
252 			RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
253 			goto err;
254 			}
255 
256 		/* Parameters to the signature algorithm can also be used to
257 		   create forgeries */
258 		if(sig->algor->parameter
259 		   && ASN1_TYPE_get(sig->algor->parameter) != V_ASN1_NULL)
260 			{
261 			RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
262 			goto err;
263 			}
264 
265 		sigtype=OBJ_obj2nid(sig->algor->algorithm);
266 
267 
268 	#ifdef RSA_DEBUG
269 		/* put a backward compatibility flag in EAY */
270 		fprintf(stderr,"in(%s) expect(%s)\n",OBJ_nid2ln(sigtype),
271 			OBJ_nid2ln(dtype));
272 	#endif
273 		if (sigtype != dtype)
274 			{
275 			if (((dtype == NID_md5) &&
276 				(sigtype == NID_md5WithRSAEncryption)) ||
277 				((dtype == NID_md2) &&
278 				(sigtype == NID_md2WithRSAEncryption)))
279 				{
280 				/* ok, we will let it through */
281 #if !defined(OPENSSL_NO_STDIO) && !defined(OPENSSL_SYS_WIN16)
282 				fprintf(stderr,"signature has problems, re-make with post SSLeay045\n");
283 #endif
284 				}
285 			else
286 				{
287 				RSAerr(RSA_F_INT_RSA_VERIFY,
288 						RSA_R_ALGORITHM_MISMATCH);
289 				goto err;
290 				}
291 			}
292 		if (rm)
293 			{
294 			const EVP_MD *md;
295 			md = EVP_get_digestbynid(dtype);
296 			if (md && (EVP_MD_size(md) != sig->digest->length))
297 				RSAerr(RSA_F_INT_RSA_VERIFY,
298 						RSA_R_INVALID_DIGEST_LENGTH);
299 			else
300 				{
301 				memcpy(rm, sig->digest->data,
302 							sig->digest->length);
303 				*prm_len = sig->digest->length;
304 				ret = 1;
305 				}
306 			}
307 		else if (((unsigned int)sig->digest->length != m_len) ||
308 			(memcmp(m,sig->digest->data,m_len) != 0))
309 			{
310 			RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
311 			}
312 		else
313 			ret=1;
314 	}
315 err:
316 	if (sig != NULL) X509_SIG_free(sig);
317 	if (s != NULL)
318 		{
319 		OPENSSL_cleanse(s,(unsigned int)siglen);
320 		OPENSSL_free(s);
321 		}
322 	return(ret);
323 	}
324 
325 int RSA_verify(int dtype, const unsigned char *m, unsigned int m_len,
326 		const unsigned char *sigbuf, unsigned int siglen,
327 		RSA *rsa)
328 	{
329 
330 	if((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_verify)
331 		{
332 		return rsa->meth->rsa_verify(dtype, m, m_len,
333 			sigbuf, siglen, rsa);
334 		}
335 
336 	return int_rsa_verify(dtype, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
337 	}
338