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
70int 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 */
158static 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
173int 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	}
315err:
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
325int 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