rsa_sign.c revision 296341 
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        RSAerr(RSA_F_RSA_SIGN, RSA_R_NON_FIPS_RSA_METHOD);
84        return 0;
85    }
86#endif
87    if ((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_sign) {
88        return rsa->meth->rsa_sign(type, m, m_len, sigret, siglen, rsa);
89    }
90    /* Special case: SSL signature, just check the length */
91    if (type == NID_md5_sha1) {
92        if (m_len != SSL_SIG_LENGTH) {
93            RSAerr(RSA_F_RSA_SIGN, RSA_R_INVALID_MESSAGE_LENGTH);
94            return (0);
95        }
96        i = SSL_SIG_LENGTH;
97        s = m;
98    } else {
99        sig.algor = &algor;
100        sig.algor->algorithm = OBJ_nid2obj(type);
101        if (sig.algor->algorithm == NULL) {
102            RSAerr(RSA_F_RSA_SIGN, RSA_R_UNKNOWN_ALGORITHM_TYPE);
103            return (0);
104        }
105        if (sig.algor->algorithm->length == 0) {
106            RSAerr(RSA_F_RSA_SIGN,
107                   RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
108            return (0);
109        }
110        parameter.type = V_ASN1_NULL;
111        parameter.value.ptr = NULL;
112        sig.algor->parameter = &parameter;
113
114        sig.digest = &digest;
115        sig.digest->data = (unsigned char *)m; /* TMP UGLY CAST */
116        sig.digest->length = m_len;
117
118        i = i2d_X509_SIG(&sig, NULL);
119    }
120    j = RSA_size(rsa);
121    if (i > (j - RSA_PKCS1_PADDING_SIZE)) {
122        RSAerr(RSA_F_RSA_SIGN, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
123        return (0);
124    }
125    if (type != NID_md5_sha1) {
126        tmps = (unsigned char *)OPENSSL_malloc((unsigned int)j + 1);
127        if (tmps == NULL) {
128            RSAerr(RSA_F_RSA_SIGN, ERR_R_MALLOC_FAILURE);
129            return (0);
130        }
131        p = tmps;
132        i2d_X509_SIG(&sig, &p);
133        s = tmps;
134    }
135    i = RSA_private_encrypt(i, s, sigret, rsa, RSA_PKCS1_PADDING);
136    if (i <= 0)
137        ret = 0;
138    else
139        *siglen = i;
140
141    if (type != NID_md5_sha1) {
142        OPENSSL_cleanse(tmps, (unsigned int)j + 1);
143        OPENSSL_free(tmps);
144    }
145    return (ret);
146}
147
148/*
149 * Check DigestInfo structure does not contain extraneous data by reencoding
150 * using DER and checking encoding against original.
151 */
152static int rsa_check_digestinfo(X509_SIG *sig, const unsigned char *dinfo,
153                                int dinfolen)
154{
155    unsigned char *der = NULL;
156    int derlen;
157    int ret = 0;
158    derlen = i2d_X509_SIG(sig, &der);
159    if (derlen <= 0)
160        return 0;
161    if (derlen == dinfolen && !memcmp(dinfo, der, derlen))
162        ret = 1;
163    OPENSSL_cleanse(der, derlen);
164    OPENSSL_free(der);
165    return ret;
166}
167
168int int_rsa_verify(int dtype, const unsigned char *m,
169                   unsigned int m_len,
170                   unsigned char *rm, size_t *prm_len,
171                   const unsigned char *sigbuf, size_t siglen, RSA *rsa)
172{
173    int i, ret = 0, sigtype;
174    unsigned char *s;
175    X509_SIG *sig = NULL;
176
177#ifdef OPENSSL_FIPS
178    if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
179        && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) {
180        RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_NON_FIPS_RSA_METHOD);
181        return 0;
182    }
183#endif
184
185    if (siglen != (unsigned int)RSA_size(rsa)) {
186        RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_WRONG_SIGNATURE_LENGTH);
187        return (0);
188    }
189
190    if ((dtype == NID_md5_sha1) && rm) {
191        i = RSA_public_decrypt((int)siglen,
192                               sigbuf, rm, rsa, RSA_PKCS1_PADDING);
193        if (i <= 0)
194            return 0;
195        *prm_len = i;
196        return 1;
197    }
198
199    s = (unsigned char *)OPENSSL_malloc((unsigned int)siglen);
200    if (s == NULL) {
201        RSAerr(RSA_F_INT_RSA_VERIFY, ERR_R_MALLOC_FAILURE);
202        goto err;
203    }
204    if ((dtype == NID_md5_sha1) && (m_len != SSL_SIG_LENGTH)) {
205        RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH);
206        goto err;
207    }
208    i = RSA_public_decrypt((int)siglen, sigbuf, s, rsa, RSA_PKCS1_PADDING);
209
210    if (i <= 0)
211        goto err;
212    /*
213     * Oddball MDC2 case: signature can be OCTET STRING. check for correct
214     * tag and length octets.
215     */
216    if (dtype == NID_mdc2 && i == 18 && s[0] == 0x04 && s[1] == 0x10) {
217        if (rm) {
218            memcpy(rm, s + 2, 16);
219            *prm_len = 16;
220            ret = 1;
221        } else if (memcmp(m, s + 2, 16))
222            RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
223        else
224            ret = 1;
225    }
226
227    /* Special case: SSL signature */
228    if (dtype == NID_md5_sha1) {
229        if ((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH))
230            RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
231        else
232            ret = 1;
233    } else {
234        const unsigned char *p = s;
235        sig = d2i_X509_SIG(NULL, &p, (long)i);
236
237        if (sig == NULL)
238            goto err;
239
240        /* Excess data can be used to create forgeries */
241        if (p != s + i || !rsa_check_digestinfo(sig, s, i)) {
242            RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
243            goto err;
244        }
245
246        /*
247         * Parameters to the signature algorithm can also be used to create
248         * forgeries
249         */
250        if (sig->algor->parameter
251            && ASN1_TYPE_get(sig->algor->parameter) != V_ASN1_NULL) {
252            RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
253            goto err;
254        }
255
256        sigtype = OBJ_obj2nid(sig->algor->algorithm);
257
258#ifdef RSA_DEBUG
259        /* put a backward compatibility flag in EAY */
260        fprintf(stderr, "in(%s) expect(%s)\n", OBJ_nid2ln(sigtype),
261                OBJ_nid2ln(dtype));
262#endif
263        if (sigtype != dtype) {
264            if (((dtype == NID_md5) &&
265                 (sigtype == NID_md5WithRSAEncryption)) ||
266                ((dtype == NID_md2) &&
267                 (sigtype == NID_md2WithRSAEncryption))) {
268                /* ok, we will let it through */
269#if !defined(OPENSSL_NO_STDIO) && !defined(OPENSSL_SYS_WIN16)
270                fprintf(stderr,
271                        "signature has problems, re-make with post SSLeay045\n");
272#endif
273            } else {
274                RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_ALGORITHM_MISMATCH);
275                goto err;
276            }
277        }
278        if (rm) {
279            const EVP_MD *md;
280            md = EVP_get_digestbynid(dtype);
281            if (md && (EVP_MD_size(md) != sig->digest->length))
282                RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_DIGEST_LENGTH);
283            else {
284                memcpy(rm, sig->digest->data, sig->digest->length);
285                *prm_len = sig->digest->length;
286                ret = 1;
287            }
288        } else if (((unsigned int)sig->digest->length != m_len) ||
289                   (memcmp(m, sig->digest->data, m_len) != 0)) {
290            RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
291        } else
292            ret = 1;
293    }
294 err:
295    if (sig != NULL)
296        X509_SIG_free(sig);
297    if (s != NULL) {
298        OPENSSL_cleanse(s, (unsigned int)siglen);
299        OPENSSL_free(s);
300    }
301    return (ret);
302}
303
304int RSA_verify(int dtype, const unsigned char *m, unsigned int m_len,
305               const unsigned char *sigbuf, unsigned int siglen, RSA *rsa)
306{
307
308    if ((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_verify) {
309        return rsa->meth->rsa_verify(dtype, m, m_len, sigbuf, siglen, rsa);
310    }
311
312    return int_rsa_verify(dtype, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
313}
314