rsa_sign.c revision 296465
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 66/* Size of an SSL signature: MD5+SHA1 */ 67#define SSL_SIG_LENGTH 36 68 69int RSA_sign(int type, const unsigned char *m, unsigned int m_len, 70 unsigned char *sigret, unsigned int *siglen, RSA *rsa) 71{ 72 X509_SIG sig; 73 ASN1_TYPE parameter; 74 int i, j, ret = 1; 75 unsigned char *p, *tmps = NULL; 76 const unsigned char *s = NULL; 77 X509_ALGOR algor; 78 ASN1_OCTET_STRING digest; 79 if ((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_sign) { 80 return rsa->meth->rsa_sign(type, m, m_len, sigret, siglen, rsa); 81 } 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 /* NB: in FIPS mode block anything that isn't a TLS signature */ 92#ifdef OPENSSL_FIPS 93 if (FIPS_mode() && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) { 94 RSAerr(RSA_F_RSA_SIGN, RSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE); 95 return 0; 96 } 97#endif 98 sig.algor = &algor; 99 sig.algor->algorithm = OBJ_nid2obj(type); 100 if (sig.algor->algorithm == NULL) { 101 RSAerr(RSA_F_RSA_SIGN, RSA_R_UNKNOWN_ALGORITHM_TYPE); 102 return (0); 103 } 104 if (sig.algor->algorithm->length == 0) { 105 RSAerr(RSA_F_RSA_SIGN, 106 RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD); 107 return (0); 108 } 109 parameter.type = V_ASN1_NULL; 110 parameter.value.ptr = NULL; 111 sig.algor->parameter = ¶meter; 112 113 sig.digest = &digest; 114 sig.digest->data = (unsigned char *)m; /* TMP UGLY CAST */ 115 sig.digest->length = m_len; 116 117 i = i2d_X509_SIG(&sig, NULL); 118 } 119 j = RSA_size(rsa); 120 if (i > (j - RSA_PKCS1_PADDING_SIZE)) { 121 RSAerr(RSA_F_RSA_SIGN, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY); 122 return (0); 123 } 124 if (type != NID_md5_sha1) { 125 tmps = (unsigned char *)OPENSSL_malloc((unsigned int)j + 1); 126 if (tmps == NULL) { 127 RSAerr(RSA_F_RSA_SIGN, ERR_R_MALLOC_FAILURE); 128 return (0); 129 } 130 p = tmps; 131 i2d_X509_SIG(&sig, &p); 132 s = tmps; 133 } 134#ifdef OPENSSL_FIPS 135 /* Bypass algorithm blocking: this is allowed if we get this far */ 136 i = rsa->meth->rsa_priv_enc(i, s, sigret, rsa, RSA_PKCS1_PADDING); 137#else 138 i = RSA_private_encrypt(i, s, sigret, rsa, RSA_PKCS1_PADDING); 139#endif 140 if (i <= 0) 141 ret = 0; 142 else 143 *siglen = i; 144 145 if (type != NID_md5_sha1) { 146 OPENSSL_cleanse(tmps, (unsigned int)j + 1); 147 OPENSSL_free(tmps); 148 } 149 return (ret); 150} 151 152/* 153 * Check DigestInfo structure does not contain extraneous data by reencoding 154 * using DER and checking encoding against original. 155 */ 156static int rsa_check_digestinfo(X509_SIG *sig, const unsigned char *dinfo, 157 int dinfolen) 158{ 159 unsigned char *der = NULL; 160 int derlen; 161 int ret = 0; 162 derlen = i2d_X509_SIG(sig, &der); 163 if (derlen <= 0) 164 return 0; 165 if (derlen == dinfolen && !memcmp(dinfo, der, derlen)) 166 ret = 1; 167 OPENSSL_cleanse(der, derlen); 168 OPENSSL_free(der); 169 return ret; 170} 171 172int RSA_verify(int dtype, const unsigned char *m, unsigned int m_len, 173 unsigned char *sigbuf, unsigned int siglen, RSA *rsa) 174{ 175 int i, ret = 0, sigtype; 176 unsigned char *s; 177 X509_SIG *sig = NULL; 178 179 if (siglen != (unsigned int)RSA_size(rsa)) { 180 RSAerr(RSA_F_RSA_VERIFY, RSA_R_WRONG_SIGNATURE_LENGTH); 181 return (0); 182 } 183 184 if ((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_verify) { 185 return rsa->meth->rsa_verify(dtype, m, m_len, sigbuf, siglen, rsa); 186 } 187 188 s = (unsigned char *)OPENSSL_malloc((unsigned int)siglen); 189 if (s == NULL) { 190 RSAerr(RSA_F_RSA_VERIFY, ERR_R_MALLOC_FAILURE); 191 goto err; 192 } 193 if (dtype == NID_md5_sha1) { 194 if (m_len != SSL_SIG_LENGTH) { 195 RSAerr(RSA_F_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH); 196 goto err; 197 } 198 } 199 /* NB: in FIPS mode block anything that isn't a TLS signature */ 200#ifdef OPENSSL_FIPS 201 else if (FIPS_mode() && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW)) { 202 RSAerr(RSA_F_RSA_VERIFY, RSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE); 203 return 0; 204 } 205 /* Bypass algorithm blocking: this is allowed */ 206 i = rsa->meth->rsa_pub_dec((int)siglen, sigbuf, s, rsa, 207 RSA_PKCS1_PADDING); 208#else 209 i = RSA_public_decrypt((int)siglen, sigbuf, s, rsa, RSA_PKCS1_PADDING); 210#endif 211 212 if (i <= 0) 213 goto err; 214 215 /* Special case: SSL signature */ 216 if (dtype == NID_md5_sha1) { 217 if ((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH)) 218 RSAerr(RSA_F_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 219 else 220 ret = 1; 221 } else { 222 const unsigned char *p = s; 223 sig = d2i_X509_SIG(NULL, &p, (long)i); 224 225 if (sig == NULL) 226 goto err; 227 228 /* Excess data can be used to create forgeries */ 229 if (p != s + i || !rsa_check_digestinfo(sig, s, i)) { 230 RSAerr(RSA_F_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 231 goto err; 232 } 233 234 /* 235 * Parameters to the signature algorithm can also be used to create 236 * forgeries 237 */ 238 if (sig->algor->parameter 239 && ASN1_TYPE_get(sig->algor->parameter) != V_ASN1_NULL) { 240 RSAerr(RSA_F_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 241 goto err; 242 } 243 244 sigtype = OBJ_obj2nid(sig->algor->algorithm); 245 246#ifdef RSA_DEBUG 247 /* put a backward compatibility flag in EAY */ 248 fprintf(stderr, "in(%s) expect(%s)\n", OBJ_nid2ln(sigtype), 249 OBJ_nid2ln(dtype)); 250#endif 251 if (sigtype != dtype) { 252 if (((dtype == NID_md5) && 253 (sigtype == NID_md5WithRSAEncryption)) || 254 ((dtype == NID_md2) && 255 (sigtype == NID_md2WithRSAEncryption))) { 256 /* ok, we will let it through */ 257#if !defined(OPENSSL_NO_STDIO) && !defined(OPENSSL_SYS_WIN16) 258 fprintf(stderr, 259 "signature has problems, re-make with post SSLeay045\n"); 260#endif 261 } else { 262 RSAerr(RSA_F_RSA_VERIFY, RSA_R_ALGORITHM_MISMATCH); 263 goto err; 264 } 265 } 266 if (((unsigned int)sig->digest->length != m_len) || 267 (memcmp(m, sig->digest->data, m_len) != 0)) { 268 RSAerr(RSA_F_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 269 } else 270 ret = 1; 271 } 272 err: 273 if (sig != NULL) 274 X509_SIG_free(sig); 275 if (s != NULL) { 276 OPENSSL_cleanse(s, (unsigned int)siglen); 277 OPENSSL_free(s); 278 } 279 return (ret); 280} 281