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 RSAerr(RSA_F_RSA_SIGN, RSA_R_NON_FIPS_RSA_METHOD); 84 return 0; 85 } 86 #endif 87 if (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 = ¶meter; 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 */ 152 static 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 } 167 168 int 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 } else if (dtype == NID_md5_sha1) { 227 /* Special case: SSL signature */ 228 if ((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH)) 229 RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 230 else 231 ret = 1; 232 } else { 233 const unsigned char *p = s; 234 sig = d2i_X509_SIG(NULL, &p, (long)i); 235 236 if (sig == NULL) 237 goto err; 238 239 /* Excess data can be used to create forgeries */ 240 if (p != s + i || !rsa_check_digestinfo(sig, s, i)) { 241 RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 242 goto err; 243 } 244 245 /* 246 * Parameters to the signature algorithm can also be used to create 247 * forgeries 248 */ 249 if (sig->algor->parameter 250 && ASN1_TYPE_get(sig->algor->parameter) != V_ASN1_NULL) { 251 RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 252 goto err; 253 } 254 255 sigtype = OBJ_obj2nid(sig->algor->algorithm); 256 257 #ifdef RSA_DEBUG 258 /* put a backward compatibility flag in EAY */ 259 fprintf(stderr, "in(%s) expect(%s)\n", OBJ_nid2ln(sigtype), 260 OBJ_nid2ln(dtype)); 261 #endif 262 if (sigtype != dtype) { 263 RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_ALGORITHM_MISMATCH); 264 goto err; 265 } 266 if (rm) { 267 const EVP_MD *md; 268 md = EVP_get_digestbynid(dtype); 269 if (md && (EVP_MD_size(md) != sig->digest->length)) 270 RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_DIGEST_LENGTH); 271 else { 272 memcpy(rm, sig->digest->data, sig->digest->length); 273 *prm_len = sig->digest->length; 274 ret = 1; 275 } 276 } else if (((unsigned int)sig->digest->length != m_len) || 277 (memcmp(m, sig->digest->data, m_len) != 0)) { 278 RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE); 279 } else 280 ret = 1; 281 } 282 err: 283 if (sig != NULL) 284 X509_SIG_free(sig); 285 if (s != NULL) { 286 OPENSSL_cleanse(s, (unsigned int)siglen); 287 OPENSSL_free(s); 288 } 289 return (ret); 290 } 291 292 int RSA_verify(int dtype, const unsigned char *m, unsigned int m_len, 293 const unsigned char *sigbuf, unsigned int siglen, RSA *rsa) 294 { 295 296 if (rsa->meth->rsa_verify) { 297 return rsa->meth->rsa_verify(dtype, m, m_len, sigbuf, siglen, rsa); 298 } 299 300 return int_rsa_verify(dtype, m, m_len, NULL, NULL, sigbuf, siglen, rsa); 301 } 302