crypto/rsa/rsa_sign.c

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