rsa_sign.c

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/* crypto/rsa/rsa_sign.c */
/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson ([email protected]).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young ([email protected])"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson ([email protected])"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/objects.h>
#include <openssl/x509.h>
#include "rsa_locl.h"

/* Size of an SSL signature: MD5+SHA1 */
#define SSL_SIG_LENGTH  36

int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
         unsigned char *sigret, unsigned int *siglen, RSA *rsa)
    {
    X509_SIG sig;
    ASN1_TYPE parameter;
    int i,j,ret=1;
    unsigned char *p, *tmps = NULL;
    const unsigned char *s = NULL;
    X509_ALGOR algor;
    ASN1_OCTET_STRING digest;
#ifdef OPENSSL_FIPS
    if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
            && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
        {
        RSAerr(RSA_F_RSA_SIGN, RSA_R_NON_FIPS_RSA_METHOD);
        return 0;
        }
#endif
    if((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_sign)
        {
        return rsa->meth->rsa_sign(type, m, m_len,
            sigret, siglen, rsa);
        }
    /* Special case: SSL signature, just check the length */
    if(type == NID_md5_sha1) {
        if(m_len != SSL_SIG_LENGTH) {
            RSAerr(RSA_F_RSA_SIGN,RSA_R_INVALID_MESSAGE_LENGTH);
            return(0);
        }
        i = SSL_SIG_LENGTH;
        s = m;
    } else {
        sig.algor= &algor;
        sig.algor->algorithm=OBJ_nid2obj(type);
        if (sig.algor->algorithm == NULL)
            {
            RSAerr(RSA_F_RSA_SIGN,RSA_R_UNKNOWN_ALGORITHM_TYPE);
            return(0);
            }
        if (sig.algor->algorithm->length == 0)
            {
            RSAerr(RSA_F_RSA_SIGN,RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
            return(0);
            }
        parameter.type=V_ASN1_NULL;
        parameter.value.ptr=NULL;
        sig.algor->parameter= &parameter;

        sig.digest= &digest;
        sig.digest->data=(unsigned char *)m; /* TMP UGLY CAST */
        sig.digest->length=m_len;

        i=i2d_X509_SIG(&sig,NULL);
    }
    j=RSA_size(rsa);
    if (i > (j-RSA_PKCS1_PADDING_SIZE))
        {
        RSAerr(RSA_F_RSA_SIGN,RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
        return(0);
        }
    if(type != NID_md5_sha1) {
        tmps=(unsigned char *)OPENSSL_malloc((unsigned int)j+1);
        if (tmps == NULL)
            {
            RSAerr(RSA_F_RSA_SIGN,ERR_R_MALLOC_FAILURE);
            return(0);
            }
        p=tmps;
        i2d_X509_SIG(&sig,&p);
        s=tmps;
    }
    i=RSA_private_encrypt(i,s,sigret,rsa,RSA_PKCS1_PADDING);
    if (i <= 0)
        ret=0;
    else
        *siglen=i;

    if(type != NID_md5_sha1) {
        OPENSSL_cleanse(tmps,(unsigned int)j+1);
        OPENSSL_free(tmps);
    }
    return(ret);
    }

int int_rsa_verify(int dtype, const unsigned char *m,
              unsigned int m_len,
              unsigned char *rm, size_t *prm_len,
              const unsigned char *sigbuf, size_t siglen,
              RSA *rsa)
    {
    int i,ret=0,sigtype;
    unsigned char *s;
    X509_SIG *sig=NULL;

#ifdef OPENSSL_FIPS
    if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
            && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
        {
        RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_NON_FIPS_RSA_METHOD);
        return 0;
        }
#endif

    if (siglen != (unsigned int)RSA_size(rsa))
        {
        RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_WRONG_SIGNATURE_LENGTH);
        return(0);
        }

    if((dtype == NID_md5_sha1) && rm)
        {
        i = RSA_public_decrypt((int)siglen,
                    sigbuf,rm,rsa,RSA_PKCS1_PADDING);
        if (i <= 0)
            return 0;
        *prm_len = i;
        return 1;
        }

    s=(unsigned char *)OPENSSL_malloc((unsigned int)siglen);
    if (s == NULL)
        {
        RSAerr(RSA_F_INT_RSA_VERIFY,ERR_R_MALLOC_FAILURE);
        goto err;
        }
    if((dtype == NID_md5_sha1) && (m_len != SSL_SIG_LENGTH) ) {
            RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_INVALID_MESSAGE_LENGTH);
            goto err;
    }
    i=RSA_public_decrypt((int)siglen,sigbuf,s,rsa,RSA_PKCS1_PADDING);

    if (i <= 0) goto err;
    /* Oddball MDC2 case: signature can be OCTET STRING.
     * check for correct tag and length octets.
     */
    if (dtype == NID_mdc2 && i == 18 && s[0] == 0x04 && s[1] == 0x10)
        {
        if (rm)
            {
            memcpy(rm, s + 2, 16);
            *prm_len = 16;
            ret = 1;
            }
        else if(memcmp(m, s + 2, 16))
            RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
        else
            ret = 1;
        }

    /* Special case: SSL signature */
    if(dtype == NID_md5_sha1) {
        if((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH))
                RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
        else ret = 1;
    } else {
        const unsigned char *p=s;
        sig=d2i_X509_SIG(NULL,&p,(long)i);

        if (sig == NULL) goto err;

        /* Excess data can be used to create forgeries */
        if(p != s+i)
            {
            RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
            goto err;
            }

        /* Parameters to the signature algorithm can also be used to
           create forgeries */
        if(sig->algor->parameter
           && ASN1_TYPE_get(sig->algor->parameter) != V_ASN1_NULL)
            {
            RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
            goto err;
            }

        sigtype=OBJ_obj2nid(sig->algor->algorithm);


    #ifdef RSA_DEBUG
        /* put a backward compatibility flag in EAY */
        fprintf(stderr,"in(%s) expect(%s)\n",OBJ_nid2ln(sigtype),
            OBJ_nid2ln(dtype));
    #endif
        if (sigtype != dtype)
            {
            if (((dtype == NID_md5) &&
                (sigtype == NID_md5WithRSAEncryption)) ||
                ((dtype == NID_md2) &&
                (sigtype == NID_md2WithRSAEncryption)))
                {
                /* ok, we will let it through */
#if !defined(OPENSSL_NO_STDIO) && !defined(OPENSSL_SYS_WIN16)
                fprintf(stderr,"signature has problems, re-make with post SSLeay045\n");
#endif
                }
            else
                {
                RSAerr(RSA_F_INT_RSA_VERIFY,
                        RSA_R_ALGORITHM_MISMATCH);
                goto err;
                }
            }
        if (rm)
            {
            const EVP_MD *md;
            md = EVP_get_digestbynid(dtype);
            if (md && (EVP_MD_size(md) != sig->digest->length))
                RSAerr(RSA_F_INT_RSA_VERIFY,
                        RSA_R_INVALID_DIGEST_LENGTH);
            else
                {
                memcpy(rm, sig->digest->data,
                            sig->digest->length);
                *prm_len = sig->digest->length;
                ret = 1;
                }
            }
        else if (((unsigned int)sig->digest->length != m_len) ||
            (memcmp(m,sig->digest->data,m_len) != 0))
            {
            RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE);
            }
        else
            ret=1;
    }
err:
    if (sig != NULL) X509_SIG_free(sig);
    if (s != NULL)
        {
        OPENSSL_cleanse(s,(unsigned int)siglen);
        OPENSSL_free(s);
        }
    return(ret);
    }

int RSA_verify(int dtype, const unsigned char *m, unsigned int m_len,
        const unsigned char *sigbuf, unsigned int siglen,
        RSA *rsa)
    {

    if((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_verify)
        {
        return rsa->meth->rsa_verify(dtype, m, m_len,
            sigbuf, siglen, rsa);
        }

    return int_rsa_verify(dtype, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
    }