A local copy of OpenSSL from GitHub
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/*
* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/objects.h>
#include <openssl/x509.h>
#include "internal/x509_int.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;
if (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 (OBJ_length(sig.algor->algorithm) == 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 = 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_clear_free(tmps, (unsigned int)j + 1);
return (ret);
}
/*
* Check DigestInfo structure does not contain extraneous data by reencoding
* using DER and checking encoding against original.
*/
static int rsa_check_digestinfo(X509_SIG *sig, const unsigned char *dinfo,
int dinfolen)
{
unsigned char *der = NULL;
int derlen;
int ret = 0;
derlen = i2d_X509_SIG(sig, &der);
if (derlen <= 0)
return 0;
if (derlen == dinfolen && !memcmp(dinfo, der, derlen))
ret = 1;
OPENSSL_clear_free(der, derlen);
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;
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 = 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;
}
} else if (dtype == NID_md5_sha1) {
/* Special case: SSL signature */
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 || !rsa_check_digestinfo(sig, 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);
if (sigtype != dtype) {
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:
X509_SIG_free(sig);
OPENSSL_clear_free(s, (unsigned int)siglen);
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->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);
}