pineapple/externals/libressl/crypto/rsa/rsa_sign.c
2022-04-24 22:29:35 +02:00

278 lines
8.9 KiB
C
Executable file

/* $OpenBSD: rsa_sign.c,v 1.34 2022/01/07 11:13:55 tb Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* 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 (tjh@cryptsoft.com).
*
* 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 (eay@cryptsoft.com)"
* 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 (tjh@cryptsoft.com)"
*
* 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 <string.h>
#include <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/objects.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>
#include "asn1_locl.h"
#include "rsa_locl.h"
#include "x509_lcl.h"
/* Size of an SSL signature: MD5+SHA1 */
#define SSL_SIG_LENGTH 36
static int encode_pkcs1(unsigned char **, int *, int , const unsigned char *,
unsigned int);
/*
* encode_pkcs1 encodes a DigestInfo prefix of hash `type' and digest `m', as
* described in EMSA-PKCS-v1_5-ENCODE, RFC 8017 section 9. step 2. This
* encodes the DigestInfo (T and tLen) but does not add the padding.
*
* On success, it returns one and sets `*out' to a newly allocated buffer
* containing the result and `*out_len' to its length. Freeing `*out' is
* the caller's responsibility. Failure is indicated by zero.
*/
static int
encode_pkcs1(unsigned char **out, int *out_len, int type,
const unsigned char *m, unsigned int m_len)
{
X509_SIG sig;
X509_ALGOR algor;
ASN1_TYPE parameter;
ASN1_OCTET_STRING digest;
uint8_t *der = NULL;
int len;
sig.algor = &algor;
if ((sig.algor->algorithm = OBJ_nid2obj(type)) == NULL) {
RSAerror(RSA_R_UNKNOWN_ALGORITHM_TYPE);
return 0;
}
if (sig.algor->algorithm->length == 0) {
RSAerror(
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;
if ((len = i2d_X509_SIG(&sig, &der)) < 0)
return 0;
*out = der;
*out_len = len;
return 1;
}
int
RSA_sign(int type, const unsigned char *m, unsigned int m_len,
unsigned char *sigret, unsigned int *siglen, RSA *rsa)
{
const unsigned char *encoded = NULL;
unsigned char *tmps = NULL;
int encrypt_len, encoded_len = 0, ret = 0;
if ((rsa->flags & RSA_FLAG_SIGN_VER) && rsa->meth->rsa_sign != NULL)
return rsa->meth->rsa_sign(type, m, m_len, sigret, siglen, rsa);
/* Compute the encoded digest. */
if (type == NID_md5_sha1) {
/*
* NID_md5_sha1 corresponds to the MD5/SHA1 combination in
* TLS 1.1 and earlier. It has no DigestInfo wrapper but
* otherwise is RSASSA-PKCS-v1.5.
*/
if (m_len != SSL_SIG_LENGTH) {
RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
return 0;
}
encoded_len = SSL_SIG_LENGTH;
encoded = m;
} else {
if (!encode_pkcs1(&tmps, &encoded_len, type, m, m_len))
goto err;
encoded = tmps;
}
if (encoded_len > RSA_size(rsa) - RSA_PKCS1_PADDING_SIZE) {
RSAerror(RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
goto err;
}
if ((encrypt_len = RSA_private_encrypt(encoded_len, encoded, sigret,
rsa, RSA_PKCS1_PADDING)) <= 0)
goto err;
*siglen = encrypt_len;
ret = 1;
err:
freezero(tmps, (size_t)encoded_len);
return (ret);
}
/*
* int_rsa_verify verifies an RSA signature in `sigbuf' using `rsa'. It may be
* called in two modes. If `rm' is NULL, it verifies the signature for the
* digest `m'. Otherwise, it recovers the digest from the signature, writing the
* digest to `rm' and the length to `*prm_len'. `type' is the NID of the digest
* algorithm to use. It returns one on successful verification and zero
* otherwise.
*/
int
int_rsa_verify(int type, const unsigned char *m, unsigned int m_len,
unsigned char *rm, size_t *prm_len, const unsigned char *sigbuf,
size_t siglen, RSA *rsa)
{
unsigned char *decrypt_buf, *encoded = NULL;
int decrypt_len, encoded_len = 0, ret = 0;
if (siglen != (size_t)RSA_size(rsa)) {
RSAerror(RSA_R_WRONG_SIGNATURE_LENGTH);
return 0;
}
/* Recover the encoded digest. */
if ((decrypt_buf = malloc(siglen)) == NULL) {
RSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
if ((decrypt_len = RSA_public_decrypt((int)siglen, sigbuf, decrypt_buf,
rsa, RSA_PKCS1_PADDING)) <= 0)
goto err;
if (type == NID_md5_sha1) {
/*
* NID_md5_sha1 corresponds to the MD5/SHA1 combination in
* TLS 1.1 and earlier. It has no DigestInfo wrapper but
* otherwise is RSASSA-PKCS1-v1_5.
*/
if (decrypt_len != SSL_SIG_LENGTH) {
RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
goto err;
}
if (rm != NULL) {
memcpy(rm, decrypt_buf, SSL_SIG_LENGTH);
*prm_len = SSL_SIG_LENGTH;
} else {
if (m_len != SSL_SIG_LENGTH) {
RSAerror(RSA_R_INVALID_MESSAGE_LENGTH);
goto err;
}
if (timingsafe_bcmp(decrypt_buf,
m, SSL_SIG_LENGTH) != 0) {
RSAerror(RSA_R_BAD_SIGNATURE);
goto err;
}
}
} else {
/*
* If recovering the digest, extract a digest-sized output from
* the end of `decrypt_buf' for `encode_pkcs1', then compare the
* decryption output as in a standard verification.
*/
if (rm != NULL) {
const EVP_MD *md;
if ((md = EVP_get_digestbynid(type)) == NULL) {
RSAerror(RSA_R_UNKNOWN_ALGORITHM_TYPE);
goto err;
}
if ((m_len = EVP_MD_size(md)) > (size_t)decrypt_len) {
RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
goto err;
}
m = decrypt_buf + decrypt_len - m_len;
}
/* Construct the encoded digest and ensure it matches */
if (!encode_pkcs1(&encoded, &encoded_len, type, m, m_len))
goto err;
if (encoded_len != decrypt_len ||
timingsafe_bcmp(encoded, decrypt_buf, encoded_len) != 0) {
RSAerror(RSA_R_BAD_SIGNATURE);
goto err;
}
/* Output the recovered digest. */
if (rm != NULL) {
memcpy(rm, m, m_len);
*prm_len = m_len;
}
}
ret = 1;
err:
freezero(encoded, (size_t)encoded_len);
freezero(decrypt_buf, 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->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);
}