/*
* Copyright 2005-2021 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (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
*/
/*
* RSA low level APIs are deprecated for public use, but still ok for
* internal use.
*/
#include "internal/deprecated.h"
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/rand.h>
#include <openssl/sha.h>
#include "rsa_local.h"
static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
#if defined(_MSC_VER) && defined(_ARM_)
# pragma optimize("g", off)
#endif
int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
const EVP_MD *Hash, const unsigned char *EM,
int sLen)
{
return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
}
int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
const EVP_MD *Hash, const EVP_MD *mgf1Hash,
const unsigned char *EM, int sLen)
{
int i;
int ret = 0;
int hLen, maskedDBLen, MSBits, emLen;
const unsigned char *H;
unsigned char *DB = NULL;
EVP_MD_CTX *ctx = EVP_MD_CTX_new();
unsigned char H_[EVP_MAX_MD_SIZE];
if (ctx == NULL)
goto err;
if (mgf1Hash == NULL)
mgf1Hash = Hash;
hLen = EVP_MD_size(Hash);
if (hLen < 0)
goto err;
/*-
* Negative sLen has special meanings:
* -1 sLen == hLen
* -2 salt length is autorecovered from signature
* -3 salt length is maximized
* -N reserved
*/
if (sLen == RSA_PSS_SALTLEN_DIGEST) {
sLen = hLen;
} else if (sLen < RSA_PSS_SALTLEN_MAX) {
ERR_raise(ERR_LIB_RSA, RSA_R_SLEN_CHECK_FAILED);
goto err;
}
MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
emLen = RSA_size(rsa);
if (EM[0] & (0xFF << MSBits)) {
ERR_raise(ERR_LIB_RSA, RSA_R_FIRST_OCTET_INVALID);
goto err;
}
if (MSBits == 0) {
EM++;
emLen--;
}
if (emLen < hLen + 2) {
ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE);
goto err;
}
if (sLen == RSA_PSS_SALTLEN_MAX) {
sLen = emLen - hLen - 2;
} else if (sLen > emLen - hLen - 2) { /* sLen can be small negative */
ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE);
goto err;
}
if (EM[emLen - 1] != 0xbc) {
ERR_raise(ERR_LIB_RSA, RSA_R_LAST_OCTET_INVALID);
goto err;
}
maskedDBLen = emLen - hLen - 1;
H = EM + maskedDBLen;
DB = OPENSSL_malloc(maskedDBLen);
if (DB == NULL) {
ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
goto err;
}
if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
goto err;
for (i = 0; i < maskedDBLen; i++)
DB[i] ^= EM[i];
if (MSBits)
DB[0] &= 0xFF >> (8 - MSBits);
for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ;
if (DB[i++] != 0x1) {
ERR_raise(ERR_LIB_RSA, RSA_R_SLEN_RECOVERY_FAILED);
goto err;
}
if (sLen != RSA_PSS_SALTLEN_AUTO && (maskedDBLen - i) != sLen) {
ERR_raise_data(ERR_LIB_RSA, RSA_R_SLEN_CHECK_FAILED,
"expected: %d retrieved: %d", sLen,
maskedDBLen - i);
goto err;
}
if (!EVP_DigestInit_ex(ctx, Hash, NULL)
|| !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
|| !EVP_DigestUpdate(ctx, mHash, hLen))
goto err;
if (maskedDBLen - i) {
if (!EVP_DigestUpdate(ctx, DB + i, maskedDBLen - i))
goto err;
}
if (!EVP_DigestFinal_ex(ctx, H_, NULL))
goto err;
if (memcmp(H_, H, hLen)) {
ERR_raise(ERR_LIB_RSA, RSA_R_BAD_SIGNATURE);
ret = 0;
} else {
ret = 1;
}
err:
OPENSSL_free(DB);
EVP_MD_CTX_free(ctx);
return ret;
}
int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
const unsigned char *mHash,
const EVP_MD *Hash, int sLen)
{
return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
}
int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
const unsigned char *mHash,
const EVP_MD *Hash, const EVP_MD *mgf1Hash,
int sLen)
{
int i;
int ret = 0;
int hLen, maskedDBLen, MSBits, emLen;
unsigned char *H, *salt = NULL, *p;
EVP_MD_CTX *ctx = NULL;
if (mgf1Hash == NULL)
mgf1Hash = Hash;
hLen = EVP_MD_size(Hash);
if (hLen < 0)
goto err;
/*-
* Negative sLen has special meanings:
* -1 sLen == hLen
* -2 salt length is maximized
* -3 same as above (on signing)
* -N reserved
*/
if (sLen == RSA_PSS_SALTLEN_DIGEST) {
sLen = hLen;
} else if (sLen == RSA_PSS_SALTLEN_MAX_SIGN) {
sLen = RSA_PSS_SALTLEN_MAX;
} else if (sLen < RSA_PSS_SALTLEN_MAX) {
ERR_raise(ERR_LIB_RSA, RSA_R_SLEN_CHECK_FAILED);
goto err;
}
MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
emLen = RSA_size(rsa);
if (MSBits == 0) {
*EM++ = 0;
emLen--;
}
if (emLen < hLen + 2) {
ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
goto err;
}
if (sLen == RSA_PSS_SALTLEN_MAX) {
sLen = emLen - hLen - 2;
} else if (sLen > emLen - hLen - 2) {
ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
goto err;
}
if (sLen > 0) {
salt = OPENSSL_malloc(sLen);
if (salt == NULL) {
ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
goto err;
}
if (RAND_bytes_ex(rsa->libctx, salt, sLen) <= 0)
goto err;
}
maskedDBLen = emLen - hLen - 1;
H = EM + maskedDBLen;
ctx = EVP_MD_CTX_new();
if (ctx == NULL)
goto err;
if (!EVP_DigestInit_ex(ctx, Hash, NULL)
|| !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
|| !EVP_DigestUpdate(ctx, mHash, hLen))
goto err;
if (sLen && !EVP_DigestUpdate(ctx, salt, sLen))
goto err;
if (!EVP_DigestFinal_ex(ctx, H, NULL))
goto err;
/* Generate dbMask in place then perform XOR on it */
if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
goto err;
p = EM;
/*
* Initial PS XORs with all zeroes which is a NOP so just update pointer.
* Note from a test above this value is guaranteed to be non-negative.
*/
p += emLen - sLen - hLen - 2;
*p++ ^= 0x1;
if (sLen > 0) {
for (i = 0; i < sLen; i++)
*p++ ^= salt[i];
}
if (MSBits)
EM[0] &= 0xFF >> (8 - MSBits);
/* H is already in place so just set final 0xbc */
EM[emLen - 1] = 0xbc;
ret = 1;
err:
EVP_MD_CTX_free(ctx);
OPENSSL_clear_free(salt, (size_t)sLen); /* salt != NULL implies sLen > 0 */
return ret;
}
/*
* The defaults for PSS restrictions are defined in RFC 8017, A.2.3 RSASSA-PSS
* (https://tools.ietf.org/html/rfc8017#appendix-A.2.3):
*
* If the default values of the hashAlgorithm, maskGenAlgorithm, and
* trailerField fields of RSASSA-PSS-params are used, then the algorithm
* identifier will have the following value:
*
* rSASSA-PSS-Default-Identifier RSASSA-AlgorithmIdentifier ::= {
* algorithm id-RSASSA-PSS,
* parameters RSASSA-PSS-params : {
* hashAlgorithm sha1,
* maskGenAlgorithm mgf1SHA1,
* saltLength 20,
* trailerField trailerFieldBC
* }
* }
*
* RSASSA-AlgorithmIdentifier ::= AlgorithmIdentifier {
* {PKCS1Algorithms}
* }
*/
static const RSA_PSS_PARAMS_30 default_RSASSA_PSS_params = {
NID_sha1, /* default hashAlgorithm */
{
NID_mgf1, /* default maskGenAlgorithm */
NID_sha1 /* default MGF1 hash */
},
20, /* default saltLength */
1 /* default trailerField (0xBC) */
};
int ossl_rsa_pss_params_30_set_defaults(RSA_PSS_PARAMS_30 *rsa_pss_params)
{
if (rsa_pss_params == NULL)
return 0;
*rsa_pss_params = default_RSASSA_PSS_params;
return 1;
}
int ossl_rsa_pss_params_30_is_unrestricted(const RSA_PSS_PARAMS_30 *rsa_pss_params)
{
static RSA_PSS_PARAMS_30 pss_params_cmp = { 0, };
return rsa_pss_params == NULL
|| memcmp(rsa_pss_params, &pss_params_cmp,
sizeof(*rsa_pss_params)) == 0;
}
int ossl_rsa_pss_params_30_copy(RSA_PSS_PARAMS_30 *to,
const RSA_PSS_PARAMS_30 *from)
{
memcpy(to, from, sizeof(*to));
return 1;
}
int ossl_rsa_pss_params_30_set_hashalg(RSA_PSS_PARAMS_30 *rsa_pss_params,
int hashalg_nid)
{
if (rsa_pss_params == NULL)
return 0;
rsa_pss_params->hash_algorithm_nid = hashalg_nid;
return 1;
}
int ossl_rsa_pss_params_30_set_maskgenalg(RSA_PSS_PARAMS_30 *rsa_pss_params,
int maskgenalg_nid)
{
if (rsa_pss_params == NULL)
return 0;
rsa_pss_params->mask_gen.algorithm_nid = maskgenalg_nid;
return 1;
}
int ossl_rsa_pss_params_30_set_maskgenhashalg(RSA_PSS_PARAMS_30 *rsa_pss_params,
int maskgenhashalg_nid)
{
if (rsa_pss_params == NULL)
return 0;
rsa_pss_params->mask_gen.hash_algorithm_nid = maskgenhashalg_nid;
return 1;
}
int ossl_rsa_pss_params_30_set_saltlen(RSA_PSS_PARAMS_30 *rsa_pss_params,
int saltlen)
{
if (rsa_pss_params == NULL)
return 0;
rsa_pss_params->salt_len = saltlen;
return 1;
}
int ossl_rsa_pss_params_30_set_trailerfield(RSA_PSS_PARAMS_30 *rsa_pss_params,
int trailerfield)
{
if (rsa_pss_params == NULL)
return 0;
rsa_pss_params->trailer_field = trailerfield;
return 1;
}
int ossl_rsa_pss_params_30_hashalg(const RSA_PSS_PARAMS_30 *rsa_pss_params)
{
if (rsa_pss_params == NULL)
return default_RSASSA_PSS_params.hash_algorithm_nid;
return rsa_pss_params->hash_algorithm_nid;
}
int ossl_rsa_pss_params_30_maskgenalg(const RSA_PSS_PARAMS_30 *rsa_pss_params)
{
if (rsa_pss_params == NULL)
return default_RSASSA_PSS_params.mask_gen.algorithm_nid;
return rsa_pss_params->mask_gen.algorithm_nid;
}
int ossl_rsa_pss_params_30_maskgenhashalg(const RSA_PSS_PARAMS_30 *rsa_pss_params)
{
if (rsa_pss_params == NULL)
return default_RSASSA_PSS_params.hash_algorithm_nid;
return rsa_pss_params->mask_gen.hash_algorithm_nid;
}
int ossl_rsa_pss_params_30_saltlen(const RSA_PSS_PARAMS_30 *rsa_pss_params)
{
if (rsa_pss_params == NULL)
return default_RSASSA_PSS_params.salt_len;
return rsa_pss_params->salt_len;
}
int ossl_rsa_pss_params_30_trailerfield(const RSA_PSS_PARAMS_30 *rsa_pss_params)
{
if (rsa_pss_params == NULL)
return default_RSASSA_PSS_params.trailer_field;
return rsa_pss_params->trailer_field;
}
#if defined(_MSC_VER)
# pragma optimize("",on)
#endif