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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include "error/s2n_errno.h"
#include "stuffer/s2n_stuffer.h"
#include "crypto/s2n_hash.h"
#include "crypto/s2n_rsa_pss.h"
#include "crypto/s2n_rsa_signing.h"
#include "crypto/s2n_pkey.h"
#include "utils/s2n_blob.h"
#include "utils/s2n_safety.h"
static int s2n_hash_alg_to_NID[] = {
[S2N_HASH_MD5_SHA1] = NID_md5_sha1,
[S2N_HASH_SHA1] = NID_sha1,
[S2N_HASH_SHA224] = NID_sha224,
[S2N_HASH_SHA256] = NID_sha256,
[S2N_HASH_SHA384] = NID_sha384,
[S2N_HASH_SHA512] = NID_sha512 };
int s2n_hash_NID_type(s2n_hash_algorithm alg, int *out)
{
switch(alg) {
case S2N_HASH_MD5_SHA1:
case S2N_HASH_SHA1:
case S2N_HASH_SHA224:
case S2N_HASH_SHA256:
case S2N_HASH_SHA384:
case S2N_HASH_SHA512:
*out = s2n_hash_alg_to_NID[alg];
break;
default:
S2N_ERROR(S2N_ERR_HASH_INVALID_ALGORITHM);
}
return 0;
}
int s2n_rsa_pkcs1v15_sign(const struct s2n_pkey *priv, struct s2n_hash_state *digest, struct s2n_blob *signature)
{
uint8_t digest_length;
int NID_type;
GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
GUARD(s2n_hash_NID_type(digest->alg, &NID_type));
lte_check(digest_length, S2N_MAX_DIGEST_LEN);
const s2n_rsa_private_key *key = &priv->key.rsa_key;
uint8_t digest_out[S2N_MAX_DIGEST_LEN];
GUARD(s2n_hash_digest(digest, digest_out, digest_length));
unsigned int signature_size = signature->size;
GUARD_OSSL(RSA_sign(NID_type, digest_out, digest_length, signature->data, &signature_size, key->rsa), S2N_ERR_SIGN);
S2N_ERROR_IF(signature_size > signature->size, S2N_ERR_SIZE_MISMATCH);
signature->size = signature_size;
return 0;
}
int s2n_rsa_pkcs1v15_verify(const struct s2n_pkey *pub, struct s2n_hash_state *digest, struct s2n_blob *signature)
{
uint8_t digest_length;
int digest_NID_type;
GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
GUARD(s2n_hash_NID_type(digest->alg, &digest_NID_type));
lte_check(digest_length, S2N_MAX_DIGEST_LEN);
const s2n_rsa_public_key *key = &pub->key.rsa_key;
uint8_t digest_out[S2N_MAX_DIGEST_LEN];
GUARD(s2n_hash_digest(digest, digest_out, digest_length));
GUARD_OSSL(RSA_verify(digest_NID_type, digest_out, digest_length, signature->data, signature->size, key->rsa), S2N_ERR_VERIFY_SIGNATURE);
return 0;
}
/* this function returns whether RSA PSS signing is supported */
int s2n_is_rsa_pss_signing_supported()
{
return RSA_PSS_SIGNING_SUPPORTED;
}
#if RSA_PSS_SIGNING_SUPPORTED
const EVP_MD* s2n_hash_alg_to_evp_alg(s2n_hash_algorithm alg)
{
switch (alg) {
case S2N_HASH_MD5_SHA1:
return EVP_md5_sha1();
case S2N_HASH_SHA1:
return EVP_sha1();
case S2N_HASH_SHA224:
return EVP_sha224();
case S2N_HASH_SHA256:
return EVP_sha256();
case S2N_HASH_SHA384:
return EVP_sha384();
case S2N_HASH_SHA512:
return EVP_sha512();
default:
return NULL;
}
}
/* On some versions of OpenSSL, "EVP_PKEY_CTX_set_signature_md()" is just a macro that casts digest_alg to "void*",
* which fails to compile when the "-Werror=cast-qual" compiler flag is enabled. So we work around this OpenSSL
* issue by turning off this compiler check for this one function with a cast through. */
static int s2n_evp_pkey_ctx_set_rsa_signature_digest(EVP_PKEY_CTX *ctx, const EVP_MD* digest_alg)
{
GUARD_OSSL(EVP_PKEY_CTX_set_signature_md(ctx,(EVP_MD*) (uintptr_t) digest_alg), S2N_ERR_INVALID_SIGNATURE_ALGORITHM);
GUARD_OSSL(EVP_PKEY_CTX_set_rsa_mgf1_md(ctx, (EVP_MD*) (uintptr_t) digest_alg), S2N_ERR_INVALID_SIGNATURE_ALGORITHM);
return 0;
}
static void s2n_evp_pkey_ctx_free(EVP_PKEY_CTX **ctx)
{
EVP_PKEY_CTX_free(*ctx);
}
int s2n_rsa_pss_sign(const struct s2n_pkey *priv, struct s2n_hash_state *digest, struct s2n_blob *signature_out)
{
notnull_check(priv);
uint8_t digest_length;
uint8_t digest_data[S2N_MAX_DIGEST_LEN];
GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
GUARD(s2n_hash_digest(digest, digest_data, digest_length));
const EVP_MD* digest_alg = s2n_hash_alg_to_evp_alg(digest->alg);
notnull_check(digest_alg);
/* For more info see: https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_sign.html */
DEFER_CLEANUP(EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new(priv->pkey, NULL), s2n_evp_pkey_ctx_free);
notnull_check(ctx);
size_t signature_len = signature_out->size;
GUARD_OSSL(EVP_PKEY_sign_init(ctx), S2N_ERR_SIGN);
GUARD_OSSL(EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PSS_PADDING), S2N_ERR_SIGN);
GUARD(s2n_evp_pkey_ctx_set_rsa_signature_digest(ctx, digest_alg));
GUARD_OSSL(EVP_PKEY_CTX_set_rsa_pss_saltlen(ctx, RSA_PSS_SALTLEN_DIGEST), S2N_ERR_SIGN);
/* Calling EVP_PKEY_sign() with NULL will only update the signature_len parameter so users can validate sizes. */
GUARD_OSSL(EVP_PKEY_sign(ctx, NULL, &signature_len, digest_data, digest_length), S2N_ERR_SIGN);
S2N_ERROR_IF(signature_len > signature_out->size, S2N_ERR_SIZE_MISMATCH);
/* Actually sign the the digest */
GUARD_OSSL(EVP_PKEY_sign(ctx, signature_out->data, &signature_len, digest_data, digest_length), S2N_ERR_SIGN);
signature_out->size = signature_len;
return 0;
}
int s2n_rsa_pss_verify(const struct s2n_pkey *pub, struct s2n_hash_state *digest, struct s2n_blob *signature_in)
{
notnull_check(pub);
uint8_t digest_length;
uint8_t digest_data[S2N_MAX_DIGEST_LEN];
GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
GUARD(s2n_hash_digest(digest, digest_data, digest_length));
const EVP_MD* digest_alg = s2n_hash_alg_to_evp_alg(digest->alg);
notnull_check(digest_alg);
/* For more info see: https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_verify.html */
DEFER_CLEANUP(EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new(pub->pkey, NULL), s2n_evp_pkey_ctx_free);
notnull_check(ctx);
GUARD_OSSL(EVP_PKEY_verify_init(ctx), S2N_ERR_VERIFY_SIGNATURE);
GUARD_OSSL(EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PSS_PADDING), S2N_ERR_SIGN);
GUARD(s2n_evp_pkey_ctx_set_rsa_signature_digest(ctx, digest_alg));
GUARD_OSSL(EVP_PKEY_verify(ctx, signature_in->data, signature_in->size, digest_data, digest_length), S2N_ERR_VERIFY_SIGNATURE);
return 0;
}
#else
int s2n_rsa_pss_sign(const struct s2n_pkey *priv, struct s2n_hash_state *digest, struct s2n_blob *signature_out)
{
S2N_ERROR(S2N_RSA_PSS_NOT_SUPPORTED);
}
int s2n_rsa_pss_verify(const struct s2n_pkey *pub, struct s2n_hash_state *digest, struct s2n_blob *signature_in)
{
S2N_ERROR(S2N_RSA_PSS_NOT_SUPPORTED);
}
#endif
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