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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 "crypto/s2n_rsa_signing.h"
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include "crypto/s2n_hash.h"
#include "crypto/s2n_pkey.h"
#include "crypto/s2n_rsa_pss.h"
#include "error/s2n_errno.h"
#include "stuffer/s2n_stuffer.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:
POSIX_BAIL(S2N_ERR_HASH_INVALID_ALGORITHM);
}
return 0;
}
int s2n_rsa_pkcs1v15_sign_digest(const struct s2n_pkey *priv, s2n_hash_algorithm hash_alg,
struct s2n_blob *digest, struct s2n_blob *signature)
{
POSIX_ENSURE_REF(priv);
POSIX_ENSURE_REF(digest);
POSIX_ENSURE_REF(signature);
int NID_type = 0;
POSIX_GUARD(s2n_hash_NID_type(hash_alg, &NID_type));
const s2n_rsa_private_key *rsa_key = &priv->key.rsa_key;
unsigned int signature_size = signature->size;
/* Safety: RSA_sign does not mutate the key */
POSIX_GUARD_OSSL(RSA_sign(NID_type, digest->data, digest->size, signature->data, &signature_size,
s2n_unsafe_rsa_get_non_const(rsa_key)),
S2N_ERR_SIGN);
POSIX_ENSURE(signature_size <= signature->size, S2N_ERR_SIZE_MISMATCH);
signature->size = signature_size;
return S2N_SUCCESS;
}
int s2n_rsa_pkcs1v15_sign(const struct s2n_pkey *priv, struct s2n_hash_state *digest, struct s2n_blob *signature)
{
POSIX_ENSURE_REF(digest);
uint8_t digest_length = 0;
POSIX_GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
POSIX_ENSURE_LTE(digest_length, S2N_MAX_DIGEST_LEN);
uint8_t digest_out[S2N_MAX_DIGEST_LEN] = { 0 };
POSIX_GUARD(s2n_hash_digest(digest, digest_out, digest_length));
struct s2n_blob digest_blob = { 0 };
POSIX_GUARD(s2n_blob_init(&digest_blob, digest_out, digest_length));
POSIX_GUARD(s2n_rsa_pkcs1v15_sign_digest(priv, digest->alg, &digest_blob, signature));
return S2N_SUCCESS;
}
int s2n_rsa_pkcs1v15_verify(const struct s2n_pkey *pub, struct s2n_hash_state *digest, struct s2n_blob *signature)
{
uint8_t digest_length = 0;
int digest_NID_type = 0;
POSIX_GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
POSIX_GUARD(s2n_hash_NID_type(digest->alg, &digest_NID_type));
POSIX_ENSURE_LTE(digest_length, S2N_MAX_DIGEST_LEN);
const s2n_rsa_public_key *rsa_key = &pub->key.rsa_key;
uint8_t digest_out[S2N_MAX_DIGEST_LEN];
POSIX_GUARD(s2n_hash_digest(digest, digest_out, digest_length));
/* Safety: RSA_verify does not mutate the key */
POSIX_GUARD_OSSL(RSA_verify(digest_NID_type, digest_out, digest_length, signature->data, signature->size,
s2n_unsafe_rsa_get_non_const(rsa_key)),
S2N_ERR_VERIFY_SIGNATURE);
return 0;
}
/* this function returns whether RSA PSS signing is supported */
int s2n_is_rsa_pss_signing_supported()
{
#if defined(S2N_LIBCRYPTO_SUPPORTS_RSA_PSS_SIGNING)
return 1;
#else
return 0;
#endif
}
#if defined(S2N_LIBCRYPTO_SUPPORTS_RSA_PSS_SIGNING)
static int s2n_evp_pkey_ctx_set_rsa_signature_digest(EVP_PKEY_CTX *ctx, const EVP_MD *digest_alg)
{
POSIX_GUARD_OSSL(S2N_EVP_PKEY_CTX_set_signature_md(ctx, digest_alg), S2N_ERR_INVALID_SIGNATURE_ALGORITHM);
POSIX_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_digest(const struct s2n_pkey *priv, s2n_hash_algorithm hash_alg,
struct s2n_blob *digest_in, struct s2n_blob *signature_out)
{
POSIX_ENSURE_REF(priv);
POSIX_ENSURE_REF(digest_in);
POSIX_ENSURE_REF(signature_out);
const EVP_MD *digest_alg = s2n_hash_alg_to_evp_md(hash_alg);
POSIX_ENSURE_REF(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);
POSIX_ENSURE_REF(ctx);
size_t signature_len = signature_out->size;
POSIX_GUARD_OSSL(EVP_PKEY_sign_init(ctx), S2N_ERR_SIGN);
POSIX_GUARD_OSSL(EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PSS_PADDING), S2N_ERR_SIGN);
POSIX_GUARD(s2n_evp_pkey_ctx_set_rsa_signature_digest(ctx, digest_alg));
POSIX_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. */
POSIX_GUARD_OSSL(EVP_PKEY_sign(ctx, NULL, &signature_len, digest_in->data, digest_in->size), S2N_ERR_SIGN);
POSIX_ENSURE(signature_len <= signature_out->size, S2N_ERR_SIZE_MISMATCH);
/* Actually sign the digest */
POSIX_GUARD_OSSL(EVP_PKEY_sign(ctx, signature_out->data, &signature_len, digest_in->data, digest_in->size), S2N_ERR_SIGN);
signature_out->size = signature_len;
return S2N_SUCCESS;
}
int s2n_rsa_pss_sign(const struct s2n_pkey *priv, struct s2n_hash_state *digest, struct s2n_blob *signature_out)
{
POSIX_ENSURE_REF(digest);
uint8_t digest_length = 0;
uint8_t digest_data[S2N_MAX_DIGEST_LEN] = { 0 };
POSIX_GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
POSIX_GUARD(s2n_hash_digest(digest, digest_data, digest_length));
struct s2n_blob digest_blob = { 0 };
POSIX_GUARD(s2n_blob_init(&digest_blob, digest_data, digest_length));
POSIX_GUARD(s2n_rsa_pss_sign_digest(priv, digest->alg, &digest_blob, signature_out));
return S2N_SUCCESS;
}
int s2n_rsa_pss_verify(const struct s2n_pkey *pub, struct s2n_hash_state *digest, struct s2n_blob *signature_in)
{
POSIX_ENSURE_REF(pub);
uint8_t digest_length = 0;
uint8_t digest_data[S2N_MAX_DIGEST_LEN];
POSIX_GUARD(s2n_hash_digest_size(digest->alg, &digest_length));
POSIX_GUARD(s2n_hash_digest(digest, digest_data, digest_length));
const EVP_MD *digest_alg = s2n_hash_alg_to_evp_md(digest->alg);
POSIX_ENSURE_REF(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);
POSIX_ENSURE_REF(ctx);
POSIX_GUARD_OSSL(EVP_PKEY_verify_init(ctx), S2N_ERR_VERIFY_SIGNATURE);
POSIX_GUARD_OSSL(EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PSS_PADDING), S2N_ERR_VERIFY_SIGNATURE);
POSIX_GUARD(s2n_evp_pkey_ctx_set_rsa_signature_digest(ctx, digest_alg));
POSIX_GUARD_OSSL(EVP_PKEY_CTX_set_rsa_pss_saltlen(ctx, RSA_PSS_SALTLEN_DIGEST), S2N_ERR_VERIFY_SIGNATURE);
POSIX_GUARD_OSSL(EVP_PKEY_verify(ctx, signature_in->data, signature_in->size,
digest_data, digest_length),
S2N_ERR_VERIFY_SIGNATURE);
return S2N_SUCCESS;
}
#else
int s2n_rsa_pss_sign_digest(const struct s2n_pkey *priv, s2n_hash_algorithm hash_alg,
struct s2n_blob *digest_in, struct s2n_blob *signature_out)
{
POSIX_BAIL(S2N_ERR_RSA_PSS_NOT_SUPPORTED);
}
int s2n_rsa_pss_sign(const struct s2n_pkey *priv, struct s2n_hash_state *digest, struct s2n_blob *signature_out)
{
POSIX_BAIL(S2N_ERR_RSA_PSS_NOT_SUPPORTED);
}
int s2n_rsa_pss_verify(const struct s2n_pkey *pub, struct s2n_hash_state *digest, struct s2n_blob *signature_in)
{
POSIX_BAIL(S2N_ERR_RSA_PSS_NOT_SUPPORTED);
}
#endif
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