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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/rc4.h>
#include "crypto/s2n_cipher.h"
#include "crypto/s2n_fips.h"
#include "crypto/s2n_openssl.h"
#include "utils/s2n_blob.h"
#include "utils/s2n_safety.h"
#if S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)
#error #include "openssl/provider.h"
DEFINE_POINTER_CLEANUP_FUNC(OSSL_LIB_CTX *, OSSL_LIB_CTX_free);
#endif
static EVP_CIPHER *s2n_rc4_cipher = NULL;
S2N_RESULT s2n_rc4_init()
{
/* In Openssl-3.0, RC4 is only available from the "legacy" provider,
* which is not loaded in the default library context.
*/
#if defined(S2N_LIBCRYPTO_SUPPORTS_EVP_RC4) && S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)
DEFER_CLEANUP(OSSL_LIB_CTX *lib_ctx = OSSL_LIB_CTX_new(), OSSL_LIB_CTX_free_pointer);
RESULT_ENSURE_REF(lib_ctx);
RESULT_ENSURE_REF(OSSL_PROVIDER_load(lib_ctx, "legacy"));
s2n_rc4_cipher = EVP_CIPHER_fetch(lib_ctx, "rc4", "provider=legacy");
RESULT_ENSURE_REF(s2n_rc4_cipher);
#endif
return S2N_RESULT_OK;
}
S2N_RESULT s2n_rc4_cleanup()
{
#if S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)
EVP_CIPHER_free(s2n_rc4_cipher);
#endif
return S2N_RESULT_OK;
}
static S2N_RESULT s2n_get_rc4_cipher(const EVP_CIPHER **cipher)
{
RESULT_ENSURE_REF(cipher);
*cipher = NULL;
if (s2n_is_in_fips_mode()) {
*cipher = NULL;
} else if (s2n_rc4_cipher) {
*cipher = s2n_rc4_cipher;
#if S2N_LIBCRYPTO_SUPPORTS_EVP_RC4
} else {
*cipher = EVP_rc4();
#endif
}
RESULT_ENSURE(*cipher, S2N_ERR_UNIMPLEMENTED);
return S2N_RESULT_OK;
}
static uint8_t s2n_stream_cipher_rc4_available()
{
const EVP_CIPHER *cipher = NULL;
if (s2n_result_is_ok(s2n_get_rc4_cipher(&cipher)) && cipher) {
return 1;
}
return 0;
}
static int s2n_stream_cipher_rc4_encrypt(struct s2n_session_key *key, struct s2n_blob *in, struct s2n_blob *out)
{
POSIX_ENSURE_GTE(out->size, in->size);
/* len is set by EVP_EncryptUpdate and checked post operation */
int len = 0;
POSIX_GUARD_OSSL(EVP_EncryptUpdate(key->evp_cipher_ctx, out->data, &len, in->data, in->size), S2N_ERR_ENCRYPT);
POSIX_ENSURE((int64_t) len == (int64_t) in->size, S2N_ERR_DECRYPT);
return 0;
}
static int s2n_stream_cipher_rc4_decrypt(struct s2n_session_key *key, struct s2n_blob *in, struct s2n_blob *out)
{
POSIX_ENSURE_GTE(out->size, in->size);
/* len is set by EVP_DecryptUpdate and checked post operation */
int len = 0;
POSIX_GUARD_OSSL(EVP_DecryptUpdate(key->evp_cipher_ctx, out->data, &len, in->data, in->size), S2N_ERR_DECRYPT);
POSIX_ENSURE((int64_t) len == (int64_t) in->size, S2N_ERR_DECRYPT);
return 0;
}
static int s2n_stream_cipher_rc4_set_encryption_key(struct s2n_session_key *key, struct s2n_blob *in)
{
POSIX_ENSURE_EQ(in->size, 16);
const EVP_CIPHER *evp_rc4 = NULL;
POSIX_GUARD_RESULT(s2n_get_rc4_cipher(&evp_rc4));
POSIX_GUARD_OSSL(EVP_EncryptInit_ex(key->evp_cipher_ctx, evp_rc4, NULL, in->data, NULL), S2N_ERR_KEY_INIT);
return S2N_SUCCESS;
}
static int s2n_stream_cipher_rc4_set_decryption_key(struct s2n_session_key *key, struct s2n_blob *in)
{
POSIX_ENSURE_EQ(in->size, 16);
const EVP_CIPHER *evp_rc4 = NULL;
POSIX_GUARD_RESULT(s2n_get_rc4_cipher(&evp_rc4));
POSIX_GUARD_OSSL(EVP_DecryptInit_ex(key->evp_cipher_ctx, evp_rc4, NULL, in->data, NULL), S2N_ERR_KEY_INIT);
return S2N_SUCCESS;
}
static int s2n_stream_cipher_rc4_init(struct s2n_session_key *key)
{
s2n_evp_ctx_init(key->evp_cipher_ctx);
return 0;
}
static int s2n_stream_cipher_rc4_destroy_key(struct s2n_session_key *key)
{
EVP_CIPHER_CTX_cleanup(key->evp_cipher_ctx);
return 0;
}
const struct s2n_cipher s2n_rc4 = {
.type = S2N_STREAM,
.key_material_size = 16,
.io.stream = {
.decrypt = s2n_stream_cipher_rc4_decrypt,
.encrypt = s2n_stream_cipher_rc4_encrypt },
.is_available = s2n_stream_cipher_rc4_available,
.init = s2n_stream_cipher_rc4_init,
.set_decryption_key = s2n_stream_cipher_rc4_set_decryption_key,
.set_encryption_key = s2n_stream_cipher_rc4_set_encryption_key,
.destroy_key = s2n_stream_cipher_rc4_destroy_key,
};
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