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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"
static const EVP_CIPHER *s2n_evp_rc4()
{
#ifdef S2N_LIBCRYPTO_SUPPORTS_EVP_RC4
return EVP_rc4();
#else
return NULL;
#endif
}
static uint8_t s2n_stream_cipher_rc4_available()
{
if (s2n_is_in_fips_mode()) {
return 0;
}
/* RC4 MIGHT be available in Openssl-3.0, depending on whether or not the
* "legacy" provider is loaded. However, for simplicity, assume that RC4
* is unavailable.
*/
if (S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)) {
return 0;
}
return (s2n_evp_rc4() ? 1 : 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);
POSIX_GUARD_OSSL(EVP_EncryptInit_ex(key->evp_cipher_ctx, s2n_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);
POSIX_GUARD_OSSL(EVP_DecryptInit_ex(key->evp_cipher_ctx, s2n_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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