linux/net/mptcp/crypto.c

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// SPDX-License-Identifier: GPL-2.0
/* Multipath TCP cryptographic functions
* Copyright (c) 2017 - 2019, Intel Corporation.
*
* Note: This code is based on mptcp_ctrl.c, mptcp_ipv4.c, and
* mptcp_ipv6 from multipath-tcp.org, authored by:
*
* Sébastien Barré <sebastien.barre@uclouvain.be>
* Christoph Paasch <christoph.paasch@uclouvain.be>
* Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
* Gregory Detal <gregory.detal@uclouvain.be>
* Fabien Duchêne <fabien.duchene@uclouvain.be>
* Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
* Lavkesh Lahngir <lavkesh51@gmail.com>
* Andreas Ripke <ripke@neclab.eu>
* Vlad Dogaru <vlad.dogaru@intel.com>
* Octavian Purdila <octavian.purdila@intel.com>
* John Ronan <jronan@tssg.org>
* Catalin Nicutar <catalin.nicutar@gmail.com>
* Brandon Heller <brandonh@stanford.edu>
*/
#include <linux/kernel.h>
#include <linux/cryptohash.h>
#include <asm/unaligned.h>
#include "protocol.h"
struct sha1_state {
u32 workspace[SHA_WORKSPACE_WORDS];
u32 digest[SHA_DIGEST_WORDS];
unsigned int count;
};
static void sha1_init(struct sha1_state *state)
{
sha_init(state->digest);
state->count = 0;
}
static void sha1_update(struct sha1_state *state, u8 *input)
{
sha_transform(state->digest, input, state->workspace);
state->count += SHA_MESSAGE_BYTES;
}
static void sha1_pad_final(struct sha1_state *state, u8 *input,
unsigned int length, __be32 *mptcp_hashed_key)
{
int i;
input[length] = 0x80;
memset(&input[length + 1], 0, SHA_MESSAGE_BYTES - length - 9);
put_unaligned_be64((length + state->count) << 3,
&input[SHA_MESSAGE_BYTES - 8]);
sha_transform(state->digest, input, state->workspace);
for (i = 0; i < SHA_DIGEST_WORDS; ++i)
put_unaligned_be32(state->digest[i], &mptcp_hashed_key[i]);
memzero_explicit(state->workspace, SHA_WORKSPACE_WORDS << 2);
}
void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn)
{
__be32 mptcp_hashed_key[SHA_DIGEST_WORDS];
u8 input[SHA_MESSAGE_BYTES];
struct sha1_state state;
sha1_init(&state);
put_unaligned_be64(key, input);
sha1_pad_final(&state, input, 8, mptcp_hashed_key);
if (token)
*token = be32_to_cpu(mptcp_hashed_key[0]);
if (idsn)
*idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[3]));
}
void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
u32 *hash_out)
{
u8 input[SHA_MESSAGE_BYTES * 2];
struct sha1_state state;
u8 key1be[8];
u8 key2be[8];
int i;
put_unaligned_be64(key1, key1be);
put_unaligned_be64(key2, key2be);
/* Generate key xored with ipad */
memset(input, 0x36, SHA_MESSAGE_BYTES);
for (i = 0; i < 8; i++)
input[i] ^= key1be[i];
for (i = 0; i < 8; i++)
input[i + 8] ^= key2be[i];
put_unaligned_be32(nonce1, &input[SHA_MESSAGE_BYTES]);
put_unaligned_be32(nonce2, &input[SHA_MESSAGE_BYTES + 4]);
sha1_init(&state);
sha1_update(&state, input);
/* emit sha256(K1 || msg) on the second input block, so we can
* reuse 'input' for the last hashing
*/
sha1_pad_final(&state, &input[SHA_MESSAGE_BYTES], 8,
(__force __be32 *)&input[SHA_MESSAGE_BYTES]);
/* Prepare second part of hmac */
memset(input, 0x5C, SHA_MESSAGE_BYTES);
for (i = 0; i < 8; i++)
input[i] ^= key1be[i];
for (i = 0; i < 8; i++)
input[i + 8] ^= key2be[i];
sha1_init(&state);
sha1_update(&state, input);
sha1_pad_final(&state, &input[SHA_MESSAGE_BYTES], SHA_DIGEST_WORDS << 2,
(__be32 *)hash_out);
}