linux/net/mptcp/crypto.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/* Multipath TCP cryptographic functions
   3 * Copyright (c) 2017 - 2019, Intel Corporation.
   4 *
   5 * Note: This code is based on mptcp_ctrl.c, mptcp_ipv4.c, and
   6 *       mptcp_ipv6 from multipath-tcp.org, authored by:
   7 *
   8 *       S\xC3\xA9bastien Barr\xC3\xA9 <sebastien.barre@uclouvain.be>
   9 *       Christoph Paasch <christoph.paasch@uclouvain.be>
  10 *       Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
  11 *       Gregory Detal <gregory.detal@uclouvain.be>
  12 *       Fabien Duch\xC3\xAAne <fabien.duchene@uclouvain.be>
  13 *       Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
  14 *       Lavkesh Lahngir <lavkesh51@gmail.com>
  15 *       Andreas Ripke <ripke@neclab.eu>
  16 *       Vlad Dogaru <vlad.dogaru@intel.com>
  17 *       Octavian Purdila <octavian.purdila@intel.com>
  18 *       John Ronan <jronan@tssg.org>
  19 *       Catalin Nicutar <catalin.nicutar@gmail.com>
  20 *       Brandon Heller <brandonh@stanford.edu>
  21 */
  22
  23#include <linux/kernel.h>
  24#include <crypto/sha2.h>
  25#include <asm/unaligned.h>
  26
  27#include "protocol.h"
  28
  29#define SHA256_DIGEST_WORDS (SHA256_DIGEST_SIZE / 4)
  30
  31void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn)
  32{
  33        __be32 mptcp_hashed_key[SHA256_DIGEST_WORDS];
  34        __be64 input = cpu_to_be64(key);
  35
  36        sha256((__force u8 *)&input, sizeof(input), (u8 *)mptcp_hashed_key);
  37
  38        if (token)
  39                *token = be32_to_cpu(mptcp_hashed_key[0]);
  40        if (idsn)
  41                *idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[6]));
  42}
  43
  44void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac)
  45{
  46        u8 input[SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE];
  47        u8 key1be[8];
  48        u8 key2be[8];
  49        int i;
  50
  51        if (WARN_ON_ONCE(len > SHA256_DIGEST_SIZE))
  52                len = SHA256_DIGEST_SIZE;
  53
  54        put_unaligned_be64(key1, key1be);
  55        put_unaligned_be64(key2, key2be);
  56
  57        /* Generate key xored with ipad */
  58        memset(input, 0x36, SHA256_BLOCK_SIZE);
  59        for (i = 0; i < 8; i++)
  60                input[i] ^= key1be[i];
  61        for (i = 0; i < 8; i++)
  62                input[i + 8] ^= key2be[i];
  63
  64        memcpy(&input[SHA256_BLOCK_SIZE], msg, len);
  65
  66        /* emit sha256(K1 || msg) on the second input block, so we can
  67         * reuse 'input' for the last hashing
  68         */
  69        sha256(input, SHA256_BLOCK_SIZE + len, &input[SHA256_BLOCK_SIZE]);
  70
  71        /* Prepare second part of hmac */
  72        memset(input, 0x5C, SHA256_BLOCK_SIZE);
  73        for (i = 0; i < 8; i++)
  74                input[i] ^= key1be[i];
  75        for (i = 0; i < 8; i++)
  76                input[i + 8] ^= key2be[i];
  77
  78        sha256(input, SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE, hmac);
  79}
  80
  81#if IS_MODULE(CONFIG_MPTCP_KUNIT_TEST)
  82EXPORT_SYMBOL_GPL(mptcp_crypto_hmac_sha);
  83#endif
  84