net/mptcp/crypto.c

   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  *       Sébastien Barré <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 Duchêne <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 <linux/unaligned.h>
  26
  27 #include "protocol.h"
  28
  29 #define SHA256_DIGEST_WORDS (SHA256_DIGEST_SIZE / 4)
  30
  31 void 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
  44 void 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)
  82 EXPORT_SYMBOL_GPL(mptcp_crypto_hmac_sha);
  83 #endif