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 <asm/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
84
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