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 
mptcp_crypto_key_sha(u64 key,u32 * token,u64 * idsn)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 
mptcp_crypto_hmac_sha(u64 key1,u64 key2,u8 * msg,int len,void * hmac)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