Commit 65492c5a authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: move from sha1 (v0) to sha256 (v1) 



For simplicity's sake use directly sha256 primitives (and pull them
as a required build dep).
Add optional, boot-time self-tests for the hmac function.

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarChristoph Paasch <cpaasch@apple.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 048d19d4

net/mptcp/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ config MPTCP 
	bool "MPTCP: Multipath TCP"

	depends on INET

	select SKB_EXTENSIONS

	select CRYPTO_LIB_SHA256

	help

	  Multipath TCP (MPTCP) connections send and receive data over multiple

	  subflows in order to utilize multiple network paths. Each subflow
@@ -14,3 +15,12 @@ config MPTCP_IPV6 
	depends on MPTCP

	select IPV6

	default y



config MPTCP_HMAC_TEST

	bool "Tests for MPTCP HMAC implementation"

	default n

	help

	  This option enable boot time self-test for the HMAC implementation

	  used by the MPTCP code



	  Say N if you are unsure.

net/mptcp/crypto.c

+85 −55
Original line number Diff line number Diff line
@@ -21,67 +21,36 @@ 
 */



#include <linux/kernel.h>

#include <linux/cryptohash.h>

#include <crypto/sha.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);

}

#define SHA256_DIGEST_WORDS (SHA256_DIGEST_SIZE / 4)



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;

	__be32 mptcp_hashed_key[SHA256_DIGEST_WORDS];

	__be64 input = cpu_to_be64(key);

	struct sha256_state state;



	sha1_init(&state);

	put_unaligned_be64(key, input);

	sha1_pad_final(&state, input, 8, mptcp_hashed_key);

	sha256_init(&state);

	sha256_update(&state, (__force u8 *)&input, sizeof(input));

	sha256_final(&state, (u8 *)mptcp_hashed_key);



	if (token)

		*token = be32_to_cpu(mptcp_hashed_key[0]);

	if (idsn)

		*idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[3]));

		*idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[6]));

}



void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,

			   u32 *hash_out)

			   void *hmac)

{

	u8 input[SHA_MESSAGE_BYTES * 2];

	struct sha1_state state;

	u8 input[SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE];

	__be32 mptcp_hashed_key[SHA256_DIGEST_WORDS];

	__be32 *hash_out = (__force __be32 *)hmac;

	struct sha256_state state;

	u8 key1be[8];

	u8 key2be[8];

	int i;
@@ -96,17 +65,16 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2, 
	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]);

	put_unaligned_be32(nonce1, &input[SHA256_BLOCK_SIZE]);

	put_unaligned_be32(nonce2, &input[SHA256_BLOCK_SIZE + 4]);



	sha1_init(&state);

	sha1_update(&state, input);

	sha256_init(&state);

	sha256_update(&state, input, SHA256_BLOCK_SIZE + 8);



	/* 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]);

	sha256_final(&state, &input[SHA256_BLOCK_SIZE]);



	/* Prepare second part of hmac */

	memset(input, 0x5C, SHA_MESSAGE_BYTES);
@@ -115,8 +83,70 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2, 
	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);

	sha256_init(&state);

	sha256_update(&state, input, SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE);

	sha256_final(&state, (u8 *)mptcp_hashed_key);



	/* takes only first 160 bits */

	for (i = 0; i < 5; i++)

		hash_out[i] = mptcp_hashed_key[i];

}



#ifdef CONFIG_MPTCP_HMAC_TEST

struct test_cast {

	char *key;

	char *msg;

	char *result;

};



/* we can't reuse RFC 4231 test vectors, as we have constraint on the

 * input and key size, and we truncate the output.

 */

static struct test_cast tests[] = {

	{

		.key = "0b0b0b0b0b0b0b0b",

		.msg = "48692054",

		.result = "8385e24fb4235ac37556b6b886db106284a1da67",

	},

	{

		.key = "aaaaaaaaaaaaaaaa",

		.msg = "dddddddd",

		.result = "2c5e219164ff1dca1c4a92318d847bb6b9d44492",

	},

	{

		.key = "0102030405060708",

		.msg = "cdcdcdcd",

		.result = "e73b9ba9969969cefb04aa0d6df18ec2fcc075b6",

	},

};



static int __init test_mptcp_crypto(void)

{

	char hmac[20], hmac_hex[41];

	u32 nonce1, nonce2;

	u64 key1, key2;

	int i, j;



	for (i = 0; i < ARRAY_SIZE(tests); ++i) {

		/* mptcp hmap will convert to be before computing the hmac */

		key1 = be64_to_cpu(*((__be64 *)&tests[i].key[0]));

		key2 = be64_to_cpu(*((__be64 *)&tests[i].key[8]));

		nonce1 = be32_to_cpu(*((__be32 *)&tests[i].msg[0]));

		nonce2 = be32_to_cpu(*((__be32 *)&tests[i].msg[4]));



		mptcp_crypto_hmac_sha(key1, key2, nonce1, nonce2, hmac);

		for (j = 0; j < 20; ++j)

			sprintf(&hmac_hex[j << 1], "%02x", hmac[j] & 0xff);

		hmac_hex[40] = 0;



		if (memcmp(hmac_hex, tests[i].result, 40))

			pr_err("test %d failed, got %s expected %s", i,

			       hmac_hex, tests[i].result);

		else

			pr_info("test %d [ ok ]", i);

	}

	return 0;

}



late_initcall(test_mptcp_crypto);

#endif

net/mptcp/options.c

+7 −2
Original line number Diff line number Diff line
@@ -9,6 +9,11 @@ 
#include <net/mptcp.h>

#include "protocol.h"



static bool mptcp_cap_flag_sha256(u8 flags)

{

	return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;

}



void mptcp_parse_option(const unsigned char *ptr, int opsize,

			struct tcp_options_received *opt_rx)

{
@@ -29,7 +34,7 @@ void mptcp_parse_option(const unsigned char *ptr, int opsize, 
			break;



		flags = *ptr++;

		if (!((flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA1) ||

		if (!mptcp_cap_flag_sha256(flags) ||

		    (flags & MPTCP_CAP_EXTENSIBILITY))

			break;
@@ -399,7 +404,7 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts) 
		*ptr++ = htonl((TCPOPT_MPTCP << 24) | (len << 16) |

			       (MPTCPOPT_MP_CAPABLE << 12) |

			       (MPTCP_SUPPORTED_VERSION << 8) |

			       MPTCP_CAP_HMAC_SHA1);

			       MPTCP_CAP_HMAC_SHA256);

		put_unaligned_be64(opts->sndr_key, ptr);

		ptr += 2;

		if (OPTION_MPTCP_MPC_ACK & opts->suboptions) {

net/mptcp/protocol.h

+2 −2
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ 
#define MPTCP_VERSION_MASK	(0x0F)

#define MPTCP_CAP_CHECKSUM_REQD	BIT(7)

#define MPTCP_CAP_EXTENSIBILITY	BIT(6)

#define MPTCP_CAP_HMAC_SHA1	BIT(0)

#define MPTCP_CAP_HMAC_SHA256	BIT(0)

#define MPTCP_CAP_FLAG_MASK	(0x3F)



/* MPTCP DSS flags */
@@ -216,7 +216,7 @@ static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn) 
}



void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,

			   u32 *hash_out);

			   void *hash_out);



static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)

{