From 65492c5a6ab5df5091a77562dbcca2d2dc3877c0 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 21 Jan 2020 16:56:30 -0800 Subject: [PATCH] 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: Paolo Abeni Signed-off-by: Christoph Paasch Signed-off-by: David S. Miller --- net/mptcp/Kconfig | 10 ++++ net/mptcp/crypto.c | 140 ++++++++++++++++++++++++++----------------- net/mptcp/options.c | 9 ++- net/mptcp/protocol.h | 4 +- 4 files changed, 104 insertions(+), 59 deletions(-) diff --git a/net/mptcp/Kconfig b/net/mptcp/Kconfig index c1a99f07a4cd..5db56d2218c5 100644 --- a/net/mptcp/Kconfig +++ b/net/mptcp/Kconfig @@ -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. diff --git a/net/mptcp/crypto.c b/net/mptcp/crypto.c index bbd6d01af211..40d1bb18fd60 100644 --- a/net/mptcp/crypto.c +++ b/net/mptcp/crypto.c @@ -21,67 +21,36 @@ */ #include -#include +#include #include #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 diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 1fa8496f3551..1aec742ca8e1 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -9,6 +9,11 @@ #include #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) { diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index a8fad7d78565..a355bb1cf31b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -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) { -- 2.20.1