From 9a3bab6b05383f1e4c3716b3615500c51285959e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 24 Sep 2013 06:19:57 -0700 Subject: net: net_secret should not depend on TCP A host might need net_secret[] and never open a single socket. Problem added in commit aebda156a570782 ("net: defer net_secret[] initialization") Based on prior patch from Hannes Frederic Sowa. Reported-by: Hannes Frederic Sowa Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/core/secure_seq.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) (limited to 'net/core/secure_seq.c') diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c index 6a2f13cee86..3f1ec1586ae 100644 --- a/net/core/secure_seq.c +++ b/net/core/secure_seq.c @@ -10,11 +10,24 @@ #include -static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned; +#define NET_SECRET_SIZE (MD5_MESSAGE_BYTES / 4) -void net_secret_init(void) +static u32 net_secret[NET_SECRET_SIZE] ____cacheline_aligned; + +static void net_secret_init(void) { - get_random_bytes(net_secret, sizeof(net_secret)); + u32 tmp; + int i; + + if (likely(net_secret[0])) + return; + + for (i = NET_SECRET_SIZE; i > 0;) { + do { + get_random_bytes(&tmp, sizeof(tmp)); + } while (!tmp); + cmpxchg(&net_secret[--i], 0, tmp); + } } #ifdef CONFIG_INET @@ -42,6 +55,7 @@ __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr, u32 hash[MD5_DIGEST_WORDS]; u32 i; + net_secret_init(); memcpy(hash, saddr, 16); for (i = 0; i < 4; i++) secret[i] = net_secret[i] + (__force u32)daddr[i]; @@ -63,6 +77,7 @@ u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, u32 hash[MD5_DIGEST_WORDS]; u32 i; + net_secret_init(); memcpy(hash, saddr, 16); for (i = 0; i < 4; i++) secret[i] = net_secret[i] + (__force u32) daddr[i]; @@ -82,6 +97,7 @@ __u32 secure_ip_id(__be32 daddr) { u32 hash[MD5_DIGEST_WORDS]; + net_secret_init(); hash[0] = (__force __u32) daddr; hash[1] = net_secret[13]; hash[2] = net_secret[14]; @@ -96,6 +112,7 @@ __u32 secure_ipv6_id(const __be32 daddr[4]) { __u32 hash[4]; + net_secret_init(); memcpy(hash, daddr, 16); md5_transform(hash, net_secret); @@ -107,6 +124,7 @@ __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, { u32 hash[MD5_DIGEST_WORDS]; + net_secret_init(); hash[0] = (__force u32)saddr; hash[1] = (__force u32)daddr; hash[2] = ((__force u16)sport << 16) + (__force u16)dport; @@ -121,6 +139,7 @@ u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) { u32 hash[MD5_DIGEST_WORDS]; + net_secret_init(); hash[0] = (__force u32)saddr; hash[1] = (__force u32)daddr; hash[2] = (__force u32)dport ^ net_secret[14]; @@ -140,6 +159,7 @@ u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, u32 hash[MD5_DIGEST_WORDS]; u64 seq; + net_secret_init(); hash[0] = (__force u32)saddr; hash[1] = (__force u32)daddr; hash[2] = ((__force u16)sport << 16) + (__force u16)dport; @@ -164,6 +184,7 @@ u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, u64 seq; u32 i; + net_secret_init(); memcpy(hash, saddr, 16); for (i = 0; i < 4; i++) secret[i] = net_secret[i] + daddr[i]; -- cgit v1.2.3-70-g09d2 From cb03db9d0e964568407fb08ea46cc2b6b7f67587 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Sat, 5 Oct 2013 17:56:59 -0300 Subject: net: secure_seq: Fix warning when CONFIG_IPV6 and CONFIG_INET are not selected net_secret() is only used when CONFIG_IPV6 or CONFIG_INET are selected. Building a defconfig with both of these symbols unselected (Using the ARM at91sam9rl_defconfig, for example) leads to the following build warning: $ make at91sam9rl_defconfig # # configuration written to .config # $ make net/core/secure_seq.o scripts/kconfig/conf --silentoldconfig Kconfig CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h make[1]: `include/generated/mach-types.h' is up to date. CALL scripts/checksyscalls.sh CC net/core/secure_seq.o net/core/secure_seq.c:17:13: warning: 'net_secret_init' defined but not used [-Wunused-function] Fix this warning by protecting the definition of net_secret() with these symbols. Reported-by: Olof Johansson Signed-off-by: Fabio Estevam Signed-off-by: David S. Miller --- net/core/secure_seq.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/core/secure_seq.c') diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c index 3f1ec1586ae..8d9d05edd2e 100644 --- a/net/core/secure_seq.c +++ b/net/core/secure_seq.c @@ -10,6 +10,7 @@ #include +#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET) #define NET_SECRET_SIZE (MD5_MESSAGE_BYTES / 4) static u32 net_secret[NET_SECRET_SIZE] ____cacheline_aligned; @@ -29,6 +30,7 @@ static void net_secret_init(void) cmpxchg(&net_secret[--i], 0, tmp); } } +#endif #ifdef CONFIG_INET static u32 seq_scale(u32 seq) -- cgit v1.2.3-70-g09d2