[PATCH net-next] tcp: md5: check md5 signature without socket lock
From: Dmitry Popov <hidden>
Date: 2014-08-04 22:54:58
Also in:
lkml
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
Since a8afca032 (tcp: md5: protects md5sig_info with RCU) tcp_md5_do_lookup
doesn't require socket lock, rcu_read_lock is enough. Therefore socket lock is
no longer required for tcp_v{4,6}_inbound_md5_hash too, so we can move these
calls (wrapped with rcu_read_{,un}lock) outside of bh_{,un}lock_sock:
from tcp_v{4,6}_do_rcv to tcp_v{4,6}_rcv.
Signed-off-by: Dmitry Popov <redacted>
---
net/ipv4/tcp_ipv4.c | 36 +++++++++++++++++++++++++-----------
net/ipv6/tcp_ipv6.c | 25 +++++++++++++++++++------
2 files changed, 44 insertions(+), 17 deletions(-)diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 77cccda..f2779b1 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -1182,7 +1182,8 @@ clear_hash_noput: } EXPORT_SYMBOL(tcp_v4_md5_hash_skb); -static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) +static bool __tcp_v4_inbound_md5_hash(struct sock *sk, + const struct sk_buff *skb) { /* * This gets called for each TCP segment that arrives
@@ -1235,6 +1236,17 @@ static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) return false; } +static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) +{ + bool ret; + + rcu_read_lock(); + ret = __tcp_v4_inbound_md5_hash(sk, skb); + rcu_read_unlock(); + + return ret; +} + #endif struct request_sock_ops tcp_request_sock_ops __read_mostly = {
@@ -1539,16 +1551,6 @@ static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) { struct sock *rsk; -#ifdef CONFIG_TCP_MD5SIG - /* - * We really want to reject the packet as early as possible - * if: - * o We're expecting an MD5'd packet and this is no MD5 tcp option - * o There is an MD5 option and we're not expecting one - */ - if (tcp_v4_inbound_md5_hash(sk, skb)) - goto discard; -#endif if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ struct dst_entry *dst = sk->sk_rx_dst;
@@ -1751,6 +1753,18 @@ process: if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; + +#ifdef CONFIG_TCP_MD5SIG + /* + * We really want to reject the packet as early as possible + * if: + * o We're expecting an MD5'd packet and this is no MD5 tcp option + * o There is an MD5 option and we're not expecting one + */ + if (tcp_v4_inbound_md5_hash(sk, skb)) + goto discard_and_relse; +#endif + nf_reset(skb); if (sk_filter(sk, skb))
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 229239a..226a237 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c@@ -676,7 +676,8 @@ clear_hash_noput: return 1; } -static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) +static int __tcp_v6_inbound_md5_hash(struct sock *sk, + const struct sk_buff *skb) { const __u8 *hash_location = NULL; struct tcp_md5sig_key *hash_expected;
@@ -716,6 +717,18 @@ static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) } return 0; } + +static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) +{ + int ret; + + rcu_read_lock(); + ret = __tcp_v6_inbound_md5_hash(sk, skb); + rcu_read_unlock(); + + return ret; +} + #endif struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
@@ -1346,11 +1359,6 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) if (skb->protocol == htons(ETH_P_IP)) return tcp_v4_do_rcv(sk, skb); -#ifdef CONFIG_TCP_MD5SIG - if (tcp_v6_inbound_md5_hash(sk, skb)) - goto discard; -#endif - if (sk_filter(sk, skb)) goto discard;
@@ -1523,6 +1531,11 @@ process: if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; +#ifdef CONFIG_TCP_MD5SIG + if (tcp_v6_inbound_md5_hash(sk, skb)) + goto discard_and_relse; +#endif + if (sk_filter(sk, skb)) goto discard_and_relse;