diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-11 17:15:31 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-07-13 12:56:49 +0100 |
| commit | 12b8d9ca7e678abc48195294494f1815b555d658 (patch) | |
| tree | eb0cf7b142f2ba30550f218d87781524b11ee14b | |
| parent | 4785a66702f086cf2ea84bdbe6ec921f274bd9f2 (diff) | |
| download | lwn-12b8d9ca7e678abc48195294494f1815b555d658.tar.gz lwn-12b8d9ca7e678abc48195294494f1815b555d658.zip | |
tcp: Fix a data-race around sysctl_tcp_ecn_fallback.
While reading sysctl_tcp_ecn_fallback, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 492135557dc0 ("tcp: add rfc3168, section 6.1.1.1. fallback")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 2 |
2 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 5e308c1715af..108fd86f2718 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -685,6 +685,8 @@ static struct ctl_table ipv4_net_table[] = { .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, }, { .procname = "ip_dynaddr", diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 3dc17551ce25..11aa0ab10bba 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -346,7 +346,7 @@ static void tcp_ecn_send_syn(struct sock *sk, struct sk_buff *skb) static void tcp_ecn_clear_syn(struct sock *sk, struct sk_buff *skb) { - if (sock_net(sk)->ipv4.sysctl_tcp_ecn_fallback) + if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_fallback)) /* tp->ecn_flags are cleared at a later point in time when * SYN ACK is ultimatively being received. */ |