Messages in this thread Patch in this message | | | From | Kuniyuki Iwashima <> | Subject | [PATCH v1 net 13/15] tcp: Fix a data-race around sysctl_tcp_ecn_fallback. | Date | Mon, 11 Jul 2022 17:15:31 -0700 |
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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> --- CC: Daniel Borkmann <daniel@iogearbox.net> CC: Florian Westphal <fw@strlen.de> CC: Mirja Kühlewind <mirja.kuehlewind@tik.ee.ethz.ch> CC: Brian Trammell <trammell@tik.ee.ethz.ch> --- net/ipv4/sysctl_net_ipv4.c | 2 ++ net/ipv4/tcp_output.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-)
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. */ -- 2.30.2
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