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authorKuniyuki Iwashima <kuniyu@amazon.com>2022-07-20 19:50:19 +0300
committerDavid S. Miller <davem@davemloft.net>2022-07-22 14:06:17 +0300
commit0f1e4d06591d0a7907c71f7b6d1c79f8a4de8098 (patch)
tree5dc1a8cbc4a9887bbf7c43a97bcec98835173e4e
parent780476488844e070580bfc9e3bc7832ec1cea883 (diff)
downloadlinux-0f1e4d06591d0a7907c71f7b6d1c79f8a4de8098.tar.xz
tcp: Fix data-races around sysctl_tcp_workaround_signed_windows.
While reading sysctl_tcp_workaround_signed_windows, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 15d99e02baba ("[TCP]: sysctl to allow TCP window > 32767 sans wscale") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp_output.c4
-rw-r--r--net/mptcp/options.c2
2 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c38e07b50639..88f7d51e6691 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -230,7 +230,7 @@ void tcp_select_initial_window(const struct sock *sk, int __space, __u32 mss,
* which we interpret as a sign the remote TCP is not
* misinterpreting the window field as a signed quantity.
*/
- if (sock_net(sk)->ipv4.sysctl_tcp_workaround_signed_windows)
+ if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_workaround_signed_windows))
(*rcv_wnd) = min(space, MAX_TCP_WINDOW);
else
(*rcv_wnd) = min_t(u32, space, U16_MAX);
@@ -285,7 +285,7 @@ static u16 tcp_select_window(struct sock *sk)
* scaled window.
*/
if (!tp->rx_opt.rcv_wscale &&
- sock_net(sk)->ipv4.sysctl_tcp_workaround_signed_windows)
+ READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_workaround_signed_windows))
new_win = min(new_win, MAX_TCP_WINDOW);
else
new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale));
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index bd8f0f425be4..30d289044e71 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1271,7 +1271,7 @@ raise_win:
if (unlikely(th->syn))
new_win = min(new_win, 65535U) << tp->rx_opt.rcv_wscale;
if (!tp->rx_opt.rcv_wscale &&
- sock_net(ssk)->ipv4.sysctl_tcp_workaround_signed_windows)
+ READ_ONCE(sock_net(ssk)->ipv4.sysctl_tcp_workaround_signed_windows))
new_win = min(new_win, MAX_TCP_WINDOW);
else
new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale));