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From: Mat Martineau <>
Cc: Florian Westphal <>,,,,,,,
	Mat Martineau <>
Subject: [PATCH net 1/4] mptcp: remove tcp ulp setsockopt support
Date: Tue, 14 Dec 2021 15:16:01 -0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

From: Florian Westphal <>

TCP_ULP setsockopt cannot be used for mptcp because its already
used internally to plumb subflow (tcp) sockets to the mptcp layer.

syzbot managed to trigger a crash for mptcp connections that are
in fallback mode:

KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 1083 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0
RIP: 0010:tls_build_proto net/tls/tls_main.c:776 [inline]
 __tcp_set_ulp net/ipv4/tcp_ulp.c:139 [inline]
 tcp_set_ulp+0x428/0x4c0 net/ipv4/tcp_ulp.c:160
 do_tcp_setsockopt+0x455/0x37c0 net/ipv4/tcp.c:3391
 mptcp_setsockopt+0x1b47/0x2400 net/mptcp/sockopt.c:638

Remove support for TCP_ULP setsockopt.

Fixes: d9e4c1291810 ("mptcp: only admit explicitly supported sockopt")
Signed-off-by: Florian Westphal <>
Signed-off-by: Mat Martineau <>
 net/mptcp/sockopt.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 0f1e661c2032..f8efd478ac97 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -525,7 +525,6 @@ static bool mptcp_supported_sockopt(int level, int optname)
 		case TCP_NODELAY:
-		case TCP_ULP:
 		case TCP_CORK:

  reply	other threads:[~2021-12-14 23:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-14 23:16 [PATCH net 0/4] mptcp: Fixes for ULP, a deadlock, and netlink docs Mat Martineau
2021-12-14 23:16 ` Mat Martineau [this message]
2021-12-14 23:16 ` [PATCH net 2/4] mptcp: clear 'kern' flag from fallback sockets Mat Martineau
2021-12-14 23:16 ` [PATCH net 3/4] mptcp: fix deadlock in __mptcp_push_pending() Mat Martineau
2021-12-14 23:16 ` [PATCH net 4/4] mptcp: add missing documented NL params Mat Martineau
2021-12-15  4:40 ` [PATCH net 0/4] mptcp: Fixes for ULP, a deadlock, and netlink docs patchwork-bot+netdevbpf

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