| Message ID | 20211205192700.25396-1-fw@strlen.de (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [mptcp] mptcp: remove tcp ulp setsockopt support | expand |
On Sun, 5 Dec 2021 20:27:00 +0100 Florian Westphal wrote: > 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: Fallback mode meaning ops are NULL? I'm slightly confused by this report. > 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. > > Reported-by: syzbot+1fd9b69cde42967d1add@syzkaller.appspotmail.com > Signed-off-by: Florian Westphal <fw@strlen.de>
On Mon, 6 Dec 2021 07:53:26 -0800 Jakub Kicinski wrote: > On Sun, 5 Dec 2021 20:27:00 +0100 Florian Westphal wrote: > > 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: > > Fallback mode meaning ops are NULL? I'm slightly confused by this > report. Ah, it's the socket not the ops. > > 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. > > > > Reported-by: syzbot+1fd9b69cde42967d1add@syzkaller.appspotmail.com > > Signed-off-by: Florian Westphal <fw@strlen.de>
On Mon, 6 Dec 2021, Jakub Kicinski wrote: > On Mon, 6 Dec 2021 07:53:26 -0800 Jakub Kicinski wrote: >> On Sun, 5 Dec 2021 20:27:00 +0100 Florian Westphal wrote: >>> 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: >> >> Fallback mode meaning ops are NULL? I'm slightly confused by this >> report. > > Ah, it's the socket not the ops. > >>> 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. >>> >>> Reported-by: syzbot+1fd9b69cde42967d1add@syzkaller.appspotmail.com >>> Signed-off-by: Florian Westphal <fw@strlen.de> Jakub - If you could mark this as "Not Applicable" in netdevbpf patchwork, we'll apply it to the mptcp tree and resubmit to netdev with some related patches. Thanks, -- Mat Martineau Intel
On Mon, 6 Dec 2021 10:44:16 -0800 (PST) Mat Martineau wrote: > If you could mark this as "Not Applicable" in netdevbpf patchwork, we'll > apply it to the mptcp tree and resubmit to netdev with some related > patches. For sure, I was asking because technically I added the code that hit the oops to tls a week or so ago, so I wanted to make sure it's not my fault ;) Marked in pw appropriately now.
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 3c3db22fd36a..aa3fcd86dbe2 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -543,7 +543,6 @@ static bool mptcp_supported_sockopt(int level, int optname) case TCP_NODELAY: case TCP_THIN_LINEAR_TIMEOUTS: case TCP_CONGESTION: - case TCP_ULP: case TCP_CORK: case TCP_KEEPIDLE: case TCP_KEEPINTVL:
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. Reported-by: syzbot+1fd9b69cde42967d1add@syzkaller.appspotmail.com Signed-off-by: Florian Westphal <fw@strlen.de> ---