* Re: [PATCH net 1/2] net: tls: explicitly disallow disconnect
2025-04-15 3:16 ` [PATCH net 1/2] net: tls: explicitly disallow disconnect Ihor Solodrai
@ 2025-04-15 8:24 ` Paolo Abeni
2025-04-15 10:43 ` Jiayuan Chen
1 sibling, 0 replies; 3+ messages in thread
From: Paolo Abeni @ 2025-04-15 8:24 UTC (permalink / raw)
To: Ihor Solodrai, Jakub Kicinski, davem
Cc: netdev, edumazet, andrew+netdev, horms, borisp, john.fastabend,
sd, syzbot+b4cd76826045a1eb93c1, bpf, jiayuan.chen,
Alexei Starovoitov
On 4/15/25 5:16 AM, Ihor Solodrai wrote:
> On 4/4/25 11:03 AM, Jakub Kicinski wrote:
>> syzbot discovered that it can disconnect a TLS socket and then
>> run into all sort of unexpected corner cases. I have a vague
>> recollection of Eric pointing this out to us a long time ago.
>> Supporting disconnect is really hard, for one thing if offload
>> is enabled we'd need to wait for all packets to be _acked_.
>> Disconnect is not commonly used, disallow it.
>>
>> The immediate problem syzbot run into is the warning in the strp,
>> but that's just the easiest bug to trigger:
>>
>> WARNING: CPU: 0 PID: 5834 at net/tls/tls_strp.c:486 tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486
>> RIP: 0010:tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486
>> Call Trace:
>> <TASK>
>> tls_rx_rec_wait+0x280/0xa60 net/tls/tls_sw.c:1363
>> tls_sw_recvmsg+0x85c/0x1c30 net/tls/tls_sw.c:2043
>> inet6_recvmsg+0x2c9/0x730 net/ipv6/af_inet6.c:678
>> sock_recvmsg_nosec net/socket.c:1023 [inline]
>> sock_recvmsg+0x109/0x280 net/socket.c:1045
>> __sys_recvfrom+0x202/0x380 net/socket.c:2237
>>
>> Fixes: 3c4d7559159b ("tls: kernel TLS support")
>> Reported-by: syzbot+b4cd76826045a1eb93c1@syzkaller.appspotmail.com
>> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
>
> Hi everyone.
>
> This patch has broken a BPF selftest and as a result BPF CI:
> * https://github.com/kernel-patches/bpf/actions/runs/14458537639
> * https://github.com/kernel-patches/bpf/actions/runs/14457178732
>
> The test in question is test_sockmap_ktls_disconnect_after_delete
> (tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c) [1].
>
> Since the test is about disconnect use-case, and the patch disallows
> it, I assume it's appropriate to simply remove the test?
Ideally, yes. disconnect() implementation by its own nature error and
race prone, I guess TLS adds some more spice to it. Unless there is a
real end-user scenario behind it, removing the disconnect()
implementation is by far the best option.
Still the test presence hints at some possible use-case[???]. Was it
created using the plain tcp test cases as a template?
Thanks,
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH net 1/2] net: tls: explicitly disallow disconnect
2025-04-15 3:16 ` [PATCH net 1/2] net: tls: explicitly disallow disconnect Ihor Solodrai
2025-04-15 8:24 ` Paolo Abeni
@ 2025-04-15 10:43 ` Jiayuan Chen
1 sibling, 0 replies; 3+ messages in thread
From: Jiayuan Chen @ 2025-04-15 10:43 UTC (permalink / raw)
To: Ihor Solodrai, Jakub Kicinski, davem
Cc: netdev, edumazet, pabeni, andrew+netdev, horms, borisp,
john.fastabend, sd, Jakub Kicinski, syzbot+b4cd76826045a1eb93c1,
bpf, Alexei Starovoitov
April 15, 2025 at 11:16, "Ihor Solodrai" <ihor.solodrai@linux.dev> wrote:
>
> On 4/4/25 11:03 AM, Jakub Kicinski wrote:
>
> >
> > syzbot discovered that it can disconnect a TLS socket and then
> >
> > run into all sort of unexpected corner cases. I have a vague
> >
> > recollection of Eric pointing this out to us a long time ago.
> >
> > Supporting disconnect is really hard, for one thing if offload
> >
> > is enabled we'd need to wait for all packets to be _acked_.
> >
> > Disconnect is not commonly used, disallow it.
> >
> > The immediate problem syzbot run into is the warning in the strp,
> >
> > but that's just the easiest bug to trigger:
> >
> > WARNING: CPU: 0 PID: 5834 at net/tls/tls_strp.c:486 tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486
> >
> > RIP: 0010:tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486
> >
> > Call Trace:
> >
> > <TASK>
> >
> > tls_rx_rec_wait+0x280/0xa60 net/tls/tls_sw.c:1363
> >
> > tls_sw_recvmsg+0x85c/0x1c30 net/tls/tls_sw.c:2043
> >
> > inet6_recvmsg+0x2c9/0x730 net/ipv6/af_inet6.c:678
> >
> > sock_recvmsg_nosec net/socket.c:1023 [inline]
> >
> > sock_recvmsg+0x109/0x280 net/socket.c:1045
> >
> > __sys_recvfrom+0x202/0x380 net/socket.c:2237
> >
> > Fixes: 3c4d7559159b ("tls: kernel TLS support")
> >
> > Reported-by: syzbot+b4cd76826045a1eb93c1@syzkaller.appspotmail.com
> >
> > Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> >
>
> Hi everyone.
>
> This patch has broken a BPF selftest and as a result BPF CI:
>
> * https://github.com/kernel-patches/bpf/actions/runs/14458537639
>
> * https://github.com/kernel-patches/bpf/actions/runs/14457178732
>
> The test in question is test_sockmap_ktls_disconnect_after_delete
>
> (tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c) [1].
>
> Since the test is about disconnect use-case, and the patch disallows
>
> it, I assume it's appropriate to simply remove the test?
>
> Please let me know. Thanks.
>
> [1] https://web.git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/tree/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c#n28
>
> >
> > ---
> > net/tls/tls_main.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> > diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
> > index cb86b0bf9a53..a3ccb3135e51 100644
> > --- a/net/tls/tls_main.c
> > +++ b/net/tls/tls_main.c
> > @@ -852,6 +852,11 @@ static int tls_setsockopt(struct sock *sk, int level, int optname,
> > return do_tls_setsockopt(sk, optname, optval, optlen);
> > }
> >
> >
> > +static int tls_disconnect(struct sock *sk, int flags)
> >
> > +{
> > + return -EOPNOTSUPP;
> > +}
> > +
> > struct tls_context *tls_ctx_create(struct sock *sk)
> > {
> > struct inet_connection_sock *icsk = inet_csk(sk);
> >
> > @@ -947,6 +952,7 @@ static void build_protos(struct proto prot[TLS_NUM_CONFIG][TLS_NUM_CONFIG],
> >
> > prot[TLS_BASE][TLS_BASE] = *base;
> > prot[TLS_BASE][TLS_BASE].setsockopt = tls_setsockopt;
> > prot[TLS_BASE][TLS_BASE].getsockopt = tls_getsockopt;
> > + prot[TLS_BASE][TLS_BASE].disconnect = tls_disconnect;
> > prot[TLS_BASE][TLS_BASE].close = tls_sk_proto_close;
> >
> >
> > prot[TLS_SW][TLS_BASE] = prot[TLS_BASE][TLS_BASE];
> >
>
The original selftest patch d1ba1204f2ee was to re-produce the endless
loop fiexed by 4da6a196f93b.
sk->sk_prot->unhash
tcp_bpf_unhash
sk->sk_prot->unhash
...
It's try to use disconnect to trigger unhash handler.
I believe we can remove it and use another selftest
instead later.
^ permalink raw reply [flat|nested] 3+ messages in thread