| Message ID | trinity-f8e0937a-cf0e-4d80-a76e-d9a958ba3ef1-1612535522360@3c-app-gmx-bap12 (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net/vmw_vsock: improve locking in vsock_connect_timeout() | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | warning | 7 maintainers not CCed: jhansen@vmware.com colin.king@canonical.com stefanha@redhat.com andraprs@amazon.com bergwolf@gmail.com davem@davemloft.net jeffv@google.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 19 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
On Fri, Feb 05, 2021 at 03:32:02PM +0100, Norbert Slusarek wrote: >From: Norbert Slusarek <nslusarek@gmx.net> >Date: Fri, 5 Feb 2021 13:14:05 +0100 >Subject: [PATCH] net/vmw_vsock: improve locking in vsock_connect_timeout() > >A possible locking issue in vsock_connect_timeout() was recognized by >Eric Dumazet which might cause a null pointer dereference in >vsock_transport_cancel_pkt(). This patch assures that >vsock_transport_cancel_pkt() will be called within the lock, so a race >condition won't occur which could result in vsk->transport to be set to NULL. > >Fixes: 380feae0def7 ("vsock: cancel packets when failing to connect") I have a doubt about the tag to use, since until we introduced transports in commit c0cfa2d8a788 ("vsock: add multi-transports support") this issue didn't cause many problems. But it must be said that in the commit 380feae0def7 ("vsock: cancel packets when failing to connect") the vsock_transport_cancel_pkt() was called with the lock held in vsock_stream_connect() and without lock in vsock_connect_timeout(), so maybe this tag is okay. Anyway, the patch LGTM: Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> >Reported-by: Eric Dumazet <eric.dumazet@gmail.com> >Signed-off-by: Norbert Slusarek <nslusarek@gmx.net> >--- > net/vmw_vsock/af_vsock.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c >index 6894f21dc147..ad7dd9d93b5b 100644 >--- a/net/vmw_vsock/af_vsock.c >+++ b/net/vmw_vsock/af_vsock.c >@@ -1243,7 +1243,6 @@ static void vsock_connect_timeout(struct work_struct *work) > { > struct sock *sk; > struct vsock_sock *vsk; >- int cancel = 0; > > vsk = container_of(work, struct vsock_sock, connect_work.work); > sk = sk_vsock(vsk); >@@ -1254,11 +1253,9 @@ static void vsock_connect_timeout(struct work_struct *work) > sk->sk_state = TCP_CLOSE; > sk->sk_err = ETIMEDOUT; > sk->sk_error_report(sk); >- cancel = 1; >+ vsock_transport_cancel_pkt(vsk); > } > release_sock(sk); >- if (cancel) >- vsock_transport_cancel_pkt(vsk); > > sock_put(sk); > } >-- >2.30.0 >
On Fri, 5 Feb 2021 18:19:51 +0100 Stefano Garzarella wrote: > On Fri, Feb 05, 2021 at 03:32:02PM +0100, Norbert Slusarek wrote: > >From: Norbert Slusarek <nslusarek@gmx.net> > >Date: Fri, 5 Feb 2021 13:14:05 +0100 > >Subject: [PATCH] net/vmw_vsock: improve locking in vsock_connect_timeout() > > > >A possible locking issue in vsock_connect_timeout() was recognized by > >Eric Dumazet which might cause a null pointer dereference in > >vsock_transport_cancel_pkt(). This patch assures that > >vsock_transport_cancel_pkt() will be called within the lock, so a race > >condition won't occur which could result in vsk->transport to be set to NULL. > > > >Fixes: 380feae0def7 ("vsock: cancel packets when failing to connect") > > I have a doubt about the tag to use, since until we introduced > transports in commit c0cfa2d8a788 ("vsock: add multi-transports > support") this issue didn't cause many problems. > > But it must be said that in the commit 380feae0def7 ("vsock: cancel > packets when failing to connect") the vsock_transport_cancel_pkt() was > called with the lock held in vsock_stream_connect() and without lock in > vsock_connect_timeout(), so maybe this tag is okay. > > Anyway, the patch LGTM: > > Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Applied, thanks!
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 6894f21dc147..ad7dd9d93b5b 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1243,7 +1243,6 @@ static void vsock_connect_timeout(struct work_struct *work) { struct sock *sk; struct vsock_sock *vsk; - int cancel = 0; vsk = container_of(work, struct vsock_sock, connect_work.work); sk = sk_vsock(vsk); @@ -1254,11 +1253,9 @@ static void vsock_connect_timeout(struct work_struct *work) sk->sk_state = TCP_CLOSE; sk->sk_err = ETIMEDOUT; sk->sk_error_report(sk); - cancel = 1; + vsock_transport_cancel_pkt(vsk); } release_sock(sk); - if (cancel) - vsock_transport_cancel_pkt(vsk); sock_put(sk); }