| From foo@baz Sun 09 Jun 2019 09:24:16 AM CEST |
| From: Willem de Bruijn <willemb@google.com> |
| Date: Fri, 31 May 2019 12:37:23 -0400 |
| Subject: packet: unconditionally free po->rollover |
| |
| From: Willem de Bruijn <willemb@google.com> |
| |
| [ Upstream commit afa0925c6fcc6a8f610e996ca09bc3215048033c ] |
| |
| Rollover used to use a complex RCU mechanism for assignment, which had |
| a race condition. The below patch fixed the bug and greatly simplified |
| the logic. |
| |
| The feature depends on fanout, but the state is private to the socket. |
| Fanout_release returns f only when the last member leaves and the |
| fanout struct is to be freed. |
| |
| Destroy rollover unconditionally, regardless of fanout state. |
| |
| Fixes: 57f015f5eccf2 ("packet: fix crash in fanout_demux_rollover()") |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Diagnosed-by: Dmitry Vyukov <dvyukov@google.com> |
| Signed-off-by: Willem de Bruijn <willemb@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/packet/af_packet.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/net/packet/af_packet.c |
| +++ b/net/packet/af_packet.c |
| @@ -3016,8 +3016,8 @@ static int packet_release(struct socket |
| |
| synchronize_net(); |
| |
| + kfree(po->rollover); |
| if (f) { |
| - kfree(po->rollover); |
| fanout_release_data(f); |
| kfree(f); |
| } |