From: Xie He xie.he.0141@gmail.com
[ Upstream commit 4ee18c179e5e815fa5575e0d2db0c05795a804ee ]
The x25_disconnect function in x25_subr.c would decrease the refcount of "x25->neighbour" (struct x25_neigh) and reset this pointer to NULL.
However, the x25_rx_call_request function in af_x25.c, which is called when we receive a connection request, does not increase the refcount when it assigns the pointer.
Fix this issue by increasing the refcount of "struct x25_neigh" in x25_rx_call_request.
This patch fixes frequent kernel crashes when using AF_X25 sockets.
Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect") Cc: Martin Schiller ms@dev.tdt.de Signed-off-by: Xie He xie.he.0141@gmail.com Link: https://lore.kernel.org/r/20201112103506.5875-1-xie.he.0141@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/x25/af_x25.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index 372f4194db5a..b3db0b0a52f5 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -1049,6 +1049,7 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb, makex25->lci = lci; makex25->dest_addr = dest_addr; makex25->source_addr = source_addr; + x25_neigh_hold(nb); makex25->neighbour = nb; makex25->facilities = facilities; makex25->dte_facilities= dte_facilities;