rxrpc: Fix NULL pointer deref due to call->conn being cleared on disconnect
[ Upstream commit 5273a191dca65a675dc0bcf3909e59c6933e2831 ]
When a call is disconnected, the connection pointer from the call is
cleared to make sure it isn't used again and to prevent further attempted
transmission for the call. Unfortunately, there might be a daemon trying
to use it at the same time to transmit a packet.
Fix this by keeping call->conn set, but setting a flag on the call to
indicate disconnection instead.
Remove also the bits in the transmission functions where the conn pointer is
checked and a ref taken under spinlock as this is now redundant.
Fixes: 8d94aa381dab ("rxrpc: Calls shouldn't hold socket refs")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 64389f4..d568c96 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -96,7 +96,7 @@
*/
int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping)
{
- struct rxrpc_connection *conn = NULL;
+ struct rxrpc_connection *conn;
struct rxrpc_ack_buffer *pkt;
struct msghdr msg;
struct kvec iov[2];
@@ -106,18 +106,14 @@
int ret;
u8 reason;
- spin_lock_bh(&call->lock);
- if (call->conn)
- conn = rxrpc_get_connection_maybe(call->conn);
- spin_unlock_bh(&call->lock);
- if (!conn)
+ if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
return -ECONNRESET;
pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
- if (!pkt) {
- rxrpc_put_connection(conn);
+ if (!pkt)
return -ENOMEM;
- }
+
+ conn = call->conn;
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->peer->srx.transport_len;
@@ -204,7 +200,6 @@
}
out:
- rxrpc_put_connection(conn);
kfree(pkt);
return ret;
}
@@ -214,20 +209,18 @@
*/
int rxrpc_send_abort_packet(struct rxrpc_call *call)
{
- struct rxrpc_connection *conn = NULL;
+ struct rxrpc_connection *conn;
struct rxrpc_abort_buffer pkt;
struct msghdr msg;
struct kvec iov[1];
rxrpc_serial_t serial;
int ret;
- spin_lock_bh(&call->lock);
- if (call->conn)
- conn = rxrpc_get_connection_maybe(call->conn);
- spin_unlock_bh(&call->lock);
- if (!conn)
+ if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
return -ECONNRESET;
+ conn = call->conn;
+
msg.msg_name = &call->peer->srx.transport;
msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
@@ -255,7 +248,6 @@
ret = kernel_sendmsg(conn->params.local->socket,
&msg, iov, 1, sizeof(pkt));
- rxrpc_put_connection(conn);
return ret;
}