rxrpc: Fix a null ptr deref in rxrpc_fill_out_ack()
rxrpc_fill_out_ack() needs to be passed the connection pointer from its
caller rather than using call->conn as the call may be disconnected in
parallel with it, clearing call->conn, leading to:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: rxrpc_send_ack_packet+0x231/0x6a4
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 71e6f71..8ee8b2d 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -35,7 +35,8 @@ struct rxrpc_abort_buffer {
/*
* Fill out an ACK packet.
*/
-static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
+static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
+ struct rxrpc_call *call,
struct rxrpc_ack_buffer *pkt,
rxrpc_seq_t *_hard_ack,
rxrpc_seq_t *_top,
@@ -77,8 +78,8 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
} while (before_eq(seq, top));
}
- mtu = call->conn->params.peer->if_mtu;
- mtu -= call->conn->params.peer->hdrsize;
+ mtu = conn->params.peer->if_mtu;
+ mtu -= conn->params.peer->hdrsize;
jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
pkt->ackinfo.rxMTU = htonl(rxrpc_rx_mtu);
pkt->ackinfo.maxMTU = htonl(mtu);
@@ -148,7 +149,7 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping)
}
call->ackr_reason = 0;
}
- n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top, reason);
+ n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
spin_unlock_bh(&call->lock);