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Commit 1457cc4c authored by David Howells's avatar David Howells
Browse files

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: default avatarDavid Howells <dhowells@redhat.com>
parent 20acbd9a

net/rxrpc/output.c

+5 −4
Original line number Diff line number Diff line
@@ -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);