From 1457cc4cfb93511de347d1d0a1c9da3e826b66fe Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 2 Nov 2017 15:06:55 +0000 Subject: [PATCH] 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 --- net/rxrpc/output.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index 71e6f713fbe7..8ee8b2d4a3eb 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);