From: YueHaibing yuehaibing@huawei.com
[ Upstream commit 4c21daae3dbc9f8536cc18e6e53627821fa2c90c ]
tipc_sendstream() may send zero length packet, then tipc_msg_append() do not alloc skb, skb_peek_tail() will get NULL, msg_set_ack_required will trigger NULL pointer dereference.
Reported-by: syzbot+8eac6d030e7807c21d32@syzkaller.appspotmail.com Fixes: 0a3e060f340d ("tipc: add test for Nagle algorithm effectiveness") Signed-off-by: YueHaibing yuehaibing@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/tipc/socket.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 62fc871a8d673..f02f2abf6e3c0 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1589,8 +1589,12 @@ static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dlen) tsk->pkt_cnt += skb_queue_len(txq); } else { skb = skb_peek_tail(txq); - msg_set_ack_required(buf_msg(skb)); - tsk->expect_ack = true; + if (skb) { + msg_set_ack_required(buf_msg(skb)); + tsk->expect_ack = true; + } else { + tsk->expect_ack = false; + } tsk->msg_acc = 0; tsk->pkt_cnt = 0; }