| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.7 015/112] tipc: Fix NULL pointer dereference in __tipc_sendstream() | Date | Tue, 7 Jul 2020 17:16:20 +0200 |
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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; } -- 2.25.1
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