Commit aa3a0220 authored Jan 29, 2016 by Ken-ichirou MATSUZAWA Committed by David S. Miller Jan 29, 2016

netlink: not trim skb for mmaped socket when dump



We should not trim skb for mmaped socket since its buf size is fixed
and userspace will read as frame which data equals head. mmaped
socket will not call recvmsg, means max_recvmsg_len is 0,
skb_reserve was not called before commit: db65a3aa.

Fixes: db65a3aa (netlink: Trim skb to alloc size to avoid MSG_TRUNC)
Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7256eac1

net/netlink/af_netlink.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2831,6 +2831,7 @@ static int netlink_dump(struct sock *sk)
		* reasonable static buffer based on the expected largest dump of a
		* single netdev. The outcome is MSG_TRUNC error.
		*/
		if (!netlink_rx_is_mmaped(sk))
		skb_reserve(skb, skb_tailroom(skb) - alloc_size);
		netlink_skb_set_owner_r(skb, sk);

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