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linux-next/net/netlink
Eric Dumazet 158f323b98 net: adjust skb->truesize in pskb_expand_head()
Slava Shwartsman reported a warning in skb_try_coalesce(), when we
detect skb->truesize is completely wrong.

In his case, issue came from IPv6 reassembly coping with malicious
datagrams, that forced various pskb_may_pull() to reallocate a bigger
skb->head than the one allocated by NIC driver before entering GRO
layer.

Current code does not change skb->truesize, leaving this burden to
callers if they care enough.

Blindly changing skb->truesize in pskb_expand_head() is not
easy, as some producers might track skb->truesize, for example
in xmit path for back pressure feedback (sk->sk_wmem_alloc)

We can detect the cases where it should be safe to change
skb->truesize :

1) skb is not attached to a socket.
2) If it is attached to a socket, destructor is sock_edemux()

My audit gave only two callers doing their own skb->truesize
manipulation.

I had to remove skb parameter in sock_edemux macro when
CONFIG_INET is not set to avoid a compile error.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Slava Shwartsman <slavash@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-27 12:03:29 -05:00
..
af_netlink.c net: adjust skb->truesize in pskb_expand_head() 2017-01-27 12:03:29 -05:00
af_netlink.h netlink: Call cb->done from a worker thread 2016-11-29 19:48:38 -05:00
diag.c netlink: netlink_diag_dump() runs without locks 2016-11-03 16:16:51 -04:00
genetlink.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-15 10:54:36 -05:00
Kconfig netlink: remove mmapped netlink support 2016-02-18 11:42:18 -05:00
Makefile netlink: Diag core and basic socket info dumping (v2) 2013-03-21 12:38:03 -04:00