tree fc3b89ed8e66d3f99f9322efc812e8c7bcd60509
parent 2fec6bb6f484b1a88b4a325724234d6cfd08c918
author Thomas Graf <tgraf@suug.ch> 1396627065 +0200
committer Pablo Neira Ayuso <pablo@netfilter.org> 1396712782 +0200

netfilter: Can't fail and free after table replacement

All xtables variants suffer from the defect that the copy_to_user()
to copy the counters to user memory may fail after the table has
already been exchanged and thus exposed. Return an error at this
point will result in freeing the already exposed table. Any
subsequent packet processing will result in a kernel panic.

We can't copy the counters before exposing the new tables as we
want provide the counter state after the old table has been
unhooked. Therefore convert this into a silent error.

Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>