Florian Westphal 57ebd808a9 netfilter: add back stackpointer size checks
The rationale for removing the check is only correct for rulesets
generated by ip(6)tables.

In iptables, a jump can only occur to a user-defined chain, i.e.
because we size the stack based on number of user-defined chains we
cannot exceed stack size.

However, the underlying binary format has no such restriction,
and the validation step only ensures that the jump target is a
valid rule start point.

IOW, its possible to build a rule blob that has no user-defined
chains but does contain a jump.

If this happens, no jump stack gets allocated and crash occurs
because no jumpstack was allocated.

Fixes: 7814b6ec6d0d6 ("netfilter: xtables: don't save/restore jumpstack offset")
Reported-by: syzbot+e783f671527912cd9403@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-02-14 20:47:41 +01:00
..
2017-11-01 12:19:03 +09:00
2017-11-27 16:20:04 -05:00
2017-11-27 16:20:04 -05:00
2017-11-08 16:12:33 +09:00
2018-02-06 11:44:32 -05:00
2017-11-27 16:20:04 -05:00
2018-02-07 21:47:10 -05:00
2018-01-30 19:03:48 -08:00
2018-02-01 09:51:57 -08:00