netfilter: ebtables: CONFIG_COMPAT: don't trust userland offsets

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We need to make sure the offsets are not out of range of the
total size.
Also check that they are in ascending order.

The WARN_ON triggered by syzkaller (it sets panic_on_warn) is
changed to also bail out, no point in continuing parsing.

Briefly tested with simple ruleset of
-A INPUT --limit 1/s' --log
plus jump to custom chains using 32bit ebtables binary.

Reported-by: <syzbot+845a53d13171abf8bf29@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

...

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Florian Westphal 2018-02-19 01:24:15 +01:00 • committed by Pablo Neira Ayuso

parent fc6a5d0601

commit b718121685

1 changed files with 12 additions and 1 deletions

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net/bridge/netfilter/ebtables.c

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