Re: [PATCH 1/1] netfilter: nf_tables: fib: Drop IPV6 packages if IPv6 is disabled on boot
From: Florian Westphal
Date: Tue Aug 20 2019 - 01:36:15 EST
Leonardo Bras <leonardo@xxxxxxxxxxxxx> wrote:
> If IPv6 is disabled on boot (ipv6.disable=1), but nft_fib_inet ends up
> dealing with a IPv6 package, it causes a kernel panic in
> fib6_node_lookup_1(), crashing in bad_page_fault.
>
> The panic is caused by trying to deference a very low address (0x38
> in ppc64le), due to ipv6.fib6_main_tbl = NULL.
> BUG: Kernel NULL pointer dereference at 0x00000038
>
> Fix this behavior by dropping IPv6 packages if !ipv6_mod_enabled().
Wouldn't fib_netdev.c have the same problem?
If so, might be better to place this test in both
nft_fib6_eval_type and nft_fib6_eval.