If IPv6 is disabled on boot (ipv6.disable=1), but nft_fib_inet ends up
dealing with a IPv6 packet, 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 packets if !ipv6_mod_enabled().
Signed-off-by: Leonardo Bras <[email protected]>
---
Changes from v2:
- Replace veredict.code from NF_DROP to NFT_BREAK
- Updated commit message (s/package/packet)
Changes from v1:
- Move drop logic from nft_fib_inet_eval() to nft_fib6_eval{,_type}
so it can affect other usages of these functions.
net/ipv6/netfilter/nft_fib_ipv6.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c
index 7ece86afd079..8496e43b73bd 100644
--- a/net/ipv6/netfilter/nft_fib_ipv6.c
+++ b/net/ipv6/netfilter/nft_fib_ipv6.c
@@ -125,6 +125,11 @@ void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs,
u32 *dest = ®s->data[priv->dreg];
struct ipv6hdr *iph, _iph;
+ if (!ipv6_mod_enabled()) {
+ regs->verdict.code = NFT_BREAK;
+ return;
+ }
+
iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
if (!iph) {
regs->verdict.code = NFT_BREAK;
@@ -150,6 +155,11 @@ void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
struct rt6_info *rt;
int lookup_flags;
+ if (!ipv6_mod_enabled()) {
+ regs->verdict.code = NFT_BREAK;
+ return;
+ }
+
if (priv->flags & NFTA_FIB_F_IIF)
oif = nft_in(pkt);
else if (priv->flags & NFTA_FIB_F_OIF)
--
2.20.1