From: Leonardo Bras <leonardo@linux.ibm.com>
To: netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Leonardo Bras <leonardo@linux.ibm.com>,
Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@netfilter.org>,
Florian Westphal <fw@strlen.de>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 1/1] netfilter: nf_tables: fib: Drop IPV6 packages if IPv6 is disabled on boot
Date: Mon, 19 Aug 2019 21:58:21 -0300 [thread overview]
Message-ID: <20190820005821.2644-1-leonardo@linux.ibm.com> (raw)
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().
Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
net/netfilter/nft_fib_inet.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/netfilter/nft_fib_inet.c b/net/netfilter/nft_fib_inet.c
index 465432e0531b..0017afab3c51 100644
--- a/net/netfilter/nft_fib_inet.c
+++ b/net/netfilter/nft_fib_inet.c
@@ -2,6 +2,7 @@
#include <linux/kernel.h>
#include <linux/init.h>
+#include <linux/ipv6.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
@@ -28,6 +29,8 @@ static void nft_fib_inet_eval(const struct nft_expr *expr,
}
break;
case NFPROTO_IPV6:
+ if (!ipv6_mod_enabled())
+ break;
switch (priv->result) {
case NFT_FIB_RESULT_OIF:
case NFT_FIB_RESULT_OIFNAME:
--
2.20.1
next reply other threads:[~2019-08-20 0:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 0:58 Leonardo Bras [this message]
2019-08-20 5:36 ` [PATCH 1/1] netfilter: nf_tables: fib: Drop IPV6 packages if IPv6 is disabled on boot Florian Westphal
2019-08-20 16:15 ` Leonardo Bras
2019-08-21 9:58 ` Pablo Neira Ayuso
2019-08-21 14:14 ` Leonardo Bras
2019-08-26 16:47 ` Leonardo Bras
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