From: Leonardo Bras <leonardo@linux.ibm.com>
To: netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
bridge@lists.linux-foundation.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>,
Roopa Prabhu <roopa@cumulusnetworks.com>,
Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH v4 1/2] netfilter: Terminate rule eval if protocol=IPv6 and ipv6 module is disabled
Date: Fri, 30 Aug 2019 15:13:53 -0300 [thread overview]
Message-ID: <20190830181354.26279-2-leonardo@linux.ibm.com> (raw)
In-Reply-To: <20190830181354.26279-1-leonardo@linux.ibm.com>
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
The kernel panic was reproduced in a host that disabled IPv6 on boot and
have to process guest packets (coming from a bridge) using it's ip6tables.
Terminate rule evaluation when packet protocol is IPv6 but the ipv6 module
is not loaded.
Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
net/netfilter/nft_fib_netdev.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/netfilter/nft_fib_netdev.c b/net/netfilter/nft_fib_netdev.c
index 2cf3f32fe6d2..a2e726ae7f07 100644
--- a/net/netfilter/nft_fib_netdev.c
+++ b/net/netfilter/nft_fib_netdev.c
@@ -14,6 +14,7 @@
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
+#include <net/ipv6.h>
#include <net/netfilter/nft_fib.h>
@@ -34,6 +35,8 @@ static void nft_fib_netdev_eval(const struct nft_expr *expr,
}
break;
case ETH_P_IPV6:
+ if (!ipv6_mod_enabled())
+ break;
switch (priv->result) {
case NFT_FIB_RESULT_OIF:
case NFT_FIB_RESULT_OIFNAME:
--
2.20.1
next prev parent reply other threads:[~2019-08-30 18:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-30 18:13 [PATCH v4 0/2] Drop IPV6 packets if IPv6 is disabled on boot Leonardo Bras
2019-08-30 18:13 ` Leonardo Bras [this message]
2019-08-30 20:58 ` [PATCH v4 1/2] netfilter: Terminate rule eval if protocol=IPv6 and ipv6 module is disabled Florian Westphal
2019-09-03 16:46 ` Leonardo Bras
2019-09-03 16:49 ` Pablo Neira Ayuso
2019-09-03 16:56 ` Leonardo Bras
2019-09-03 17:05 ` Florian Westphal
2019-09-03 19:31 ` Pablo Neira Ayuso
2019-09-03 19:48 ` Florian Westphal
2019-09-03 20:19 ` Pablo Neira Ayuso
2019-09-03 20:35 ` Florian Westphal
2019-09-03 20:55 ` Pablo Neira Ayuso
2019-09-03 20:55 ` Pablo Neira Ayuso
2019-08-30 18:13 ` [PATCH v4 2/2] net: br_netfiler_hooks: Drops IPv6 packets if IPv6 module is not loaded Leonardo Bras
2019-08-30 20:55 ` Florian Westphal
2019-08-31 4:42 ` Leonardo Bras
2019-08-31 8:43 ` Florian Westphal
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