[PATCH] netfilter: nfnetlink: fix insufficient validation in nfnetlink_bind
From: Pablo Neira Ayuso
Date: Fri Nov 14 2014 - 12:14:33 EST
Make sure the netlink group exists, otherwise this trigger an out of
bound array memory access from the netlink_bind() path. This splat
can only be triggered only by superuser.
[ 180.203600] UBSan: Undefined behaviour in ../net/netfilter/nfnetlink.c:467:28
[ 180.204249] index 9 is out of range for type 'int [9]'
[ 180.204697] CPU: 0 PID: 1771 Comm: trinity-main Not tainted 3.18.0-rc4-mm1+ #122
[ 180.205365] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org
+04/01/2014
[ 180.206498] 0000000000000018 0000000000000000 0000000000000009 ffff88007bdf7da8
[ 180.207220] ffffffff82b0ef5f 0000000000000092 ffffffff845ae2e0 ffff88007bdf7db8
[ 180.207887] ffffffff8199e489 ffff88007bdf7e18 ffffffff8199ea22 0000003900000000
[ 180.208639] Call Trace:
[ 180.208857] dump_stack (lib/dump_stack.c:52)
[ 180.209370] ubsan_epilogue (lib/ubsan.c:174)
[ 180.209849] __ubsan_handle_out_of_bounds (lib/ubsan.c:400)
[ 180.210512] nfnetlink_bind (net/netfilter/nfnetlink.c:467)
[ 180.210986] netlink_bind (net/netlink/af_netlink.c:1483)
[ 180.211495] SYSC_bind (net/socket.c:1541)
Moreover, define the missing nf_tables and nf_acct multicast groups
too to skip.
Reported-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nfnetlink.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 6c5a915..13c2e17 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -47,6 +47,8 @@ static const int nfnl_group2type[NFNLGRP_MAX+1] = {
[NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
[NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
[NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
+ [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
+ [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
};
void nfnl_lock(__u8 subsys_id)
@@ -464,7 +466,12 @@ static void nfnetlink_rcv(struct sk_buff *skb)
static int nfnetlink_bind(int group)
{
const struct nfnetlink_subsystem *ss;
- int type = nfnl_group2type[group];
+ int type;
+
+ if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
+ return -EINVAL;
+
+ type = nfnl_group2type[group];
rcu_read_lock();
ss = nfnetlink_get_subsys(type);
@@ -514,6 +521,9 @@ static int __init nfnetlink_init(void)
{
int i;
+ for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
+ BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
+
for (i=0; i<NFNL_SUBSYS_COUNT; i++)
mutex_init(&table[i].mutex);
--
1.7.10.4
--X1bOJ3K7DJ5YkBrT--
--
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