From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org
Subject: [PATCH 1/5] netfilter: ctnetlink: add a range check for l3/l4 protonum
Date: Tue, 8 Sep 2020 17:09:43 +0200 [thread overview]
Message-ID: <20200908150947.12623-2-pablo@netfilter.org> (raw)
In-Reply-To: <20200908150947.12623-1-pablo@netfilter.org>
From: Will McVicker <willmcvicker@google.com>
The indexes to the nf_nat_l[34]protos arrays come from userspace. So
check the tuple's family, e.g. l3num, when creating the conntrack in
order to prevent an OOB memory access during setup. Here is an example
kernel panic on 4.14.180 when userspace passes in an index greater than
NFPROTO_NUMPROTO.
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in:...
Process poc (pid: 5614, stack limit = 0x00000000a3933121)
CPU: 4 PID: 5614 Comm: poc Tainted: G S W O 4.14.180-g051355490483
Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM
task: 000000002a3dfffe task.stack: 00000000a3933121
pc : __cfi_check_fail+0x1c/0x24
lr : __cfi_check_fail+0x1c/0x24
...
Call trace:
__cfi_check_fail+0x1c/0x24
name_to_dev_t+0x0/0x468
nfnetlink_parse_nat_setup+0x234/0x258
ctnetlink_parse_nat_setup+0x4c/0x228
ctnetlink_new_conntrack+0x590/0xc40
nfnetlink_rcv_msg+0x31c/0x4d4
netlink_rcv_skb+0x100/0x184
nfnetlink_rcv+0xf4/0x180
netlink_unicast+0x360/0x770
netlink_sendmsg+0x5a0/0x6a4
___sys_sendmsg+0x314/0x46c
SyS_sendmsg+0xb4/0x108
el0_svc_naked+0x34/0x38
This crash is not happening since 5.4+, however, ctnetlink still
allows for creating entries with unsupported layer 3 protocol number.
Fixes: c1d10adb4a521 ("[NETFILTER]: Add ctnetlink port for nf_conntrack")
Signed-off-by: Will McVicker <willmcvicker@google.com>
[pablo@netfilter.org: rebased original patch on top of nf.git]
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_conntrack_netlink.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 832eabecfbdd..d65846aa8059 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1404,7 +1404,8 @@ ctnetlink_parse_tuple_filter(const struct nlattr * const cda[],
if (err < 0)
return err;
-
+ if (l3num != NFPROTO_IPV4 && l3num != NFPROTO_IPV6)
+ return -EOPNOTSUPP;
tuple->src.l3num = l3num;
if (flags & CTA_FILTER_FLAG(CTA_IP_DST) ||
--
2.20.1
next prev parent reply other threads:[~2020-09-08 20:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 15:09 [PATCH 0/5] Netfilter fixes for net Pablo Neira Ayuso
2020-09-08 15:09 ` Pablo Neira Ayuso [this message]
2020-09-08 15:09 ` [PATCH 2/5] netfilter: nf_tables: coalesce multiple notifications into one skbuff Pablo Neira Ayuso
2020-09-08 15:09 ` [PATCH 3/5] netfilter: ctnetlink: fix mark based dump filtering regression Pablo Neira Ayuso
2020-09-08 15:09 ` [PATCH 4/5] netfilter: conntrack: nf_conncount_init is failing with IPv6 disabled Pablo Neira Ayuso
2020-09-08 15:09 ` [PATCH 5/5] netfilter: nft_meta: use socket user_ns to retrieve skuid and skgid Pablo Neira Ayuso
2020-09-09 3:08 ` [PATCH 0/5] Netfilter fixes for net David Miller
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