This is a note to let you know that I've just added the patch titled
ipv4: igmp: fix refcnt uaf issue when receiving igmp query packet
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipv4-igmp-fix-refcnt-uaf-issue-when-receiving-igmp-q.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cf4937dd9cf10cac29442fd8294aebbd3b2129f3
Author: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
Date: Thu Nov 23 15:13:14 2023 +0800
ipv4: igmp: fix refcnt uaf issue when receiving igmp query packet
[ Upstream commit e2b706c691905fe78468c361aaabc719d0a496f1 ]
When I perform the following test operations:
1.ip link add br0 type bridge
2.brctl addif br0 eth0
3.ip addr add 239.0.0.1/32 dev eth0
4.ip addr add 239.0.0.1/32 dev br0
5.ip addr add 224.0.0.1/32 dev br0
6.while ((1))
do
ifconfig br0 up
ifconfig br0 down
done
7.send IGMPv2 query packets to port eth0 continuously. For example,
./mausezahn ethX -c 0 "01 00 5e 00 00 01 00 72 19 88 aa 02 08 00 45 00 00
1c 00 01 00 00 01 02 0e 7f c0 a8 0a b7 e0 00 00 01 11 64 ee 9b 00 00 00 00"
The preceding tests may trigger the refcnt uaf issue of the mc list. The
stack is as follows:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 21 PID: 144 at lib/refcount.c:25 refcount_warn_saturate (lib/refcount.c:25)
CPU: 21 PID: 144 Comm: ksoftirqd/21 Kdump: loaded Not tainted 6.7.0-rc1-next-20231117-dirty #80
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:refcount_warn_saturate (lib/refcount.c:25)
RSP: 0018:ffffb68f00657910 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff8a00c3bf96c0 RCX: ffff8a07b6160908
RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff8a07b6160900
RBP: ffff8a00cba36862 R08: 0000000000000000 R09: 00000000ffff7fff
R10: ffffb68f006577c0 R11: ffffffffb0fdcdc8 R12: ffff8a00c3bf9680
R13: ffff8a00c3bf96f0 R14: 0000000000000000 R15: ffff8a00d8766e00
FS: 0000000000000000(0000) GS:ffff8a07b6140000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f10b520b28 CR3: 000000039741a000 CR4: 00000000000006f0
Call Trace:
<TASK>
igmp_heard_query (net/ipv4/igmp.c:1068)
igmp_rcv (net/ipv4/igmp.c:1132)
ip_protocol_deliver_rcu (net/ipv4/ip_input.c:205)
ip_local_deliver_finish (net/ipv4/ip_input.c:234)
__netif_receive_skb_one_core (net/core/dev.c:5529)
netif_receive_skb_internal (net/core/dev.c:5729)
netif_receive_skb (net/core/dev.c:5788)
br_handle_frame_finish (net/bridge/br_input.c:216)
nf_hook_bridge_pre (net/bridge/br_input.c:294)
__netif_receive_skb_core (net/core/dev.c:5423)
__netif_receive_skb_list_core (net/core/dev.c:5606)
__netif_receive_skb_list (net/core/dev.c:5674)
netif_receive_skb_list_internal (net/core/dev.c:5764)
napi_gro_receive (net/core/gro.c:609)
e1000_clean_rx_irq (drivers/net/ethernet/intel/e1000/e1000_main.c:4467)
e1000_clean (drivers/net/ethernet/intel/e1000/e1000_main.c:3805)
__napi_poll (net/core/dev.c:6533)
net_rx_action (net/core/dev.c:6735)
__do_softirq (kernel/softirq.c:554)
run_ksoftirqd (kernel/softirq.c:913)
smpboot_thread_fn (kernel/smpboot.c:164)
kthread (kernel/kthread.c:388)
ret_from_fork (arch/x86/kernel/process.c:153)
ret_from_fork_asm (arch/x86/entry/entry_64.S:250)
</TASK>
The root causes are as follows:
Thread A Thread B
... netif_receive_skb
br_dev_stop ...
br_multicast_leave_snoopers ...
__ip_mc_dec_group ...
__igmp_group_dropped igmp_rcv
igmp_stop_timer igmp_heard_query //ref = 1
ip_ma_put igmp_mod_timer
refcount_dec_and_test igmp_start_timer //ref = 0
... refcount_inc //ref increases from 0
When the device receives an IGMPv2 Query message, it starts the timer
immediately, regardless of whether the device is running. If the device is
down and has left the multicast group, it will cause the mc list refcount
uaf issue.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index cb031e851c127..715f99e76826e 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -218,8 +218,10 @@ static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
int tv = prandom_u32() % max_delay;
im->tm_running = 1;
- if (!mod_timer(&im->timer, jiffies+tv+2))
- refcount_inc(&im->refcnt);
+ if (refcount_inc_not_zero(&im->refcnt)) {
+ if (mod_timer(&im->timer, jiffies + tv + 2))
+ ip_ma_put(im);
+ }
}
static void igmp_gq_start_timer(struct in_device *in_dev)
