diff options
| author | Nikita Zhandarovich <n.zhandarovich@fintech.ru> | 2024-01-17 09:21:02 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-01-18 09:52:30 -0800 |
| commit | 2e7ef287f07c74985f1bf2858bedc62bd9ebf155 (patch) | |
| tree | 853355e1dc0476234df2656a4481241a539b4640 /net/ipv6 | |
| parent | bc9291dea7eca74b4a24bbdc173d7fde99c78718 (diff) | |
ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work
idev->mc_ifc_count can be written over without proper locking.
Originally found by syzbot [1], fix this issue by encapsulating calls
to mld_ifc_stop_work() (and mld_gq_stop_work() for good measure) with
mutex_lock() and mutex_unlock() accordingly as these functions
should only be called with mc_lock per their declarations.
[1]
BUG: KCSAN: data-race in ipv6_mc_down / mld_ifc_work
write to 0xffff88813a80c832 of 1 bytes by task 3771 on cpu 0:
mld_ifc_stop_work net/ipv6/mcast.c:1080 [inline]
ipv6_mc_down+0x10a/0x280 net/ipv6/mcast.c:2725
addrconf_ifdown+0xe32/0xf10 net/ipv6/addrconf.c:3949
addrconf_notify+0x310/0x980
notifier_call_chain kernel/notifier.c:93 [inline]
raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461
__dev_notify_flags+0x205/0x3d0
dev_change_flags+0xab/0xd0 net/core/dev.c:8685
do_setlink+0x9f6/0x2430 net/core/rtnetlink.c:2916
rtnl_group_changelink net/core/rtnetlink.c:3458 [inline]
__rtnl_newlink net/core/rtnetlink.c:3717 [inline]
rtnl_newlink+0xbb3/0x1670 net/core/rtnetlink.c:3754
rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576
netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910
...
write to 0xffff88813a80c832 of 1 bytes by task 22 on cpu 1:
mld_ifc_work+0x54c/0x7b0 net/ipv6/mcast.c:2653
process_one_work kernel/workqueue.c:2627 [inline]
process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700
worker_thread+0x525/0x730 kernel/workqueue.c:2781
...
Fixes: 2d9a93b4902b ("mld: convert from timer to delayed work")
Reported-by: syzbot+a9400cabb1d784e49abf@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000994e09060ebcdffb@google.com/
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Acked-by: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://lore.kernel.org/r/20240117172102.12001-1-n.zhandarovich@fintech.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/mcast.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index b75d3c9d41bb..bc6e0a0bad3c 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -2722,8 +2722,12 @@ void ipv6_mc_down(struct inet6_dev *idev) synchronize_net(); mld_query_stop_work(idev); mld_report_stop_work(idev); + + mutex_lock(&idev->mc_lock); mld_ifc_stop_work(idev); mld_gq_stop_work(idev); + mutex_unlock(&idev->mc_lock); + mld_dad_stop_work(idev); } |