From: Hoang Huu Le hoang.h.le@dektech.com.au
commit fdeba99b1e58ecd18c2940c453e19e4ef20ff591 upstream.
Syzbot has reported those issues as:
================================================================== BUG: KASAN: use-after-free in tipc_bcast_get_mode+0x3ab/0x400 net/tipc/bcast.c:759 Read of size 1 at addr ffff88805e6b3571 by task kworker/0:6/3850
CPU: 0 PID: 3850 Comm: kworker/0:6 Not tainted 5.8.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events tipc_net_finalize_work
Thread 1's call trace: [...] kfree+0x103/0x2c0 mm/slab.c:3757 <- bcbase releasing tipc_bcast_stop+0x1b0/0x2f0 net/tipc/bcast.c:721 tipc_exit_net+0x24/0x270 net/tipc/core.c:112 [...]
Thread 2's call trace: [...] tipc_bcast_get_mode+0x3ab/0x400 net/tipc/bcast.c:759 <- bcbase has already been freed by Thread 1
tipc_node_broadcast+0x9e/0xcc0 net/tipc/node.c:1744 tipc_nametbl_publish+0x60b/0x970 net/tipc/name_table.c:752 tipc_net_finalize net/tipc/net.c:141 [inline] tipc_net_finalize+0x1fa/0x310 net/tipc/net.c:131 tipc_net_finalize_work+0x55/0x80 net/tipc/net.c:150 [...]
================================================================== BUG: KASAN: use-after-free in tipc_named_reinit+0xef/0x290 net/tipc/name_distr.c:344 Read of size 8 at addr ffff888052ab2000 by task kworker/0:13/30628 CPU: 0 PID: 30628 Comm: kworker/0:13 Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events tipc_net_finalize_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1f0/0x31e lib/dump_stack.c:118 print_address_description+0x66/0x5a0 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 tipc_named_reinit+0xef/0x290 net/tipc/name_distr.c:344 tipc_net_finalize+0x85/0xe0 net/tipc/net.c:138 tipc_net_finalize_work+0x50/0x70 net/tipc/net.c:150 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 [...] Freed by task 14058: save_stack mm/kasan/common.c:48 [inline] set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x220 mm/slab.c:3757 tipc_exit_net+0x29/0x50 net/tipc/core.c:113 ops_exit_list net/core/net_namespace.c:186 [inline] cleanup_net+0x708/0xba0 net/core/net_namespace.c:603 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
Fix it by calling flush_scheduled_work() to make sure the tipc_net_finalize_work() stopped before releasing bcbase object.
Reported-by: syzbot+6ea1f7a8df64596ef4d7@syzkaller.appspotmail.com Reported-by: syzbot+e9cc557752ab126c1b99@syzkaller.appspotmail.com Acked-by: Jon Maloy jmaloy@redhat.com Signed-off-by: Hoang Huu Le hoang.h.le@dektech.com.au Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/tipc/core.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -88,6 +88,11 @@ out_sk_rht: static void __net_exit tipc_exit_net(struct net *net) { tipc_net_stop(net); + + /* Make sure the tipc_net_finalize_work stopped + * before releasing the resources. + */ + flush_scheduled_work(); tipc_bcast_stop(net); tipc_nametbl_stop(net); tipc_sk_rht_destroy(net);