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| author | Zqiang <qiang.zhang@windriver.com> | 2021-05-26 13:08:26 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-05-26 09:03:56 -0600 |
| commit | 3743c1723bfc62e69dbf022417720eed3f431b29 (patch) | |
| tree | 21155f50d954f3d79d5babcf0bd5aa12cc306585 | |
| parent | 17a91051fe63b40ec651b80097c9fff5b093fdc5 (diff) | |
| download | linux-3743c1723bfc62e69dbf022417720eed3f431b29.tar.gz linux-3743c1723bfc62e69dbf022417720eed3f431b29.tar.bz2 linux-3743c1723bfc62e69dbf022417720eed3f431b29.zip | |
io-wq: Fix UAF when wakeup wqe in hash waitqueue
BUG: KASAN: use-after-free in __wake_up_common+0x637/0x650
Read of size 8 at addr ffff8880304250d8 by task iou-wrk-28796/28802
Call Trace:
__dump_stack [inline]
dump_stack+0x141/0x1d7
print_address_description.constprop.0.cold+0x5b/0x2c6
__kasan_report [inline]
kasan_report.cold+0x7c/0xd8
__wake_up_common+0x637/0x650
__wake_up_common_lock+0xd0/0x130
io_worker_handle_work+0x9dd/0x1790
io_wqe_worker+0xb2a/0xd40
ret_from_fork+0x1f/0x30
Allocated by task 28798:
kzalloc_node [inline]
io_wq_create+0x3c4/0xdd0
io_init_wq_offload [inline]
io_uring_alloc_task_context+0x1bf/0x6b0
__io_uring_add_task_file+0x29a/0x3c0
io_uring_add_task_file [inline]
io_uring_install_fd [inline]
io_uring_create [inline]
io_uring_setup+0x209a/0x2bd0
do_syscall_64+0x3a/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 28798:
kfree+0x106/0x2c0
io_wq_destroy+0x182/0x380
io_wq_put [inline]
io_wq_put_and_exit+0x7a/0xa0
io_uring_clean_tctx [inline]
__io_uring_cancel+0x428/0x530
io_uring_files_cancel
do_exit+0x299/0x2a60
do_group_exit+0x125/0x310
get_signal+0x47f/0x2150
arch_do_signal_or_restart+0x2a8/0x1eb0
handle_signal_work[inline]
exit_to_user_mode_loop [inline]
exit_to_user_mode_prepare+0x171/0x280
__syscall_exit_to_user_mode_work [inline]
syscall_exit_to_user_mode+0x19/0x60
do_syscall_64+0x47/0xb0
entry_SYSCALL_64_after_hwframe
There are the following scenarios, hash waitqueue is shared by
io-wq1 and io-wq2. (note: wqe is worker)
io-wq1:worker2 | locks bit1
io-wq2:worker1 | waits bit1
io-wq1:worker3 | waits bit1
io-wq1:worker2 | completes all wqe bit1 work items
io-wq1:worker2 | drop bit1, exit
io-wq2:worker1 | locks bit1
io-wq1:worker3 | can not locks bit1, waits bit1 and exit
io-wq1 | exit and free io-wq1
io-wq2:worker1 | drops bit1
io-wq1:worker3 | be waked up, even though wqe is freed
After all iou-wrk belonging to io-wq1 have exited, remove wqe
form hash waitqueue, it is guaranteed that there will be no more
wqe belonging to io-wq1 in the hash waitqueue.
Reported-by: syzbot+6cb11ade52aa17095297@syzkaller.appspotmail.com
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Link: https://lore.kernel.org/r/20210526050826.30500-1-qiang.zhang@windriver.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/io-wq.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c index de9b7ba3ba01..b3e8624a37d0 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -1006,13 +1006,16 @@ static void io_wq_exit_workers(struct io_wq *wq) struct io_wqe *wqe = wq->wqes[node]; io_wq_for_each_worker(wqe, io_wq_worker_wake, NULL); - spin_lock_irq(&wq->hash->wait.lock); - list_del_init(&wq->wqes[node]->wait.entry); - spin_unlock_irq(&wq->hash->wait.lock); } rcu_read_unlock(); io_worker_ref_put(wq); wait_for_completion(&wq->worker_done); + + for_each_node(node) { + spin_lock_irq(&wq->hash->wait.lock); + list_del_init(&wq->wqes[node]->wait.entry); + spin_unlock_irq(&wq->hash->wait.lock); + } put_task_struct(wq->task); wq->task = NULL; } |