[PATCH 5.2 114/131] io_uring: fix KASAN use after free in io_sq_wq_submit_work
From: Greg Kroah-Hartman
Date: Mon Aug 05 2019 - 09:25:09 EST
From: Jackie Liu <liuyun01@xxxxxxxxxx>
commit d0ee879187df966ef638031b5f5183078d672141 upstream.
[root@localhost ~]# ./liburing/test/link
QEMU Standard PC report that:
[ 29.379892] CPU: 0 PID: 84 Comm: kworker/u2:2 Not tainted 5.3.0-rc2-00051-g4010b622f1d2-dirty #86
[ 29.379902] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[ 29.379913] Workqueue: io_ring-wq io_sq_wq_submit_work
[ 29.379929] Call Trace:
[ 29.379953] dump_stack+0xa9/0x10e
[ 29.379970] ? io_sq_wq_submit_work+0xbf4/0xe90
[ 29.379986] print_address_description.cold.6+0x9/0x317
[ 29.379999] ? io_sq_wq_submit_work+0xbf4/0xe90
[ 29.380010] ? io_sq_wq_submit_work+0xbf4/0xe90
[ 29.380026] __kasan_report.cold.7+0x1a/0x34
[ 29.380044] ? io_sq_wq_submit_work+0xbf4/0xe90
[ 29.380061] kasan_report+0xe/0x12
[ 29.380076] io_sq_wq_submit_work+0xbf4/0xe90
[ 29.380104] ? io_sq_thread+0xaf0/0xaf0
[ 29.380152] process_one_work+0xb59/0x19e0
[ 29.380184] ? pwq_dec_nr_in_flight+0x2c0/0x2c0
[ 29.380221] worker_thread+0x8c/0xf40
[ 29.380248] ? __kthread_parkme+0xab/0x110
[ 29.380265] ? process_one_work+0x19e0/0x19e0
[ 29.380278] kthread+0x30b/0x3d0
[ 29.380292] ? kthread_create_on_node+0xe0/0xe0
[ 29.380311] ret_from_fork+0x3a/0x50
[ 29.380635] Allocated by task 209:
[ 29.381255] save_stack+0x19/0x80
[ 29.381268] __kasan_kmalloc.constprop.6+0xc1/0xd0
[ 29.381279] kmem_cache_alloc+0xc0/0x240
[ 29.381289] io_submit_sqe+0x11bc/0x1c70
[ 29.381300] io_ring_submit+0x174/0x3c0
[ 29.381311] __x64_sys_io_uring_enter+0x601/0x780
[ 29.381322] do_syscall_64+0x9f/0x4d0
[ 29.381336] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 29.381633] Freed by task 84:
[ 29.382186] save_stack+0x19/0x80
[ 29.382198] __kasan_slab_free+0x11d/0x160
[ 29.382210] kmem_cache_free+0x8c/0x2f0
[ 29.382220] io_put_req+0x22/0x30
[ 29.382230] io_sq_wq_submit_work+0x28b/0xe90
[ 29.382241] process_one_work+0xb59/0x19e0
[ 29.382251] worker_thread+0x8c/0xf40
[ 29.382262] kthread+0x30b/0x3d0
[ 29.382272] ret_from_fork+0x3a/0x50
[ 29.382569] The buggy address belongs to the object at ffff888067172140
which belongs to the cache io_kiocb of size 224
[ 29.384692] The buggy address is located 120 bytes inside of
224-byte region [ffff888067172140, ffff888067172220)
[ 29.386723] The buggy address belongs to the page:
[ 29.387575] page:ffffea00019c5c80 refcount:1 mapcount:0 mapping:ffff88806ace5180 index:0x0
[ 29.387587] flags: 0x100000000000200(slab)
[ 29.387603] raw: 0100000000000200 dead000000000100 dead000000000122 ffff88806ace5180
[ 29.387617] raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
[ 29.387624] page dumped because: kasan: bad access detected
[ 29.387920] Memory state around the buggy address:
[ 29.388771] ffff888067172080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[ 29.390062] ffff888067172100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
[ 29.391325] >ffff888067172180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 29.392578] ^
[ 29.393480] ffff888067172200: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
[ 29.394744] ffff888067172280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 29.396003] ==================================================================
[ 29.397260] Disabling lock debugging due to kernel taint
io_sq_wq_submit_work free and read req again.
Cc: Zhengyuan Liu <liuzhengyuan@xxxxxxxxxx>
Cc: linux-block@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: f7b76ac9d17e ("io_uring: fix counter inc/dec mismatch in async_list")
Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1692,6 +1692,7 @@ restart:
do {
struct sqe_submit *s = &req->submit;
const struct io_uring_sqe *sqe = s->sqe;
+ unsigned int flags = req->flags;
/* Ensure we clear previously set non-block flag */
req->rw.ki_flags &= ~IOCB_NOWAIT;
@@ -1737,7 +1738,7 @@ restart:
kfree(sqe);
/* req from defer and link list needn't decrease async cnt */
- if (req->flags & (REQ_F_IO_DRAINED | REQ_F_LINK_DONE))
+ if (flags & (REQ_F_IO_DRAINED | REQ_F_LINK_DONE))
goto out;
if (!async_list)