KASAN detect following BUG:
[ 778.215311] ==================================================================
[ 778.216696] BUG: KASAN: use-after-free in rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[ 778.219037] Read of size 8 at addr ffff88b1d6516c28 by task tee/8842
[ 778.220500] CPU: 37 PID: 8842 Comm: tee Kdump: loaded Not tainted 5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71
[ 778.220529] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020
[ 778.220555] Call Trace:
[ 778.220609] dump_stack+0x99/0xcb
[ 778.220667] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[ 778.220715] print_address_description.constprop.7+0x1e/0x230
[ 778.220750] ? freeze_kernel_threads+0x73/0x73
[ 778.220896] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[ 778.220932] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[ 778.220994] kasan_report.cold.9+0x37/0x7c
[ 778.221066] ? kobject_put+0x80/0x270
[ 778.221102] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[ 778.221184] rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[ 778.221240] rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server]
[ 778.221304] ? sysfs_file_ops+0x90/0x90
[ 778.221353] kernfs_fop_write+0x141/0x240
[ 778.221451] vfs_write+0x142/0x4d0
[ 778.221553] ksys_write+0xc0/0x160
[ 778.221602] ? __ia32_sys_read+0x50/0x50
[ 778.221684] ? lockdep_hardirqs_on_prepare+0x13d/0x210
[ 778.221718] ? syscall_enter_from_user_mode+0x1c/0x50
[ 778.221821] do_syscall_64+0x33/0x40
[ 778.221862] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 778.221896] RIP: 0033:0x7f4affdd9504
[ 778.221928] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 f9 61 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53
[ 778.221956] RSP: 002b:00007fffebb36b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 778.222011] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f4affdd9504
[ 778.222038] RDX: 0000000000000002 RSI: 00007fffebb36c50 RDI: 0000000000000003
[ 778.222066] RBP: 00007fffebb36c50 R08: 0000556a151aa600 R09: 00007f4affeb1540
[ 778.222094] R10: fffffffffffffc19 R11: 0000000000000246 R12: 0000556a151aa520
[ 778.222121] R13: 0000000000000002 R14: 00007f4affea6760 R15: 0000000000000002
[ 778.222764] Allocated by task 3212:
[ 778.223285] kasan_save_stack+0x19/0x40
[ 778.223316] __kasan_kmalloc.constprop.7+0xc1/0xd0
[ 778.223347] kmem_cache_alloc_trace+0x186/0x350
[ 778.223382] rnbd_srv_rdma_ev+0xf16/0x1690 [rnbd_server]
[ 778.223422] process_io_req+0x4d1/0x670 [rtrs_server]
[ 778.223573] __ib_process_cq+0x10a/0x350 [ib_core]
[ 778.223709] ib_cq_poll_work+0x31/0xb0 [ib_core]
[ 778.223743] process_one_work+0x521/0xa90
[ 778.223773] worker_thread+0x65/0x5b0
[ 778.223802] kthread+0x1f2/0x210
[ 778.223833] ret_from_fork+0x22/0x30
[ 778.224296] Freed by task 8842:
[ 778.224800] kasan_save_stack+0x19/0x40
[ 778.224829] kasan_set_track+0x1c/0x30
[ 778.224860] kasan_set_free_info+0x1b/0x30
[ 778.224889] __kasan_slab_free+0x108/0x150
[ 778.224919] slab_free_freelist_hook+0x64/0x190
[ 778.224947] kfree+0xe2/0x650
[ 778.224982] rnbd_destroy_sess_dev+0x2fa/0x3b0 [rnbd_server]
[ 778.225011] kobject_put+0xda/0x270
[ 778.225046] rnbd_srv_sess_dev_force_close+0x30/0x60 [rnbd_server]
[ 778.225081] rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server]
[ 778.225111] kernfs_fop_write+0x141/0x240
[ 778.225140] vfs_write+0x142/0x4d0
[ 778.225169] ksys_write+0xc0/0x160
[ 778.225198] do_syscall_64+0x33/0x40
[ 778.225227] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 778.226506] The buggy address belongs to the object at ffff88b1d6516c00
which belongs to the cache kmalloc-512 of size 512
[ 778.227464] The buggy address is located 40 bytes inside of
512-byte region [ffff88b1d6516c00, ffff88b1d6516e00)
The problem is in the sess_dev release function we call
rnbd_destroy_sess_dev, and could free the sess_dev already, but we still
set the keep_id in rnbd_srv_sess_dev_force_close, which lead to use
after free.
To fix it, move the keep_id before the sysfs removal, and cache the
rnbd_srv_session for lock accessing,
Fixes: 786998050cbc ("block/rnbd-srv: close a mapped device from server side.")
Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx>
Reviewed-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
---
drivers/block/rnbd/rnbd-srv.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index b8e44331e494..a6a68d44f517 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -338,10 +338,12 @@ static int rnbd_srv_link_ev(struct rtrs_srv *rtrs,
void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev)
{
- mutex_lock(&sess_dev->sess->lock);
- rnbd_srv_destroy_dev_session_sysfs(sess_dev);
- mutex_unlock(&sess_dev->sess->lock);
+ struct rnbd_srv_session *sess = sess_dev->sess;
+
sess_dev->keep_id = true;
+ mutex_lock(&sess->lock);
+ rnbd_srv_destroy_dev_session_sysfs(sess_dev);
+ mutex_unlock(&sess->lock);
}
static int process_msg_close(struct rtrs_srv *rtrs,
--
2.25.1
