[PATCH 4.4 076/113] ocfs2: fix a NULL pointer dereference when call ocfs2_update_inode_fsync_trans()

Greg Kroah-Hartman
2020-02-27T13:43:22Z

From: wangyan <wangyan122@huawei.com>

[ Upstream commit 9f16ca48fc818a17de8be1f75d08e7f4addc4497 ]

I found a NULL pointer dereference in ocfs2_update_inode_fsync_trans(),
handle->h_transaction may be NULL in this situation:

ocfs2_file_write_iter
->__generic_file_write_iter
->generic_perform_write
->ocfs2_write_begin
->ocfs2_write_begin_nolock
->ocfs2_write_cluster_by_desc
->ocfs2_write_cluster
->ocfs2_mark_extent_written
->ocfs2_change_extent_flag
->ocfs2_split_extent
->ocfs2_try_to_merge_extent
->ocfs2_extend_rotate_transaction
->ocfs2_extend_trans
->jbd2_journal_restart
->jbd2__journal_restart
// handle->h_transaction is NULL here
->handle->h_transaction = NULL;
->start_this_handle
/* journal aborted due to storage
network disconnection, return error */
->return -EROFS;
/* line 3806 in ocfs2_try_to_merge_extent (),
it will ignore ret error. */
->ret = 0;
->...
->ocfs2_write_end
->ocfs2_write_end_nolock
->ocfs2_update_inode_fsync_trans
// NULL pointer dereference
->oi->i_sync_tid = handle->h_transaction->t_tid;

The information of NULL pointer dereference as follows:
JBD2: Detected IO errors while flushing file data on dm-11-45
Aborting journal on device dm-11-45.
JBD2: Error -5 detected when updating journal superblock for dm-11-45.
(dd,22081,3):ocfs2_extend_trans:474 ERROR: status = -30
(dd,22081,3):ocfs2_try_to_merge_extent:3877 ERROR: status = -30
Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000008
Mem abort info:
ESR = 0x96000004
Exception class = DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp = 00000000e74e1338
[0000000000000008] pgd=0000000000000000
Internal error: Oops: 96000004 [#1] SMP
Process dd (pid: 22081, stack limit = 0x00000000584f35a9)
CPU: 3 PID: 22081 Comm: dd Kdump: loaded
Hardware name: Huawei TaiShan 2280 V2/BC82AMDD, BIOS 0.98 08/25/2019
pstate: 60400009 (nZCv daif +PAN -UAO)
pc : ocfs2_write_end_nolock+0x2b8/0x550 [ocfs2]
lr : ocfs2_write_end_nolock+0x2a0/0x550 [ocfs2]
sp : ffff0000459fba70
x29: ffff0000459fba70 x28: 0000000000000000
x27: ffff807ccf7f1000 x26: 0000000000000001
x25: ffff807bdff57970 x24: ffff807caf1d4000
x23: ffff807cc79e9000 x22: 0000000000001000
x21: 000000006c6cd000 x20: ffff0000091d9000
x19: ffff807ccb239db0 x18: ffffffffffffffff
x17: 000000000000000e x16: 0000000000000007
x15: ffff807c5e15bd78 x14: 0000000000000000
x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000001
x9 : 0000000000000228 x8 : 000000000000000c
x7 : 0000000000000fff x6 : ffff807a308ed6b0
x5 : ffff7e01f10967c0 x4 : 0000000000000018
x3 : d0bc661572445600 x2 : 0000000000000000
x1 : 000000001b2e0200 x0 : 0000000000000000
Call trace:
ocfs2_write_end_nolock+0x2b8/0x550 [ocfs2]
ocfs2_write_end+0x4c/0x80 [ocfs2]
generic_perform_write+0x108/0x1a8
__generic_file_write_iter+0x158/0x1c8
ocfs2_file_write_iter+0x668/0x950 [ocfs2]
__vfs_write+0x11c/0x190
vfs_write+0xac/0x1c0
ksys_write+0x6c/0xd8
__arm64_sys_write+0x24/0x30
el0_svc_common+0x78/0x130
el0_svc_handler+0x38/0x78
el0_svc+0x8/0xc

To prevent NULL pointer dereference in this situation, we use
is_handle_aborted() before using handle->h_transaction->t_tid.

Link: http://lkml.kernel.org/r/03e750ab-9ade-83aa-b000-b9e81e34e539@huawei.com
Signed-off-by: Yan Wang <wangyan122@huawei.com>
Reviewed-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ocfs2/journal.h | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index f4cd3c3e9fb70..0a4d2cbf512f8 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -637,9 +637,11 @@ static inline void ocfs2_update_inode_fsync_trans(handle_t *handle,
{
struct ocfs2_inode_info *oi = OCFS2_I(inode);

- oi->i_sync_tid = handle->h_transaction->t_tid;
- if (datasync)
- oi->i_datasync_tid = handle->h_transaction->t_tid;
+ if (!is_handle_aborted(handle)) {
+ oi->i_sync_tid = handle->h_transaction->t_tid;
+ if (datasync)
+ oi->i_datasync_tid = handle->h_transaction->t_tid;
+ }
}

#endif /* OCFS2_JOURNAL_H */
--
2.20.1