From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Subject: fs: ocfs2: fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc()
In ocfs2_info_scan_inode_alloc(), there is an if statement on line 283
to check whether inode_alloc is NULL:
if (inode_alloc)
When inode_alloc is NULL, it is used on line 287:
ocfs2_inode_lock(inode_alloc, &bh, 0);
ocfs2_inode_lock_full_nested(inode, ...)
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
Thus, a possible null-pointer dereference may occur.
To fix this bug, inode_alloc is checked on line 286.
This bug is found by a static analysis tool STCheck written by us.
Link: http://lkml.kernel.org/r/20190726033717.32359-1-baijiaju1990@xxxxxxxxx
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ocfs2/ioctl.c~fs-ocfs2-fix-a-possible-null-pointer-dereference-in-ocfs2_info_scan_inode_alloc
+++ a/fs/ocfs2/ioctl.c
@@ -283,7 +283,7 @@ static int ocfs2_info_scan_inode_alloc(s
if (inode_alloc)
inode_lock(inode_alloc);
- if (o2info_coherent(&fi->ifi_req)) {
+ if (inode_alloc && o2info_coherent(&fi->ifi_req)) {
status = ocfs2_inode_lock(inode_alloc, &bh, 0);
if (status < 0) {
mlog_errno(status);
_
