Commit 164f7e58 authored by Pan Bian's avatar Pan Bian Committed by Linus Torvalds

ocfs2: fix potential use after free

ocfs2_get_dentry() calls iput(inode) to drop the reference count of
inode, and if the reference count hits 0, inode is freed.  However, in
this function, it then reads inode->i_generation, which may result in a
use after free bug.  Move the put operation later.

Link: http://lkml.kernel.org/r/1543109237-110227-1-git-send-email-bianpan2016@163.com
Fixes: 781f200c("ocfs2: Remove masklog ML_EXPORT.")
Signed-off-by: default avatarPan Bian <bianpan2016@163.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
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 <ge.changwei@h3c.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 95feeabb
...@@ -125,10 +125,10 @@ static struct dentry *ocfs2_get_dentry(struct super_block *sb, ...@@ -125,10 +125,10 @@ static struct dentry *ocfs2_get_dentry(struct super_block *sb,
check_gen: check_gen:
if (handle->ih_generation != inode->i_generation) { if (handle->ih_generation != inode->i_generation) {
iput(inode);
trace_ocfs2_get_dentry_generation((unsigned long long)blkno, trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
handle->ih_generation, handle->ih_generation,
inode->i_generation); inode->i_generation);
iput(inode);
result = ERR_PTR(-ESTALE); result = ERR_PTR(-ESTALE);
goto bail; goto bail;
} }
......
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