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authorPan Bian <bianpan2016@163.com>2018-11-30 14:10:54 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-30 14:56:15 -0800
commit164f7e586739d07eb56af6f6d66acebb11f315c8 (patch)
treea49af6943dcf92e4616bfbb6aac9b061e548d776 /fs
parent95feeabb77149f7d48f05bde61d75621c57db67e (diff)
downloadlinux-164f7e586739d07eb56af6f6d66acebb11f315c8.tar.gz
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: 781f200cb7a("ocfs2: Remove masklog ML_EXPORT.")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Andrew 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ocfs2/export.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c
index 9f88188060db..4bf8d5854b27 100644
--- a/fs/ocfs2/export.c
+++ b/fs/ocfs2/export.c
@@ -125,10 +125,10 @@ check_err:
 
 check_gen:
 	if (handle->ih_generation != inode->i_generation) {
-		iput(inode);
 		trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
 						  handle->ih_generation,
 						  inode->i_generation);
+		iput(inode);
 		result = ERR_PTR(-ESTALE);
 		goto bail;
 	}