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authorPan Bian <bianpan2016@163.com>2018-11-25 01:58:02 +0100
committerJan Kara <jack@suse.cz>2018-11-27 10:21:15 +0100
commitecebf55d27a11538ea84aee0be643dd953f830d5 (patch)
tree5f017acb4a15f183e2c0bbb28ffe4487824c6493 /fs/ext2/xattr.c
parentext2: initialize opts.s_mount_opt as zero before using it (diff)
downloadlinux-ecebf55d27a11538ea84aee0be643dd953f830d5.tar.xz
linux-ecebf55d27a11538ea84aee0be643dd953f830d5.zip
ext2: fix potential use after free
The function ext2_xattr_set calls brelse(bh) to drop the reference count of bh. After that, bh may be freed. However, following brelse(bh), it reads bh->b_data via macro HDR(bh). This may result in a use-after-free bug. This patch moves brelse(bh) after reading field. CC: stable@vger.kernel.org Signed-off-by: Pan Bian <bianpan2016@163.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ext2/xattr.c')
-rw-r--r--fs/ext2/xattr.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 62d9a659a8ff..dd8f10db82e9 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -612,9 +612,9 @@ skip_replace:
}
cleanup:
- brelse(bh);
if (!(bh && header == HDR(bh)))
kfree(header);
+ brelse(bh);
up_write(&EXT2_I(inode)->xattr_sem);
return error;