| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 14/91] ext2: fix potential use after free | Date | Tue, 11 Dec 2018 16:40:33 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Pan Bian <bianpan2016@163.com>
commit ecebf55d27a11538ea84aee0be643dd953f830d5 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext2/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -605,9 +605,9 @@ skip_replace: } cleanup: - brelse(bh); if (!(bh && header == HDR(bh))) kfree(header); + brelse(bh); up_write(&EXT2_I(inode)->xattr_sem); return error;
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