3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pan Bian <bianpan2016@xxxxxxx> 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@xxxxxxxxxxxxxxx Signed-off-by: Pan Bian <bianpan2016@xxxxxxx> Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext2/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -606,9 +606,9 @@ skip_replace: } cleanup: - brelse(bh); if (!(bh && header == HDR(bh))) kfree(header); + brelse(bh); up_write(&EXT2_I(inode)->xattr_sem); return error;
