[PATCH] Suspected information leak (mem pages) in ext2

I think I have discovered a potential security problem in ext2: when a
new directory is created, the ext2 block written to disk is not
initialized.

Included is a proposed patch for Linux 2.6 (ext2_make_empty() function):

CAN-2005-0400 is assigned to this issue.

Signed-off-by: Chris Wright <chrisw@osdl.org>

fs/ext2/dir.c

@@ -592,6 +592,7 @@ int ext2_make_empty(struct inode *inode, struct inode *parent)
 		goto fail;
 	}
 	kaddr = kmap_atomic(page, KM_USER0);
+       memset(kaddr, 0, chunk_size);
 	de = (struct ext2_dir_entry_2 *)kaddr;
 	de->name_len = 1;
 	de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));