linux-kernel - [PATCH 3.16 341/366] ext2: fix a block leak

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <lsq.1539530741.879805266@decadent.org.uk>
Date:   Sun, 14 Oct 2018 16:25:41 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Al Viro" <viro@...iv.linux.org.uk>
Subject: [PATCH 3.16 341/366] ext2: fix a block leak

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <viro@...iv.linux.org.uk>

commit 5aa1437d2d9a068c0334bd7c9dafa8ec4f97f13b upstream.

open file, unlink it, then use ioctl(2) to make it immutable or
append only.  Now close it and watch the blocks *not* freed...

Immutable/append-only checks belong in ->setattr().
Note: the bug is old and backport to anything prior to 737f2e93b972
("ext2: convert to use the new truncate convention") will need
these checks lifted into ext2_setattr().

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/ext2/inode.c | 10 ----------
 1 file changed, 10 deletions(-)

--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1169,21 +1169,11 @@ do_indirects:
 
 static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
 {
-	/*
-	 * XXX: it seems like a bug here that we don't allow
-	 * IS_APPEND inode to have blocks-past-i_size trimmed off.
-	 * review and fix this.
-	 *
-	 * Also would be nice to be able to handle IO errors and such,
-	 * but that's probably too much to ask.
-	 */
 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
 	    S_ISLNK(inode->i_mode)))
 		return;
 	if (ext2_inode_is_fast_symlink(inode))
 		return;
-	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
-		return;
 	__ext2_truncate_blocks(inode, offset);
 }