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

Ben Hutchings
2018-10-14T23:11:54Z

From: Al Viro <viro@zeniv.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@zeniv.linux.org.uk>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.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);
}