linux-kernel - [123/165] ext4: Prevent creation of files larger than RLIMIT

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Date:	Fri, 30 Jul 2010 10:15:51 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Nikanth Karthikesan <knikanth@...e.de>,
	Amit Arora <aarora@...ibm.com>, "Theodore Tso" <tytso@....edu>
Subject: [123/165] ext4: Prevent creation of files larger than RLIMIT_FSIZE using fallocate

2.6.32-stable review patch.  If anyone has any objections, please let us know.

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

commit 6d19c42b7cf81c39632b6d4dbc514e8449bcd346 upstream (as of v2.6.34-git13)

Currently using posix_fallocate one can bypass an RLIMIT_FSIZE limit
and create a file larger than the limit. Add a check for that.

Signed-off-by: Nikanth Karthikesan <knikanth@...e.de>
Signed-off-by: Amit Arora <aarora@...ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
 fs/ext4/extents.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3607,6 +3607,11 @@ long ext4_fallocate(struct inode *inode,
 	 */
 	credits = ext4_chunk_trans_blocks(inode, max_blocks);
 	mutex_lock(&inode->i_mutex);
+	ret = inode_newsize_ok(inode, (len + offset));
+	if (ret) {
+		mutex_unlock(&inode->i_mutex);
+		return ret;
+	}
 retry:
 	while (ret >= 0 && ret < max_blocks) {
 		block = block + ret;


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