linux-ext4 - [PATCH v2.6.32.y 44/53] ext4: Prevent creation of files larger than RLIMIT

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Message-Id: <1275274206-3900-44-git-send-email-tytso@mit.edu>
Date:	Sun, 30 May 2010 22:49:57 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	stable@...nel.org
Cc:	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	Nikanth Karthikesan <knikanth@...e.de>,
	Amit Arora <aarora@...ibm.com>, "Theodore Ts'o" <tytso@....edu>
Subject: [PATCH v2.6.32.y 44/53] ext4: Prevent creation of files larger than RLIMIT_FSIZE using fallocate

From: Nikanth Karthikesan <knikanth@...e.de>

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>
---
 fs/ext4/extents.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index cd4cccc..aca259f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3607,6 +3607,11 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
 	 */
 	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;
-- 
1.6.6.1.1.g974db.dirty

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