From: Nikanth Karthikesan <knikanth@suse.de>
Date: Mon, 31 May 2010 02:49:57 +0000 (-0400)
Subject: ext4: Prevent creation of files larger than RLIMIT_FSIZE using fallocate
X-Git-Tag: firefly_0821_release~10186^2~1310
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0a27a9e513fa9a229745fe94e42b020f66a7ec10;p=firefly-linux-kernel-4.4.55.git

ext4: Prevent creation of files larger than RLIMIT_FSIZE using fallocate

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@suse.de>
Signed-off-by: Amit Arora <aarora@in.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index cd4ccccaf2d9..aca259f4b5b4 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;