From: Phil Turnbull <phil.turnbull@oracle.com>
Date: Thu, 15 Sep 2016 16:20:12 +0000 (-0400)
Subject: configfs: Return -EFBIG from configfs_write_bin_file.
X-Git-Tag: v4.7.6~48
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=71b4a3c04e5b9e69f2b53aac5248a7b34cd57bae;p=thirdparty%2Fkernel%2Fstable.git

configfs: Return -EFBIG from configfs_write_bin_file.

commit 42857cf512cb34c2c8cb50f1e766689d979d64e0 upstream.

The check for writing more than cb_max_size bytes does not 'goto out' so
it is a no-op which allows users to vmalloc an arbitrary amount.

Fixes: 03607ace807b ("configfs: implement binary attributes")
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index bbc1252a59f5f..2ddfa05d71f52 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -333,6 +333,7 @@ configfs_write_bin_file(struct file *file, const char __user *buf,
 		if (bin_attr->cb_max_size &&
 			*ppos + count > bin_attr->cb_max_size) {
 			len = -EFBIG;
+			goto out;
 		}
 
 		tbuf = vmalloc(*ppos + count);