linux-kernel - [PATCH] configfs: Return -EFBIG from configfs_write_bin

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Date:   Thu, 15 Sep 2016 12:20:12 -0400
From:   Phil Turnbull <phil.turnbull@...cle.com>
To:     linux-kernel@...r.kernel.org
Cc:     Christoph Hellwig <hch@....de>, Joel Becker <jlbec@...lplan.org>,
        Phil Turnbull <phil.turnbull@...cle.com>
Subject: [PATCH] configfs: Return -EFBIG from configfs_write_bin_file.

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@...cle.com>
---
 fs/configfs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index c30cf49b69d2..2c6312db8516 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);
-- 
2.9.0.rc2