From: Chris Mason <chris.mason@oracle.com>
Date: Fri, 3 Feb 2012 16:07:40 +0000 (-0500)
Subject: RDS: check access on pages before doing copy_to_user
X-Git-Tag: v4.1.12-92~319^2^2~2^2~61
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=818291d8116edfde5d436f4e14f8a51f80e7ece6;p=users%2Fjedix%2Flinux-maple.git

RDS: check access on pages before doing copy_to_user

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Bang Nguyen <bang.nguyen@oracle.com>
---

diff --git a/net/rds/page.c b/net/rds/page.c
index b94b8e119d4b2..fe5adbb5aa417 100644
--- a/net/rds/page.c
+++ b/net/rds/page.c
@@ -56,6 +56,14 @@ int rds_page_copy_user(struct page *page, unsigned long offset,
 	unsigned long ret;
 	void *addr;
 
+	if (to_user)
+		ret = access_ok(VERIFY_WRITE, ptr, bytes);
+	else
+		ret = access_ok(VERIFY_READ, ptr, bytes);
+
+	if (!ret)
+		return -EFAULT;
+
 	if (to_user)
 		rds_stats_add(s_copy_to_user, bytes);
 	else