[PATCH 1/5] mtd: block2mtd: Check for valid user supplied erase size

From: "Pali Rohár" <pali.rohar@gmail.com>
To: Joern Engel <joern@lazybastard.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	Boris Brezillon <boris.brezillon@free-electrons.com>,
	Marek Vasut <marek.vasut@gmail.com>,
	Richard Weinberger <richard@nod.at>,
	Cyrille Pitchen <cyrille.pitchen@atmel.com>,
	Artem Bityutskiy <dedekind1@gmail.com>
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	"Pali Rohár" <pali.rohar@gmail.com>
Subject: [PATCH 1/5] mtd: block2mtd: Check for valid user supplied erase size
Date: Fri,  2 Jun 2017 17:43:38 +0200	[thread overview]
Message-ID: <1496418222-23483-2-git-send-email-pali.rohar@gmail.com> (raw)
In-Reply-To: <1496418222-23483-1-git-send-email-pali.rohar@gmail.com>

Erase size is limited to 32bit unsigned integer, but value parsed from user
is limited up to size_t C type.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
---
 drivers/mtd/devices/block2mtd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index 7c887f1..ee47cdd 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -419,7 +419,7 @@ static int block2mtd_setup2(const char *val)
 
 	if (token[1]) {
 		ret = parse_num(&erase_size, token[1]);
-		if (ret) {
+		if (ret || erase_size > U32_MAX) {
 			pr_err("illegal erase size\n");
 			return 0;
 		}
-- 
1.7.9.5
