mtd: nand: atmel: fix buffer overflow in atmel_pmecc_user

When calculating the size needed by struct atmel_pmecc_user *user,
the dmu and delta buffer sizes were forgotten.
This lead to a memory corruption (especially with a large ecc_strength).

Link: http://lkml.kernel.org/r/1506503157.3016.5.camel@gmail.com
Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Cc: stable@vger.kernel.org
Reported-by: Richard Genoud <richard.genoud@gmail.com>
Pointed-at-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Reviewed-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/atmel/pmecc.c

@@ -363,7 +363,7 @@ atmel_pmecc_create_user(struct atmel_pmecc *pmecc,
 	size += (req->ecc.strength + 1) * sizeof(u16);
 	/* Reserve space for mu, dmu and delta. */
 	size = ALIGN(size, sizeof(s32));
-	size += (req->ecc.strength + 1) * sizeof(s32);
+	size += (req->ecc.strength + 1) * sizeof(s32) * 3;
 
 	user = kzalloc(size, GFP_KERNEL);
 	if (!user)