UBI: block: Avoid disk size integer overflow

This patch fixes the issue that on very large UBI volumes
UBI block does not work correctly.
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/ubi/block.c

@@ -378,9 +378,11 @@ int ubiblock_create(struct ubi_volume_info *vi)
 {
 	struct ubiblock *dev;
 	struct gendisk *gd;
-	int disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
+	u64 disk_capacity = ((u64)vi->size * vi->usable_leb_size) >> 9;
 	int ret;
 
+	if ((sector_t)disk_capacity != disk_capacity)
+		return -EFBIG;
 	/* Check that the volume isn't already handled */
 	mutex_lock(&devices_mutex);
 	if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
@@ -500,8 +502,13 @@ int ubiblock_remove(struct ubi_volume_info *vi)
 static int ubiblock_resize(struct ubi_volume_info *vi)
 {
 	struct ubiblock *dev;
-	int disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
+	u64 disk_capacity = ((u64)vi->size * vi->usable_leb_size) >> 9;
 
+	if ((sector_t)disk_capacity != disk_capacity) {
+		ubi_warn("%s: the volume is too big, cannot resize (%d LEBs)",
+			 dev->gd->disk_name, vi->size);
+		return -EFBIG;
+	}
 	/*
 	 * Need to lock the device list until we stop using the device,
 	 * otherwise the device struct might get released in