[PATCH v2 3/3] UBI: block: Avoid disk size integer overflow

[Ezequiel Garcia]

From: Richard Weinberger <richard at nod.at>

This patch fixes the issue that on very large UBI volumes
UBI block does not work correctly.

Signed-off-by: Richard Weinberger <richard at nod.at>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
---
 drivers/mtd/ubi/block.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 502f508..c1bb567 100644
--- a/drivers/mtd/ubi/block.c
+++ b/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)) {
@@ -498,8 +500,13 @@ 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
-- 
1.9.1