ubi: Refuse attaching if mtd's erasesize is 0

[ Upstream commit 017c73a34a661a861712f7cc1393a123e5b2208c ]

There exists mtd devices with zero erasesize, which will trigger a
divide-by-zero exception while attaching ubi device.
Fix it by refusing attaching if mtd's erasesize is 0.

Fixes: 801c135ce73d ("UBI: Unsorted Block Images")
Reported-by: Yu Hao <yhao016@ucr.edu>
Link: https://lore.kernel.org/lkml/977347543.226888.1682011999468.JavaMail.zimbra@nod.at/T/
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 4ee1ff84076dcc64d82a1eadc94b4c371849400f..f42e4b9fdea1a3eab42f33dfa8a59198ec88a873 100644 (file)
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -869,6 +869,13 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
                return -EINVAL;
        }
 
+       /* UBI cannot work on flashes with zero erasesize. */
+       if (!mtd->erasesize) {
+               pr_err("ubi: refuse attaching mtd%d - zero erasesize flash is not supported\n",
+                       mtd->index);
+               return -EINVAL;
+       }
+
        if (ubi_num == UBI_DEV_NUM_AUTO) {
                /* Search for an empty slot in the @ubi_devices array */
                for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)