[PATCH] block: add capacity validation in bdev_add_partition()

["min15.li" <min15.li@samsung.com>]

In the function bdev_add_partition(),there is no check that the start
and end sectors exceed the size of the disk before calling add_partition.
When we call the block's ioctl interface directly to add a partition,
and the capacity of the disk is set to 0 by driver,the command will
continue to execute.

Signed-off-by: min15.li <min15.li@samsung.com>
---
 block/partitions/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 49e0496ff23c..9806a804e1a4 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -445,6 +445,12 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
 		goto out;
 	}
 
+	if (start >= get_capacity(disk) ||
+		start + length > get_capacity(disk)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	if (partition_overlaps(disk, start, length, -1)) {
 		ret = -EBUSY;
 		goto out;
-- 
2.34.1