[PATCH v5.10] block: add check that partition length needs to be aligned with block size

[Ashwin Dayanand Kamat]

From: Min Li <min15.li@xxxxxxxxxxx>

[ Upstream commit 6f64f866aa1ae6975c95d805ed51d7e9433a0016]

Before calling add partition or resize partition, there is no check
on whether the length is aligned with the logical block size.
If the logical block size of the disk is larger than 512 bytes,
then the partition size maybe not the multiple of the logical block size,
and when the last sector is read, bio_truncate() will adjust the bio size,
resulting in an IO error if the size of the read command is smaller than
the logical block size.If integrity data is supported, this will also
result in a null pointer dereference when calling bio_integrity_free.

Cc:  <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Min Li <min15.li@xxxxxxxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20230629142517.121241-1-min15.li@xxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Ashwin Dayanand Kamat <ashwin.kamat@xxxxxxxxxxxx>
---
 block/ioctl.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index e7eed7dad..c490d67fe 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -17,7 +17,7 @@ static int blkpg_do_ioctl(struct block_device *bdev,
 			  struct blkpg_partition __user *upart, int op)
 {
 	struct blkpg_partition p;
-	long long start, length;
+	sector_t start, length;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
@@ -32,6 +32,12 @@ static int blkpg_do_ioctl(struct block_device *bdev,
 	if (op == BLKPG_DEL_PARTITION)
 		return bdev_del_partition(bdev, p.pno);
 
+	if (p.start < 0 || p.length <= 0 || p.start + p.length < 0)
+		return -EINVAL;
+	/* Check that the partition is aligned to the block size */
+	if (!IS_ALIGNED(p.start | p.length, bdev_logical_block_size(bdev)))
+		return -EINVAL;
+
 	start = p.start >> SECTOR_SHIFT;
 	length = p.length >> SECTOR_SHIFT;
 
@@ -46,9 +52,6 @@ static int blkpg_do_ioctl(struct block_device *bdev,
 
 	switch (op) {
 	case BLKPG_ADD_PARTITION:
-		/* check if partition is aligned to blocksize */
-		if (p.start & (bdev_logical_block_size(bdev) - 1))
-			return -EINVAL;
 		return bdev_add_partition(bdev, p.pno, start, length);
 	case BLKPG_RESIZE_PARTITION:
 		return bdev_resize_partition(bdev, p.pno, start, length);
-- 
2.35.6