Merge: block: fix integer overflow in BLKSECDISCARD

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/5663

JIRA: https://issues.redhat.com/browse/RHEL-64512
CVE: CVE-2024-49994

Signed-off-by: Ming Lei <[email protected]>

Approved-by: Chris von Recklinghausen <[email protected]>
Approved-by: Ewan D. Milne <[email protected]>
Approved-by: CKI KWF Bot <[email protected]>

Merged-by: Rado Vrbovsky <[email protected]>

Author: emmil

block/ioctl.c

@@ -127,7 +127,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
 		return -EINVAL;
 
 	filemap_invalidate_lock(inode->i_mapping);
-	err = truncate_bdev_range(bdev, mode, start, start + len - 1);
+	err = truncate_bdev_range(bdev, mode, start, end - 1);
 	if (err)
 		goto fail;
 
@@ -164,7 +164,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
 static int blk_ioctl_secure_erase(struct block_device *bdev, blk_mode_t mode,
 		void __user *argp)
 {
-	uint64_t start, len;
+	uint64_t start, len, end;
 	uint64_t range[2];
 	int err;
 
@@ -179,11 +179,12 @@ static int blk_ioctl_secure_erase(struct block_device *bdev, blk_mode_t mode,
 	len = range[1];
 	if ((start & 511) || (len & 511))
 		return -EINVAL;
-	if (start + len > bdev_nr_bytes(bdev))
+	if (check_add_overflow(start, len, &end) ||
+	    end > bdev_nr_bytes(bdev))
 		return -EINVAL;
 
 	filemap_invalidate_lock(bdev->bd_inode->i_mapping);
-	err = truncate_bdev_range(bdev, mode, start, start + len - 1);
+	err = truncate_bdev_range(bdev, mode, start, end - 1);
 	if (!err)
 		err = blkdev_issue_secure_erase(bdev, start >> 9, len >> 9,
 						GFP_KERNEL);