CVE-2022-50506

Description

In the Linux kernel, the following vulnerability has been resolved: drbd: only clone bio if we have a backing device Commit c347a787e34cb (drbd: set ->bi_bdev in drbd_req_new) moved a bio_set_dev call (which has since been removed) to "earlier", from drbd_request_prepare to drbd_req_new. The problem is that this accesses device->ldev->backing_bdev, which is not NULL-checked at this point. When we don't have an ldev (i.e. when the DRBD device is diskless), this leads to a null pointer deref. So, only allocate the private_bio if we actually have a disk. This is also a small optimization, since we don't clone the bio to only to immediately free it again in the diskless case.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

References

• https://git.kernel.org/stable/c/05580a3bbf3cec677cb00a85dfeb21d6a9b48eaf ↗
• https://git.kernel.org/stable/c/6d42ddf7f27b6723549ee6d4c8b1b418b59bf6b5 ↗