Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
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.