CVE-2024-47809
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk12th percentile - higher than 12% of all known CVEs
Summary
In the Linux kernel's DLM (Distributed Lock Manager), a vulnerability was found causing a possible null pointer dereference in a logging function when called from request_lock(), as lkb->lkb_resource is not yet assigned. Additionally, a resource name could be a non-printable byte array, leading to incorrect ASCII assumption.
Risk Assessment
The risk involves a potential kernel panic if the null pointer dereference is triggered, leading to system crash. While hard to exploit in normal usage, code changes could increase the likelihood of hitting this issue.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit removing resource name from log output). Monitor patch availability for your distribution and apply it as part of routine updates.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: dlm: fix possible lkb_resource null dereference This patch fixes a possible null pointer dereference when this function is called from request_lock() as lkb->lkb_resource is not assigned yet, only after validate_lock_args() by calling attach_lkb(). Another issue is that a resource name could be a non printable bytearray and we cannot assume to be ASCII coded. The log functionality is probably never being hit when DLM is used in normal way and no debug logging is enabled. The null pointer dereference can only occur on a new created lkb that does not have the resource assigned yet, it probably never hits the null pointer dereference but we should be sure that other changes might not change this behaviour and we actually can hit the mentioned null pointer dereference. In this patch we just drop the printout of the resource name, the lkb id is enough to make a possible connection to a resource name if this exists.