CVE-2024-35972

What it actually does

The vulnerability is a memory leak in bnxt_rdma_aux_device_init where a kzalloc failure for the ulp structure leaves the previously allocated edev structure unreferenced, preventing its release in the cleanup path.

Why it matters to the business

Systems using Broadcom NetXtreme Ethernet adapters with RDMA support may experience gradual memory exhaustion under repeated initialization failures, causing performance degradation or crashes in long-running environments with high driver load.

How an attack unfolds

A local attacker triggers allocation failures during RDMA auxiliary device initialization to cause the edev leak on each attempt; over time this exhausts kernel memory without requiring code execution.

How to fix it

Update the Linux kernel to a version containing commit c60ed825530b8c0cc2b524efd39b1d696ec54004, which assigns the edev pointer immediately after allocation so the cleanup path can free it on failure.

How to confirm the fix worked

Inspect the bnxt_rdma_aux_device_init function in the kernel source to confirm edev is assigned right after kzalloc; enable kmemleak and trigger init failures to verify no leaked edev objects remain.

Typical attack path

1. Obtain local user access on a system with the vulnerable bnxt_en driver
2. Repeatedly induce kzalloc failures for ulp in bnxt_rdma_aux_device_init
3. Observe increasing unreferenced memory usage leading to resource exhaustion

How to detect it

Enable kernel memory leak detectors such as kmemleak and search for unreferenced edev allocations from bnxt_rdma_aux_device_init; review kernel logs for bnxt_en initialization failures and monitor overall memory usage trends unrelated to running processes.

What your security team should do

• Apply the kernel update with the referenced commit on all systems using affected bnxt_en hardware
• Prioritize updates on servers with RDMA workloads due to higher initialization frequency
• Reboot into the patched kernel and validate with memory debugging tools before returning systems to production