CVE-2024-50147

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix command bitmask initialization

Command bitmask have a dedicated bit for MANAGE_PAGES command, this bit

isn't Initialize during command bitmask Initialization, only during

MANAGE_PAGES.

In addition, mlx5_cmd_trigger_completions() is trying to trigger

completion for MANAGE_PAGES command as well.

Hence, in case health error occurred before any MANAGE_PAGES command

have been invoke (for example, during mlx5_enable_hca()),

mlx5_cmd_trigger_completions() will try to trigger completion for

MANAGE_PAGES command, which will result in null-ptr-deref error.[1]

Fix it by Initialize command bitmask correctly.

While at it, re-write the code for better understanding.

[1]

BUG: KASAN: null-ptr-deref in mlx5_cmd_trigger_completions+0x1db/0x600 [mlx5_core]

Write of size 4 at addr 0000000000000214 by task kworker/u96:2/12078

CPU: 10 PID: 12078 Comm: kworker/u96:2 Not tainted 6.9.0-rc2_for_upstream_debug_2024_04_07_19_

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References