CVE-2024-56702

/// Technical description

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

bpf: Mark raw_tp arguments with PTR_MAYBE_NULL

Arguments to a raw tracepoint are tagged as trusted, which carries the

semantics that the pointer will be non-NULL. However, in certain cases,

a raw tracepoint argument may end up being NULL. More context about this

issue is available in [0].

Thus, there is a discrepancy between the reality, that raw_tp arguments

can actually be NULL, and the verifier's knowledge, that they are never

NULL, causing explicit NULL checks to be deleted, and accesses to such

pointers potentially crashing the kernel.

To fix this, mark raw_tp arguments as PTR_MAYBE_NULL, and then special

case the dereference and pointer arithmetic to permit it, and allow

passing them into helpers/kfuncs; these exceptions are made for raw_tp

programs only. Ensure that we don't do this when ref_obj_id > 0, as in

that case this is an acquired object and doesn't need such adjustment.

The reason we do mask_raw_t

/// 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