CVE-2024-47728

/// Technical description

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

bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error

For all non-tracing helpers which formerly had ARG_PTR_TO_{LONG,INT} as input

arguments, zero the value for the case of an error as otherwise it could leak

memory. For tracing, it is not needed given CAP_PERFMON can already read all

kernel memory anyway hence bpf_get_func_arg() and bpf_get_func_ret() is skipped

in here.

Also, the MTU helpers mtu_len pointer value is being written but also read.

Technically, the MEM_UNINIT should not be there in order to always force init.

Removing MEM_UNINIT needs more verifier rework though: MEM_UNINIT right now

implies two things actually: i) write into memory, ii) memory does not have

to be initialized. If we lift MEM_UNINIT, it then becomes: i) read into memory,

ii) memory must be initialized. This means that for bpf_*_check_mtu() we're

readding the issue we're trying to fix, that is, it would then be able to

write bac

/// 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