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 back into things like .rodata BPF maps. Follow-up work will rework the MEM_UNINIT semantics such that the intent can be better expressed. For now just clear the *mtu_len on error path which can be lifted later again.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
d7a4cb9b6705a89937d12c8158a35a3145dc967a to < 8397bf78988f3ae9dbebb0200189a62a57264980affectedd7a4cb9b6705a89937d12c8158a35a3145dc967a to < a634fa8e480ac2423f86311a602f6295df2c8ed0affectedd7a4cb9b6705a89937d12c8158a35a3145dc967a to < 599d15b6d03356a97bff7a76155c5604c42a2962affectedd7a4cb9b6705a89937d12c8158a35a3145dc967a to < 594a9f5a8d2de2573a856e506f77ba7dd2cefc6aaffectedd7a4cb9b6705a89937d12c8158a35a3145dc967a to < 4b3786a6c5397dc220b1483d8e2f4867743e966faffected
Linux Linux
Default version status: affected
5.2affected0 to < 5.2unaffected6.1.113 to ≤ 6.1.*unaffected6.6.54 to ≤ 6.6.*unaffected6.10.13 to ≤ 6.10.*unaffected6.11.2 to ≤ 6.11.*unaffected6.12 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/8397bf78988f3ae9dbebb0200189a62a57264980 ↗
- https://git.kernel.org/stable/c/a634fa8e480ac2423f86311a602f6295df2c8ed0 ↗
- https://git.kernel.org/stable/c/599d15b6d03356a97bff7a76155c5604c42a2962 ↗
- https://git.kernel.org/stable/c/594a9f5a8d2de2573a856e506f77ba7dd2cefc6a ↗
- https://git.kernel.org/stable/c/4b3786a6c5397dc220b1483d8e2f4867743e966f ↗
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html ↗