bpf: Require CAP_PERFMON for untrusted read-only memory reads

Marking bpf_rdonly_cast() KF_PERFMON CAP-limits one producer of PTR_TO_MEM |
MEM_RDONLY | PTR_UNTRUSTED, but not the type itself. A global subprogram
argument tagged __arg_untrusted results in the same register with no kfunc
call.

Reported-by: STAR Labs SG <info@starlabs.sg>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260910213510.49358-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann 2026-09-10 23:35:09 +02:00 • committed by Alexei Starovoitov
commit f9191460cd