| From | David Howells <> | Subject | Re: [PATCH 18/27] bpf: Restrict kernel image access functions when the kernel is locked down | Date | Thu, 19 Oct 2017 23:48:34 +0100 |
| |
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> > @@ -65,6 +65,11 @@ BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) > > { > > int ret; > > > > + if (kernel_is_locked_down("BPF")) { > > + memset(dst, 0, size); > > + return -EPERM; > > + } > > That doesn't help the lockdown purpose. > If you don't trust the root the only way to prevent bpf read > memory is to disable the whole thing. > Have a single check in sys_bpf() to disallow everything if kernel_is_locked_down() > and don't add overhead to critical path like bpf_probe_read().
TBH, I've no idea how bpf does anything, so I can't say whether this is better, overkill or insufficient.
David
|