Messages in this thread Patch in this message | | | Date | Fri, 10 Nov 2017 10:01:50 +0900 | From | Masami Hiramatsu <> | Subject | Re: [RFC][PATCH] Lock down kprobes |
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Hi David,
On Thu, 09 Nov 2017 16:52:05 +0000 David Howells <dhowells@redhat.com> wrote: > > Lock down kprobes > > Disallow the creation of kprobes when the kernel is locked down by > preventing their registration. This prevents kprobes from being used to > access kernel memory, either to make modifications or to steal crypto data.
Is that locked-down flag changed while running the kernel, or only specified by boot parameter? If that can happen while running, we have to take care of enabling/disabling unregistering etc. too.
Thank you,
> > Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> > Signed-off-by: David Howells <dhowells@redhat.com> > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index a1606a4224e1..f06023b0936c 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1530,6 +1530,9 @@ int register_kprobe(struct kprobe *p) > struct module *probed_mod; > kprobe_opcode_t *addr; > > + if (kernel_is_locked_down("Use of kprobes")) > + return -EPERM; > + > /* Adjust probe address from symbol */ > addr = kprobe_addr(p); > if (IS_ERR(addr))
-- Masami Hiramatsu <mhiramat@kernel.org>
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