On Wed, 3 Apr 2019 17:32:41 -0700 Matthew Garrett <[email protected]> wrote:
> From: David Howells <[email protected]> > > The testmmiotrace module shouldn't be permitted when the kernel is locked > down as it can be used to arbitrarily read and write MMIO space. This is > a runtime check rather than buildtime in order to allow configurations > where the same kernel may be run in both locked down or permissive modes > depending on local policy. > > Suggested-by: Thomas Gleixner <[email protected]> > Signed-off-by: David Howells <[email protected] > Signed-off-by: Matthew Garrett <[email protected]> > cc: Thomas Gleixner <[email protected]> > cc: Steven Rostedt <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> -- Steve > cc: Ingo Molnar <[email protected]> > cc: "H. Peter Anvin" <[email protected]> > cc: [email protected] > --- > arch/x86/mm/testmmiotrace.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c > index f6ae6830b341..9e8ad665f354 100644 > --- a/arch/x86/mm/testmmiotrace.c > +++ b/arch/x86/mm/testmmiotrace.c > @@ -115,6 +115,9 @@ static int __init init(void) > { > unsigned long size = (read_far) ? (8 << 20) : (16 << 10); > > + if (kernel_is_locked_down("MMIO trace testing", LOCKDOWN_INTEGRITY)) > + return -EPERM; > + > if (mmio_address == 0) { > pr_err("you have to use the module argument mmio_address.\n"); > pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU > ARE DOING!\n");
