David Howells <dhowe...@redhat.com> writes: > From: Matthew Garrett <mj...@srcf.ucam.org> > > The kexec_load() syscall permits the loading and execution of arbitrary > code in ring 0, which is something that lock-down is meant to prevent. It > makes sense to disable kexec_load() in this situation. > > This does not affect kexec_file_load() syscall which can check for a > signature on the image to be booted.
Maybing I am missing it but I am not seeing anything that would require kexec_file_load be configured such that it checks the loaded kernel. Without that I don't see the point of disabling kexec_load. Nacked-by: "Eric W. Biederman" <ebied...@xmission.com> Eric > Signed-off-by: Matthew Garrett <mj...@srcf.ucam.org> > Signed-off-by: David Howells <dhowe...@redhat.com> > Acked-by: Dave Young <dyo...@redhat.com> > Reviewed-by: "Lee, Chun-Yi" <j...@suse.com> > Reviewed-by: James Morris <james.l.mor...@oracle.com> > cc: ke...@lists.infradead.org > --- > > kernel/kexec.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/kexec.c b/kernel/kexec.c > index aed8fb2564b3..1553ac765e73 100644 > --- a/kernel/kexec.c > +++ b/kernel/kexec.c > @@ -199,6 +199,13 @@ static inline int kexec_load_check(unsigned long > nr_segments, > if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) > return -EPERM; > > + /* > + * kexec can be used to circumvent module loading restrictions, so > + * prevent loading in that case > + */ > + if (kernel_is_locked_down("kexec of unsigned images")) > + return -EPERM; > + > /* > * Verify we have a legal set of flags > * This leaves us room for future extensions.