From: Matthew Garrett <mjg59@xxxxxxxxxxxxx> 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. Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Acked-by: Dave Young <dyoung@xxxxxxxxxx> cc: kexec@xxxxxxxxxxxxxxxxxxx Signed-off-by: Matthew Garrett <matthewgarrett@xxxxxxxxxx> --- kernel/kexec.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 68559808fdfa..8ea0ce31271f 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -207,6 +207,13 @@ static inline int kexec_load_check(unsigned long nr_segments, if (result < 0) return result; + /* + * 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. -- 2.21.0.392.gf8f6787159e-goog _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec