From: Matthew Garrett <[email protected]> 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: David Howells <[email protected]> Signed-off-by: Matthew Garrett <[email protected]> Acked-by: Dave Young <[email protected]> cc: [email protected] --- kernel/kexec.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 68559808fdfa..57047acc9a36 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -207,6 +207,14 @@ 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", + LOCKDOWN_INTEGRITY)) + 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 [email protected] http://lists.infradead.org/mailman/listinfo/kexec
