From: Chun-Yi Lee <[email protected]> When KEXEC_VERIFY_SIG is not enabled, kernel should not load images through kexec_file systemcall if the kernel is locked down unless IMA can be used to validate the image.
This code was showed in Matthew's patch but not in git: https://lkml.org/lkml/2015/3/13/778 Cc: Matthew Garrett <[email protected]> Signed-off-by: Chun-Yi Lee <[email protected]> Signed-off-by: David Howells <[email protected]> Reviewed-by: James Morris <[email protected]> cc: [email protected] --- kernel/kexec_file.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 9f48f4412297..3ba28fc3fab0 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -255,6 +255,14 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) return -EPERM; + /* Don't permit images to be loaded into trusted kernels if we're not + * going to verify the signature on them + */ + if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && + !is_ima_appraise_enabled() && + kernel_is_locked_down("kexec of unsigned images")) + return -EPERM; + /* Make sure we have a legal set of flags */ if (flags != (flags & KEXEC_FILE_FLAGS)) return -EINVAL;
