From: Chun-Yi Lee <joeyli.ker...@gmail.com> When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image through kexec_file systemcall if securelevel has been set.
This code was showed in Matthew's patch but not in git: https://lkml.org/lkml/2015/3/13/778 Cc: Matthew Garrett <mj...@srcf.ucam.org> Signed-off-by: Chun-Yi Lee <j...@suse.com> Signed-off-by: David Howells <dhowe...@redhat.com> --- kernel/kexec_file.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index b118735fea9d..f6937eecd1eb 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -268,6 +268,12 @@ 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) && kernel_is_locked_down()) + return -EPERM; + /* Make sure we have a legal set of flags */ if (flags != (flags & KEXEC_FILE_FLAGS)) return -EINVAL;
