From: Scott Wood <swood@redhat.com>
Date: Tue, 23 Apr 2019 22:48:07 +0000 (-0500)
Subject: x86/ima: Check EFI_RUNTIME_SERVICES before using
X-Git-Tag: v5.1.8~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c59e2a64128e30a16394b2fa09b7470c2e2f6f68;p=thirdparty%2Fkernel%2Fstable.git

x86/ima: Check EFI_RUNTIME_SERVICES before using

commit 558b523d46289f111d53d7c42211069063be5985 upstream.

Checking efi_enabled(EFI_BOOT) is not sufficient to ensure that
EFI runtime services are available, e.g. if efi=noruntime is used.

Without this, I get an oops on a PREEMPT_RT kernel where efi=noruntime is
the default.

Fixes: 399574c64eaf94e8 ("x86/ima: retry detecting secure boot mode")
Cc: stable@vger.kernel.org  (linux-5.0)
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kernel/ima_arch.c b/arch/x86/kernel/ima_arch.c
index e47cd9390ab4e..2a2e87717bad1 100644
--- a/arch/x86/kernel/ima_arch.c
+++ b/arch/x86/kernel/ima_arch.c
@@ -17,6 +17,11 @@ static enum efi_secureboot_mode get_sb_mode(void)
 
 	size = sizeof(secboot);
 
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		pr_info("ima: secureboot mode unknown, no efi\n");
+		return efi_secureboot_mode_unknown;
+	}
+
 	/* Get variable contents into buffer */
 	status = efi.get_variable(efi_SecureBoot_name, &efi_variable_guid,
 				  NULL, &size, &secboot);