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From: Mimi Zohar <zohar@linux.ibm.com>
To: linux-integrity <linux-integrity@vger.kernel.org>
Cc: Matthew Garrett <matthewgarrett@google.com>
Subject: [PATCH] x86/ima: check EFI SetupMode too
Date: Mon, 20 May 2019 08:15:55 -0400
Message-ID: <1558354555.4507.98.camel@linux.ibm.com> (raw)

Checking "SecureBoot" mode is not sufficient, also check "SetupMode".

Fixes: 399574c64eaf ("x86/ima: retry detecting secure boot mode")
Reported-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 arch/x86/kernel/ima_arch.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/ima_arch.c b/arch/x86/kernel/ima_arch.c
index 64b973f0e985..4c407833faca 100644
--- a/arch/x86/kernel/ima_arch.c
+++ b/arch/x86/kernel/ima_arch.c
@@ -11,10 +11,11 @@ extern struct boot_params boot_params;
 static enum efi_secureboot_mode get_sb_mode(void)
 {
 	efi_char16_t efi_SecureBoot_name[] = L"SecureBoot";
+	efi_char16_t efi_SetupMode_name[] = L"SecureBoot";
 	efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
 	efi_status_t status;
 	unsigned long size;
-	u8 secboot;
+	u8 secboot, setupmode;
 
 	size = sizeof(secboot);
 
@@ -36,7 +37,14 @@ static enum efi_secureboot_mode get_sb_mode(void)
 		return efi_secureboot_mode_unknown;
 	}
 
-	if (secboot == 0) {
+	size = sizeof(setupmode);
+	status = efi.get_variable(efi_SetupMode_name, &efi_variable_guid,
+				  NULL, &size, &setupmode);
+
+	if (status != EFI_SUCCESS)	/* ignore unknown SetupMode */
+		setupmode = 0;
+
+	if (secboot == 0 || setupmode == 1) {
 		pr_info("ima: secureboot mode disabled\n");
 		return efi_secureboot_mode_disabled;
 	}
-- 
2.7.5


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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-20 12:15 Mimi Zohar [this message]
2019-05-20 12:53 Mimi Zohar

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