From: Mimi Zohar <zohar@linux.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: Mimi Zohar <zohar@linux.ibm.com>,
linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org,
linux-kernel@vger.kernel.org, dhowells@redhat.com,
jforbes@redhat.com, seth.forshee@canonical.com,
kexec@lists.infradead.org, Nayna Jain <nayna@linux.ibm.com>
Subject: [PATCH 3/3] x86/ima: retry detecting secure boot mode
Date: Mon, 19 Nov 2018 14:56:11 -0500 [thread overview]
Message-ID: <1542657371-7019-4-git-send-email-zohar@linux.ibm.com> (raw)
In-Reply-To: <1542657371-7019-1-git-send-email-zohar@linux.ibm.com>
The secure boot mode may not be detected on boot for some reason (eg.
buggy firmware). This patch attempts one more time to detect the
secure boot mode.
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
arch/x86/kernel/Makefile | 2 ++
arch/x86/kernel/ima_arch.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
include/linux/ima.h | 2 +-
3 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index f0910a1e1db7..eb51b0e1189c 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -151,4 +151,6 @@ ifeq ($(CONFIG_X86_64),y)
obj-y += vsmp_64.o
endif
+ifdef CONFIG_EFI
obj-$(CONFIG_IMA) += ima_arch.o
+endif
diff --git a/arch/x86/kernel/ima_arch.c b/arch/x86/kernel/ima_arch.c
index 6c248616ee57..e47cd9390ab4 100644
--- a/arch/x86/kernel/ima_arch.c
+++ b/arch/x86/kernel/ima_arch.c
@@ -7,10 +7,52 @@
extern struct boot_params boot_params;
+static enum efi_secureboot_mode get_sb_mode(void)
+{
+ efi_char16_t efi_SecureBoot_name[] = L"SecureBoot";
+ efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
+ efi_status_t status;
+ unsigned long size;
+ u8 secboot;
+
+ size = sizeof(secboot);
+
+ /* Get variable contents into buffer */
+ status = efi.get_variable(efi_SecureBoot_name, &efi_variable_guid,
+ NULL, &size, &secboot);
+ if (status == EFI_NOT_FOUND) {
+ pr_info("ima: secureboot mode disabled\n");
+ return efi_secureboot_mode_disabled;
+ }
+
+ if (status != EFI_SUCCESS) {
+ pr_info("ima: secureboot mode unknown\n");
+ return efi_secureboot_mode_unknown;
+ }
+
+ if (secboot == 0) {
+ pr_info("ima: secureboot mode disabled\n");
+ return efi_secureboot_mode_disabled;
+ }
+
+ pr_info("ima: secureboot mode enabled\n");
+ return efi_secureboot_mode_enabled;
+}
+
bool arch_ima_get_secureboot(void)
{
- if (efi_enabled(EFI_BOOT) &&
- (boot_params.secure_boot == efi_secureboot_mode_enabled))
+ static enum efi_secureboot_mode sb_mode;
+ static bool initialized;
+
+ if (!initialized && efi_enabled(EFI_BOOT)) {
+ sb_mode = boot_params.secure_boot;
+
+ if (sb_mode == efi_secureboot_mode_unset)
+ sb_mode = get_sb_mode();
+ initialized = true;
+ }
+
+ if (sb_mode == efi_secureboot_mode_enabled)
return true;
else
return false;
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 5ab9134d4fd7..b5e16b8c50b7 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -30,7 +30,7 @@ extern void ima_post_path_mknod(struct dentry *dentry);
extern void ima_add_kexec_buffer(struct kimage *image);
#endif
-#ifdef CONFIG_X86
+#if defined(CONFIG_X86) && defined(CONFIG_EFI)
extern bool arch_ima_get_secureboot(void);
extern const char * const *arch_get_ima_policy(void);
#else
--
2.7.5
next prev parent reply other threads:[~2018-11-19 19:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 19:56 [PATCH 0/3] selftest/ima: fail kexec_load syscall Mimi Zohar
2018-11-19 19:56 ` [PATCH 1/3] ima: add error mesage to kexec_load Mimi Zohar
2018-11-19 19:56 ` [PATCH 2/3] selftests/ima: kexec_load syscall test Mimi Zohar
2018-11-19 19:56 ` Mimi Zohar [this message]
2019-03-07 22:28 ` [PATCH 3/3] x86/ima: retry detecting secure boot mode Matthew Garrett
[not found] ` <CAFbkSA39RwB+E4SaG_ueu-_B=y7JytEYKw1+eXNQ_eCuMfnv=g@mail.gmail.com>
2019-03-07 22:44 ` Matthew Garrett
2019-03-07 22:48 ` Mimi Zohar
2019-03-07 22:50 ` Matthew Garrett
2019-03-08 13:39 ` Mimi Zohar
2019-03-08 17:51 ` Matthew Garrett
2019-03-08 18:43 ` Mimi Zohar
2019-03-08 20:22 ` Matthew Garrett
2019-03-11 16:54 ` Mimi Zohar
2019-03-11 19:20 ` Matthew Garrett
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