Thread (2 messages) 2 messages, 2 authors, 2020-03-06

[PATCH v3] ima: add a new CONFIG for loading arch-specific policies

From: Nayna Jain <nayna@linux.ibm.com>
Date: 2020-03-06 17:39:43
Also in: linux-efi, linux-s390, linuxppc-dev, lkml
Subsystem: extended verification module (evm), integrity measurement architecture (ima), linux for powerpc (32-bit and 64-bit), s390 architecture, security subsystem, the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Madhavan Srinivasan, Michael Ellerman, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

Every time a new architecture defines the IMA architecture specific
functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
include file needs to be updated. To avoid this "noise", this patch
defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
the different architectures to select it.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Philipp Rudo <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
---
v3:
* Updated and tested the patch with improvements suggested by Michael.
It now uses "imply" instead of "select". Thanks Michael.
* Have missed replacing the CONFIG_IMA in x86 and s390 with new config,
that was resulting in redefinition when the IMA_SECURE_AND_OR_TRUSTED_BOOT
is not enabled. Thanks to Mimi for recognizing the problem.

v2:
* Fixed the issue identified by Mimi. Thanks Mimi, Ard, Heiko and Michael for
discussing the fix.

 arch/powerpc/Kconfig           | 1 +
 arch/s390/Kconfig              | 1 +
 arch/s390/kernel/Makefile      | 2 +-
 arch/x86/Kconfig               | 1 +
 arch/x86/kernel/Makefile       | 2 +-
 include/linux/ima.h            | 3 +--
 security/integrity/ima/Kconfig | 8 ++++++++
 7 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 497b7d0b2d7e..a5cfde432983 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -979,6 +979,7 @@ config PPC_SECURE_BOOT
 	bool
 	depends on PPC_POWERNV
 	depends on IMA_ARCH_POLICY
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT
 	help
 	  Systems with firmware secure boot enabled need to define security
 	  policies to extend secure boot to the OS. This config allows a user
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 8abe77536d9d..4a502fbcb800 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -195,6 +195,7 @@ config S390
 	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
 	select SWIOTLB
 	select GENERIC_ALLOCATOR
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT if IMA_ARCH_POLICY
 
 
 config SCHED_OMIT_FRAME_POINTER
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 2b1203cf7be6..578a6fa82ea4 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -70,7 +70,7 @@ obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 obj-$(CONFIG_KEXEC_FILE)	+= machine_kexec_file.o kexec_image.o
 obj-$(CONFIG_KEXEC_FILE)	+= kexec_elf.o
 
-obj-$(CONFIG_IMA)		+= ima_arch.o
+obj-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT)	+= ima_arch.o
 
 obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o perf_cpum_cf_common.o
 obj-$(CONFIG_PERF_EVENTS)	+= perf_cpum_cf.o perf_cpum_sf.o
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index beea77046f9b..7f5bfaf0cbd2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -230,6 +230,7 @@ config X86
 	select VIRT_TO_BUS
 	select X86_FEATURE_NAMES		if PROC_FS
 	select PROC_PID_ARCH_STATUS		if PROC_FS
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT	if EFI && IMA_ARCH_POLICY
 
 config INSTRUCTION_DECODER
 	def_bool y
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 9b294c13809a..7f131ceba136 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -155,5 +155,5 @@ ifeq ($(CONFIG_X86_64),y)
 endif
 
 ifdef CONFIG_EFI
-obj-$(CONFIG_IMA)			+= ima_arch.o
+obj-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT)	+= ima_arch.o
 endif
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 1659217e9b60..aefe758f4466 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -30,8 +30,7 @@ extern void ima_kexec_cmdline(const void *buf, int size);
 extern void ima_add_kexec_buffer(struct kimage *image);
 #endif
 
-#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) \
-	|| defined(CONFIG_PPC_SECURE_BOOT)
+#ifdef CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT
 extern bool arch_ima_get_secureboot(void);
 extern const char * const *arch_get_ima_policy(void);
 #else
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 3f3ee4e2eb0d..2baaf196c6d8 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -327,3 +327,11 @@ config IMA_QUEUE_EARLY_BOOT_KEYS
 	depends on IMA_MEASURE_ASYMMETRIC_KEYS
 	depends on SYSTEM_TRUSTED_KEYRING
 	default y
+
+config IMA_SECURE_AND_OR_TRUSTED_BOOT
+	bool
+	depends on IMA_ARCH_POLICY
+	default n
+	help
+	   This option is selected by architectures to enable secure and/or
+	   trusted boot based on IMA runtime policies.
-- 
2.18.1
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