Thread (4 messages) flat view 4 messages, 4 authors, 2020-03-12
STALE2349d REVIEWED: 7 (7M)

1 review trailer.

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

From: Nayna Jain <nayna@linux.ibm.com>
Date: 2020-03-09 00:58:08
Also in: linux-efi, linux-integrity, linux-s390, 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, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

From: Nayna Jain <redacted>

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>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Philipp Rudo <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
---
v3:
* Removes CONFIG_IMA dependency. Thanks Ard.
* Updated the patch with improvements suggested by Michael. It now uses
"imply" instead of "select". Thanks Michael.
* Replaced the CONFIG_IMA in x86 and s390 with new config, else it was
resulting in redefinition when the IMA_SECURE_AND_OR_TRUSTED_BOOT
is not enabled. Thanks to Mimi for identifying the problem.
* Removed "#ifdef EFI" check in the arch/x86/Makefile for compiling
ima_arch.c file.
* Ard, Thanks for your Acked-by. I have changed the arch/x86/Makefile in
this version. Can you please review again and confirm ?
* Rudo, Thanks for your review. I have changed arch/s390/Makefile as well.
Can you also please review again ?

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       | 4 +---
 include/linux/ima.h            | 3 +--
 security/integrity/ima/Kconfig | 7 +++++++
 7 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 497b7d0b2d7e..5b9f1cba2a44 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
+	imply 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..59c216af6264 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
+	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
 
 
 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..dcf5b1729f7c 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
+	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
 
 config INSTRUCTION_DECODER
 	def_bool y
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 9b294c13809a..cfef37a27def 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -154,6 +154,4 @@ ifeq ($(CONFIG_X86_64),y)
 	obj-y				+= vsmp_64.o
 endif
 
-ifdef CONFIG_EFI
-obj-$(CONFIG_IMA)			+= ima_arch.o
-endif
+obj-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT)	+= ima_arch.o
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..edde88dbe576 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -327,3 +327,10 @@ 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
+       help
+          This option is selected by architectures to enable secure and/or
+          trusted boot based on IMA runtime policies.
-- 
2.17.1
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