PowerNV systems use a Linux-based bootloader, which rely on the IMA subsystem to enforce different secure boot modes. Since the verification policy may differ based on the secure boot mode of the system, the policies must be defined at runtime. This patch implements arch-specific support to define IMA policy rules based on the runtime secure boot mode of the system. This patch provides arch-specific IMA policies if PPC_SECURE_BOOT config is enabled.
Unified · Split
| @@ -938,6 +938,7 @@ config PPC_SECURE_BOOT · 937 unmodified lines | ||
| 938 | 938 | prompt "Enable secure boot support" |
| 939 | 939 | bool |
| 940 | 940 | depends on PPC_POWERNV |
| 941 | + depends on IMA_ARCH_POLICY | |
| 941 | 942 | help |
| 942 | 943 | Systems with firmware secure boot enabled need to define security |
| 943 | 944 | policies to extend secure boot to the OS. This config allows a user |
| @@ -161,7 +161,7 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),) · 160 unmodified lines | ||
| 161 | 161 | obj-y += ucall.o |
| 162 | 162 | endif |
| 163 | 163 | |
| 164 | −obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o | |
| 164 | +obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o ima_arch.o | |
| 165 | 165 | |
| 166 | 166 | # Disable GCOV, KCOV & sanitizers in odd or sensitive code |
| 167 | 167 | GCOV_PROFILE_prom_init.o := n |
| @@ -0,0 +1,43 @@ | ||
| 1 | +// SPDX-License-Identifier: GPL-2.0 | |
| 2 | +/* | |
| 3 | + * Copyright (C) 2019 IBM Corporation | |
| 4 | + * Author: Nayna Jain | |
| 5 | + */ | |
| 6 | + | |
| 7 | +#include <linux/ima.h> | |
| 8 | +#include <asm/secure_boot.h> | |
| 9 | + | |
| 10 | +bool arch_ima_get_secureboot(void) | |
| 11 | +{ | |
| 12 | + return is_ppc_secureboot_enabled(); | |
| 13 | +} | |
| 14 | + | |
| 15 | +/* | |
| 16 | + * The "secure_rules" are enabled only on "secureboot" enabled systems. | |
| 17 | + * These rules verify the file signatures against known good values. | |
| 18 | + * The "appraise_type=imasig|modsig" option allows the known good signature | |
| 19 | + * to be stored as an xattr or as an appended signature. | |
| 20 | + * | |
| 21 | + * To avoid duplicate signature verification as much as possible, the IMA | |
| 22 | + * policy rule for module appraisal is added only if CONFIG_MODULE_SIG_FORCE | |
| 23 | + * is not enabled. | |
| 24 | + */ | |
| 25 | +static const char *const secure_rules[] = { | |
| 26 | + "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig", | |
| 27 | +#ifndef CONFIG_MODULE_SIG_FORCE | |
| 28 | + "appraise func=MODULE_CHECK appraise_type=imasig|modsig", | |
| 29 | +#endif | |
| 30 | + NULL | |
| 31 | +}; | |
| 32 | + | |
| 33 | +/* | |
| 34 | + * Returns the relevant IMA arch-specific policies based on the system secure | |
| 35 | + * boot state. | |
| 36 | + */ | |
| 37 | +const char *const *arch_get_ima_policy(void) | |
| 38 | +{ | |
| 39 | + if (is_ppc_secureboot_enabled()) | |
| 40 | + return secure_rules; | |
| 41 | + | |
| 42 | + return NULL; | |
| 43 | +} | |
| @@ -29,7 +29,8 @@ extern void ima_kexec_cmdline(const void *buf, int size); · 28 unmodified lines | ||
| 29 | 29 | extern void ima_add_kexec_buffer(struct kimage *image); |
| 30 | 30 | #endif |
| 31 | 31 | |
| 32 | −#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) | |
| 32 | +#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) \ | |
| 33 | + || defined(CONFIG_PPC_SECURE_BOOT) | |
| 33 | 34 | extern bool arch_ima_get_secureboot(void); |
| 34 | 35 | extern const char * const *arch_get_ima_policy(void); |
| 35 | 36 | #else |