[PATCH v9 3/8] powerpc: detect the trusted boot state of the system
From: Nayna Jain <nayna@linux.ibm.com>
Date: 2019-10-24 03:47:57
Also in:
linux-efi, linux-integrity, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
While secure boot permits only properly verified signed kernels to be booted, trusted boot calculates the file hash of the kernel image and stores the measurement prior to boot, that can be subsequently compared against good known values via attestation services. This patch reads the trusted boot state of a PowerNV system. The state is used to conditionally enable additional measurement rules in the IMA arch-specific policies. Signed-off-by: Nayna Jain <nayna@linux.ibm.com> --- arch/powerpc/include/asm/secure_boot.h | 6 ++++++ arch/powerpc/kernel/secure_boot.c | 26 ++++++++++++++++++++++++++ 2 files changed, 32 insertions(+)
diff --git a/arch/powerpc/include/asm/secure_boot.h b/arch/powerpc/include/asm/secure_boot.h
index 07d0fe0ca81f..a2ff556916c6 100644
--- a/arch/powerpc/include/asm/secure_boot.h
+++ b/arch/powerpc/include/asm/secure_boot.h@@ -11,6 +11,7 @@ #ifdef CONFIG_PPC_SECURE_BOOT bool is_ppc_secureboot_enabled(void); +bool is_ppc_trustedboot_enabled(void); #else
@@ -19,5 +20,10 @@ static inline bool is_ppc_secureboot_enabled(void) return false; } +static inline bool is_ppc_trustedboot_enabled(void) +{ + return false; +} + #endif #endif
diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
index 63dc82c50862..a6a5f17ede03 100644
--- a/arch/powerpc/kernel/secure_boot.c
+++ b/arch/powerpc/kernel/secure_boot.c@@ -7,6 +7,17 @@ #include <linux/of.h> #include <asm/secure_boot.h> +static struct device_node *get_ppc_fw_sb_node(void) +{ + static const struct of_device_id ids[] = { + { .compatible = "ibm,secureboot-v1", }, + { .compatible = "ibm,secureboot-v2", }, + {}, + }; + + return of_find_matching_node(NULL, ids); +} + bool is_ppc_secureboot_enabled(void) { struct device_node *node;
@@ -30,3 +41,18 @@ bool is_ppc_secureboot_enabled(void) pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled"); return enabled; } + +bool is_ppc_trustedboot_enabled(void) +{ + struct device_node *node; + bool enabled = false; + + node = get_ppc_fw_sb_node(); + enabled = of_property_read_bool(node, "trusted-enabled"); + + of_node_put(node); + + pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled"); + + return enabled; +}
--
2.20.1