[PATCH v8 3/8] powerpc: detect the trusted boot state of the system
From: Nayna Jain <nayna@linux.ibm.com>
Date: 2019-10-19 18:06:50
Also in:
linux-efi, linux-integrity, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
While secure boot permits only properly verified signed kernels to be booted, trusted boot takes a measurement of the kernel image 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 | 24 ++++++++++++++++++++++++ 2 files changed, 30 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 99bba7915629..9753470ab08a 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;
@@ -28,3 +39,16 @@ 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"); + + pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled"); + + return enabled; +}
--
2.20.1