powerpc: Detect the trusted boot state of the system

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 <[email protected]> Signed-off-by: Eric Richter <[email protected]> Signed-off-by: Michael Ellerman <[email protected]> Link: https://lore.kernel.org/r/[email protected]
tprrt · Nov 12, 2019 · 2702809 · 2702809
1 parent 4238fad
commit 2702809
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diff --git 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
@@ -33,3 +33,18 @@ bool is_ppc_secureboot_enabled(void)
 
 	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;
+}