[PATCH v4 03/12] capsule: authenticate: Add capsule public key in platform's dtb

[Sughosh Ganu]

The EFI capsule authentication logic in u-boot expects the public key
in the form of an EFI Signature List(ESL) to be provided as part of
the platform's dtb. Currently, the embedding of the ESL file into the
dtb needs to be done manually.

Add a signature node in the u-boot dtsi file and include the public
key through the capsule-key property. This file is per architecture,
and is currently being added for sandbox and arm architectures. It
will have to be added for other architectures which need to enable
capsule authentication support.

The path to the ESL file is specified through the
CONFIG_EFI_CAPSULE_ESL_FILE symbol.

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---
Changes since V3:
* Put the two ifdef statements together in arm architecture's
  u-boot.dtsi file.
* Remove the extra blank line in the Kconfig.

 arch/arm/dts/u-boot.dtsi     | 17 +++++++++++++++++
 arch/sandbox/dts/u-boot.dtsi | 17 +++++++++++++++++
 lib/efi_loader/Kconfig       | 10 ++++++++++
 lib/efi_loader/Makefile      |  7 +++++++
 4 files changed, 51 insertions(+)
 create mode 100644 arch/arm/dts/u-boot.dtsi
 create mode 100644 arch/sandbox/dts/u-boot.dtsi

diff --git a/arch/arm/dts/u-boot.dtsi b/arch/arm/dts/u-boot.dtsi
new file mode 100644
index 0000000000..2a9359c43c
--- /dev/null
+++ b/arch/arm/dts/u-boot.dtsi
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Devicetree file with miscellaneous nodes that will be included
+ * at build time into the DTB. Currently being used for including
+ * capsule related information.
+ *
+ */
+
+#ifdef CONFIG_EFI_HAVE_CAPSULE_SUPPORT
+#ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
+/ {
+	signature {
+		capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
+	};
+};
+#endif /* CONFIG_EFI_CAPSULE_AUTHENTICATE */
+#endif /* CONFIG_EFI_HAVE_CAPSULE_SUPPORT */
diff --git a/arch/sandbox/dts/u-boot.dtsi b/arch/sandbox/dts/u-boot.dtsi
new file mode 100644
index 0000000000..60bd004937
--- /dev/null
+++ b/arch/sandbox/dts/u-boot.dtsi
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Devicetree file with miscellaneous nodes that will be included
+ * at build time into the DTB. Currently being used for including
+ * capsule related information.
+ *
+ */
+
+#ifdef CONFIG_EFI_HAVE_CAPSULE_SUPPORT
+/ {
+#ifdef CONFIG_EFI_CAPSULE_AUTHENTICATE
+	signature {
+		capsule-key = /incbin/(CONFIG_EFI_CAPSULE_ESL_FILE);
+	};
+#endif
+};
+#endif /* CONFIG_EFI_HAVE_CAPSULE_SUPPORT */
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index a22e47616f..9abb9a4db3 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -235,6 +235,16 @@ config EFI_CAPSULE_MAX
 	  Select the max capsule index value used for capsule report
 	  variables. This value is used to create CapsuleMax variable.
 
+config EFI_CAPSULE_ESL_FILE
+	string "Path to the EFI Signature List File"
+	default ""
+	depends on EFI_CAPSULE_AUTHENTICATE
+	help
+	  Provides the absolute path to the EFI Signature List
+	  file which will be embedded in the platform's device
+	  tree and used for capsule authentication at the time
+	  of capsule update.
+
 config EFI_DEVICE_PATH_TO_TEXT
 	bool "Device path to text protocol"
 	default y
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 1a8c8d7cab..c52c9d27bd 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -89,3 +89,10 @@ obj-$(CONFIG_EFI_ECPT) += efi_conformance.o
 
 EFI_VAR_SEED_FILE := $(subst $\",,$(CONFIG_EFI_VAR_SEED_FILE))
 $(obj)/efi_var_seed.o: $(srctree)/$(EFI_VAR_SEED_FILE)
+
+ifeq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),y)
+EFI_CAPSULE_KEY_PATH := $(subst $\",,$(CONFIG_EFI_CAPSULE_ESL_FILE))
+ifeq ("$(wildcard $(EFI_CAPSULE_KEY_PATH))","")
+$(error .esl cerificate not found. Configure your CONFIG_EFI_CAPSULE_ESL_FILE)
+endif
+endif
-- 
2.34.1