[PATCH v4 2/6] lib: ecdsa: Add skeleton to implement ecdsa verification in u-boot

[Alexandru Gagniuc <mr.nuke.me@gmail.com>]

Prepare the source tree for accepting implementations of the ECDSA
algorithm. This patch deals with the boring aspects of Makefiles and
Kconfig files.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
 include/image.h          | 10 +++++-----
 include/u-boot/rsa.h     |  2 +-
 lib/Kconfig              |  1 +
 lib/Makefile             |  1 +
 lib/ecdsa/Kconfig        | 23 +++++++++++++++++++++++
 lib/ecdsa/Makefile       |  1 +
 lib/ecdsa/ecdsa-verify.c | 13 +++++++++++++
 7 files changed, 45 insertions(+), 6 deletions(-)
 create mode 100644 lib/ecdsa/Kconfig
 create mode 100644 lib/ecdsa/Makefile
 create mode 100644 lib/ecdsa/ecdsa-verify.c

diff --git a/include/image.h b/include/image.h
index 3ff3c035a7..9b95f6783b 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1224,20 +1224,20 @@ int calculate_hash(const void *data, int data_len, const char *algo,
 #if defined(USE_HOSTCC)
 # if defined(CONFIG_FIT_SIGNATURE)
 #  define IMAGE_ENABLE_SIGN	1
-#  define IMAGE_ENABLE_VERIFY	1
+#  define IMAGE_ENABLE_VERIFY_RSA	1
 #  define IMAGE_ENABLE_VERIFY_ECDSA	1
 #  define FIT_IMAGE_ENABLE_VERIFY	1
 #  include <openssl/evp.h>
 # else
 #  define IMAGE_ENABLE_SIGN	0
-#  define IMAGE_ENABLE_VERIFY	0
+#  define IMAGE_ENABLE_VERIFY_RSA	0
 # define IMAGE_ENABLE_VERIFY_ECDSA	0
 #  define FIT_IMAGE_ENABLE_VERIFY	0
 # endif
 #else
 # define IMAGE_ENABLE_SIGN	0
-# define IMAGE_ENABLE_VERIFY		CONFIG_IS_ENABLED(RSA_VERIFY)
-# define IMAGE_ENABLE_VERIFY_ECDSA	0
+# define IMAGE_ENABLE_VERIFY_RSA	CONFIG_IS_ENABLED(RSA_VERIFY)
+# define IMAGE_ENABLE_VERIFY_ECDSA	CONFIG_IS_ENABLED(ECDSA_VERIFY)
 # define FIT_IMAGE_ENABLE_VERIFY	CONFIG_IS_ENABLED(FIT_SIGNATURE)
 #endif
 
@@ -1293,7 +1293,7 @@ struct image_region {
 	int size;
 };
 
-#if IMAGE_ENABLE_VERIFY
+#if FIT_IMAGE_ENABLE_VERIFY
 # include <u-boot/hash-checksum.h>
 #endif
 struct checksum_algo {
diff --git a/include/u-boot/rsa.h b/include/u-boot/rsa.h
index bed1c097c2..eb258fca4c 100644
--- a/include/u-boot/rsa.h
+++ b/include/u-boot/rsa.h
@@ -81,7 +81,7 @@ static inline int rsa_add_verify_data(struct image_sign_info *info,
 }
 #endif
 
-#if IMAGE_ENABLE_VERIFY
+#if IMAGE_ENABLE_VERIFY_RSA
 /**
  * rsa_verify_hash() - Verify a signature against a hash
  *
diff --git a/lib/Kconfig b/lib/Kconfig
index ab8c9ccd60..584ab7b536 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -295,6 +295,7 @@ config AES
 	  supported by the algorithm but only a 128-bit key is supported at
 	  present.
 
+source lib/ecdsa/Kconfig
 source lib/rsa/Kconfig
 source lib/crypto/Kconfig
 
diff --git a/lib/Makefile b/lib/Makefile
index 6825671955..2c7c145a27 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -60,6 +60,7 @@ endif
 
 obj-$(CONFIG_$(SPL_)ACPIGEN) += acpi/
 obj-$(CONFIG_$(SPL_)MD5) += md5.o
+obj-$(CONFIG_ECDSA) += ecdsa/
 obj-$(CONFIG_$(SPL_)RSA) += rsa/
 obj-$(CONFIG_FIT_SIGNATURE) += hash-checksum.o
 obj-$(CONFIG_SHA1) += sha1.o
diff --git a/lib/ecdsa/Kconfig b/lib/ecdsa/Kconfig
new file mode 100644
index 0000000000..a95c4ff581
--- /dev/null
+++ b/lib/ecdsa/Kconfig
@@ -0,0 +1,23 @@
+config ECDSA
+	bool "Enable ECDSA support"
+	depends on DM
+	help
+	  This enables the ECDSA (elliptic curve signature) algorithm for FIT
+	  image verification in U-Boot. The ECDSA algorithm is implemented
+	  using the driver model, so CONFIG_DM is required by this library.
+	  See doc/uImage.FIT/signature.txt for more details.
+	  ECDSA is enabled for mkimage regardless of this option.
+
+if ECDSA
+
+config ECDSA_VERIFY
+	bool "Enable ECDSA verification support in U-Boot."
+	help
+	  Allow ECDSA signatures to be recognized and verified in U-Boot.
+
+config SPL_ECDSA_VERIFY
+	bool "Enable ECDSA verification support in SPL"
+	help
+	  Allow ECDSA signatures to be recognized and verified in SPL.
+
+endif
diff --git a/lib/ecdsa/Makefile b/lib/ecdsa/Makefile
new file mode 100644
index 0000000000..771d6d3135
--- /dev/null
+++ b/lib/ecdsa/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_$(SPL_)ECDSA_VERIFY) += ecdsa-verify.o
diff --git a/lib/ecdsa/ecdsa-verify.c b/lib/ecdsa/ecdsa-verify.c
new file mode 100644
index 0000000000..d2e6a40f4a
--- /dev/null
+++ b/lib/ecdsa/ecdsa-verify.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020, Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ */
+
+#include <u-boot/ecdsa.h>
+
+int ecdsa_verify(struct image_sign_info *info,
+		 const struct image_region region[], int region_count,
+		 uint8_t *sig, uint sig_len)
+{
+	return -EOPNOTSUPP;
+}
-- 
2.26.3