mbedtls: add config option to compile with hkdf

This adds a config option to allow compiling with HKDF algorithm support
to support applications that require this feature.

Signed-off-by: Etan Kissling <etan_kissling@apple.com>

diff --git a/package/libs/mbedtls/Makefile b/package/libs/mbedtls/Makefile
index 27f50f8ddee37ff0c5cff06f2f12e64887dc7fa2..79650b594a26153e628a7022717871eb84d0c7fe 100644 (file)
--- a/package/libs/mbedtls/Makefile
+++ b/package/libs/mbedtls/Makefile
@@ -21,7 +21,9 @@ PKG_LICENSE:=GPL-2.0-or-later
 PKG_LICENSE_FILES:=gpl-2.0.txt
 PKG_CPE_ID:=cpe:/a:arm:mbed_tls
 
-PKG_CONFIG_DEPENDS:=CONFIG_LIBMBEDTLS_DEBUG_C
+PKG_CONFIG_DEPENDS := \
+       CONFIG_LIBMBEDTLS_DEBUG_C \
+       CONFIG_LIBMBEDTLS_HKDF_C
 
 include $(INCLUDE_DIR)/package.mk
 include $(INCLUDE_DIR)/cmake.mk
@@ -57,6 +59,14 @@ config LIBMBEDTLS_DEBUG_C
         by around 60 KiB (for an ARMv5 platform).
 
         Usually, you don't need this, so don't select this if you're unsure.
+
+config LIBMBEDTLS_HKDF_C
+       depends on PACKAGE_libmbedtls
+       bool "Enable the HKDF algorithm (RFC 5869)"
+       default n
+       help
+        This option adds support for the Hashed Message Authentication Code
+        (HMAC)-based key derivation function (HKDF).
 endef
 
 define Package/mbedtls-util
@@ -97,6 +107,13 @@ define Build/Configure
             END { exit(rc) }' $(PKG_BUILD_DIR)/include/mbedtls/config.h \
             >$(PKG_BUILD_DIR)/include/mbedtls/config.h.new && \
        mv $(PKG_BUILD_DIR)/include/mbedtls/config.h.new $(PKG_BUILD_DIR)/include/mbedtls/config.h
+
+       awk 'BEGIN { rc = 1 } \
+            /#define MBEDTLS_HKDF_C/ { $$$$0 = "$(if $(CONFIG_LIBMBEDTLS_HKDF_C),,// )#define MBEDTLS_HKDF_C"; rc = 0 } \
+            { print } \
+            END { exit(rc) }' $(PKG_BUILD_DIR)/include/mbedtls/config.h \
+            >$(PKG_BUILD_DIR)/include/mbedtls/config.h.new && \
+       mv $(PKG_BUILD_DIR)/include/mbedtls/config.h.new $(PKG_BUILD_DIR)/include/mbedtls/config.h
 endef
 
 define Build/InstallDev