crypto: add support for the mbedTLS backend

Closes libssh2#132

cmake/FindmbedTLS.cmake

@@ -0,0 +1,64 @@
+# - Try to find mbedTLS
+# Once done this will define
+#
+# Read-Only variables
+#  MBEDTLS_FOUND - system has mbedTLS
+#  MBEDTLS_INCLUDE_DIR - the mbedTLS include directory
+#  MBEDTLS_LIBRARY_DIR - the mbedTLS library directory
+#  MBEDTLS_LIBRARIES - Link these to use mbedTLS
+#  MBEDTLS_LIBRARY - path to mbedTLS library
+#  MBEDX509_LIBRARY - path to mbedTLS X.509 library
+#  MBEDCRYPTO_LIBRARY - path to mbedTLS Crypto library
+
+FIND_PATH(MBEDTLS_INCLUDE_DIR mbedtls/version.h)
+
+IF(MBEDTLS_INCLUDE_DIR AND MBEDTLS_LIBRARIES)
+    # Already in cache, be silent
+    SET(MBEDTLS_FIND_QUIETLY TRUE)
+ENDIF()
+
+FIND_LIBRARY(MBEDTLS_LIBRARY NAMES mbedtls libmbedtls libmbedx509)
+FIND_LIBRARY(MBEDX509_LIBRARY NAMES mbedx509 libmbedx509)
+FIND_LIBRARY(MBEDCRYPTO_LIBRARY NAMES mbedcrypto libmbedcrypto)
+
+IF(MBEDTLS_INCLUDE_DIR AND MBEDTLS_LIBRARY AND MBEDX509_LIBRARY AND MBEDCRYPTO_LIBRARY)
+     SET(MBEDTLS_FOUND TRUE)
+ENDIF()
+
+IF(MBEDTLS_FOUND)
+    # split mbedTLS into -L and -l linker options, so we can set them for pkg-config
+    GET_FILENAME_COMPONENT(MBEDTLS_LIBRARY_DIR ${MBEDTLS_LIBRARY} PATH)
+    GET_FILENAME_COMPONENT(MBEDTLS_LIBRARY_FILE ${MBEDTLS_LIBRARY} NAME_WE)
+    GET_FILENAME_COMPONENT(MBEDX509_LIBRARY_FILE ${MBEDX509_LIBRARY} NAME_WE)
+    GET_FILENAME_COMPONENT(MBEDCRYPTO_LIBRARY_FILE ${MBEDCRYPTO_LIBRARY} NAME_WE)
+    STRING(REGEX REPLACE "^lib" "" MBEDTLS_LIBRARY_FILE ${MBEDTLS_LIBRARY_FILE})
+    STRING(REGEX REPLACE "^lib" "" MBEDX509_LIBRARY_FILE ${MBEDX509_LIBRARY_FILE})
+    STRING(REGEX REPLACE "^lib" "" MBEDCRYPTO_LIBRARY_FILE ${MBEDCRYPTO_LIBRARY_FILE})
+    SET(MBEDTLS_LIBRARIES "-L${MBEDTLS_LIBRARY_DIR} -l${MBEDTLS_LIBRARY_FILE} -l${MBEDX509_LIBRARY_FILE} -l${MBEDCRYPTO_LIBRARY_FILE}")
+
+    IF(NOT MBEDTLS_FIND_QUIETLY)
+        MESSAGE(STATUS "Found mbedTLS:")
+        FILE(READ ${MBEDTLS_INCLUDE_DIR}/mbedtls/version.h MBEDTLSCONTENT)
+        STRING(REGEX MATCH "MBEDTLS_VERSION_STRING +\"[0-9|.]+\"" MBEDTLSMATCH ${MBEDTLSCONTENT})
+        IF (MBEDTLSMATCH)
+            STRING(REGEX REPLACE "MBEDTLS_VERSION_STRING +\"([0-9|.]+)\"" "\\1" MBEDTLS_VERSION ${MBEDTLSMATCH})
+            MESSAGE(STATUS "  version ${MBEDTLS_VERSION}")
+        ENDIF(MBEDTLSMATCH)
+        MESSAGE(STATUS "  TLS: ${MBEDTLS_LIBRARY}")
+        MESSAGE(STATUS "  X509: ${MBEDX509_LIBRARY}")
+        MESSAGE(STATUS "  Crypto: ${MBEDCRYPTO_LIBRARY}")
+    ENDIF(NOT MBEDTLS_FIND_QUIETLY)
+ELSE(MBEDTLS_FOUND)
+    IF(MBEDTLS_FIND_REQUIRED)
+        MESSAGE(FATAL_ERROR "Could not find mbedTLS")
+    ENDIF(MBEDTLS_FIND_REQUIRED)
+ENDIF(MBEDTLS_FOUND)
+
+MARK_AS_ADVANCED(
+    MBEDTLS_INCLUDE_DIR
+    MBEDTLS_LIBRARY_DIR
+    MBEDTLS_LIBRARIES
+    MBEDTLS_LIBRARY
+    MBEDX509_LIBRARY
+    MBEDCRYPTO_LIBRARY
+)

src/CMakeLists.txt

@@ -48,7 +48,7 @@ set(CRYPTO_BACKEND
   ""
   CACHE
   STRING
-  "The backend to use for cryptography: OpenSSL, Libgcrypt or WinCNG,
+  "The backend to use for cryptography: OpenSSL, Libgcrypt or WinCNG, mbedTLS
 or empty to try any available")
 
 # If the crypto backend was given, rather than searching for the first
@@ -151,6 +151,21 @@ if(CRYPTO_BACKEND STREQUAL "WinCNG" OR NOT CRYPTO_BACKEND)
   endif()
 endif()
 
+if(CRYPTO_BACKEND STREQUAL "mbedTLS" OR NOT CRYPTO_BACKEND)
+
+  find_package(mbedTLS ${SPECIFIC_CRYPTO_REQUIREMENT})
+
+  if(MBEDTLS_FOUND)
+    set(CRYPTO_BACKEND "mbedTLS")
+    set(CRYPTO_SOURCES mbedtls.c mbedtls.h)
+    list(APPEND PRIVATE_COMPILE_DEFINITIONS LIBSSH2_MBEDTLS)
+    list(APPEND PRIVATE_INCLUDE_DIRECTORIES ${MBEDTLS_INCLUDE_DIR})
+    list(APPEND LIBRARIES ${MBEDTLS_LIBRARIES})
+    list(APPEND PC_LIBS -lmbedcrypto)
+    link_directories(${MBEDTLS_LIBRARY_DIR})
+  endif()
+endif()
+
 if(NOT CRYPTO_BACKEND)
   message(FATAL_ERROR "No suitable cryptography backend found.")
 endif()

src/crypto.h

@@ -54,6 +54,10 @@
 #include "os400qc3.h"
 #endif
 
+#ifdef LIBSSH2_MBEDTLS
+#include "mbedtls.h"
+#endif
+
 int _libssh2_rsa_new(libssh2_rsa_ctx ** rsa,
                      const unsigned char *edata,
                      unsigned long elen,