Link libjitterentropy into libcrypto.a (aws#511)

When building static FIPS build we were building a separate
`libjitterentropy.a` instead of linking it into `libcrypto.a`.
This hasn't caused any issues in our build and test system because
we had a `target_link_libraries` directive which instructs CMake
to always add `libjitterentropy.a` whenever `libcrypto.a` is linked
to another binary. However, if one tries to compile a program and link
it with `libcrypto.a` directly, the linker will complain about
missing symbol definitions from `libjitterentropy.a` and they will
have to link `libjitterentropy.a` as well. This should not be
a requirement, AWS-LC `libcrypto.a` should be a stand-alone library.
With this change we fix that.

crypto/CMakeLists.txt

@@ -503,7 +503,12 @@ target_compile_definitions(crypto_objects PRIVATE BORINGSSL_IMPLEMENTATION)
 add_dependencies(crypto_objects global_target)
 
 function(build_libcrypto name module_source)
-  add_library(${name} $<TARGET_OBJECTS:crypto_objects> ${CRYPTO_FIPS_OBJECTS} ${module_source})
+  if(FIPS)
+    add_library(${name} $<TARGET_OBJECTS:crypto_objects> ${CRYPTO_FIPS_OBJECTS} ${module_source} $<TARGET_OBJECTS:jitterentropy>)
+  else()
+    add_library(${name} $<TARGET_OBJECTS:crypto_objects> ${CRYPTO_FIPS_OBJECTS} ${module_source})
+  endif()
+
   add_dependencies(${name}  global_target)
 
   if(FIPS_DELOCATE OR FIPS_SHARED)
@@ -517,9 +522,6 @@ function(build_libcrypto name module_source)
     target_link_libraries(${name} PUBLIC pthread)
   endif()
 
-  if(FIPS)
-    target_link_libraries(${name} PRIVATE jitterentropy)
-  endif()
   target_include_directories(${name} SYSTEM PUBLIC
           $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../include>
           $<INSTALL_INTERFACE:include>)
@@ -708,10 +710,6 @@ if(BUILD_TESTING)
   add_dependencies(${CRYPTO_TEST_EXEC} global_target)
 
   target_link_libraries(${CRYPTO_TEST_EXEC} test_support_lib boringssl_gtest crypto)
-  if(FIPS)
-    target_link_libraries(${CRYPTO_TEST_EXEC} jitterentropy)
-    add_dependencies(${CRYPTO_TEST_EXEC} jitterentropy)
-  endif()
   if(WIN32)
     target_link_libraries(${CRYPTO_TEST_EXEC} ws2_32)
   endif()

third_party/jitterentropy/CMakeLists.txt

@@ -21,13 +21,7 @@ if(MSVC)
 else()
     set(JITTER_COMPILE_FLAGS "-DAWSLC -fwrapv --param ssp-buffer-size=4 -fvisibility=hidden -fPIE -Wcast-align -Wmissing-field-initializers -Wshadow -Wswitch-enum -Wextra -Wall -pedantic -fPIC -O0 -fwrapv -Wconversion")
 endif()
+
 set_source_files_properties(${JITTER_SOURCES} PROPERTIES COMPILE_FLAGS ${JITTER_COMPILE_FLAGS})
-add_library(jitterentropy STATIC ${JITTER_SOURCES})
+add_library(jitterentropy OBJECT ${JITTER_SOURCES})
 
-if(NOT BUILD_SHARED_LIBS)
-    install(TARGETS jitterentropy
-            EXPORT crypto-targets
-            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-            )
-endif()