diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a66a37fa4..23154a2c6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -475,7 +475,7 @@ if(USE_CUSTOM_LIBCXX)
     CXX_STANDARD_REQUIRED TRUE
   )
   # libc++abi depends on libc++ internal headers.
-  set_property(TARGET libcxx libcxxabi APPEND PROPERTY INCLUDE_DIRECTORIES "${CMAKE_SOURCE_DIR}/util/bot/libcxx/src")
+  set_property(TARGET libcxx libcxxabi APPEND PROPERTY INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}/util/bot/libcxx/src")
   target_link_libraries(libcxx libcxxabi)
 endif()
 
@@ -551,16 +551,16 @@ endif()
 if(FIPS)
   add_custom_target(
     acvp_tests
-    COMMAND ${GO_EXECUTABLE} build -o ${CMAKE_BINARY_DIR}/acvptool
+    COMMAND ${GO_EXECUTABLE} build -o ${CMAKE_CURRENT_BINARY_DIR}/acvptool
             boringssl.googlesource.com/boringssl/util/fipstools/acvp/acvptool
-    COMMAND ${GO_EXECUTABLE} build -o ${CMAKE_BINARY_DIR}/testmodulewrapper
+    COMMAND ${GO_EXECUTABLE} build -o ${CMAKE_CURRENT_BINARY_DIR}/testmodulewrapper
             boringssl.googlesource.com/boringssl/util/fipstools/acvp/acvptool/testmodulewrapper
     COMMAND cd util/fipstools/acvp/acvptool/test &&
             ${GO_EXECUTABLE} run check_expected.go
-            -tool ${CMAKE_BINARY_DIR}/acvptool
-            -module-wrappers modulewrapper:$<TARGET_FILE:modulewrapper>,testmodulewrapper:${CMAKE_BINARY_DIR}/testmodulewrapper
+            -tool ${CMAKE_CURRENT_BINARY_DIR}/acvptool
+            -module-wrappers modulewrapper:$<TARGET_FILE:modulewrapper>,testmodulewrapper:${CMAKE_CURRENT_BINARY_DIR}/testmodulewrapper
             -tests tests.json
-    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
     DEPENDS modulewrapper
     USES_TERMINAL)
 
@@ -582,12 +582,12 @@ set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS
 add_custom_target(
     run_tests
     COMMAND ${GO_EXECUTABLE} run util/all_tests.go -build-dir
-            ${CMAKE_BINARY_DIR}
+            ${CMAKE_CURRENT_BINARY_DIR}
     COMMAND cd ssl/test/runner &&
             ${GO_EXECUTABLE} test -shim-path $<TARGET_FILE:bssl_shim>
               ${HANDSHAKER_ARGS} ${RUNNER_ARGS}
     COMMAND ${GO_EXECUTABLE} test ${GO_TESTS}
-    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
     DEPENDS all_tests bssl_shim handshaker fips_specific_tests_if_any
     USES_TERMINAL)
 
diff --git a/src/cmake/go.cmake b/src/cmake/go.cmake
index 6aca79a89..61a01f519 100644
--- a/src/cmake/go.cmake
+++ b/src/cmake/go.cmake
@@ -13,7 +13,7 @@ if(NOT GO_EXECUTABLE)
 endif()
 
 function(go_executable dest package)
-  set(godeps "${CMAKE_SOURCE_DIR}/util/godeps.go")
+  set(godeps "${PROJECT_SOURCE_DIR}/util/godeps.go")
   if(NOT CMAKE_GENERATOR STREQUAL "Ninja")
     # The DEPFILE parameter to add_custom_command only works with Ninja. Query
     # the sources at configure time. Additionally, everything depends on go.mod.
@@ -30,7 +30,7 @@ function(go_executable dest package)
                        COMMAND ${GO_EXECUTABLE} build
                                -o ${CMAKE_CURRENT_BINARY_DIR}/${dest} ${package}
                        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-                       DEPENDS ${sources} ${CMAKE_SOURCE_DIR}/go.mod)
+                       DEPENDS ${sources} ${PROJECT_SOURCE_DIR}/go.mod)
   else()
     # Ninja expects the target in the depfile to match the output. This is a
     # relative path from the build directory.
@@ -46,7 +46,7 @@ function(go_executable dest package)
                        COMMAND ${GO_EXECUTABLE} run ${godeps} -format depfile
                                -target ${target} -pkg ${package} -out ${depfile}
                        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-                       DEPENDS ${godeps} ${CMAKE_SOURCE_DIR}/go.mod
+                       DEPENDS ${godeps} ${PROJECT_SOURCE_DIR}/go.mod
                        DEPFILE ${depfile})
   endif()
 endfunction()
diff --git a/src/crypto/CMakeLists.txt b/src/crypto/CMakeLists.txt
index f917b79eb..8ece558a7 100644
--- a/src/crypto/CMakeLists.txt
+++ b/src/crypto/CMakeLists.txt
@@ -296,7 +296,7 @@ if(OPENSSL_NASM)
   target_sources(crypto PRIVATE ${CRYPTO_SOURCES_NASM})
 endif()
 target_include_directories(crypto PUBLIC
-  $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/include>
+  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:include>
 )
 install_if_enabled(TARGETS crypto EXPORT OpenSSLTargets ${INSTALL_DESTINATION_DEFAULT})
diff --git a/src/rust/CMakeLists.txt b/src/rust/CMakeLists.txt
index 019976bcc..422905f32 100644
--- a/src/rust/CMakeLists.txt
+++ b/src/rust/CMakeLists.txt
@@ -3,7 +3,7 @@ add_library(rust_wrapper STATIC rust_wrapper.c)
 target_link_libraries(rust_wrapper crypto)
 
 # Generate architecture-specific wrappers.
-set(WRAPPER_TARGET ${CMAKE_BINARY_DIR}/rust/src/wrapper_${RUST_BINDINGS}.rs)
+set(WRAPPER_TARGET ${CMAKE_CURRENT_BINARY_DIR}/src/wrapper_${RUST_BINDINGS}.rs)
 set(COMMAND ${BINDGEN_EXECUTABLE} "wrapper.h"
             -o ${WRAPPER_TARGET}
             --no-derive-default