Merge "linker: disallow W + E PT_LOAD segments"

am: e8087022c1

Change-Id: I1732f395e90b4589720b3be89084ea1bd287c18d

linker/linker_phdr.cpp

@@ -604,9 +604,16 @@ bool ElfReader::LoadSegments() {
     }
 
     if (file_length != 0) {
+      int prot = PFLAGS_TO_PROT(phdr->p_flags);
+      // W + E PT_LOAD segments are not allowed.
+      if ((prot & (PROT_EXEC | PROT_WRITE)) == (PROT_EXEC | PROT_WRITE)) {
+        DL_ERR_AND_LOG("\"%s\": W + E load segments are not allowed", name_.c_str());
+        return false;
+      }
+
       void* seg_addr = mmap64(reinterpret_cast<void*>(seg_page_start),
                             file_length,
-                            PFLAGS_TO_PROT(phdr->p_flags),
+                            prot,
                             MAP_FIXED|MAP_PRIVATE,
                             fd_,
                             file_offset_ + file_page_start);

tests/Android.mk

@@ -16,6 +16,20 @@
 
 LOCAL_PATH := $(call my-dir)
 
+# Move prebuilt test elf-files to $(TARGET_OUT_NATIVE_TESTS)
+include $(CLEAR_VARS)
+LOCAL_MULTILIB := both
+LOCAL_MODULE := libtest_invalid-rw_load_segment.so
+LOCAL_MODULE_PATH_32 := $($(TARGET_2ND_ARCH_VAR_PREFIX)TARGET_OUT_DATA_NATIVE_TESTS)/prebuilt-elf-files
+LOCAL_MODULE_PATH_64 := $(TARGET_OUT_DATA_NATIVE_TESTS)/prebuilt-elf-files
+LOCAL_MODULE_CLASS := SHARED_LIBRARY
+
+LOCAL_SRC_FILES_arm := prebuilt-elf-files/arm/$(LOCAL_MODULE)
+LOCAL_SRC_FILES_arm64 := prebuilt-elf-files/arm64/$(LOCAL_MODULE)
+LOCAL_SRC_FILES_x86 := prebuilt-elf-files/x86/$(LOCAL_MODULE)
+LOCAL_SRC_FILES_x86_64 := prebuilt-elf-files/x86_64/$(LOCAL_MODULE)
+include $(BUILD_PREBUILT)
+
 ifeq ($(HOST_OS)-$(HOST_ARCH),$(filter $(HOST_OS)-$(HOST_ARCH),linux-x86 linux-x86_64))
 build_host := true
 else

tests/dlfcn_test.cpp

@@ -1142,3 +1142,23 @@ TEST(dlfcn, dt_runpath_absolute_path) {
 
   dlclose(handle);
 }
+
+// Bionic specific tests
+#if defined(__BIONIC__)
+
+#if defined(__LP64__)
+#define NATIVE_TESTS_PATH "/nativetest64"
+#else
+#define NATIVE_TESTS_PATH "/nativetest"
+#endif
+
+#define PREBUILT_ELF_PATH NATIVE_TESTS_PATH "/prebuilt-elf-files"
+
+TEST(dlfcn, dlopen_invalid_rw_load_segment) {
+  std::string libpath = std::string(getenv("ANDROID_DATA")) + PREBUILT_ELF_PATH + "/libtest_invalid-rw_load_segment.so";
+  void* handle = dlopen(libpath.c_str(), RTLD_NOW);
+  ASSERT_TRUE(handle == nullptr);
+  std::string expected_dlerror = std::string("dlopen failed: \"") + libpath + "\": W + E load segments are not allowed";
+  ASSERT_STREQ(expected_dlerror.c_str(), dlerror());
+}
+#endif