linker: add test for zero shdr offset

Bug: http://b/30795430
Change-Id: I03853257c4b632ad9daaf1e90f9620678397cff0
Test: bionic-unit-tests --gtest_filter=dlfcn.dlopen_invalid*

tests/Android.mk

@@ -35,6 +35,9 @@ include $(LOCAL_PATH)/Android.build.prebuilt.mk
 bionic_tests_module := libtest_invalid-empty_shdr_table.so
 include $(LOCAL_PATH)/Android.build.prebuilt.mk
 
+bionic_tests_module := libtest_invalid-zero_shdr_table_offset.so
+include $(LOCAL_PATH)/Android.build.prebuilt.mk
+
 ifeq ($(HOST_OS)-$(HOST_ARCH),$(filter $(HOST_OS)-$(HOST_ARCH),linux-x86 linux-x86_64))
 build_host := true
 else

tests/dlfcn_test.cpp

@@ -1194,4 +1194,12 @@ TEST(dlfcn, dlopen_invalid_empty_shdr_table) {
   ASSERT_STREQ(expected_dlerror.c_str(), dlerror());
 }
 
+TEST(dlfcn, dlopen_invalid_zero_shdr_table_offset) {
+  std::string libpath = std::string(getenv("ANDROID_DATA")) + PREBUILT_ELF_PATH + "/libtest_invalid-zero_shdr_table_offset.so";
+  void* handle = dlopen(libpath.c_str(), RTLD_NOW);
+  ASSERT_TRUE(handle == nullptr);
+  std::string expected_dlerror = std::string("dlopen failed: \"") + libpath + "\" has invalid shdr offset/size: 0/";
+  ASSERT_SUBSTR(expected_dlerror.c_str(), dlerror());
+}
+
 #endif