Fix CFI initialization crash on x86.
Bug: 34752378
Test: bionic tests
Change-Id: If8e33f76a1a2d83356d818fed506ea624f579860
diff --git a/libdl/libdl_cfi.cpp b/libdl/libdl_cfi.cpp
index 362b093..8458564 100644
--- a/libdl/libdl_cfi.cpp
+++ b/libdl/libdl_cfi.cpp
@@ -29,10 +29,12 @@
char padding[PAGE_SIZE - sizeof(v)];
} shadow_base_storage alignas(PAGE_SIZE);
+// __cfi_init is called by the loader as soon as the shadow is mapped. This may happen very early
+// during startup, before libdl.so global constructors, and, on i386, even before __libc_sysinfo is
+// initialized. This function should not do any system calls.
extern "C" uintptr_t* __cfi_init(uintptr_t shadow_base) {
shadow_base_storage.v = shadow_base;
static_assert(sizeof(shadow_base_storage) == PAGE_SIZE, "");
- mprotect(&shadow_base_storage, PAGE_SIZE, PROT_READ);
return &shadow_base_storage.v;
}
diff --git a/linker/linker_cfi.cpp b/linker/linker_cfi.cpp
index e9cdab6..28d2eaf 100644
--- a/linker/linker_cfi.cpp
+++ b/linker/linker_cfi.cpp
@@ -193,6 +193,7 @@
shadow_start = reinterpret_cast<uintptr_t* (*)(uintptr_t)>(cfi_init)(p);
CHECK(shadow_start != nullptr);
CHECK(*shadow_start == p);
+ mprotect(shadow_start, PAGE_SIZE, PROT_READ);
return true;
}
diff --git a/tests/cfi_test.cpp b/tests/cfi_test.cpp
index 0f93edb..a73fd34 100644
--- a/tests/cfi_test.cpp
+++ b/tests/cfi_test.cpp
@@ -1,7 +1,25 @@
-#include <gtest/gtest.h>
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
#include <dlfcn.h>
+#include <gtest/gtest.h>
#include "BionicDeathTest.h"
+#include "gtest_globals.h"
+#include "utils.h"
// Private libdl interface.
extern "C" {
@@ -92,3 +110,24 @@
handle = dlopen("libcfi-test-bad.so", RTLD_NOW | RTLD_LOCAL);
ASSERT_FALSE(handle != nullptr) << dlerror();
}
+
+// cfi_test_helper exports __cfi_check, which triggers CFI initialization at startup.
+TEST(cfi_test, early_init) {
+#if defined(__BIONIC__)
+ std::string helper = get_testlib_root() + "/cfi_test_helper/cfi_test_helper";
+ ExecTestHelper eth;
+ eth.SetArgs({ helper.c_str(), nullptr });
+ eth.Run([&]() { execve(helper.c_str(), eth.GetArgs(), eth.GetEnv()); }, 0, nullptr);
+#endif
+}
+
+// cfi_test_helper2 depends on a library that exports __cfi_check, which triggers CFI initialization
+// at startup.
+TEST(cfi_test, early_init2) {
+#if defined(__BIONIC__)
+ std::string helper = get_testlib_root() + "/cfi_test_helper2/cfi_test_helper2";
+ ExecTestHelper eth;
+ eth.SetArgs({ helper.c_str(), nullptr });
+ eth.Run([&]() { execve(helper.c_str(), eth.GetArgs(), eth.GetEnv()); }, 0, nullptr);
+#endif
+}
diff --git a/tests/libs/Android.bp b/tests/libs/Android.bp
index b5855af..9f9c407 100644
--- a/tests/libs/Android.bp
+++ b/tests/libs/Android.bp
@@ -494,3 +494,20 @@
cfi: false,
},
}
+
+cc_test {
+ name: "cfi_test_helper",
+ host_supported: false,
+ defaults: ["bionic_testlib_defaults"],
+ srcs: ["cfi_test_helper.cpp"],
+ ldflags: [" -Wl,-export-dynamic-symbol=__cfi_check"],
+}
+
+cc_test {
+ name: "cfi_test_helper2",
+ host_supported: false,
+ defaults: ["bionic_testlib_defaults"],
+ srcs: ["cfi_test_helper2.cpp"],
+ shared_libs: ["libcfi-test"],
+ ldflags: ["-Wl,--rpath,${ORIGIN}/.."],
+}
diff --git a/tests/libs/cfi_test_helper.cpp b/tests/libs/cfi_test_helper.cpp
new file mode 100644
index 0000000..ff313a2
--- /dev/null
+++ b/tests/libs/cfi_test_helper.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "libs_utils.h"
+
+// This library is built for all targets, including host tests, so __cfi_slowpath may not be
+// present. But it is only used in the bionic loader tests.
+extern "C" __attribute__((weak)) void __cfi_slowpath(uint64_t, void*);
+
+static int g_count;
+
+// Mock a CFI-enabled library without relying on the compiler.
+extern "C" __attribute__((aligned(4096))) void __cfi_check(uint64_t /*CallSiteTypeId*/,
+ void* /*TargetAddr*/, void* /*Diag*/) {
+ ++g_count;
+}
+
+void preinit_ctor() {
+ CHECK(g_count == 0);
+ __cfi_slowpath(42, reinterpret_cast<void*>(&preinit_ctor));
+ CHECK(g_count == 1);
+}
+
+__attribute__((section(".preinit_array"), used)) void (*preinit_ctor_p)(void) = preinit_ctor;
+
+__attribute__((constructor, used)) void ctor() {
+ CHECK(g_count == 1);
+ __cfi_slowpath(42, reinterpret_cast<void*>(&ctor));
+ CHECK(g_count == 2);
+}
+
+int main(void) {
+ CHECK(g_count == 2);
+ __cfi_slowpath(42, reinterpret_cast<void*>(&main));
+ CHECK(g_count == 3);
+ return 0;
+}
diff --git a/tests/libs/cfi_test_helper2.cpp b/tests/libs/cfi_test_helper2.cpp
new file mode 100644
index 0000000..11a6036
--- /dev/null
+++ b/tests/libs/cfi_test_helper2.cpp
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <dlfcn.h>
+
+#include "libs_utils.h"
+
+int main(void) {
+ void* handle;
+ // libcfi-test.so does some basic testing in a global constructor. Check that it is linked.
+ handle = dlopen("libcfi-test.so", RTLD_NOW | RTLD_NOLOAD);
+ CHECK(handle != nullptr);
+ dlclose(handle);
+ return 0;
+}
diff --git a/tests/libs/cfi_test_lib.cpp b/tests/libs/cfi_test_lib.cpp
index b0e2f42..959b102 100644
--- a/tests/libs/cfi_test_lib.cpp
+++ b/tests/libs/cfi_test_lib.cpp
@@ -1,3 +1,19 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
diff --git a/tests/libs/libs_utils.h b/tests/libs/libs_utils.h
new file mode 100644
index 0000000..f11cbe7
--- /dev/null
+++ b/tests/libs/libs_utils.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LIBS_UTILS_H
+#define LIBS_UTILS_H
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define CHECK(x) \
+ do { \
+ fprintf(stderr, "CHECK(" #x ") failed at %s:%d\n", __FILE__, __LINE__); \
+ if (!(x)) abort(); \
+ } while (0)
+
+#endif // LIBS_UTILS_H
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 9d809f0..ddf0df5 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -1203,52 +1203,6 @@
}
}
-class ExecTestHelper {
- public:
- char** GetArgs() { return const_cast<char**>(args_.data()); }
- char** GetEnv() { return const_cast<char**>(env_.data()); }
-
- void SetArgs(const std::vector<const char*> args) { args_ = args; }
- void SetEnv(const std::vector<const char*> env) { env_ = env; }
-
- void Run(const std::function<void ()>& child_fn,
- int expected_exit_status,
- const char* expected_output) {
- int fds[2];
- ASSERT_NE(pipe2(fds, 0), -1);
-
- pid_t pid = fork();
- ASSERT_NE(pid, -1);
-
- if (pid == 0) {
- // Child.
- close(fds[0]);
- dup2(fds[1], STDOUT_FILENO);
- dup2(fds[1], STDERR_FILENO);
- if (fds[1] != STDOUT_FILENO && fds[1] != STDERR_FILENO) close(fds[1]);
- child_fn();
- FAIL();
- }
-
- // Parent.
- close(fds[1]);
- std::string output;
- char buf[BUFSIZ];
- ssize_t bytes_read;
- while ((bytes_read = TEMP_FAILURE_RETRY(read(fds[0], buf, sizeof(buf)))) > 0) {
- output.append(buf, bytes_read);
- }
- close(fds[0]);
-
- AssertChildExited(pid, expected_exit_status);
- ASSERT_EQ(expected_output, output);
- }
-
- private:
- std::vector<const char*> args_;
- std::vector<const char*> env_;
-};
-
#if defined(__GLIBC__)
#define BIN_DIR "/bin/"
#else
diff --git a/tests/utils.h b/tests/utils.h
index 79eed10..0b9b886 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -125,8 +125,13 @@
static inline void AssertChildExited(int pid, int expected_exit_status) {
int status;
ASSERT_EQ(pid, waitpid(pid, &status, 0));
- ASSERT_TRUE(WIFEXITED(status));
- ASSERT_EQ(expected_exit_status, WEXITSTATUS(status));
+ if (expected_exit_status >= 0) {
+ ASSERT_TRUE(WIFEXITED(status));
+ ASSERT_EQ(expected_exit_status, WEXITSTATUS(status));
+ } else {
+ ASSERT_TRUE(WIFSIGNALED(status));
+ ASSERT_EQ(-expected_exit_status, WTERMSIG(status));
+ }
}
// The absolute path to the executable
@@ -142,4 +147,59 @@
char** get_argv();
char** get_envp();
+class ExecTestHelper {
+ public:
+ char** GetArgs() {
+ return const_cast<char**>(args_.data());
+ }
+ char** GetEnv() {
+ return const_cast<char**>(env_.data());
+ }
+
+ void SetArgs(const std::vector<const char*> args) {
+ args_ = args;
+ }
+ void SetEnv(const std::vector<const char*> env) {
+ env_ = env;
+ }
+
+ void Run(const std::function<void()>& child_fn, int expected_exit_status,
+ const char* expected_output) {
+ int fds[2];
+ ASSERT_NE(pipe2(fds, 0), -1);
+
+ pid_t pid = fork();
+ ASSERT_NE(pid, -1);
+
+ if (pid == 0) {
+ // Child.
+ close(fds[0]);
+ dup2(fds[1], STDOUT_FILENO);
+ dup2(fds[1], STDERR_FILENO);
+ if (fds[1] != STDOUT_FILENO && fds[1] != STDERR_FILENO) close(fds[1]);
+ child_fn();
+ FAIL();
+ }
+
+ // Parent.
+ close(fds[1]);
+ std::string output;
+ char buf[BUFSIZ];
+ ssize_t bytes_read;
+ while ((bytes_read = TEMP_FAILURE_RETRY(read(fds[0], buf, sizeof(buf)))) > 0) {
+ output.append(buf, bytes_read);
+ }
+ close(fds[0]);
+
+ AssertChildExited(pid, expected_exit_status);
+ if (expected_output != nullptr) {
+ ASSERT_EQ(expected_output, output);
+ }
+ }
+
+ private:
+ std::vector<const char*> args_;
+ std::vector<const char*> env_;
+};
+
#endif
