[MTE] remap stacks with PROT_MTE when requested by dlopened library
BYPASS_INCLUSIVE_LANGUAGE_REASON="man" refers to manual not person
Bug: 318749472
Test: atest pthread on MTE enabled device
Test: atest memtag_stack_dlopen_test on MTE enabled device
Test: manual with NDK r26b built app with fsanitize=memtag-stack
Change-Id: Iac191c31b87ccbdc6a52c63ddd22e7b440354202
diff --git a/libc/bionic/heap_tagging.cpp b/libc/bionic/heap_tagging.cpp
index 230899a..6fdd1e0 100644
--- a/libc/bionic/heap_tagging.cpp
+++ b/libc/bionic/heap_tagging.cpp
@@ -57,6 +57,7 @@
break;
case M_HEAP_TAGGING_LEVEL_SYNC:
case M_HEAP_TAGGING_LEVEL_ASYNC:
+ atomic_store(&globals->memtag, true);
atomic_store(&globals->memtag_stack, __libc_shared_globals()->initial_memtag_stack);
break;
default:
@@ -116,6 +117,7 @@
globals->heap_pointer_tag = static_cast<uintptr_t>(0xffull << UNTAG_SHIFT);
}
atomic_store(&globals->memtag_stack, false);
+ atomic_store(&globals->memtag, false);
});
if (heap_tagging_level != M_HEAP_TAGGING_LEVEL_TBI) {
diff --git a/libc/bionic/libc_init_dynamic.cpp b/libc/bionic/libc_init_dynamic.cpp
index c61810e..295484b 100644
--- a/libc/bionic/libc_init_dynamic.cpp
+++ b/libc/bionic/libc_init_dynamic.cpp
@@ -39,11 +39,12 @@
* all dynamic linking has been performed.
*/
+#include <elf.h>
#include <stddef.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
-#include <stdint.h>
-#include <elf.h>
+#include "bionic/pthread_internal.h"
#include "libc_init_common.h"
#include "private/bionic_defs.h"
@@ -59,6 +60,10 @@
extern int __cxa_atexit(void (*)(void *), void *, void *);
};
+void memtag_stack_dlopen_callback() {
+ __pthread_internal_remap_stack_with_mte();
+}
+
// Use an initializer so __libc_sysinfo will have a fallback implementation
// while .preinit_array constructors run.
#if defined(__i386__)
@@ -156,6 +161,10 @@
__libc_init_mte_late();
+ // This roundabout way is needed so we don't use the static libc linked into the linker, which
+ // will not affect the process.
+ __libc_shared_globals()->memtag_stack_dlopen_callback = memtag_stack_dlopen_callback;
+
exit(slingshot(args.argc - __libc_shared_globals()->initial_linker_arg_count,
args.argv + __libc_shared_globals()->initial_linker_arg_count,
args.envp));
diff --git a/libc/bionic/pthread_attr.cpp b/libc/bionic/pthread_attr.cpp
index de4cc9e..f6c0401 100644
--- a/libc/bionic/pthread_attr.cpp
+++ b/libc/bionic/pthread_attr.cpp
@@ -155,36 +155,6 @@
return 0;
}
-static uintptr_t __get_main_stack_startstack() {
- FILE* fp = fopen("/proc/self/stat", "re");
- if (fp == nullptr) {
- async_safe_fatal("couldn't open /proc/self/stat: %m");
- }
-
- char line[BUFSIZ];
- if (fgets(line, sizeof(line), fp) == nullptr) {
- async_safe_fatal("couldn't read /proc/self/stat: %m");
- }
-
- fclose(fp);
-
- // See man 5 proc. There's no reason comm can't contain ' ' or ')',
- // so we search backwards for the end of it. We're looking for this field:
- //
- // startstack %lu (28) The address of the start (i.e., bottom) of the stack.
- uintptr_t startstack = 0;
- const char* end_of_comm = strrchr(line, ')');
- if (sscanf(end_of_comm + 1, " %*c "
- "%*d %*d %*d %*d %*d "
- "%*u %*u %*u %*u %*u %*u %*u "
- "%*d %*d %*d %*d %*d %*d "
- "%*u %*u %*d %*u %*u %*u %" SCNuPTR, &startstack) != 1) {
- async_safe_fatal("couldn't parse /proc/self/stat");
- }
-
- return startstack;
-}
-
static int __pthread_attr_getstack_main_thread(void** stack_base, size_t* stack_size) {
ErrnoRestorer errno_restorer;
@@ -198,28 +168,11 @@
if (stack_limit.rlim_cur == RLIM_INFINITY) {
stack_limit.rlim_cur = 8 * 1024 * 1024;
}
-
- // Ask the kernel where our main thread's stack started.
- uintptr_t startstack = __get_main_stack_startstack();
-
- // Hunt for the region that contains that address.
- FILE* fp = fopen("/proc/self/maps", "re");
- if (fp == nullptr) {
- async_safe_fatal("couldn't open /proc/self/maps: %m");
- }
- char line[BUFSIZ];
- while (fgets(line, sizeof(line), fp) != nullptr) {
- uintptr_t lo, hi;
- if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR, &lo, &hi) == 2) {
- if (lo <= startstack && startstack <= hi) {
- *stack_size = stack_limit.rlim_cur;
- *stack_base = reinterpret_cast<void*>(hi - *stack_size);
- fclose(fp);
- return 0;
- }
- }
- }
- async_safe_fatal("stack not found in /proc/self/maps");
+ uintptr_t lo, hi;
+ __find_main_stack_limits(&lo, &hi);
+ *stack_size = stack_limit.rlim_cur;
+ *stack_base = reinterpret_cast<void*>(hi - *stack_size);
+ return 0;
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
diff --git a/libc/bionic/pthread_internal.cpp b/libc/bionic/pthread_internal.cpp
index 6a7ee2f..bfe2f98 100644
--- a/libc/bionic/pthread_internal.cpp
+++ b/libc/bionic/pthread_internal.cpp
@@ -40,6 +40,7 @@
#include "private/ErrnoRestorer.h"
#include "private/ScopedRWLock.h"
#include "private/bionic_futex.h"
+#include "private/bionic_globals.h"
#include "private/bionic_tls.h"
static pthread_internal_t* g_thread_list = nullptr;
@@ -119,6 +120,89 @@
return nullptr;
}
+static uintptr_t __get_main_stack_startstack() {
+ FILE* fp = fopen("/proc/self/stat", "re");
+ if (fp == nullptr) {
+ async_safe_fatal("couldn't open /proc/self/stat: %m");
+ }
+
+ char line[BUFSIZ];
+ if (fgets(line, sizeof(line), fp) == nullptr) {
+ async_safe_fatal("couldn't read /proc/self/stat: %m");
+ }
+
+ fclose(fp);
+
+ // See man 5 proc. There's no reason comm can't contain ' ' or ')',
+ // so we search backwards for the end of it. We're looking for this field:
+ //
+ // startstack %lu (28) The address of the start (i.e., bottom) of the stack.
+ uintptr_t startstack = 0;
+ const char* end_of_comm = strrchr(line, ')');
+ if (sscanf(end_of_comm + 1,
+ " %*c "
+ "%*d %*d %*d %*d %*d "
+ "%*u %*u %*u %*u %*u %*u %*u "
+ "%*d %*d %*d %*d %*d %*d "
+ "%*u %*u %*d %*u %*u %*u %" SCNuPTR,
+ &startstack) != 1) {
+ async_safe_fatal("couldn't parse /proc/self/stat");
+ }
+
+ return startstack;
+}
+
+void __find_main_stack_limits(uintptr_t* low, uintptr_t* high) {
+ // Ask the kernel where our main thread's stack started.
+ uintptr_t startstack = __get_main_stack_startstack();
+
+ // Hunt for the region that contains that address.
+ FILE* fp = fopen("/proc/self/maps", "re");
+ if (fp == nullptr) {
+ async_safe_fatal("couldn't open /proc/self/maps: %m");
+ }
+ char line[BUFSIZ];
+ while (fgets(line, sizeof(line), fp) != nullptr) {
+ uintptr_t lo, hi;
+ if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR, &lo, &hi) == 2) {
+ if (lo <= startstack && startstack <= hi) {
+ *low = lo;
+ *high = hi;
+ fclose(fp);
+ return;
+ }
+ }
+ }
+ async_safe_fatal("stack not found in /proc/self/maps");
+}
+
+void __pthread_internal_remap_stack_with_mte() {
+#if defined(__aarch64__)
+ // If process doesn't have MTE enabled, we don't need to do anything.
+ if (!__libc_globals->memtag) return;
+ bool prev = true;
+ __libc_globals.mutate(
+ [&prev](libc_globals* globals) { prev = atomic_exchange(&globals->memtag_stack, true); });
+ if (prev) return;
+ uintptr_t lo, hi;
+ __find_main_stack_limits(&lo, &hi);
+
+ if (mprotect(reinterpret_cast<void*>(lo), hi - lo,
+ PROT_READ | PROT_WRITE | PROT_MTE | PROT_GROWSDOWN)) {
+ async_safe_fatal("error: failed to set PROT_MTE on main thread");
+ }
+ ScopedWriteLock creation_locker(&g_thread_creation_lock);
+ ScopedReadLock list_locker(&g_thread_list_lock);
+ for (pthread_internal_t* t = g_thread_list; t != nullptr; t = t->next) {
+ if (t->terminating || t->is_main()) continue;
+ if (mprotect(t->mmap_base_unguarded, t->mmap_size_unguarded,
+ PROT_READ | PROT_WRITE | PROT_MTE)) {
+ async_safe_fatal("error: failed to set PROT_MTE on thread: %d", t->tid);
+ }
+ }
+#endif
+}
+
bool android_run_on_all_threads(bool (*func)(void*), void* arg) {
// Take the locks in this order to avoid inversion (pthread_create ->
// __pthread_internal_add).
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 3b9e6a4..091f711 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -178,6 +178,7 @@
bionic_tls* bionic_tls;
int errno_value;
+ bool is_main() { return start_routine == nullptr; }
};
struct ThreadMapping {
@@ -207,6 +208,7 @@
__LIBC_HIDDEN__ pid_t __pthread_internal_gettid(pthread_t pthread_id, const char* caller);
__LIBC_HIDDEN__ void __pthread_internal_remove(pthread_internal_t* thread);
__LIBC_HIDDEN__ void __pthread_internal_remove_and_free(pthread_internal_t* thread);
+__LIBC_HIDDEN__ void __find_main_stack_limits(uintptr_t* low, uintptr_t* high);
static inline __always_inline bionic_tcb* __get_bionic_tcb() {
return reinterpret_cast<bionic_tcb*>(&__get_tls()[MIN_TLS_SLOT]);
@@ -266,6 +268,9 @@
__LIBC_HIDDEN__ extern void __bionic_atfork_run_child();
__LIBC_HIDDEN__ extern void __bionic_atfork_run_parent();
+// Re-map all threads and successively launched threads with PROT_MTE.
+__LIBC_HIDDEN__ void __pthread_internal_remap_stack_with_mte();
+
extern "C" bool android_run_on_all_threads(bool (*func)(void*), void* arg);
extern pthread_rwlock_t g_thread_creation_lock;
diff --git a/libc/private/bionic_globals.h b/libc/private/bionic_globals.h
index 8ea7d4d..08a61f0 100644
--- a/libc/private/bionic_globals.h
+++ b/libc/private/bionic_globals.h
@@ -50,6 +50,7 @@
uintptr_t heap_pointer_tag;
_Atomic(bool) memtag_stack;
_Atomic(bool) decay_time_enabled;
+ _Atomic(bool) memtag;
// In order to allow a complete switch between dispatch tables without
// the need for copying each function by function in the structure,
@@ -135,6 +136,8 @@
HeapTaggingLevel initial_heap_tagging_level = M_HEAP_TAGGING_LEVEL_NONE;
bool initial_memtag_stack = false;
int64_t heap_tagging_upgrade_timer_sec = 0;
+
+ void (*memtag_stack_dlopen_callback)() = nullptr;
};
__LIBC_HIDDEN__ libc_shared_globals* __libc_shared_globals();
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 135eaa3..ffbf136 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -2212,6 +2212,14 @@
loading_trace.End();
if (si != nullptr) {
+ if (si->has_min_version(7) && si->memtag_stack()) {
+ LD_LOG(kLogDlopen, "... dlopen enabling MTE for: realpath=\"%s\", soname=\"%s\"",
+ si->get_realpath(), si->get_soname());
+ if (auto* cb = __libc_shared_globals()->memtag_stack_dlopen_callback) {
+ cb();
+ }
+ }
+
void* handle = si->to_handle();
LD_LOG(kLogDlopen,
"... dlopen calling constructors: realpath=\"%s\", soname=\"%s\", handle=%p",
diff --git a/tests/Android.bp b/tests/Android.bp
index a53418a..c09ddad 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -1107,6 +1107,31 @@
}
cc_test {
+ name: "memtag_stack_dlopen_test",
+ enabled: false,
+ // This does not use bionic_tests_defaults because it is not supported on
+ // host.
+ arch: {
+ arm64: {
+ enabled: true,
+ },
+ },
+ sanitize: {
+ memtag_heap: true,
+ memtag_stack: false,
+ },
+ srcs: [
+ "memtag_stack_dlopen_test.cpp",
+ ],
+ shared_libs: [
+ "libbase",
+ ],
+ data_libs: ["libtest_simple_memtag_stack"],
+ header_libs: ["bionic_libc_platform_headers"],
+ test_suites: ["device-tests"],
+}
+
+cc_test {
name: "bionic-stress-tests",
defaults: [
"bionic_tests_defaults",
diff --git a/tests/libs/Android.bp b/tests/libs/Android.bp
index 0bef469..b497d2e 100644
--- a/tests/libs/Android.bp
+++ b/tests/libs/Android.bp
@@ -234,6 +234,17 @@
}
// -----------------------------------------------------------------------------
+// Library used by memtag_stack_dlopen_test tests
+// -----------------------------------------------------------------------------
+cc_test_library {
+ name: "libtest_simple_memtag_stack",
+ sanitize: {
+ memtag_stack: true,
+ },
+ srcs: ["dlopen_testlib_simple.cpp"],
+}
+
+// -----------------------------------------------------------------------------
// Libraries used by hwasan_test
// -----------------------------------------------------------------------------
cc_test_library {
diff --git a/tests/memtag_stack_dlopen_test.cpp b/tests/memtag_stack_dlopen_test.cpp
new file mode 100644
index 0000000..308af1e
--- /dev/null
+++ b/tests/memtag_stack_dlopen_test.cpp
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <thread>
+
+#include <dlfcn.h>
+#include <stdlib.h>
+
+#include <gtest/gtest.h>
+
+#include <android-base/silent_death_test.h>
+#include <android-base/test_utils.h>
+#include "utils.h"
+
+#if defined(__BIONIC__) && defined(__aarch64__)
+__attribute__((target("mte"))) bool is_stack_mte_on() {
+ alignas(16) int x = 0;
+ void* p = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(&x) + (1UL << 57));
+ void* p_cpy = p;
+ __builtin_arm_stg(p);
+ p = __builtin_arm_ldg(p);
+ __builtin_arm_stg(&x);
+ return p == p_cpy;
+}
+
+// We can't use pthread_getattr_np because that uses the rlimit rather than the actual mapping
+// bounds.
+static void find_main_stack_limits(uintptr_t* low, uintptr_t* high) {
+ uintptr_t startstack = reinterpret_cast<uintptr_t>(__builtin_frame_address(0));
+
+ // Hunt for the region that contains that address.
+ FILE* fp = fopen("/proc/self/maps", "re");
+ if (fp == nullptr) {
+ abort();
+ }
+ char line[BUFSIZ];
+ while (fgets(line, sizeof(line), fp) != nullptr) {
+ uintptr_t lo, hi;
+ if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR, &lo, &hi) == 2) {
+ if (lo <= startstack && startstack <= hi) {
+ *low = lo;
+ *high = hi;
+ fclose(fp);
+ return;
+ }
+ }
+ }
+ abort();
+}
+
+template <typename Fn>
+unsigned int fault_new_stack_page(uintptr_t low, Fn f) {
+ uintptr_t new_low;
+ uintptr_t new_high;
+ volatile char buf[4096];
+ buf[4095] = 1;
+ find_main_stack_limits(&new_low, &new_high);
+ if (new_low < low) {
+ f();
+ return new_high;
+ }
+ // Useless, but should defeat TCO.
+ return new_low + fault_new_stack_page(low, f);
+}
+
+#endif
+
+enum State { kInit, kThreadStarted, kStackRemapped };
+
+TEST(MemtagStackDlopenTest, DlopenRemapsStack) {
+#if defined(__BIONIC__) && defined(__aarch64__)
+ if (!running_with_mte()) GTEST_SKIP() << "Test requires MTE.";
+
+ std::string path = android::base::GetExecutableDirectory() + "/libtest_simple_memtag_stack.so";
+ ASSERT_EQ(0, access(path.c_str(), F_OK)); // Verify test setup.
+ EXPECT_FALSE(is_stack_mte_on());
+ std::mutex m;
+ std::condition_variable cv;
+ State state = kInit;
+
+ bool is_early_thread_mte_on = false;
+ std::thread early_th([&] {
+ {
+ std::lock_guard lk(m);
+ state = kThreadStarted;
+ }
+ cv.notify_one();
+ {
+ std::unique_lock lk(m);
+ cv.wait(lk, [&] { return state == kStackRemapped; });
+ }
+ is_early_thread_mte_on = is_stack_mte_on();
+ });
+ {
+ std::unique_lock lk(m);
+ cv.wait(lk, [&] { return state == kThreadStarted; });
+ }
+ void* handle = dlopen(path.c_str(), RTLD_NOW);
+ {
+ std::lock_guard lk(m);
+ state = kStackRemapped;
+ }
+ cv.notify_one();
+ ASSERT_NE(handle, nullptr);
+ EXPECT_TRUE(is_stack_mte_on());
+
+ bool new_stack_page_mte_on = false;
+ uintptr_t low;
+ uintptr_t high;
+ find_main_stack_limits(&low, &high);
+ fault_new_stack_page(low, [&] { new_stack_page_mte_on = is_stack_mte_on(); });
+ EXPECT_TRUE(new_stack_page_mte_on);
+
+ bool is_late_thread_mte_on = false;
+ std::thread late_th([&] { is_late_thread_mte_on = is_stack_mte_on(); });
+ late_th.join();
+ early_th.join();
+ EXPECT_TRUE(is_early_thread_mte_on);
+ EXPECT_TRUE(is_late_thread_mte_on);
+#else
+ GTEST_SKIP() << "requires bionic arm64";
+#endif
+}