Merge "Implement initial policy for memory tag checks." (80cf45a9) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/Zygote.java

+5 −0

Original line number	Diff line number	Diff line
		@@ -1060,4 +1060,9 @@ public final class Zygote {
		*/
		@FastNative
		public static native int nativeParseSigChld(byte[] in, int length, int[] out);

		/**
		* Returns whether the hardware supports memory tagging (ARM MTE).
		*/
		public static native boolean nativeSupportsMemoryTagging();
		}

core/java/com/android/internal/os/ZygoteInit.java

+9 −3

Original line number	Diff line number	Diff line
		@@ -750,9 +750,15 @@ public class ZygoteInit {
		Zygote.applyDebuggerSystemProperty(parsedArgs);
		Zygote.applyInvokeWithSystemProperty(parsedArgs);

		/* Enable pointer tagging in the system server unconditionally. Hardware support for
		* this is present in all ARMv8 CPUs; this flag has no effect on other platforms. */
		if (Zygote.nativeSupportsMemoryTagging()) {
		/* The system server is more privileged than regular app processes, so it has async
		* tag checks enabled on hardware that supports memory tagging. */
		parsedArgs.mRuntimeFlags \|= Zygote.MEMORY_TAG_LEVEL_ASYNC;
		} else {
		/* Enable pointer tagging in the system server. Hardware support for this is present
		* in all ARMv8 CPUs; this flag has no effect on other platforms. */
		parsedArgs.mRuntimeFlags \|= Zygote.MEMORY_TAG_LEVEL_TBI;
		}

		/* Enable gwp-asan on the system server with a small probability. This is the same
		* policy as applied to native processes and system apps. */

core/jni/Android.bp

+6 −0

Original line number	Diff line number	Diff line
		@@ -307,4 +307,10 @@ cc_library_shared {
		enabled: true,
		},
		},

		product_variables: {
		experimental_mte: {
		cflags: ["-DANDROID_EXPERIMENTAL_MTE"],
		},
		},
		}

core/jni/com_android_internal_os_Zygote.cpp

+53 −0

Original line number	Diff line number	Diff line
		@@ -55,6 +55,7 @@
		#include <signal.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <sys/auxv.h>
		#include <sys/capability.h>
		#include <sys/cdefs.h>
		#include <sys/eventfd.h>
		@@ -76,6 +77,8 @@
		#include <android-base/stringprintf.h>
		#include <android-base/unique_fd.h>
		#include <bionic/malloc.h>
		#include <bionic/mte.h>
		#include <bionic/mte_kernel.h>
		#include <cutils/fs.h>
		#include <cutils/multiuser.h>
		#include <cutils/sockets.h>
		@@ -355,6 +358,8 @@ enum RuntimeFlags : uint32_t {
		PROFILE_FROM_SHELL = 1 << 15,
		MEMORY_TAG_LEVEL_MASK = (1 << 19) \| (1 << 20),
		MEMORY_TAG_LEVEL_TBI = 1 << 19,
		MEMORY_TAG_LEVEL_ASYNC = 2 << 19,
		MEMORY_TAG_LEVEL_SYNC = 3 << 19,
		GWP_ASAN_LEVEL_MASK = (1 << 21) \| (1 << 22),
		GWP_ASAN_LEVEL_NEVER = 0 << 21,
		GWP_ASAN_LEVEL_LOTTERY = 1 << 21,
		@@ -1586,6 +1591,28 @@ static void BindMountStorageDirs(JNIEnv* env, jobjectArray pkg_data_info_list,
		}
		}

		#ifdef ANDROID_EXPERIMENTAL_MTE
		static void SetTagCheckingLevel(int level) {
		#ifdef __aarch64__
		if (!(getauxval(AT_HWCAP2) & HWCAP2_MTE)) {
		return;
		}

		int tagged_addr_ctrl = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
		if (tagged_addr_ctrl < 0) {
		ALOGE("prctl(PR_GET_TAGGED_ADDR_CTRL) failed: %s", strerror(errno));
		return;
		}

		tagged_addr_ctrl = (tagged_addr_ctrl & ~PR_MTE_TCF_MASK) \| level;
		if (prctl(PR_SET_TAGGED_ADDR_CTRL, tagged_addr_ctrl, 0, 0, 0) < 0) {
		ALOGE("prctl(PR_SET_TAGGED_ADDR_CTRL, %d) failed: %s", tagged_addr_ctrl,
		strerror(errno));
		}
		#endif
		}
		#endif

		// Utility routine to specialize a zygote child process.
		static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
		jint runtime_flags, jobjectArray rlimits,
		@@ -1715,7 +1742,23 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
		case RuntimeFlags::MEMORY_TAG_LEVEL_TBI:
		heap_tagging_level = M_HEAP_TAGGING_LEVEL_TBI;
		break;
		case RuntimeFlags::MEMORY_TAG_LEVEL_ASYNC:
		#ifdef ANDROID_EXPERIMENTAL_MTE
		SetTagCheckingLevel(PR_MTE_TCF_ASYNC);
		#endif
		heap_tagging_level = M_HEAP_TAGGING_LEVEL_ASYNC;
		break;
		case RuntimeFlags::MEMORY_TAG_LEVEL_SYNC:
		#ifdef ANDROID_EXPERIMENTAL_MTE
		SetTagCheckingLevel(PR_MTE_TCF_SYNC);
		#endif
		// TODO(pcc): Use SYNC here once the allocator supports it.
		heap_tagging_level = M_HEAP_TAGGING_LEVEL_ASYNC;
		break;
		default:
		#ifdef ANDROID_EXPERIMENTAL_MTE
		SetTagCheckingLevel(PR_MTE_TCF_NONE);
		#endif
		heap_tagging_level = M_HEAP_TAGGING_LEVEL_NONE;
		}
		android_mallopt(M_SET_HEAP_TAGGING_LEVEL, &heap_tagging_level, sizeof(heap_tagging_level));
		@@ -2405,6 +2448,14 @@ static jint com_android_internal_os_Zygote_nativeParseSigChld(JNIEnv* env, jclas
		return -1;
		}

		static jboolean com_android_internal_os_Zygote_nativeSupportsMemoryTagging(JNIEnv* env, jclass) {
		#if defined(__aarch64__)
		return mte_supported();
		#else
		return false;
		#endif
		}

		static const JNINativeMethod gMethods[] = {
		{"nativeForkAndSpecialize",
		"(II[II[[IILjava/lang/String;Ljava/lang/String;[I[IZLjava/lang/String;Ljava/lang/"
		@@ -2440,6 +2491,8 @@ static const JNINativeMethod gMethods[] = {
		(void*)com_android_internal_os_Zygote_nativeBoostUsapPriority},
		{"nativeParseSigChld", "([BI[I)I",
		(void*)com_android_internal_os_Zygote_nativeParseSigChld},
		{"nativeSupportsMemoryTagging", "()Z",
		(void*)com_android_internal_os_Zygote_nativeSupportsMemoryTagging},
		};

		int register_com_android_internal_os_Zygote(JNIEnv* env) {

services/core/java/com/android/server/am/ProcessList.java

+24 −5

Original line number	Diff line number	Diff line
		@@ -109,6 +109,7 @@ import com.android.internal.annotations.GuardedBy;
		import com.android.internal.annotations.VisibleForTesting;
		import com.android.internal.app.ProcessMap;
		import com.android.internal.app.procstats.ProcessStats;
		import com.android.internal.os.RuntimeInit;
		import com.android.internal.os.Zygote;
		import com.android.internal.util.ArrayUtils;
		import com.android.internal.util.FrameworkStatsLog;
		@@ -341,6 +342,14 @@ public final class ProcessList {
		@EnabledAfter(targetSdkVersion = Build.VERSION_CODES.Q)
		private static final long NATIVE_HEAP_POINTER_TAGGING = 135754954; // This is a bug id.

		/**
		* Enable memory tag checks in non-system apps. This flag will only have an effect on
		* hardware supporting the ARM Memory Tagging Extension (MTE).
		*/
		@ChangeId
		@Disabled
		private static final long NATIVE_MEMORY_TAGGING = 135772972; // This is a bug id.

		/**
		* Enable sampled memory bug detection in the app.
		* @see <a href="https://source.android.com/devices/tech/debug/gwp-asan">GWP-ASan</a>.
		@@ -1845,12 +1854,22 @@ public final class ProcessList {
		runtimeFlags \|= Zygote.USE_APP_IMAGE_STARTUP_CACHE;
		}

		// Enable heap pointer tagging, unless disabled by the app manifest, target sdk level,
		// or the compat feature.
		if (Zygote.nativeSupportsMemoryTagging()) {
		// System apps are generally more privileged than regular apps, and don't have the
		// same app compat concerns as regular apps, so we enable async tag checks for all
		// of their processes.
		if ((app.info.flags & ApplicationInfo.FLAG_SYSTEM) != 0
		\|\| mPlatformCompat.isChangeEnabled(NATIVE_MEMORY_TAGGING, app.info)) {
		runtimeFlags \|= Zygote.MEMORY_TAG_LEVEL_ASYNC;
		}
		} else {
		// Enable heap pointer tagging, unless disabled by the app manifest, target sdk
		// level, or the compat feature.
		if (app.info.allowsNativeHeapPointerTagging()
		&& mPlatformCompat.isChangeEnabled(NATIVE_HEAP_POINTER_TAGGING, app.info)) {
		runtimeFlags \|= Zygote.MEMORY_TAG_LEVEL_TBI;
		}
		}

		runtimeFlags \|= decideGwpAsanLevel(app);