Switch from local random address generation to kernel ASLR

base/android/linker/linker_jni.cc

Index: base/android/linker/linker_jni.cc
diff --git a/base/android/linker/linker_jni.cc b/base/android/linker/linker_jni.cc
index be4a5ed30df2c3b6ca99830020bb11835153200b..bf74fc36cf64d1da02b221ca92942ed24c414f79 100644
--- a/base/android/linker/linker_jni.cc
+++ b/base/android/linker/linker_jni.cc
@@ -17,6 +17,7 @@
 #include <crazy_linker.h>
 #include <jni.h>
 #include <stdlib.h>
+#include <sys/mman.h>
 #include <unistd.h>
 
 // Set this to 1 to enable debug traces to the Android log.
@@ -566,6 +567,18 @@ jlong GetPageSize(JNIEnv* env, jclass clazz) {
   return result;
 }
 
+jlong GetRandomBaseLoadAddress(JNIEnv* env, jclass clazz, jlong bytes) {
+  void* address =
+      mmap(NULL, bytes, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (address == MAP_FAILED) {
+    LOG_INFO("%s: Random base load address not determinable\n", __FUNCTION__);
+    return 0;
+  }
+  munmap(address, bytes);
+  LOG_INFO("%s: Random base load address is %p\n", __FUNCTION__, address);
+  return static_cast<jlong>(reinterpret_cast<intptr_t>(address));
+}
+
 const JNINativeMethod kNativeMethods[] = {
     {"nativeLoadLibrary",
      "("
@@ -614,7 +627,13 @@ const JNINativeMethod kNativeMethods[] = {
      "("
      ")"
      "J",
-     reinterpret_cast<void*>(&GetPageSize)}, };
+     reinterpret_cast<void*>(&GetPageSize)},
+    {"nativeGetRandomBaseLoadAddress",
+     "("
+     "J"
+     ")"
+     "J",
+     reinterpret_cast<void*>(&GetRandomBaseLoadAddress)}, };
 
 }  // namespace