NativeHelper: Do not allow arbitrary library strings in user builds

On device, only allow "libart.so" in non-debuggable (user) builds.

Bug: 16404669

(cherry picked from commit 5019faa3a6bdde33785ece0537e8b865ea7cf938)

Change-Id: Ie163c04ce40c82698dcc98ced651dafef094d8b5

1 files changed, 26 insertions, 2 deletions

diff --git a/JniInvocation.cpp b/JniInvocation.cpp
index 1764693..f4dd24e 100644
--- a/JniInvocation.cpp
+++ b/JniInvocation.cpp
@@ -50,13 +50,31 @@ JniInvocation::~JniInvocation() {
 
 #ifdef HAVE_ANDROID_OS
 static const char* kLibrarySystemProperty = "persist.sys.dalvik.vm.lib.2";
+static const char* kDebuggableSystemProperty = "ro.debuggable";
+static const char* kDebuggableFallback = "0";  // Not debuggable.
 #endif
 static const char* kLibraryFallback = "libart.so";
 
-bool JniInvocation::Init(const char* library) {
+const char* JniInvocation::GetLibrary(const char* library) {
 #ifdef HAVE_ANDROID_OS
   char default_library[PROPERTY_VALUE_MAX];
-  property_get(kLibrarySystemProperty, default_library, kLibraryFallback);
+
+  char debuggable[PROPERTY_VALUE_MAX];
+  property_get(kDebuggableSystemProperty, debuggable, kDebuggableFallback);
+
+  if (strcmp(debuggable, "1") != 0) {
+    // Not a debuggable build.
+    // Do not allow arbitrary library. Ignore the library parameter. This
+    // will also ignore the default library, but initialize to empty string
+    // for cleanliness.
+    library = kLibraryFallback;
+    default_library[0] = 0;
+  } else {
+    // Debuggable build.
+    // Accept the library parameter. For the case it is NULL, load the default
+    // library from the system property.
+    property_get(kLibrarySystemProperty, default_library, kLibraryFallback);
+  }
 #else
   const char* default_library = kLibraryFallback;
 #endif
@@ -64,6 +82,12 @@ bool JniInvocation::Init(const char* library) {
     library = default_library;
   }
 
+  return library;
+}
+
+bool JniInvocation::Init(const char* library) {
+  library = GetLibrary(library);
+
   handle_ = dlopen(library, RTLD_NOW);
   if (handle_ == NULL) {
     if (strcmp(library, kLibraryFallback) == 0) {