Zygote: Additional whitelists for runtime overlay / other static resources.

Partially cherry picked from commit 1c15c635785c64a.

These files are safe to reopen for the same reason that files in
/system/framework are. They're regular files and will not change after
the first zygote fork.

(cherry picked from commit 25cd01cc69fcad34756b00e52a79c0c54178f2e6)

Bug: 32618130
Test: m
Change-Id: I119e0bfcbf397cb331064adf148d92a5cd3ea92f

1 files changed, 30 insertions, 15 deletions

diff --git a/core/jni/fd_utils-inl.h b/core/jni/fd_utils-inl.h
index b78b8ffa2d5d..1a041f3b0c42 100644
--- a/core/jni/fd_utils-inl.h
+++ b/core/jni/fd_utils-inl.h
@@ -241,6 +241,18 @@ class FileDescriptorInfo {
     is_sock(false) {
   }
 
+  static bool StartsWith(const std::string& str, const std::string& prefix) {
+    return str.compare(0, prefix.size(), prefix) == 0;
+  }
+
+  static bool EndsWith(const std::string& str, const std::string& suffix) {
+    if (suffix.size() > str.size()) {
+      return false;
+    }
+
+    return str.compare(str.size() - suffix.size(), suffix.size(), suffix) == 0;
+  }
+
   // Returns true iff. a given path is whitelisted. A path is whitelisted
   // if it belongs to the whitelist (see kPathWhitelist) or if it's a path
   // under /system/framework that ends with ".jar" or if it is a system
@@ -252,31 +264,34 @@ class FileDescriptorInfo {
       }
     }
 
-    static const char* kFrameworksPrefix = "/system/framework/";
-    static const char* kJarSuffix = ".jar";
-    if (android::base::StartsWith(path, kFrameworksPrefix)
-        && android::base::EndsWith(path, kJarSuffix)) {
+    static const std::string kFrameworksPrefix = "/system/framework/";
+    static const std::string kJarSuffix = ".jar";
+    if (StartsWith(path, kFrameworksPrefix) && EndsWith(path, kJarSuffix)) {
       return true;
     }
 
     // Whitelist files needed for Runtime Resource Overlay, like these:
     // /system/vendor/overlay/framework-res.apk
-    // /system/vendor/overlay/PG/android-framework-runtime-resource-overlay.apk
+    // /system/vendor/overlay-subdir/pg/framework-res.apk
     // /data/resource-cache/system@vendor@overlay@framework-res.apk@idmap
-    // /data/resource-cache/system@vendor@overlay@PG@framework-res.apk@idmap
-    static const char* kOverlayDir = "/system/vendor/overlay/";
-    static const char* kApkSuffix = ".apk";
-
-    if (android::base::StartsWith(path, kOverlayDir)
-        && android::base::EndsWith(path, kApkSuffix)
+    // /data/resource-cache/system@vendor@overlay-subdir@pg@framework-res.apk@idmap
+    // See AssetManager.cpp for more details on overlay-subdir.
+    static const std::string kOverlayDir = "/system/vendor/overlay/";
+    static const std::string kVendorOverlayDir = "/vendor/overlay";
+    static const std::string kOverlaySubdir = "/system/vendor/overlay-subdir/";
+    static const std::string kApkSuffix = ".apk";
+
+    if ((StartsWith(path, kOverlayDir) || StartsWith(path, kOverlaySubdir)
+         || StartsWith(path, kVendorOverlayDir))
+        && EndsWith(path, kApkSuffix)
         && path.find("/../") == std::string::npos) {
       return true;
     }
 
-    static const char* kOverlayIdmapPrefix = "/data/resource-cache/";
-    static const char* kOverlayIdmapSuffix = ".apk@idmap";
-    if (android::base::StartsWith(path, kOverlayIdmapPrefix)
-        && android::base::EndsWith(path, kOverlayIdmapSuffix)) {
+    static const std::string kOverlayIdmapPrefix = "/data/resource-cache/";
+    static const std::string kOverlayIdmapSuffix = ".apk@idmap";
+    if (StartsWith(path, kOverlayIdmapPrefix) && EndsWith(path, kOverlayIdmapSuffix)
+        && path.find("/../") == std::string::npos) {
       return true;
     }