Remove the public libs in runtime namespace

These libs are listed in public.android.txt, but not exposed in the default namespace

Bug: 120786417
Bug: 121372395
Test: app can still DT_NEEDED libicuuc.so
Change-Id: I03dc51f04e29c2d15679c4daf82b05a812efb2db

1 files changed, 35 insertions, 0 deletions

diff --git a/libnativeloader/native_loader.cpp b/libnativeloader/native_loader.cpp
index a4e00bd0b..2631a8a55 100644
--- a/libnativeloader/native_loader.cpp
+++ b/libnativeloader/native_loader.cpp
@@ -128,6 +128,12 @@ static constexpr const char* kWhitelistedDirectories = "/data:/mnt/expand";
 
 static constexpr const char* kApexPath = "/apex/";
 
+#if defined(__LP64__)
+static constexpr const char* kRuntimeApexLibPath = "/apex/com.android.runtime/lib64";
+#else
+static constexpr const char* kRuntimeApexLibPath = "/apex/com.android.runtime/lib";
+#endif
+
 static bool is_debuggable() {
   char debuggable[PROP_VALUE_MAX];
   property_get("ro.debuggable", debuggable, "0");
@@ -399,6 +405,14 @@ class LibraryNamespaces {
       }
     }
 
+    // Remove the public libs in the runtime namespace.
+    // These libs are listed in public.android.txt, but we don't want the rest of android
+    // in default namespace to dlopen the libs.
+    // For example, libicuuc.so is exposed to classloader namespace from runtime namespace.
+    // Unfortunately, it does not have stable C symbols, and default namespace should only use
+    // stable symbols in libandroidicu.so. http://b/120786417
+    removePublicLibsIfExistsInRuntimeApex(sonames);
+
     // android_init_namespaces() expects all the public libraries
     // to be loaded so that they can be found by soname alone.
     //
@@ -493,6 +507,27 @@ class LibraryNamespaces {
     }
   }
 
+  /**
+   * Remove the public libs in runtime namespace
+   */
+  void removePublicLibsIfExistsInRuntimeApex(std::vector<std::string>& sonames) {
+    for (const std::string& lib_name : kRuntimePublicLibraries) {
+      std::string path(kRuntimeApexLibPath);
+      path.append("/").append(lib_name);
+
+      struct stat s;
+      // Do nothing if the path in /apex does not exist.
+      // Runtime APEX must be mounted since libnativeloader is in the same APEX
+      if (stat(path.c_str(), &s) != 0) {
+        continue;
+      }
+
+      auto it = std::find(sonames.begin(), sonames.end(), lib_name);
+      if (it != sonames.end()) {
+        sonames.erase(it);
+      }
+    }
+  }
 
   bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames,
                   const std::function<bool(const std::string& /* soname */,