Bug 1377614 - Part 2 - System extensions fail to load on Mac and Linux local builds. r=jimm

On Mac and Linux, allow unpacked extension resources to load from outside the extension directory if they're in the repo.

MozReview-Commit-ID: 1xsKV72aUJx

--HG--
extra : rebase_source : 1adefb0977e63935366a45dbf7c471d868655838

netwerk/protocol/res/ExtensionProtocolHandler.cpp

@@ -43,6 +43,10 @@
 #include "nsILocalFileWin.h"
 #endif
 
+#if !defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX)
+#include "mozilla/SandboxSettings.h"
+#endif
+
 #define EXTENSION_SCHEME "moz-extension"
 using mozilla::ipc::FileDescriptor;
 using OptionalIPCStream = mozilla::ipc::OptionalIPCStream;
@@ -344,6 +348,9 @@ ExtensionProtocolHandler::GetSingleton()
 
 ExtensionProtocolHandler::ExtensionProtocolHandler()
   : SubstitutingProtocolHandler(EXTENSION_SCHEME)
+#if !defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX)
+  , mAlreadyCheckedDevRepo(false)
+#endif
 {
   mUseRemoteFileChannels = IsNeckoChild() &&
     Preferences::GetBool("extensions.webextensions.protocol.remote");
@@ -498,6 +505,39 @@ ExtensionProtocolHandler::SubstituteChannel(nsIURI* aURI,
   return NS_OK;
 }
 
+#if !defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX)
+// The |aRequestedFile| argument must already be Normalize()'d
+Result<Ok, nsresult>
+ExtensionProtocolHandler::DevRepoContains(nsIFile* aRequestedFile,
+                                          bool *aResult)
+{
+  MOZ_ASSERT(!IsNeckoChild());
+  MOZ_ASSERT(aResult);
+  *aResult = false;
+
+  // On the first invocation, set mDevRepo if this is a
+  // development build with MOZ_DEVELOPER_REPO_DIR set.
+  if (!mAlreadyCheckedDevRepo) {
+    mAlreadyCheckedDevRepo = true;
+    if (mozilla::IsDevelopmentBuild()) {
+      char *developer_repo_dir = PR_GetEnv("MOZ_DEVELOPER_REPO_DIR");
+      if (developer_repo_dir) {
+        NS_TRY(NS_NewLocalFile(NS_ConvertUTF8toUTF16(developer_repo_dir),
+                               false, getter_AddRefs(mDevRepo)));
+        NS_TRY(mDevRepo->Normalize());
+      }
+    }
+  }
+
+  if (mDevRepo) {
+    // This is a development build
+    NS_TRY(mDevRepo->Contains(aRequestedFile, aResult));
+  }
+
+  return Ok();
+}
+#endif /* !defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX) */
+
 Result<nsCOMPtr<nsIInputStream>, nsresult>
 ExtensionProtocolHandler::NewStream(nsIURI* aChildURI,
                                     nsILoadInfo* aChildLoadInfo,
@@ -584,7 +624,17 @@ ExtensionProtocolHandler::NewStream(nsIURI* aChildURI,
   bool isResourceFromExtensionDir = false;
   NS_TRY(extensionDir->Contains(requestedFile, &isResourceFromExtensionDir));
   if (!isResourceFromExtensionDir) {
+#if defined(XP_WIN)
     return Err(NS_ERROR_FILE_ACCESS_DENIED);
+#elif defined(MOZ_CONTENT_SANDBOX)
+    // On a dev build, we allow an unpacked resource that isn't
+    // from the extension directory as long as it is from the repo.
+    bool isResourceFromDevRepo = false;
+    MOZ_TRY(DevRepoContains(requestedFile, &isResourceFromDevRepo));
+    if (!isResourceFromDevRepo) {
+      return Err(NS_ERROR_FILE_ACCESS_DENIED);
+    }
+#endif /* defined(XP_WIN) */
   }
 
   nsCOMPtr<nsIInputStream> inputStream;

netwerk/protocol/res/ExtensionProtocolHandler.h

@@ -148,6 +148,30 @@ private:
                                                   nsACString& aResolvedSpec,
                                                   nsIChannel** aRetVal);
 
+#if !defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX)
+  /**
+   * Sets the aResult outparam to true if we are a developer build with the
+   * repo dir environment variable set and the requested file resides in the
+   * repo dir. Developer builds may load system extensions with web-accessible
+   * resources that are symlinks to files in the repo dir. This method is for
+   * checking if an unpacked resource requested by the child is from the repo.
+   * The requested file must be already Normalized().
+   *
+   * @param aRequestedFile the requested web-accessible resource file. Argument
+   *        must be an nsIFile for which Normalize() has already been called.
+   * @param aResult outparam set to true on development builds when the
+   *        requested file resides in the repo
+   */
+  Result<Ok, nsresult> DevRepoContains(nsIFile* aRequestedFile, bool *aResult);
+
+  // On development builds, this points to development repo. Lazily set.
+  nsCOMPtr<nsIFile> mDevRepo;
+
+  // Set to true once we've already tried to load the dev repo path,
+  // allowing for lazy initialization of |mDevRepo|.
+  bool mAlreadyCheckedDevRepo;
+#endif /* !defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX) */
+
   // Used for opening JAR files off the main thread when we just need to
   // obtain a file descriptor to send back to the child.
   RefPtr<mozilla::LazyIdleThread> mFileOpenerThread;