Bug 1692220 - Allow content-process read access to libFontRegistry caches. r=haik

Differential Revision: https://phabricator.services.mozilla.com/D105801

security/sandbox/mac/Sandbox.mm

@@ -280,7 +280,11 @@ bool StartMacSandbox(MacSandboxInfo const& aInfo, std::string& aErrorMessage) {
 
   // Used for the Flash sandbox. Declared here so that they
   // stay in scope until sandbox_init_with_parameters is called.
-  std::string flashCacheDir, flashTempDir, flashPath;
+  std::string flashTempDir, flashPath;
+
+  // Used for the content process to access to parts of the cache dir,
+  // and also for the Flash sandbox (which is presumably going away soon).
+  std::string userCacheDir;
 
   if (aInfo.type == MacSandboxType_Flash) {
     profile = SandboxPolicyFlash;
@@ -311,10 +315,10 @@ bool StartMacSandbox(MacSandboxInfo const& aInfo, std::string& aErrorMessage) {
     if (!confstr(_CS_DARWIN_USER_CACHE_DIR, confStrBuf, sizeof(confStrBuf))) {
       return false;
     }
-    if (!GetRealPath(flashCacheDir, confStrBuf)) {
+    if (!GetRealPath(userCacheDir, confStrBuf)) {
       return false;
     }
-    params.push_back(flashCacheDir.c_str());
+    params.push_back(userCacheDir.c_str());
 
     // User temp dir
     params.push_back("DARWIN_USER_TEMP_DIR");
@@ -415,6 +419,17 @@ bool StartMacSandbox(MacSandboxInfo const& aInfo, std::string& aErrorMessage) {
         params.push_back("CRASH_PORT");
         params.push_back(aInfo.crashServerPort.c_str());
       }
+
+      params.push_back("DARWIN_USER_CACHE_DIR");
+      char confStrBuf[PATH_MAX];
+      if (!confstr(_CS_DARWIN_USER_CACHE_DIR, confStrBuf, sizeof(confStrBuf))) {
+        return false;
+      }
+      if (!GetRealPath(userCacheDir, confStrBuf)) {
+        return false;
+      }
+      params.push_back(userCacheDir.c_str());
+
       if (!aInfo.testingReadPath1.empty()) {
         params.push_back("TESTING_READ_PATH1");
         params.push_back(aInfo.testingReadPath1.c_str());

security/sandbox/mac/SandboxPolicyContent.h

@@ -24,6 +24,7 @@ static const char SandboxPolicyContent[] = R"SANDBOX_LITERAL(
   (define hasWindowServer (param "HAS_WINDOW_SERVER"))
   (define home-path (param "HOME_PATH"))
   (define debugWriteDir (param "DEBUG_WRITE_DIR"))
+  (define userCacheDir (param "DARWIN_USER_CACHE_DIR"))
   (define testingReadPath1 (param "TESTING_READ_PATH1"))
   (define testingReadPath2 (param "TESTING_READ_PATH2"))
   (define testingReadPath3 (param "TESTING_READ_PATH3"))
@@ -262,6 +263,11 @@ static const char SandboxPolicyContent[] = R"SANDBOX_LITERAL(
       (when testingReadPath4
         (allow file-read* (subpath testingReadPath4)))))
 
+  ; bug 1692220
+  (when userCacheDir
+    (allow file-read*
+      (subpath (string-append userCacheDir "/com.apple.FontRegistry"))))
+
   ; bug 1303987
   (if (string? debugWriteDir)
     (begin