macOS Sandbox Crash Fix

Purpose

Fixes a crash on macOS where Camoufox segfaults during content process launch due to MOZ_CRASH being triggered when GetRepoDir() or GetObjDir() fail in non-packaged builds.

Problem

In CacheSandboxParams(), the code attempts to get repository and object directory paths for sandbox whitelisting in non-packaged builds:

if (!mozilla::IsPackagedBuild()) {
  rv = nsMacUtilsImpl::GetRepoDir(getter_AddRefs(repoDir));
  if (NS_FAILED(rv)) {
    MOZ_CRASH("Failed to get path to repo dir");  // ← CRASH HERE
  }
  // ...
}

These functions (GetRepoDir and GetObjDir) read paths from the .app bundle's Info.plist file. In cross-compiled builds or unusual build configurations, these plist keys may not exist, causing the functions to fail and trigger MOZ_CRASH.

Root Cause

1. Cross-compilation from Ubuntu to macOS: The build process may not populate the development-specific plist keys (MAC_DEV_REPO_KEY, MAC_DEV_OBJ_KEY)
2. IsPackagedBuild() detection: In some build configurations, IsPackagedBuild() may incorrectly return false
3. Missing plist keys: The Info.plist doesn't contain the required development directory keys

When any of these occur, the code crashes instead of gracefully handling the missing paths.

Solution

Changed the code from crashing on failure to logging a warning and continuing without those sandbox paths:

if (NS_SUCCEEDED(rv)) {
  nsCString repoDirPath;
  (void)repoDir->GetNativePath(repoDirPath);
  info.testingReadPath3 = repoDirPath.get();
} else {
  NS_WARNING("Failed to get repo dir path for sandbox, skipping testingReadPath3");
}

Since testingReadPath3 and testingReadPath4 are optional sandbox parameters (only used for whitelisting in development builds), it's safe to skip them if they can't be determined.

Files Modified

• dom/ipc/ContentParent.cpp: Changed MOZ_CRASH to NS_WARNING for GetRepoDir() and GetObjDir() failures

Platform

macOS only (wrapped in #if defined(XP_MACOSX) && defined(MOZ_SANDBOX))

Apply Order

Apply after the Playwright patches (0-playwright.patch, 1-leak-fixes.patch) in the build sequence.

Testing

The fix can be verified by:

1. Building Camoufox with the patch via cross-compilation from Ubuntu
2. Running the macOS binary without MOZ_DISABLE_CONTENT_SANDBOX=1
3. Verifying the browser launches without crashing
4. Checking that content processes spawn correctly via about:processes
5. Looking for warning messages in console output (if running from terminal)

Notes

• This is a defensive fix that handles missing development directory paths gracefully
• The sandbox will still function correctly without testingReadPath3 and testingReadPath4
• These paths are only used in non-packaged builds for development/testing purposes
• Production/packaged builds won't even reach this code path due to IsPackagedBuild() check