Bug 1739669 - Configure hunspell rlbox sandbox for higher mem size depending on locale r=bholley

Differential Revision: https://phabricator.services.mozilla.com/D130544

extensions/spellcheck/hunspell/glue/RLBoxHunspell.cpp

@@ -41,7 +41,38 @@ RLBoxHunspell::RLBoxHunspell(const nsAutoCString& affpath,
                              const nsAutoCString& dpath)
     : mHandle(nullptr) {
   MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+#if defined(MOZ_WASM_SANDBOXING_HUNSPELL) && !defined(HAVE_64BIT_BUILD)
+  // By default, the rlbox sandbox size is smaller on 32-bit builds than the max
+  // 4GB We may need to ask for a larger sandbox size for hunspell to spellcheck
+  // in some locales See Bug 1739669 for more details
+
+  const uint64_t defaultMaxSizeForSandbox =
+      wasm_rt_get_default_max_linear_memory_size();
+
+  // We first get the size of the dictionary
+  Result<int64_t, nsresult> dictSizeResult =
+      mozHunspellFileMgrHost::GetSize(dpath);
+  MOZ_RELEASE_ASSERT(dictSizeResult.isOk());
+
+  int64_t dictSize = dictSizeResult.unwrap();
+  MOZ_RELEASE_ASSERT(dictSize >= 0);
+
+  // Next, we compute the expected memory needed for hunspell spell checking.
+  // This seems to be about 7x the size of the dictionary (See Bug 1739669)
+  const uint64_t expectedMaxMemory = 7 * dictSize;
+
+  // If we expect a higher memory usage, override the defaults
+  // else stick with the defaults for the sandbox
+  if (expectedMaxMemory > defaultMaxSizeForSandbox) {
+    mSandbox.create_sandbox(true /* abort on creation failure */,
+                            expectedMaxMemory);
+  } else {
+    mSandbox.create_sandbox();
+  }
+#else
   mSandbox.create_sandbox();
+#endif
 
   // Add the aff and dict files to allow list
   if (!affpath.IsEmpty()) {

extensions/spellcheck/hunspell/glue/mozHunspellRLBoxHost.cpp

@@ -9,7 +9,6 @@
 #include "mozHunspellRLBoxHost.h"
 #include "mozilla/DebugOnly.h"
 #include "nsContentUtils.h"
-#include "nsIChannel.h"
 #include "nsILoadInfo.h"
 #include "nsNetUtil.h"
 #include "nsUnicharUtils.h"
@@ -19,21 +18,24 @@
 using namespace mozilla;
 
 mozHunspellFileMgrHost::mozHunspellFileMgrHost(const nsCString& aFilename) {
-  DebugOnly<Result<Ok, nsresult>> result = Open(aFilename);
+  nsCOMPtr<nsIChannel> channel;
+  DebugOnly<Result<Ok, nsresult>> result = Open(aFilename, channel, mStream);
   NS_WARNING_ASSERTION(result.value.isOk(), "Failed to open Hunspell file");
 }
 
-Result<Ok, nsresult> mozHunspellFileMgrHost::Open(const nsCString& aPath) {
+/* static */
+Result<Ok, nsresult> mozHunspellFileMgrHost::Open(
+    const nsCString& aPath, nsCOMPtr<nsIChannel>& aChannel,
+    nsCOMPtr<nsIInputStream>& aStream) {
   nsCOMPtr<nsIURI> uri;
   MOZ_TRY(NS_NewURI(getter_AddRefs(uri), aPath));
 
-  nsCOMPtr<nsIChannel> channel;
   MOZ_TRY(NS_NewChannel(
-      getter_AddRefs(channel), uri, nsContentUtils::GetSystemPrincipal(),
+      getter_AddRefs(aChannel), uri, nsContentUtils::GetSystemPrincipal(),
       nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_INHERITS_SEC_CONTEXT,
       nsIContentPolicy::TYPE_OTHER));
 
-  MOZ_TRY(channel->Open(getter_AddRefs(mStream)));
+  MOZ_TRY(aChannel->Open(getter_AddRefs(aStream)));
   return Ok();
 }
 
@@ -52,6 +54,19 @@ Result<Ok, nsresult> mozHunspellFileMgrHost::ReadLine(nsCString& aLine) {
   return Ok();
 }
 
+/* static */
+Result<int64_t, nsresult> mozHunspellFileMgrHost::GetSize(
+    const nsCString& aFilename) {
+  int64_t ret = -1;
+
+  nsCOMPtr<nsIChannel> channel;
+  nsCOMPtr<nsIInputStream> stream;
+  MOZ_TRY(Open(aFilename, channel, stream));
+
+  channel->GetContentLength(&ret);
+  return ret;
+}
+
 bool mozHunspellFileMgrHost::GetLine(std::string& aResult) {
   nsAutoCString line;
   auto res = ReadLine(line);

extensions/spellcheck/hunspell/glue/mozHunspellRLBoxHost.h

@@ -18,6 +18,7 @@
 #include "mozilla/Result.h"
 #include "mozilla/ResultExtensions.h"
 #include "mozilla/RWLock.h"
+#include "nsIChannel.h"
 #include "nsIInputStream.h"
 #include "nsReadLine.h"
 
@@ -34,8 +35,12 @@ class mozHunspellFileMgrHost final {
   bool GetLine(std::string& aResult);
   int GetLineNum() const { return mLineNum; }
 
+  static Result<int64_t, nsresult> GetSize(const nsCString& aFilename);
+
  private:
-  mozilla::Result<mozilla::Ok, nsresult> Open(const nsCString& aPath);
+  static mozilla::Result<mozilla::Ok, nsresult> Open(
+      const nsCString& aPath, nsCOMPtr<nsIChannel>& aChannel,
+      nsCOMPtr<nsIInputStream>& aStream);
 
   mozilla::Result<mozilla::Ok, nsresult> ReadLine(nsCString& aLine);