Bug 1829050 - Enable STL wrapping (and thus infallible new) for wasm-sandboxed code. r=firefox-build-system-reviewers,shravanrn,andi

Differential Revision: https://phabricator.services.mozilla.com/D175981

config/external/rlbox_wasm2c_sandbox/rlbox_wasm2c_thread_locals.cpp

@@ -8,6 +8,8 @@
 // For MOZ_CRASH_UNSAFE_PRINTF
 #  include "mozilla/Assertions.h"
 
+#  include "mozilla/mozalloc_oom.h"
+
 // Load general firefox configuration of RLBox
 #  include "mozilla/rlbox/rlbox_config.h"
 #  include "mozilla/rlbox/rlbox_wasm2c_tls.hpp"
@@ -34,6 +36,13 @@ void moz_wasm2c_memgrow_failed() {
   CrashReporter::AnnotateCrashReport(
       CrashReporter::Annotation::WasmLibrarySandboxMallocFailed, true);
 }
+
+// This function is called when mozalloc_handle_oom is called from within
+// the sandbox. We redirect to that function, ignoring the ctx argument, which
+// is the sandbox itself.
+void w2c_env_mozalloc_handle_oom(void* ctx, uint32_t size) {
+  mozalloc_handle_oom(size);
+}
 }
 
 #endif

memory/mozalloc/mozalloc.cpp

@@ -103,6 +103,7 @@ void* moz_xmemdup(const void* ptr, size_t size) {
   return newPtr;
 }
 
+#ifndef __wasm__
 #  ifndef HAVE_MEMALIGN
 // We always have a definition of memalign, but system headers don't
 // necessarily come with a declaration.
@@ -118,6 +119,7 @@ void* moz_xmemalign(size_t boundary, size_t size) {
   // non-NULL ptr or errno == EINVAL
   return ptr;
 }
+#endif
 
 size_t moz_malloc_usable_size(void* ptr) {
   if (!ptr) return 0;

memory/mozalloc/mozalloc_oom.h

@@ -14,7 +14,12 @@
  * Called when memory is critically low.  Returns iff it was able to
  * remedy the critical memory situation; if not, it will abort().
  */
-MFBT_API void mozalloc_handle_oom(size_t requestedSize);
+#ifdef __wasm__
+__attribute__((import_module("env")))
+__attribute__((import_name("mozalloc_handle_oom")))
+#endif
+MFBT_API void
+mozalloc_handle_oom(size_t requestedSize);
 
 extern MFBT_DATA size_t gOOMAllocationSize;
 

memory/mozalloc/throw_gcc.h

@@ -8,6 +8,8 @@
 #ifndef mozilla_throw_gcc_h
 #define mozilla_throw_gcc_h
 
+#ifndef __wasm__
+
 #  include "mozilla/Attributes.h"
 
 #  include <stdio.h>   // snprintf
@@ -145,4 +147,6 @@ MOZ_THROW_NORETURN MOZ_EXPORT MOZ_ALWAYS_INLINE void __throw_regex_error(
 #  undef MOZ_THROW_NORETURN
 #  undef MOZ_THROW_INLINE
 
+#endif
+
 #endif  // mozilla_throw_gcc_h

python/mozbuild/mozbuild/frontend/context.py

@@ -767,6 +767,7 @@ class WasmFlags(TargetCompileFlags):
                 context.config.substs.get("MOZ_FILE_PREFIX_MAP_FLAGS"),
                 ("WASM_CFLAGS", "WASM_CXXFLAGS"),
             ),
+            ("STL", context.config.substs.get("STL_FLAGS"), ("WASM_CXXFLAGS",)),
         )
 
         TargetCompileFlags.__init__(self, context)

security/rlbox/moz.build

@@ -5,6 +5,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 WASM_SOURCES += [
+    "/memory/mozalloc/mozalloc.cpp",
     "/third_party/rlbox_wasm2c_sandbox/c_src/wasm2c_sandbox_wrapper.c",
 ]
 
@@ -47,6 +48,8 @@ AllowCompilerWarnings()
 WASM_DEFINES["MOZILLA_CLIENT"] = True
 WASM_DEFINES["_WASI_EMULATED_PROCESS_CLOCKS"] = True
 WASM_DEFINES["MOZ_IN_WASM_SANDBOX"] = True
+if CONFIG["ENABLE_CLANG_PLUGIN"]:
+    WASM_DEFINES["MOZ_CLANG_PLUGIN"] = True
 
 SANDBOXED_WASM_LIBRARY_NAME = "rlbox.wasm"