1 files changed, 141 insertions, 0 deletions
diff --git a/toolkit/xre/dllservices/mozglue/interceptor/PatcherBase.h b/toolkit/xre/dllservices/mozglue/interceptor/PatcherBase.h
new file mode 100644
index 0000000000..e39a38fafd
--- /dev/null
+++ b/toolkit/xre/dllservices/mozglue/interceptor/PatcherBase.h
@@ -0,0 +1,141 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_interceptor_PatcherBase_h
+#define mozilla_interceptor_PatcherBase_h
+
+#include "mozilla/interceptor/TargetFunction.h"
+
+namespace mozilla {
+namespace interceptor {
+
+template <typename MMPolicy>
+struct GetProcAddressSelector;
+
+template <>
+struct GetProcAddressSelector<MMPolicyOutOfProcess> {
+  FARPROC operator()(HMODULE aModule, const char* aName,
+                     const MMPolicyOutOfProcess& aMMPolicy) const {
+    auto exportSection =
+        mozilla::nt::PEExportSection<MMPolicyOutOfProcess>::Get(aModule,
+                                                                aMMPolicy);
+    return exportSection.GetProcAddress(aName);
+  }
+};
+
+template <>
+struct GetProcAddressSelector<MMPolicyInProcess> {
+  FARPROC operator()(HMODULE aModule, const char* aName,
+                     const MMPolicyInProcess&) const {
+    // PEExportSection works for MMPolicyInProcess, too, but the native
+    // GetProcAddress is still better because PEExportSection does not
+    // solve a forwarded entry.
+    return ::GetProcAddress(aModule, aName);
+  }
+};
+
+template <typename VMPolicy>
+class WindowsDllPatcherBase {
+ protected:
+  typedef typename VMPolicy::MMPolicyT MMPolicyT;
+
+  template <typename... Args>
+  explicit WindowsDllPatcherBase(Args&&... aArgs)
+      : mVMPolicy(std::forward<Args>(aArgs)...) {}
+
+  ReadOnlyTargetFunction<MMPolicyT> ResolveRedirectedAddress(
+      FARPROC aOriginalFunction) {
+    uintptr_t currAddr = reinterpret_cast<uintptr_t>(aOriginalFunction);
+
+#if defined(_M_IX86) || defined(_M_X64)
+    uintptr_t prevAddr = 0;
+    while (prevAddr != currAddr) {
+      ReadOnlyTargetFunction<MMPolicyT> currFunc(mVMPolicy, currAddr);
+      prevAddr = currAddr;
+
+      // If function entry is jmp rel8 stub to the internal implementation, we
+      // resolve redirected address from the jump target.
+      uintptr_t nextAddr = 0;
+      if (currFunc.IsRelativeShortJump(&nextAddr)) {
+        int8_t offset = nextAddr - currFunc.GetAddress() - 2;
+
+#  if defined(_M_X64)
+        // We redirect to the target of a short jump backwards if the target
+        // is another jump (only 32-bit displacement is currently supported).
+        // This case is used by GetFileAttributesW in Win7 x64.
+        if ((offset < 0) && (currFunc.IsValidAtOffset(2 + offset))) {
+          ReadOnlyTargetFunction<MMPolicyT> redirectFn(mVMPolicy, nextAddr);
+          if (redirectFn.IsIndirectNearJump(&nextAddr)) {
+            return redirectFn;
+          }
+        }
+#  endif
+
+        // We check the downstream has enough nop-space only when the offset is
+        // positive.  Otherwise we stop chasing redirects and let the caller
+        // fail to hook.
+        if (offset > 0) {
+          bool isNopSpace = true;
+          for (int8_t i = 0; i < offset; i++) {
+            if (currFunc[2 + i] != 0x90) {
+              isNopSpace = false;
+              break;
+            }
+          }
+
+          if (isNopSpace) {
+            currAddr = nextAddr;
+          }
+        }
+#  if defined(_M_X64)
+      } else if (currFunc.IsIndirectNearJump(&nextAddr) ||
+                 currFunc.IsRelativeNearJump(&nextAddr)) {
+#  else
+      } else if (currFunc.IsIndirectNearJump(&nextAddr)) {
+#  endif
+        // If function entry is jmp [disp32] such as used by kernel32, we
+        // resolve redirected address from import table. For x64, we resolve
+        // a relative near jump for TestDllInterceptor with --disable-optimize.
+        currAddr = nextAddr;
+      }
+    }
+#endif  // defined(_M_IX86) || defined(_M_X64)
+
+    if (currAddr != reinterpret_cast<uintptr_t>(aOriginalFunction) &&
+        !mVMPolicy.IsPageAccessible(currAddr)) {
+      currAddr = reinterpret_cast<uintptr_t>(aOriginalFunction);
+    }
+    return ReadOnlyTargetFunction<MMPolicyT>(mVMPolicy, currAddr);
+  }
+
+ public:
+  FARPROC GetProcAddress(HMODULE aModule, const char* aName) const {
+    GetProcAddressSelector<MMPolicyT> selector;
+    return selector(aModule, aName, mVMPolicy);
+  }
+
+  bool IsPageAccessible(uintptr_t aAddress) const {
+    return mVMPolicy.IsPageAccessible(aAddress);
+  }
+
+#if defined(NIGHTLY_BUILD)
+  const Maybe<DetourError>& GetLastDetourError() const {
+    return mVMPolicy.GetLastDetourError();
+  }
+#endif  // defined(NIGHTLY_BUILD)
+  template <typename... Args>
+  void SetLastDetourError(Args&&... aArgs) {
+    mVMPolicy.SetLastDetourError(std::forward<Args>(aArgs)...);
+  }
+
+ protected:
+  VMPolicy mVMPolicy;
+};
+
+}  // namespace interceptor
+}  // namespace mozilla
+
+#endif  // mozilla_interceptor_PatcherBase_h