gnu: webkitgtk: Disable SharedArrayBuffers to mitigate Spectre.

* gnu/packages/patches/webkitgtk-mitigate-spectre.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/webkit.scm (webkitgtk)[source]: Add patch.

2 files changed, 110 insertions, 2 deletions

diff --git a/gnu/packages/patches/webkitgtk-mitigate-spectre.patch b/gnu/packages/patches/webkitgtk-mitigate-spectre.patch
new file mode 100644
index 0000000000..3d983ede66
--- /dev/null
+++ b/gnu/packages/patches/webkitgtk-mitigate-spectre.patch
@@ -0,0 +1,107 @@
+Disable SharedArrayBuffers to mitigate Spectre.  Based on:
+
+  https://trac.webkit.org/changeset/226386/webkit
+
+Backported to webkitgtk-2.18.4 by Mark H Weaver <mhw@netris.org>
+
+
+--- webkitgtk-2.18.4/Source/JavaScriptCore/runtime/JSGlobalObject.h.orig	2017-12-19 02:23:07.000000000 -0500
++++ webkitgtk-2.18.4/Source/JavaScriptCore/runtime/JSGlobalObject.h	2018-01-06 19:28:55.985066986 -0500
+@@ -338,8 +338,10 @@
+     WriteBarrier<Structure> m_moduleLoaderStructure;
+     WriteBarrier<JSArrayBufferPrototype> m_arrayBufferPrototype;
+     WriteBarrier<Structure> m_arrayBufferStructure;
++#if ENABLE(SHARED_ARRAY_BUFFER)
+     WriteBarrier<JSArrayBufferPrototype> m_sharedArrayBufferPrototype;
+     WriteBarrier<Structure> m_sharedArrayBufferStructure;
++#endif
+ 
+ #define DEFINE_STORAGE_FOR_SIMPLE_TYPE(capitalName, lowerName, properName, instanceType, jsName, prototypeBase) \
+     WriteBarrier<capitalName ## Prototype> m_ ## lowerName ## Prototype; \
+@@ -670,8 +672,13 @@
+         switch (sharingMode) {
+         case ArrayBufferSharingMode::Default:
+             return m_arrayBufferPrototype.get();
++#if ENABLE(SHARED_ARRAY_BUFFER)
+         case ArrayBufferSharingMode::Shared:
+             return m_sharedArrayBufferPrototype.get();
++#else
++        default:
++            return m_arrayBufferPrototype.get();
++#endif
+         }
+     }
+     Structure* arrayBufferStructure(ArrayBufferSharingMode sharingMode) const
+@@ -679,8 +686,13 @@
+         switch (sharingMode) {
+         case ArrayBufferSharingMode::Default:
+             return m_arrayBufferStructure.get();
++#if ENABLE(SHARED_ARRAY_BUFFER)
+         case ArrayBufferSharingMode::Shared:
+             return m_sharedArrayBufferStructure.get();
++#else
++        default:
++            return m_arrayBufferStructure.get();
++#endif
+         }
+         RELEASE_ASSERT_NOT_REACHED();
+         return nullptr;
+--- webkitgtk-2.18.4/Source/JavaScriptCore/runtime/JSGlobalObject.cpp.orig	2017-12-19 02:23:07.000000000 -0500
++++ webkitgtk-2.18.4/Source/JavaScriptCore/runtime/JSGlobalObject.cpp	2018-01-06 19:27:16.628574304 -0500
+@@ -574,8 +574,10 @@
+     
+     m_arrayBufferPrototype.set(vm, this, JSArrayBufferPrototype::create(vm, this, JSArrayBufferPrototype::createStructure(vm, this, m_objectPrototype.get()), ArrayBufferSharingMode::Default));
+     m_arrayBufferStructure.set(vm, this, JSArrayBuffer::createStructure(vm, this, m_arrayBufferPrototype.get()));
++#if ENABLE(SHARED_ARRAY_BUFFER)
+     m_sharedArrayBufferPrototype.set(vm, this, JSArrayBufferPrototype::create(vm, this, JSArrayBufferPrototype::createStructure(vm, this, m_objectPrototype.get()), ArrayBufferSharingMode::Shared));
+     m_sharedArrayBufferStructure.set(vm, this, JSArrayBuffer::createStructure(vm, this, m_sharedArrayBufferPrototype.get()));
++#endif
+ 
+     m_iteratorPrototype.set(vm, this, IteratorPrototype::create(vm, this, IteratorPrototype::createStructure(vm, this, m_objectPrototype.get())));
+     m_generatorPrototype.set(vm, this, GeneratorPrototype::create(vm, this, GeneratorPrototype::createStructure(vm, this, m_iteratorPrototype.get())));
+@@ -620,10 +622,11 @@
+     
+     JSArrayBufferConstructor* arrayBufferConstructor = JSArrayBufferConstructor::create(vm, JSArrayBufferConstructor::createStructure(vm, this, m_functionPrototype.get()), m_arrayBufferPrototype.get(), m_speciesGetterSetter.get(), ArrayBufferSharingMode::Default);
+     m_arrayBufferPrototype->putDirectWithoutTransition(vm, vm.propertyNames->constructor, arrayBufferConstructor, DontEnum);
++#if ENABLE(SHARED_ARRAY_BUFFER)
+     JSArrayBufferConstructor* sharedArrayBufferConstructor = nullptr;
+     sharedArrayBufferConstructor = JSArrayBufferConstructor::create(vm, JSArrayBufferConstructor::createStructure(vm, this, m_functionPrototype.get()), m_sharedArrayBufferPrototype.get(), m_speciesGetterSetter.get(), ArrayBufferSharingMode::Shared);
+     m_sharedArrayBufferPrototype->putDirectWithoutTransition(vm, vm.propertyNames->constructor, sharedArrayBufferConstructor, DontEnum);
+-    
++#endif
+ #define CREATE_CONSTRUCTOR_FOR_SIMPLE_TYPE(capitalName, lowerName, properName, instanceType, jsName, prototypeBase) \
+ capitalName ## Constructor* lowerName ## Constructor = capitalName ## Constructor::create(vm, capitalName ## Constructor::createStructure(vm, this, m_functionPrototype.get()), m_ ## lowerName ## Prototype.get(), m_speciesGetterSetter.get()); \
+ m_ ## lowerName ## Prototype->putDirectWithoutTransition(vm, vm.propertyNames->constructor, lowerName ## Constructor, DontEnum); \
+@@ -686,7 +689,9 @@
+     putDirectWithoutTransition(vm, vm.propertyNames->builtinNames().ArrayPrivateName(), arrayConstructor, DontEnum | DontDelete | ReadOnly);
+ 
+     putDirectWithoutTransition(vm, vm.propertyNames->ArrayBuffer, arrayBufferConstructor, DontEnum);
++#if ENABLE(SHARED_ARRAY_BUFFER)
+     putDirectWithoutTransition(vm, vm.propertyNames->SharedArrayBuffer, sharedArrayBufferConstructor, DontEnum);
++#endif
+ 
+ #define PUT_CONSTRUCTOR_FOR_SIMPLE_TYPE(capitalName, lowerName, properName, instanceType, jsName, prototypeBase) \
+ putDirectWithoutTransition(vm, vm.propertyNames-> jsName, lowerName ## Constructor, DontEnum); \
+@@ -1288,8 +1293,10 @@
+     
+     visitor.append(thisObject->m_arrayBufferPrototype);
+     visitor.append(thisObject->m_arrayBufferStructure);
++#if ENABLE(SHARED_ARRAY_BUFFER)
+     visitor.append(thisObject->m_sharedArrayBufferPrototype);
+     visitor.append(thisObject->m_sharedArrayBufferStructure);
++#endif
+ 
+ #define VISIT_SIMPLE_TYPE(CapitalName, lowerName, properName, instanceType, jsName, prototypeBase) \
+     visitor.append(thisObject->m_ ## lowerName ## Prototype); \
+--- webkitgtk-2.18.4/Source/WTF/wtf/Platform.h.orig	2017-10-16 08:18:56.000000000 -0400
++++ webkitgtk-2.18.4/Source/WTF/wtf/Platform.h	2018-01-06 19:29:52.897349199 -0500
+@@ -1190,6 +1190,9 @@
+ #define HAVE_NS_ACTIVITY 1
+ #endif
+ 
++/* Disable SharedArrayBuffers until Spectre security concerns are mitigated. */
++#define ENABLE_SHARED_ARRAY_BUFFER 0
++
+ #if (OS(DARWIN) && USE(CG)) || (USE(FREETYPE) && !PLATFORM(GTK)) || (PLATFORM(WIN) && (USE(CG) || USE(CAIRO)))
+ #undef ENABLE_OPENTYPE_MATH
+ #define ENABLE_OPENTYPE_MATH 1
diff --git a/gnu/packages/webkit.scm b/gnu/packages/webkit.scm
index e2d753aa3d..7acc018632 100644
--- a/gnu/packages/webkit.scm
+++ b/gnu/packages/webkit.scm
@@ -2,7 +2,7 @@
 ;;; Copyright © 2015 Sou Bunnbu <iyzsong@gmail.com>
 ;;; Copyright © 2015 David Hashe <david.hashe@dhashe.com>
 ;;; Copyright © 2015 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2015, 2016, 2017 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2015, 2016, 2017, 2018 Mark H Weaver <mhw@netris.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -61,7 +61,8 @@
                                   name "-" version ".tar.xz"))
               (sha256
                (base32
-                "1f1j0r996l20cgkvbwpizn7d4yp58cy334b1pvn4kfb5c2dbpdl7"))))
+                "1f1j0r996l20cgkvbwpizn7d4yp58cy334b1pvn4kfb5c2dbpdl7"))
+              (patches (search-patches "webkitgtk-mitigate-spectre.patch"))))
     (build-system cmake-build-system)
     (arguments
      '(#:tests? #f ; no tests