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[5.7][Runtime] Don't try to demangle unprefixed untrusted names. Remove operator new/delete hackery. #59096

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Merged
merged 1 commit into from
May 26, 2022
Merged

[5.7][Runtime] Don't try to demangle unprefixed untrusted names. Remove operator new/delete hackery. #59096

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27 changes: 0 additions & 27 deletions stdlib/public/runtime/Heap.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -134,30 +134,3 @@ static void swift_slowDeallocImpl(void *ptr, size_t alignMask) {
void swift::swift_slowDealloc(void *ptr, size_t bytes, size_t alignMask) {
swift_slowDeallocImpl(ptr, alignMask);
}

#if defined(__APPLE__) && defined(__MACH__) && SWIFT_STDLIB_HAS_DARWIN_LIBMALLOC
// On Darwin, define our own, hidden operator new/delete implementations. We
// don't want to pick up any overrides that come from other code, but we also
// don't want to expose our overrides to any other code. We can't do this
// directly in C++, as the compiler has an implicit prototype with default
// visibility. However, if we implement them as C functions using the C++
// mangled names, the compiler accepts them without complaint, and the linker
// still links all internal uses with these overrides.

__attribute__((visibility(("hidden")))) extern "C" void *_Znwm(size_t size) {
return swift_slowAlloc(size, MALLOC_ALIGN_MASK);
}

__attribute__((visibility(("hidden")))) extern "C" void _ZdlPv(void *ptr) {
swift_slowDeallocImpl(ptr, MALLOC_ALIGN_MASK);
}

__attribute__((visibility(("hidden")))) extern "C" void *_Znam(size_t size) {
return swift_slowAlloc(size, MALLOC_ALIGN_MASK);
}

__attribute__((visibility(("hidden")))) extern "C" void _ZdaPv(void *ptr) {
swift_slowDeallocImpl(ptr, MALLOC_ALIGN_MASK);
}

#endif
24 changes: 21 additions & 3 deletions stdlib/public/runtime/MetadataLookup.cpp
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Expand Up @@ -1919,7 +1919,7 @@ swift_stdlib_getTypeByMangledNameUntrusted(const char *typeNameStart,
if (c >= '\x01' && c <= '\x1F')
return nullptr;
}

return swift_getTypeByMangledName(MetadataState::Complete, typeName, nullptr,
{}, {}).getType().getMetadata();
}
Expand Down Expand Up @@ -2186,6 +2186,23 @@ swift_getOpaqueTypeConformance(const void * const *arguments,
// Return the ObjC class for the given type name.
// This gets installed as a callback from libobjc.

static bool validateObjCMangledName(const char *_Nonnull typeName) {
// Accept names with a mangling prefix.
if (getManglingPrefixLength(typeName))
return true;

// Accept names that start with a digit (unprefixed mangled names).
if (isdigit(typeName[0]))
return true;

// Accept names that contain a dot.
if (strchr(typeName, '.'))
return true;

// Reject anything else.
return false;
}

// FIXME: delete this #if and dlsym once we don't
// need to build with older libobjc headers
#if !OBJC_GETCLASSHOOK_DEFINED
Expand Down Expand Up @@ -2221,8 +2238,9 @@ getObjCClassByMangledName(const char * _Nonnull typeName,
[&](const Metadata *type, unsigned index) { return nullptr; }
).getType().getMetadata();
} else {
metadata = swift_stdlib_getTypeByMangledNameUntrusted(typeStr.data(),
typeStr.size());
if (validateObjCMangledName(typeName))
metadata = swift_stdlib_getTypeByMangledNameUntrusted(typeStr.data(),
typeStr.size());
}
if (metadata) {
auto objcClass =
Expand Down