a600594d5a
This is the V8 side of the implementation. You can take a look at a prototype of the Chrome side changes in https://crrev.com/c/1273043. Chrome could also use V8's default implementation of the trap handler, see https://crrev.com/c/1290952. Bug: v8:6743 Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng Change-Id: I9bb3e717db17a4f30bbb8acfd80a1f6510d463ff Reviewed-on: https://chromium-review.googlesource.com/c/1283111 Commit-Queue: Andreas Haas <ahaas@chromium.org> Reviewed-by: Ulan Degenbaev <ulan@chromium.org> Cr-Commit-Position: refs/heads/master@{#57117}
94 lines
3.4 KiB
C++
94 lines
3.4 KiB
C++
// Copyright 2018 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include <windows.h>
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#include "include/v8.h"
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#include "src/allocation.h"
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#include "src/base/page-allocator.h"
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#include "src/trap-handler/trap-handler.h"
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#include "testing/gtest/include/gtest/gtest.h"
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namespace {
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#if V8_TRAP_HANDLER_SUPPORTED
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bool g_handler_got_executed = false;
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// The start address of the virtual memory we use to cause an exception.
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i::Address g_start_address;
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// When using V8::EnableWebAssemblyTrapHandler, we save the old one to fall back
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// on if V8 doesn't handle the exception. This allows tools like ASan to
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// register a handler early on during the process startup and still generate
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// stack traces on failures.
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class ExceptionHandlerFallbackTest : public ::testing::Test {
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protected:
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void SetUp() override {
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// Register this handler as the last handler.
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registered_handler_ = AddVectoredExceptionHandler(/*first=*/0, TestHandler);
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CHECK_NOT_NULL(registered_handler_);
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v8::PageAllocator* page_allocator = i::GetPlatformPageAllocator();
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// We only need a single page.
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size_t size = page_allocator->AllocatePageSize();
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void* hint = page_allocator->GetRandomMmapAddr();
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i::VirtualMemory mem(page_allocator, size, hint, size);
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g_start_address = mem.address();
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// Set the permissions of the memory to no-access.
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CHECK(mem.SetPermissions(g_start_address, size,
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v8::PageAllocator::kNoAccess));
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mem_ = std::move(mem);
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}
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void WriteToTestMemory(int value) {
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*reinterpret_cast<volatile int*>(g_start_address) = value;
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}
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int ReadFromTestMemory() {
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return *reinterpret_cast<volatile int*>(g_start_address);
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}
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void TearDown() override {
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// be a good citizen and remove the exception handler.
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ULONG result = RemoveVectoredExceptionHandler(registered_handler_);
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CHECK(result);
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}
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private:
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static LONG WINAPI TestHandler(EXCEPTION_POINTERS* exception) {
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g_handler_got_executed = true;
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v8::PageAllocator* page_allocator = i::GetPlatformPageAllocator();
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// Make the allocated memory accessible so that from now on memory accesses
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// do not cause an exception anymore.
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CHECK(i::SetPermissions(page_allocator, g_start_address,
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page_allocator->AllocatePageSize(),
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v8::PageAllocator::kReadWrite));
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// The memory access should work now, we can continue execution.
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return EXCEPTION_CONTINUE_EXECUTION;
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}
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i::VirtualMemory mem_;
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void* registered_handler_;
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};
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TEST_F(ExceptionHandlerFallbackTest, DoTest) {
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constexpr bool use_default_handler = true;
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CHECK(v8::V8::EnableWebAssemblyTrapHandler(use_default_handler));
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// In the original test setup the test memory is protected against any kind of
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// access. Therefore the access here causes an access violation exception,
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// which should be caught by the exception handler we install above. In the
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// exception handler we change the permission of the test memory to make it
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// accessible, and then return from the exception handler to execute the
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// memory access again. This time we expect the memory access to work.
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constexpr int test_value = 42;
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WriteToTestMemory(test_value);
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CHECK_EQ(test_value, ReadFromTestMemory());
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CHECK(g_handler_got_executed);
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v8::internal::trap_handler::RemoveTrapHandler();
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}
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#endif
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} // namespace
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