// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Defines ResolverThunk, the interface for classes that perform interceptions.
// For more details see
// http://dev.chromium.org/developers/design-documents/sandbox .
#include "base/basictypes.h"
#include "sandbox/win/src/nt_internals.h"
#ifndef SANDBOX_SRC_RESOLVER_H__
#define SANDBOX_SRC_RESOLVER_H__
namespace sandbox {
// A resolver is the object in charge of performing the actual interception of
// a function. There should be a concrete implementation of a resolver roughly
// per type of interception.
class ResolverThunk {
public:
ResolverThunk() {}
virtual ~ResolverThunk() {}
// Performs the actual interception of a function.
// target_name is an exported function from the module loaded at
// target_module, and must be replaced by interceptor_name, exported from
// interceptor_module. interceptor_entry_point can be provided instead of
// interceptor_name / interceptor_module.
// thunk_storage must point to a buffer on the child's address space, to hold
// the patch thunk, and related data. If provided, storage_used will receive
// the number of bytes used from thunk_storage.
//
// Example: (without error checking)
//
// size_t size = resolver.GetThunkSize();
// char* buffer = ::VirtualAllocEx(child_process, NULL, size,
// MEM_COMMIT, PAGE_READWRITE);
// resolver.Setup(ntdll_module, NULL, L"NtCreateFile", NULL,
// &MyReplacementFunction, buffer, size, NULL);
//
// In general, the idea is to allocate a single big buffer for all
// interceptions on the same dll, and call Setup n times.
// WARNING: This means that any data member that is specific to a single
// interception must be reset within this method.
virtual NTSTATUS Setup(const void* target_module,
const void* interceptor_module,
const char* target_name,
const char* interceptor_name,
const void* interceptor_entry_point,
void* thunk_storage,
size_t storage_bytes,
size_t* storage_used) = 0;
// Gets the address of function_name inside module (main exe).
virtual NTSTATUS ResolveInterceptor(const void* module,
const char* function_name,
const void** address);
// Gets the address of an exported function_name inside module.
virtual NTSTATUS ResolveTarget(const void* module,
const char* function_name,
void** address);
// Gets the required buffer size for this type of thunk.
virtual size_t GetThunkSize() const = 0;
protected:
// Performs basic initialization on behalf of a concrete instance of a
// resolver. That is, parameter validation and resolution of the target
// and the interceptor into the member variables.
//
// target_name is an exported function from the module loaded at
// target_module, and must be replaced by interceptor_name, exported from
// interceptor_module. interceptor_entry_point can be provided instead of
// interceptor_name / interceptor_module.
// thunk_storage must point to a buffer on the child's address space, to hold
// the patch thunk, and related data.
virtual NTSTATUS Init(const void* target_module,
const void* interceptor_module,
const char* target_name,
const char* interceptor_name,
const void* interceptor_entry_point,
void* thunk_storage,
size_t storage_bytes);
// Gets the required buffer size for the internal part of the thunk.
size_t GetInternalThunkSize() const;
// Initializes the internal part of the thunk.
// interceptor is the function to be called instead of original_function.
bool SetInternalThunk(void* storage, size_t storage_bytes,
const void* original_function, const void* interceptor);
// Holds the resolved interception target.
void* target_;
// Holds the resolved interception interceptor.
const void* interceptor_;
DISALLOW_COPY_AND_ASSIGN(ResolverThunk);
};
} // namespace sandbox
#endif // SANDBOX_SRC_RESOLVER_H__