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// Copyright (c) 2012 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.
#ifndef SANDBOX_SRC_CROSSCALL_SERVER_H_
#define SANDBOX_SRC_CROSSCALL_SERVER_H_
#include <stdint.h>
#include <string>
#include <vector>
#include "base/callback.h"
#include "base/macros.h"
#include "sandbox/win/src/crosscall_params.h"
#include "sandbox/win/src/ipc_tags.h"
// This is the IPC server interface for CrossCall: The IPC for the Sandbox
// On the server, CrossCall needs two things:
// 1) threads: Or better said, someone to provide them, that is what the
// ThreadProvider interface is defined for. These thread(s) are
// the ones that will actually execute the IPC data retrieval.
//
// 2) a dispatcher: This interface represents the way to route and process
// an IPC call given the IPC tag.
//
// The other class included here CrossCallParamsEx is the server side version
// of the CrossCallParams class of /sandbox/crosscall_params.h The difference
// is that the sever version is paranoid about the correctness of the IPC
// message and will do all sorts of verifications.
//
// A general diagram of the interaction is as follows:
//
// ------------
// | |
// ThreadProvider <--(1)Register--| IPC |
// | | Implemen |
// | | -tation |
// (2) | | OnMessage
// IPC fired --callback ------>| |--(3)---> Dispatcher
// | |
// ------------
//
// The IPC implementation sits as a middleman between the handling of the
// specifics of scheduling a thread to service the IPC and the multiple
// entities that can potentially serve each particular IPC.
namespace sandbox {
class InterceptionManager;
// This function signature is required as the callback when an IPC call fires.
// context: a user-defined pointer that was set using ThreadProvider
// reason: 0 if the callback was fired because of a timeout.
// 1 if the callback was fired because of an event.
typedef void(__stdcall* CrossCallIPCCallback)(void* context,
unsigned char reason);
// ThreadProvider models a thread factory. The idea is to decouple thread
// creation and lifetime from the inner guts of the IPC. The contract is
// simple:
// - the IPC implementation calls RegisterWait with a waitable object that
// becomes signaled when an IPC arrives and needs to be serviced.
// - when the waitable object becomes signaled, the thread provider conjures
// a thread that calls the callback (CrossCallIPCCallback) function
// - the callback function tries its best not to block and return quickly
// and should not assume that the next callback will use the same thread
// - when the callback returns the ThreadProvider owns again the thread
// and can destroy it or keep it around.
class ThreadProvider {
public:
// Registers a waitable object with the thread provider.
// client: A number to associate with all the RegisterWait calls, typically
// this is the address of the caller object. This parameter cannot
// be zero.
// waitable_object : a kernel object that can be waited on
// callback: a function pointer which is the function that will be called
// when the waitable object fires
// context: a user-provider pointer that is passed back to the callback
// when its called
virtual bool RegisterWait(const void* client,
HANDLE waitable_object,
CrossCallIPCCallback callback,
void* context) = 0;
// Removes all the registrations done with the same cookie parameter.
// This frees internal thread pool resources.
virtual bool UnRegisterWaits(void* cookie) = 0;
virtual ~ThreadProvider() {}
};
// Models the server-side of the original input parameters.
// Provides IPC buffer validation and it is capable of reading the parameters
// out of the IPC buffer.
class CrossCallParamsEx : public CrossCallParams {
public:
// Factory constructor. Pass an IPCbuffer (and buffer size) that contains a
// pending IPCcall. This constructor will:
// 1) validate the IPC buffer. returns nullptr is the IPCbuffer is malformed.
// 2) make a copy of the IPCbuffer (parameter capture)
static CrossCallParamsEx* CreateFromBuffer(void* buffer_base,
uint32_t buffer_size,
uint32_t* output_size);
// Provides IPCinput parameter raw access:
// index : the parameter to read; 0 is the first parameter
// returns nullptr if the parameter is non-existent. If it exists it also
// returns the size in *size
void* GetRawParameter(uint32_t index, uint32_t* size, ArgType* type);
// Gets a parameter that is four bytes in size.
// Returns false if the parameter does not exist or is not 32 bits wide.
bool GetParameter32(uint32_t index, uint32_t* param);
// Gets a parameter that is void pointer in size.
// Returns false if the parameter does not exist or is not void pointer sized.
bool GetParameterVoidPtr(uint32_t index, void** param);
// Gets a parameter that is a string. Returns false if the parameter does not
// exist.
bool GetParameterStr(uint32_t index, std::wstring* string);
// Gets a parameter that is an in/out buffer. Returns false is the parameter
// does not exist or if the size of the actual parameter is not equal to the
// expected size.
bool GetParameterPtr(uint32_t index, uint32_t expected_size, void** pointer);
// Frees the memory associated with the IPC parameters.
static void operator delete(void* raw_memory) throw();
private:
// Only the factory method CreateFromBuffer can construct these objects.
CrossCallParamsEx();
ParamInfo param_info_[1];
DISALLOW_COPY_AND_ASSIGN(CrossCallParamsEx);
};
// Simple helper function that sets the members of CrossCallReturn
// to the proper state to signal a basic error.
void SetCallError(ResultCode error, CrossCallReturn* call_return);
// Sets the internal status of call_return to signify the that IPC call
// completed successfully.
void SetCallSuccess(CrossCallReturn* call_return);
// Represents the client process that initiated the IPC which boils down to the
// process handle and the job object handle that contains the client process.
struct ClientInfo {
HANDLE process;
DWORD process_id;
};
// All IPC-related information to be passed to the IPC handler.
struct IPCInfo {
IpcTag ipc_tag;
const ClientInfo* client_info;
CrossCallReturn return_info;
};
// This structure identifies IPC signatures.
struct IPCParams {
IpcTag ipc_tag;
ArgType args[kMaxIpcParams];
bool Matches(IPCParams* other) const {
return !memcmp(this, other, sizeof(*other));
}
};
// Models an entity that can process an IPC message or it can route to another
// one that could handle it. When an IPC arrives the IPC implementation will:
// 1) call OnMessageReady() with the tag of the pending IPC. If the dispatcher
// returns nullptr it means that it cannot handle this IPC but if it returns
// non-null, it must be the pointer to a dispatcher that can handle it.
// 2) When the IPC finally obtains a valid Dispatcher the IPC
// implementation creates a CrossCallParamsEx from the raw IPC buffer.
// 3) It calls the returned callback, with the IPC info and arguments.
class Dispatcher {
public:
// Called from the IPC implementation to handle a specific IPC message.
typedef bool (Dispatcher::*CallbackGeneric)();
typedef bool (Dispatcher::*Callback0)(IPCInfo* ipc);
typedef bool (Dispatcher::*Callback1)(IPCInfo* ipc, void* p1);
typedef bool (Dispatcher::*Callback2)(IPCInfo* ipc, void* p1, void* p2);
typedef bool (Dispatcher::*Callback3)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3);
typedef bool (Dispatcher::*Callback4)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3,
void* p4);
typedef bool (Dispatcher::*Callback5)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3,
void* p4,
void* p5);
typedef bool (Dispatcher::*Callback6)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3,
void* p4,
void* p5,
void* p6);
typedef bool (Dispatcher::*Callback7)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3,
void* p4,
void* p5,
void* p6,
void* p7);
typedef bool (Dispatcher::*Callback8)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3,
void* p4,
void* p5,
void* p6,
void* p7,
void* p8);
typedef bool (Dispatcher::*Callback9)(IPCInfo* ipc,
void* p1,
void* p2,
void* p3,
void* p4,
void* p5,
void* p6,
void* p7,
void* p8,
void* p9);
// Called from the IPC implementation when an IPC message is ready override
// on a derived class to handle a set of IPC messages. Return nullptr if your
// subclass does not handle the message or return the pointer to the subclass
// that can handle it.
virtual Dispatcher* OnMessageReady(IPCParams* ipc, CallbackGeneric* callback);
// Called when a target proces is created, to setup the interceptions related
// with the given service (IPC).
virtual bool SetupService(InterceptionManager* manager, IpcTag service) = 0;
Dispatcher();
virtual ~Dispatcher();
protected:
// Structure that defines an IPC Call with all the parameters and the handler.
struct IPCCall {
IPCParams params;
CallbackGeneric callback;
};
// List of IPC Calls supported by the class.
std::vector<IPCCall> ipc_calls_;
};
} // namespace sandbox
#endif // SANDBOX_SRC_CROSSCALL_SERVER_H_