1 // Copyright 2019 Google LLC 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef SANDBOXED_API_VAR_ABSTRACT_H_ 16 #define SANDBOXED_API_VAR_ABSTRACT_H_ 17 18 #include <ctime> 19 #include <memory> 20 #include <string> 21 #include <type_traits> 22 23 #include "absl/base/attributes.h" 24 #include "absl/base/macros.h" 25 #include "absl/status/status.h" 26 #include "sandboxed_api/var_type.h" 27 28 namespace sandbox2 { 29 class Comms; 30 } // namespace sandbox2 31 32 namespace sapi { 33 class RPCChannel; 34 class Sandbox; 35 } // namespace sapi 36 37 namespace sapi::v { 38 39 class Ptr; 40 41 class ABSL_DEPRECATED( 42 "Use the Var::PtrXXX() family of methods instead") Pointable { 43 public: 44 enum SyncType { 45 // Do not synchronize the underlying object after/before calls. 46 kSyncNone = 0x0, 47 // Synchronize the underlying object (send the data to the sandboxee) 48 // before the call takes place. 49 kSyncBefore = 0x1, 50 // Synchronize the underlying object (retrieve data from the sandboxee) 51 // after the call has finished. 52 kSyncAfter = 0x2, 53 // Synchronize the underlying object with the remote object, by sending the 54 // data to the sandboxee before the call, and retrieving it from the 55 // sandboxee after the call has finished. 56 kSyncBoth = kSyncBefore | kSyncAfter, 57 }; 58 59 virtual ~Pointable() = default; 60 }; 61 62 // An abstract class representing variables. 63 class Var : public Pointable { 64 public: 65 Var(const Var&) = delete; 66 Var& operator=(const Var&) = delete; 67 68 virtual ~Var(); 69 70 // Returns the address of the storage (remote side). GetRemote()71 virtual void* GetRemote() const { return remote_; } 72 73 // Sets the address of the remote storage. SetRemote(void * remote)74 virtual void SetRemote(void* remote) { remote_ = remote; } 75 76 // Returns the address of the storage (local side). GetLocal()77 virtual void* GetLocal() const { return local_; } 78 79 // Returns the size of the local variable storage. 80 virtual size_t GetSize() const = 0; 81 82 // Returns the type of the variable. 83 virtual Type GetType() const = 0; 84 85 // Returns a string representation of the variable type. 86 virtual std::string GetTypeString() const = 0; 87 88 // Returns a string representation of the variable value. 89 virtual std::string ToString() const = 0; 90 91 // Functions to get pointers with certain type of synchronization schemes. 92 Ptr* PtrNone(); 93 Ptr* PtrBoth(); 94 Ptr* PtrBefore(); 95 Ptr* PtrAfter(); 96 97 protected: 98 Var() = default; 99 100 // Set pointer to local storage class. SetLocal(void * local)101 void SetLocal(void* local) { local_ = local; } 102 103 // Setter/Getter for the address of a Comms object which can be used to 104 // remotely free allocated memory backing up this variable, upon this 105 // object's end of life-time SetFreeRPCChannel(RPCChannel * rpc_channel)106 void SetFreeRPCChannel(RPCChannel* rpc_channel) { 107 free_rpc_channel_ = rpc_channel; 108 } GetFreeRPCChannel()109 RPCChannel* GetFreeRPCChannel() { return free_rpc_channel_; } 110 111 // Allocates the local variable on the remote side. The 'automatic_free' 112 // argument dictates whether the remote memory should be freed upon end of 113 // this object's lifetime. 114 virtual absl::Status Allocate(RPCChannel* rpc_channel, bool automatic_free); 115 116 // Frees the local variable on the remote side. 117 virtual absl::Status Free(RPCChannel* rpc_channel); 118 119 // Transfers the variable to the sandboxee's address space, has to be 120 // allocated there first. 121 virtual absl::Status TransferToSandboxee(RPCChannel* rpc_channel, pid_t pid); 122 123 // Transfers the variable from the sandboxee's address space. 124 virtual absl::Status TransferFromSandboxee(RPCChannel* rpc_channel, 125 pid_t pid); 126 127 private: 128 // Needed so that we can use unique_ptr with incomplete type. 129 struct PtrDeleter { 130 void operator()(Ptr* p); 131 }; 132 133 // Invokes Allocate()/Free()/Transfer*Sandboxee(). 134 friend class ::sapi::Sandbox; 135 136 std::unique_ptr<Ptr, PtrDeleter> ptr_none_; 137 std::unique_ptr<Ptr, PtrDeleter> ptr_both_; 138 std::unique_ptr<Ptr, PtrDeleter> ptr_before_; 139 std::unique_ptr<Ptr, PtrDeleter> ptr_after_; 140 141 // Pointer to local storage of the variable. 142 void* local_ = nullptr; 143 // Pointer to remote storage of the variable. 144 void* remote_ = nullptr; 145 146 // Comms which can be used to free resources allocated in the sandboxer upon 147 // this process' end of lifetime. 148 RPCChannel* free_rpc_channel_ = nullptr; 149 }; 150 151 } // namespace sapi::v 152 153 #endif // SANDBOXED_API_VAR_ABSTRACT_H_ 154