1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_BOUNDS_CHECKER_H_ 6 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BOUNDS_CHECKER_H_ 7 8 #include <stdint.h> 9 10 #include "mojo/public/cpp/system/macros.h" 11 12 namespace mojo { 13 14 class Handle; 15 16 namespace internal { 17 18 // BoundsChecker is used to validate object sizes, pointers and handle indices 19 // for payload of incoming messages. 20 class BoundsChecker { 21 public: 22 // [data, data + data_num_bytes) specifies the initial valid memory range. 23 // [0, num_handles) specifies the initial valid range of handle indices. 24 BoundsChecker(const void* data, uint32_t data_num_bytes, 25 size_t num_handles); 26 27 ~BoundsChecker(); 28 29 // Claims the specified memory range. 30 // The method succeeds if the range is valid to claim. (Please see 31 // the comments for IsValidRange().) 32 // On success, the valid memory range is shrinked to begin right after the end 33 // of the claimed range. 34 bool ClaimMemory(const void* position, uint32_t num_bytes); 35 36 // Claims the specified encoded handle (which is basically a handle index). 37 // The method succeeds if: 38 // - |encoded_handle|'s value is |kEncodedInvalidHandleValue|. 39 // - the handle is contained inside the valid range of handle indices. In this 40 // case, the valid range is shinked to begin right after the claimed handle. 41 bool ClaimHandle(const Handle& encoded_handle); 42 43 // Returns true if the specified range is not empty, and the range is 44 // contained inside the valid memory range. 45 bool IsValidRange(const void* position, uint32_t num_bytes) const; 46 47 private: 48 bool InternalIsValidRange(uintptr_t begin, uintptr_t end) const; 49 50 // [data_begin_, data_end_) is the valid memory range. 51 uintptr_t data_begin_; 52 uintptr_t data_end_; 53 54 // [handle_begin_, handle_end_) is the valid handle index range. 55 uint32_t handle_begin_; 56 uint32_t handle_end_; 57 58 MOJO_DISALLOW_COPY_AND_ASSIGN(BoundsChecker); 59 }; 60 61 } // namespace internal 62 } // namespace mojo 63 64 #endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_BOUNDS_CHECKER_H_ 65
