1 /*
2  * Copyright (C) 2007 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include <stdint.h>
20 #include <sys/types.h>
21 #include <sys/mman.h>
22 
23 #include <utils/RefBase.h>
24 #include <utils/Errors.h>
25 #include <binder/Common.h>
26 #include <binder/IInterface.h>
27 
28 namespace android {
29 
30 // ----------------------------------------------------------------------------
31 
32 class LIBBINDER_EXPORTED IMemoryHeap : public IInterface {
33 public:
34     DECLARE_META_INTERFACE(MemoryHeap)
35 
36     // flags returned by getFlags()
37     enum {
38         READ_ONLY   = 0x00000001
39     };
40 
41     virtual int         getHeapID() const = 0;
42     virtual void*       getBase() const = 0;
43     virtual size_t      getSize() const = 0;
44     virtual uint32_t    getFlags() const = 0;
45     virtual off_t       getOffset() const = 0;
46 
47     // these are there just for backward source compatibility
heapID()48     int32_t heapID() const { return getHeapID(); }
base()49     void*   base() const  { return getBase(); }
virtualSize()50     size_t  virtualSize() const { return getSize(); }
51 };
52 
53 class LIBBINDER_EXPORTED BnMemoryHeap : public BnInterface<IMemoryHeap> {
54 public:
55     // NOLINTNEXTLINE(google-default-arguments)
56     virtual status_t onTransact(
57             uint32_t code,
58             const Parcel& data,
59             Parcel* reply,
60             uint32_t flags = 0);
61 
62     BnMemoryHeap();
63 protected:
64     virtual ~BnMemoryHeap();
65 };
66 
67 // ----------------------------------------------------------------------------
68 
69 class LIBBINDER_EXPORTED IMemory : public IInterface {
70 public:
71     DECLARE_META_INTERFACE(Memory)
72 
73     // NOLINTNEXTLINE(google-default-arguments)
74     virtual sp<IMemoryHeap> getMemory(ssize_t* offset=nullptr, size_t* size=nullptr) const = 0;
75 
76     // helpers
77 
78     // Accessing the underlying pointer must be done with caution, as there are
79     // some inherent security risks associated with it. When receiving an
80     // IMemory from an untrusted process, there is currently no way to guarantee
81     // that this process would't change the content after the fact. This may
82     // lead to TOC/TOU class of security bugs. In most cases, when performance
83     // is not an issue, the recommended practice is to immediately copy the
84     // buffer upon reception, then work with the copy, e.g.:
85     //
86     // std::string private_copy(mem.size(), '\0');
87     // memcpy(private_copy.data(), mem.unsecurePointer(), mem.size());
88     //
89     // In cases where performance is an issue, this matter must be addressed on
90     // an ad-hoc basis.
91     void* unsecurePointer() const;
92 
93     size_t size() const;
94     ssize_t offset() const;
95 
96 private:
97     // These are now deprecated and are left here for backward-compatibility
98     // with prebuilts that may reference these symbol at runtime.
99     // Instead, new code should use unsecurePointer()/unsecureFastPointer(),
100     // which do the same thing, but make it more obvious that there are some
101     // security-related pitfalls associated with them.
102     void* pointer() const;
103     void* fastPointer(const sp<IBinder>& heap, ssize_t offset) const;
104 };
105 
106 class LIBBINDER_EXPORTED BnMemory : public BnInterface<IMemory> {
107 public:
108     // NOLINTNEXTLINE(google-default-arguments)
109     virtual status_t onTransact(
110             uint32_t code,
111             const Parcel& data,
112             Parcel* reply,
113             uint32_t flags = 0);
114 
115     BnMemory();
116 protected:
117     virtual ~BnMemory();
118 };
119 
120 // ----------------------------------------------------------------------------
121 
122 } // namespace android
123