1 // Copyright 2013 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 PPAPI_PROXY_NACL_MESSAGE_SCANNER_H_
6 #define PPAPI_PROXY_NACL_MESSAGE_SCANNER_H_
7 
8 #include <stdint.h>
9 
10 #include <map>
11 #include <memory>
12 #include <vector>
13 
14 #include "base/macros.h"
15 #include "base/synchronization/lock.h"
16 #include "ppapi/c/pp_resource.h"
17 #include "ppapi/proxy/ppapi_proxy_export.h"
18 
19 namespace IPC {
20 class Message;
21 }
22 
23 namespace ppapi {
24 namespace proxy {
25 
26 class SerializedHandle;
27 
28 class PPAPI_PROXY_EXPORT NaClMessageScanner {
29  public:
30   NaClMessageScanner();
31   ~NaClMessageScanner();
32 
33   // Scans the message for items that require special handling. Copies any
34   // SerializedHandles in the message into |handles| and if the message must be
35   // rewritten for NaCl, sets |new_msg_ptr| to the new message. If no handles
36   // are found, |handles| is left unchanged. If no rewriting is needed,
37   // |new_msg_ptr| is left unchanged.
38   //
39   // For normal messages, |type| is equivalent to |msg|.id(), but, if |msg| is
40   // a reply to a synchronous message, |type| is the id of the original
41   // message.
42   //
43   // See more explanation in the method definition.
44   //
45   // See chrome/nacl/nacl_ipc_adapter.cc for where this is used to help convert
46   // native handles to NaClDescs.
47   bool ScanMessage(const IPC::Message& msg,
48                    uint32_t type,
49                    std::vector<SerializedHandle>* handles,
50                    std::unique_ptr<IPC::Message>* new_msg_ptr);
51 
52   // Scans an untrusted message for items that require special handling. If the
53   // message had to be rewritten, sets |new_msg_ptr| to the new message.
54   void ScanUntrustedMessage(const IPC::Message& untrusted_msg,
55                             std::unique_ptr<IPC::Message>* new_msg_ptr);
56 
57   // FileSystem information for quota auditing.
58   class PPAPI_PROXY_EXPORT FileSystem {
59    public:
60     FileSystem();
61     ~FileSystem();
62 
reserved_quota()63     int64_t reserved_quota() const { return reserved_quota_; }
64 
65     // Adds amount to reserved quota. Returns true if reserved quota >= 0.
66     bool UpdateReservedQuota(int64_t delta);
67 
68    private:
69     base::Lock lock_;
70     // This is the remaining amount of quota reserved for the file system.
71     // Acquire the lock to modify this field, since it may be used on multiple
72     // threads.
73     int64_t reserved_quota_;
74 
75     DISALLOW_COPY_AND_ASSIGN(FileSystem);
76   };
77 
78   // FileIO information for quota auditing.
79   class PPAPI_PROXY_EXPORT FileIO {
80    public:
81     FileIO(FileSystem* file_system, int64_t max_written_offset);
82     ~FileIO();
83 
max_written_offset()84     int64_t max_written_offset() { return max_written_offset_; }
85 
86     void SetMaxWrittenOffset(int64_t max_written_offset);
87 
88     // Grows file by the given amount. Returns true on success.
89     bool Grow(int64_t amount);
90 
91    private:
92     base::Lock lock_;
93 
94     // The file system that contains this file.
95     FileSystem* file_system_;
96 
97     // The maximum written offset. This is initialized by NaClMessageScanner
98     // when the file is opened and modified by a NaClDescQuotaInterface when the
99     // plugin writes to greater maximum offsets.
100     int64_t max_written_offset_;
101 
102     DISALLOW_COPY_AND_ASSIGN(FileIO);
103   };
104 
105   FileIO* GetFile(PP_Resource file_io);
106 
107  private:
108   friend class NaClMessageScannerTest;
109   void AuditNestedMessage(PP_Resource resource,
110                           const IPC::Message& msg,
111                           SerializedHandle* handle);
112 
113   // We intercept FileSystem and FileIO messages to maintain information about
114   // file systems and open files. This is used by NaClQuotaDescs to calculate
115   // quota consumption and check it against the reserved amount.
116   typedef std::map<int32_t, FileSystem*> FileSystemMap;
117   FileSystemMap file_systems_;
118   typedef std::map<int32_t, FileIO*> FileIOMap;
119   FileIOMap files_;
120 
121   DISALLOW_COPY_AND_ASSIGN(NaClMessageScanner);
122 };
123 
124 }  // namespace proxy
125 }  // namespace ppapi
126 
127 #endif  // PPAPI_PROXY_NACL_MESSAGE_SCANNER_H_
128