CWE-ou-minkata/Sources/Plasma/PubUtilLib/plFile/plSecureStream.h

/*==LICENSE==*

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*==LICENSE==*/
#ifndef plSecureStream_h_inc
#define plSecureStream_h_inc

#include "HeadSpin.h"
#include "hsStream.h"

#if HS_BUILD_FOR_WIN32
    typedef void* HANDLE;
#   define hsFD HANDLE
#else
#   define hsFD FILE*
#endif

// A slightly more secure stream then plEncryptedStream in that it uses windows file functions
// to prevent other processes from accessing the file it is working with. It also can be set
// to download the file from a server into a temporary directory (with a mangled name) and
// delete that file on close, thereby minimizing the chance of having that file examined or
// edited.
class plSecureStream: public hsStream
{
protected:
    hsFD fRef;
    uint32_t fKey[4];

    uint32_t fActualFileSize;

    bool fBufferedStream;

    hsStream* fRAMStream;

    plFileName fWriteFileName;

    enum OpenMode {kOpenRead, kOpenWrite, kOpenFail};
    OpenMode fOpenMode;

    bool fDeleteOnExit;

    void IBufferFile();

    uint32_t IRead(uint32_t bytes, void* buffer);

    void IEncipher(uint32_t* const v, uint32_t n);
    void IDecipher(uint32_t* const v, uint32_t n);

    bool IWriteEncrypted(hsStream* sourceStream, const plFileName& outputFile);

    static bool ICheckMagicString(hsFD fp);
    static bool ICheckMagicString(hsStream* s);

public:
    plSecureStream(bool deleteOnExit = false, uint32_t* key = nil); // uses default key if you don't pass one in
    plSecureStream(hsStream* base, uint32_t* key = nil);
    ~plSecureStream();

    virtual bool Open(const plFileName& name, const char* mode = "rb");
    bool         Open(hsStream* stream);
    virtual bool Close();

    virtual uint32_t Read(uint32_t byteCount, void* buffer);
    virtual uint32_t Write(uint32_t byteCount, const void* buffer);
    virtual bool AtEnd();
    virtual void Skip(uint32_t deltaByteCount);
    virtual void Rewind();
    virtual void FastFwd();
    virtual uint32_t GetEOF();

    uint32_t GetActualFileSize() const {return fActualFileSize;}

    static bool FileEncrypt(const plFileName& fileName, uint32_t* key = nil);
    static bool FileDecrypt(const plFileName& fileName, uint32_t* key = nil);

    enum OpenSecureFileFlags
    {
        kRequireEncryption = 0x01,
        kDeleteOnExit = 0x02,
    };

    static bool IsSecureFile(const plFileName& fileName);

    // Attempts to create a read-binary stream for the requested file (delete the stream
    // when you are done with it!)
    static hsStream* OpenSecureFile(const plFileName& fileName, const uint32_t flags = kRequireEncryption, uint32_t* key = nil);
    // Attempts to create a write-binary stream for the requested file (delete the stream
    // when you are done with it!)
    static hsStream* OpenSecureFileWrite(const plFileName& fileName, uint32_t* key = nil);

    static const uint32_t kDefaultKey[4]; // our default encryption key

    // searches the parent directory of filename for the encryption key file, and reads it
    // into the key passed in. Returns false if the key file didn't exist (and sets key to
    // the default key)
    static bool GetSecureEncryptionKey(const plFileName& filename, uint32_t* key, unsigned length);

    static const char kKeyFilename[];
};

#endif // plSecureStream_h_inc