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priv.cpp

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// recommended includes in stdafx.h (or in the precompiled header, to be precise):
// windows.h, tchar.h, string, vector, algorithm, exception, sstream, iomanip

#include "stdafx.h"
#define FKSEC_NO_AUTO_INCLUDES 1
#include "fksec.h"
#include "ex.h"
#include "priv.h"

using namespace fksec;



// --- ctors/dtor ---

priv::priv()
{
    Init();
}


priv::priv( const priv &s )
{
    privNum = s.privNum;
    privName = s.privName;
    dispName = s.dispName;
    ht = 0;
    try { SetHandle( s.ht ); }
    RETHROWEX( "priv::priv(const priv&): invalid token handle" )
}


priv::priv( const LUID s )
{
    privNum = s;
    try { LookupNames(); }
    RETHROWEX( "priv::priv(const LUID): LookupNames() failed; invalid privilege LUID?" )

    ht = 0;
}


priv::priv( unsigned __int64 s )
{
    privNum.LowPart = (DWORD) ( s & 0xffffffffUI64 );
    privNum.HighPart = (DWORD) ( s >> 32 );

    try { LookupNames(); }
    RETHROWEX( "priv::priv(unsigned __int64): LookupNames() failed; invalid privilege LUID?" )

    ht = 0;
}


priv::priv( const TCHAR *name )
{
    try { LookupValue( name ); }
    RETHROWEX( "priv::priv(const TCHAR *): LookupValue() failed; invalid privilege name?" )

    ht = 0;
}


priv::~priv()
{
    try { closeToken(); }
    catch ( ex *e ) { delete e; } // eat exceptions
}



// --- assignment ---

const priv &priv::operator=( const priv &s )
{
    if ( this != &s )
    {
        privNum = s.privNum;
        privName = s.privName;
        dispName = s.dispName;
        try { closeToken(); }
        RETHROWEX( "priv::operator=(): closeToken() failed" )
        try { SetHandle( s.ht ); }
        RETHROWEX( "priv::operator=(const priv&): invalid token handle" )
    }

    return *this;
}


const priv &priv::operator=( const LUID s )
{
    privNum = s;
    try { LookupNames(); }
    RETHROWEX( "priv::operator=(const LUID): LookupNames() failed; invalid privilege LUID?" )
    return *this;
}


const priv &priv::operator=( unsigned __int64 s )
{
    privNum.LowPart = (DWORD) ( s & 0xffffffffUI64 );
    privNum.HighPart = (DWORD) ( s >> 32 );

    try { LookupNames(); }
    RETHROWEX( "priv::operator=(unsigned __int64): LookupNames() failed; invalid privilege LUID?" )
    return *this;
}


const priv &priv::operator=( const TCHAR *name )
{
    try { LookupValue( name ); }
    RETHROWEX( "priv::operator=(const TCHAR *): LookupValue() failed; invalid privilege name?" )

    return *this;
}



// --- comparisons ---

bool priv::operator==( const priv &r ) const
{
    return privNum.LowPart == r.privNum.LowPart && privNum.HighPart == r.privNum.HighPart;
}


bool priv::operator!=( const priv &r ) const
{
    return privNum.LowPart != r.privNum.LowPart || privNum.HighPart != r.privNum.HighPart;
}



// --- inserters ---

fkostream &fksec::operator<<( fkostream &o, const priv& p )
{
    bool state, haveState;

    try { state = p.GetState(); haveState = true; }
    catch ( ex & ) { haveState = false; }

    o << _T( "Privilege: " ) << p.privNum.LowPart << _T( ", " ) <<
        p.privName << _T( " (" ) << p.dispName << _T( ")" );
    if ( haveState )
        o << _T( ", state: " ) << ( state? _T( "enabled" ): _T( "disabled" ) );
    return o;
}



// --- utilities ---

const TCHAR *priv::GetPrivilegeName() const
{
    return privName.c_str();
}


const TCHAR *priv::GetDisplayName() const
{
    return dispName.c_str();
}


bool priv::Enable()
{
    try { return SetState( true ); }
    RETHROWEX( "priv::Enable(): SetState() failed" )
}


bool priv::Disable()
{
    try { return SetState( false ); }
    RETHROWEX( "priv::Disable(): SetState() failed" )
}


bool priv::Toggle()
{
    bool oldState;

    try { oldState = GetState(); }
    RETHROWEX( "priv::Toggle(): GetState() failed" )

    try { return SetState( ! oldState ); }
    RETHROWEX( "priv::Toggle(): SetState() failed" )
}


bool priv::SetState( bool newState )
{
    TOKEN_PRIVILEGES tp, otp;
    DWORD returnLength = sizeof otp;

    try { openToken(); }
    RETHROWEX( "priv::SetState(): openToken() failed" )

    tp.PrivilegeCount = 1;
    tp.Privileges[0].Luid = privNum;
    tp.Privileges[0].Attributes = newState? SE_PRIVILEGE_ENABLED: 0;

    if ( ::AdjustTokenPrivileges( ht, FALSE, &tp, sizeof tp, &otp, &returnLength ) )
    {
        if ( GetLastError() == ERROR_SUCCESS )
            // all is well, return previous state
            return !! ( ( SE_PRIVILEGE_ENABLED | SE_PRIVILEGE_ENABLED_BY_DEFAULT ) &
                otp.Privileges[0].Attributes );
        throw NEWEX32( errStubbornPriv, "priv::SetState(): AdjustTokenPrivileges() succeeded but did not set the privilege state, see ex::GetErrWin32()", GetLastError() );
    }

    throw NEWEX32( errStubbornPriv, "priv::SetState(): AdjustTokenPrivileges() failed, see ex::GetErrWin32()", GetLastError() );

    // unreachable code -- but VC 5.0 complains if this is absent
    return false;
}


bool priv::GetState() const
{
    // this limits us to 50 privs; currently defined (NT5 RC3) are 27, plus 4 logon rights.
    byte buf[sizeof TOKEN_PRIVILEGES + 50 * sizeof LUID_AND_ATTRIBUTES];
    TOKEN_PRIVILEGES &tp = *( (TOKEN_PRIVILEGES *) buf );
    DWORD returnLength, i;

    try { openToken(); }
    RETHROWEX( "priv::GetState(): openToken() failed" )

    if ( ::GetTokenInformation( ht, TokenPrivileges, &buf[0], sizeof buf, &returnLength ) )
    {
        for ( i = 0; i < tp.PrivilegeCount; ++ i )
        {
            if ( privNum.LowPart == tp.Privileges[i].Luid.LowPart &&
                privNum.HighPart == tp.Privileges[i].Luid.HighPart )
                return !! ( ( SE_PRIVILEGE_ENABLED | SE_PRIVILEGE_ENABLED_BY_DEFAULT ) & tp.Privileges[i].Attributes );
        }
        return false; // a missing priv is considered disabled
    }

    throw NEWEX32( errQueryToken, "priv::GetState(): GetTokenInformation() failed, see ex::GetErrWin32()", GetLastError() );

    // unreachable code -- but VC 5.0 complains if this is absent
    return false;
}


void priv::SetHandle( HANDLE h )
{
    try { closeToken(); }
    RETHROWEX( "priv::SetHandle(): closeToken() failed" )

    if ( h != 0 )
    {
        if ( ! ::DuplicateHandle( GetCurrentProcess(), h, GetCurrentProcess(),
            &ht, TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, FALSE, 0 ) )
            throw NEWEX32( errDupTokenHandle, "priv::SetHandle(): DuplicateHandle() failed, see ex::GetErrWin32()", GetLastError() );
    }
    else
        ht = h; // == 0
}


void priv::Init()
{
    ht = 0;
    privNum.LowPart = privNum.HighPart = 0;
    privName.erase();
    dispName.erase();
}


void priv::openToken() const
{
    DWORD rc;
    const TCHAR *func = _T( "what?" );

    if ( ht != 0 )
        return;

    rc = 0;
    func = _T( "OpenThreadToken()" );
    if ( ! ::OpenThreadToken( GetCurrentThread(), TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, FALSE, &ht ) )
        rc = GetLastError();

    // OTT() failed with something recoverable?
    if ( rc == ERROR_ACCESS_DENIED || rc == ERROR_NO_TOKEN || rc == ERROR_NO_IMPERSONATION_TOKEN )
    {
        rc = 0;
        func = _T( "OpenThreadToken() as self" );
        if ( ! ::OpenThreadToken( GetCurrentThread(), TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, TRUE, &ht ) )
            rc = GetLastError();

        // OTT() failed again? try OPT()
        if ( rc == ERROR_ACCESS_DENIED || rc == ERROR_NO_TOKEN || rc == ERROR_NO_IMPERSONATION_TOKEN )
        {
            rc = 0;
            func = _T( "OpenProcessToken()" );
            if ( ! ::OpenProcessToken( GetCurrentProcess(), TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, &ht ) )
                rc = GetLastError();
        }
    }

    if ( rc != 0 )
    {
        ht = 0;
        fkstr errstr = _T( "priv::openToken(): " ) + fkstr( func ) + _T( " failed, see ex::GetErrWin32()" );
        throw new ex( _T( __FILE__ ), __LINE__, errOpenToken, errstr.c_str(), rc );
    }
}


void priv::closeToken() const
{
    if ( ht != 0 )
    {
        if ( ! CloseHandle( ht ) )
        {
            ht = 0;
            throw NEWEX32( errCloseToken, "priv::closeToken(): CloseHandle() failed, see ex::GetErrWin32()", GetLastError() );
        }
        ht = 0;
    }
}


void priv::LookupNames() const
{
    const static DWORD initialBufLen = 128;
    DWORD namelen, buflen, langID, rc;
    BOOL result;
    TCHAR *name;

    buflen = initialBufLen;
    name = 0;
    do
    {
        buflen *= 2;
        delete [] name;
        name = new TCHAR[buflen];
        if ( name == 0 )
            throw NEWEX( errNoMemory, "priv::LookupNames(): no memory for priv name buffer" );
        namelen = buflen;
        result = ::LookupPrivilegeName( 0,
            const_cast<LUID *>( &privNum ), name, &namelen );
        rc = result? 0: GetLastError();
    } while ( ! result && rc == ERROR_INSUFFICIENT_BUFFER );

    if ( rc == 0 )
        privName = name;

    delete [] name;

    if ( rc != 0 )
        throw NEWEX32( errInvalidPriv, "priv::LookupNames(): privilege name not found", rc );

    buflen = initialBufLen;
    name = 0;
    do
    {
        buflen *= 2;
        delete [] name;
        name = new TCHAR[buflen];
        if ( name == 0 )
            throw NEWEX( errNoMemory, "priv::LookupNames(): no memory for priv display-name buffer" );
        namelen = buflen;
        result = ::LookupPrivilegeDisplayName( 0,
            privName.c_str(), name, &namelen, &langID );
        rc = result? 0: GetLastError();
    } while ( ! result && rc == ERROR_INSUFFICIENT_BUFFER );

    if ( rc == 0 )
        dispName = name;

    delete [] name;

    if ( rc != 0 )
        throw NEWEX32( errInvalidPriv, "priv::LookupNames(): privilege display-name not found", rc );
}


void priv::LookupValue( const TCHAR *name )
{
    if ( ! ::LookupPrivilegeValue( 0, name, &privNum ) )
        throw NEWEX32( errInvalidPriv, "priv::LookupValue(): privilege not found", GetLastError() );

    try { LookupNames(); }
    RETHROWEX( "priv::LookupValue(): cannot get names for privilege" )
}

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