low-level network programming is sick. some wlan-drivers don't honor struct sizes

and simply write bytes _after_ the struct... this patch makes calling
SIOCGIWRANGE more failure-proof.

3 files changed, 47 insertions, 30 deletions

diff --git a/libopie2/opienet/onetutils.cpp b/libopie2/opienet/onetutils.cpp
index fd8f9e9..b317810 100644
--- a/libopie2/opienet/onetutils.cpp
+++ b/libopie2/opienet/onetutils.cpp
@@ -178,8 +178,9 @@ void dumpBytes( const unsigned char* data, int num )
 
     for ( int i = 0; i < num; ++i )
     {
         printf( "%02x ", data[i] );
         if ( !((i+1) % 32) ) printf( "\n" );
     }
     printf( "\n\n" );
 }
+
diff --git a/libopie2/opienet/onetwork.cpp b/libopie2/opienet/onetwork.cpp
index 66fa215..789e8ca 100644
--- a/libopie2/opienet/onetwork.cpp
+++ b/libopie2/opienet/onetwork.cpp
@@ -123,18 +123,18 @@ ONetwork::InterfaceIterator ONetwork::iterator() const
 {
     return ONetwork::InterfaceIterator( _interfaces );
 }
 
 
 bool ONetwork::isWirelessInterface( const char* name ) const
 {
     int sfd = socket( AF_INET, SOCK_STREAM, 0 );
-    iwreqstruct iwr;
-    memset( &iwr, 0, sizeof( iwreqstruct ) );
+    struct iwreq iwr;
+    memset( &iwr, 0, sizeof( struct iwreq ) );
     strcpy( (char*) &iwr.ifr_name, name );
     int result = ::ioctl( sfd, SIOCGIWNAME, &iwr );
     if ( result == -1 )
         qDebug( "ONetwork::ioctl(): SIOCGIWNAME failed: %d (%s)", result, strerror( errno ) );
     else
         qDebug( "ONetwork::ioctl(): SIOCGIWNAME ok." );
     return ( result != -1 );
 }
@@ -147,17 +147,17 @@ ONetworkInterface::ONetworkInterface( QObject* parent, const char* name )
                  :QObject( parent, name ),
                  _sfd( socket( AF_INET, SOCK_DGRAM, 0 ) ), _mon( 0 )
 {
     qDebug( "ONetworkInterface::ONetworkInterface()" );
     init();
 }
 
 
-ifreqstruct& ONetworkInterface::ifr() const
+struct ifreq& ONetworkInterface::ifr() const
 {
     return _ifr;
 }
 
 
 void ONetworkInterface::init()
 {
     qDebug( "ONetworkInterface::init()" );
@@ -167,17 +167,17 @@ void ONetworkInterface::init()
     if ( _sfd == -1 )
     {
         qDebug( "ONetworkInterface::init(): Warning - can't get socket for device '%s'", name() );
         return;
     }
 }
 
 
-bool ONetworkInterface::ioctl( int call, ifreqstruct& ifreq ) const
+bool ONetworkInterface::ioctl( int call, struct ifreq& ifreq ) const
 {
     int result = ::ioctl( _sfd, call, &ifreq );
     if ( result == -1 )
         qDebug( "ONetworkInterface::ioctl(): Call %d - Status: Failed: %d (%s)", call, result, strerror( errno ) );
     else
         qDebug( "ONetworkInterface::ioctl(): Call %d - Status: Ok.", call );
     return ( result != -1 );
 }
@@ -372,17 +372,17 @@ OWirelessNetworkInterface::OWirelessNetworkInterface( QObject* parent, const cha
 }
 
 
 OWirelessNetworkInterface::~OWirelessNetworkInterface()
 {
 }
 
 
-iwreqstruct& OWirelessNetworkInterface::iwr() const
+struct iwreq& OWirelessNetworkInterface::iwr() const
 {
     return _iwr;
 }
 
 
 void OWirelessNetworkInterface::init()
 {
     qDebug( "OWirelessNetworkInterface::init()" );
@@ -412,54 +412,77 @@ QString OWirelessNetworkInterface::associatedAP() const
         mac = "<Unknown>";
     }
     return mac;
 }
 
 
 void OWirelessNetworkInterface::buildChannelList()
 {
-    // IEEE802.11(b) radio frequency channels
-    struct iw_range range;
-
     //ML: If you listen carefully enough, you can hear lots of WLAN drivers suck
     //ML: The HostAP drivers need more than sizeof struct_iw range to complete
     //ML: SIOCGIWRANGE otherwise they fail with "Invalid Argument Length".
     //ML: The Wlan-NG drivers on the otherside fail (segfault!) if you allocate
     //ML: _too much_ space. This is damn shitty crap *sigh*
-
-    _iwr.u.data.pointer = (char*) &range;
-    _iwr.u.data.length = IW_MAX_FREQUENCIES; //sizeof range;
-    _iwr.u.data.flags = 0;
-
-    if ( !wioctl( SIOCGIWRANGE ) )
+    //ML: We allocate a large memory region in RAM and check whether the
+    //ML: driver pollutes this extra space. The complaint will be made on stdout,
+    //ML: so please forward this...
+
+    struct iwreq wrq;
+    int len = sizeof( struct iw_range )*2;
+    char *buffer = (char*) malloc( len );
+    //FIXME: Validate if we actually got the memory block
+    memset( buffer, 0, len );
+    memcpy( wrq.ifr_name, name(), IFNAMSIZ);
+    wrq.u.data.pointer = (caddr_t) buffer;
+    wrq.u.data.length = sizeof( struct iw_range );
+    wrq.u.data.flags = 0;
+
+    if ( ::ioctl( _sfd, SIOCGIWRANGE, &wrq ) == -1 )
     {
         qDebug( "OWirelessNetworkInterface::buildChannelList(): SIOCGIWRANGE failed (%s) - defaulting to 11 channels", strerror( errno ) );
         _channels.insert( 2412,  1 ); // 2.412 GHz
         _channels.insert( 2417,  2 ); // 2.417 GHz
         _channels.insert( 2422,  3 ); // 2.422 GHz
         _channels.insert( 2427,  4 ); // 2.427 GHz
         _channels.insert( 2432,  5 ); // 2.432 GHz
         _channels.insert( 2437,  6 ); // 2.437 GHz
         _channels.insert( 2442,  7 ); // 2.442 GHz
         _channels.insert( 2447,  8 ); // 2.447 GHz
         _channels.insert( 2452,  9 ); // 2.452 GHz
         _channels.insert( 2457, 10 ); // 2.457 GHz
         _channels.insert( 2462, 11 ); // 2.462 GHz
     }
     else
     {
+        // <check if the driver overwrites stuff>
+        int max = 0;
+        for ( int r = sizeof( struct iw_range ); r < len; r++ )
+            if (buffer[r] != 0)
+                max = r;
+        if (max > 0)
+        {
+            qWarning( "OWirelessNetworkInterface::buildChannelList(): Driver for wireless interface '%s'"
+                    "overwrote buffer end with at least %i bytes!\n", name(), max - sizeof( struct iw_range ) );
+        }
+        // </check if the driver overwrites stuff>
+
+        struct iw_range range;
+        memcpy( &range, buffer, sizeof range );
+
         qDebug( "OWirelessNetworkInterface::buildChannelList(): Interface %s reported to have %d channels.", name(), range.num_frequency );
         for ( int i = 0; i < range.num_frequency; ++i )
         {
             int freq = (int) ( double( range.freq[i].m ) * pow( 10.0, range.freq[i].e ) / 1000000.0 );
             _channels.insert( freq, i+1 );
         }
     }
+
     qDebug( "OWirelessNetworkInterface::buildChannelList(): Channel list constructed." );
+    free(buffer);
 }
 
 
 void OWirelessNetworkInterface::buildPrivateList()
 {
     qDebug( "OWirelessNetworkInterface::buildPrivateList()" );
 
     struct iw_priv_args priv[IW_MAX_PRIV_DEF];
@@ -500,17 +523,17 @@ int OWirelessNetworkInterface::channel() const
     }
 }
 
 
 void OWirelessNetworkInterface::setChannel( int c ) const
 {
     if ( !_mon )
     {
-        memset( &_iwr, 0, sizeof( iwreqstruct ) );
+        memset( &_iwr, 0, sizeof( struct iwreq ) );
         _iwr.u.freq.m = c;
         _iwr.u.freq.e = 0;
         wioctl( SIOCSIWFREQ );
     }
     else
     {
         _mon->setChannel( c );
     }
@@ -634,17 +657,17 @@ QString OWirelessNetworkInterface::SSID() const
 void OWirelessNetworkInterface::setSSID( const QString& ssid )
 {
     _iwr.u.essid.pointer = const_cast<char*>( (const char*) ssid );
     _iwr.u.essid.length = ssid.length();
     wioctl( SIOCSIWESSID );
 }
 
 
-bool OWirelessNetworkInterface::wioctl( int call, iwreqstruct& iwreq ) const
+bool OWirelessNetworkInterface::wioctl( int call, struct iwreq& iwreq ) const
 {
     int result = ::ioctl( _sfd, call, &iwreq );
     if ( result == -1 )
         qDebug( "ONetworkInterface::wioctl(): Call %d - Status: Failed: %d (%s)", call, result, strerror( errno ) );
     else
         qDebug( "ONetworkInterface::wioctl(): Call %d - Status: Ok.", call );
     return ( result != -1 );
 }
@@ -670,17 +693,17 @@ OMonitoringInterface::OMonitoringInterface( ONetworkInterface* iface )
 OMonitoringInterface::~OMonitoringInterface()
 {
 }
 
 
 void OMonitoringInterface::setChannel( int c )
 {
     // use standard WE channel switching protocol
-    memset( &_if->_iwr, 0, sizeof( iwreqstruct ) );
+    memset( &_if->_iwr, 0, sizeof( struct iwreq ) );
     _if->_iwr.u.freq.m = c;
     _if->_iwr.u.freq.e = 0;
     _if->wioctl( SIOCSIWFREQ );
 }
 
 
 bool OMonitoringInterface::enabled() const
 {
diff --git a/libopie2/opienet/onetwork.h b/libopie2/opienet/onetwork.h
index 7c70873..509c3db 100644
--- a/libopie2/opienet/onetwork.h
+++ b/libopie2/opienet/onetwork.h
@@ -67,23 +67,16 @@
 #define SIOCIWFIRSTPRIV SIOCDEVPRIVATE
 #endif
 
 class ONetworkInterface;
 class OWirelessNetworkInterface;
 class OChannelHopper;
 class OMonitoringInterface;
 
-typedef struct ifreq ifreqstruct;
-typedef struct iwreq iwreqstruct;
-typedef struct iw_event iweventstruct;
-typedef struct iw_freq iwfreqstruct;
-typedef struct iw_priv_args iwprivargsstruct;
-typedef struct iw_range iwrangestruct;
-
 /*======================================================================================
  * ONetwork
  *======================================================================================*/
 
 class ONetwork : public QObject
 {
   Q_OBJECT
 
@@ -131,24 +124,24 @@ class ONetworkInterface : public QObject
     bool isUp() const;
     bool isLoopback() const;
     bool isWireless() const;
     QString ipV4Address() const;
     OMacAddress macAddress() const;
 
   protected:
     const int _sfd;
-    mutable ifreqstruct _ifr;
+    mutable ifreq _ifr;
     OMonitoringInterface* _mon;
 
   protected:
-    ifreqstruct& ifr() const;
+    struct ifreq& ifr() const;
     virtual void init();
     bool ioctl( int call ) const;
-    bool ioctl( int call, ifreqstruct& ) const;
+    bool ioctl( int call, struct ifreq& ) const;
 };
 
 /*======================================================================================
  * OChannelHopper
  *======================================================================================*/
 
 class OChannelHopper : public QObject
 {
@@ -217,22 +210,22 @@ class OWirelessNetworkInterface : public ONetworkInterface
 
     virtual void setSSID( const QString& );
     virtual QString SSID() const;
 
   protected:
     void buildChannelList();
     void buildPrivateList();
     virtual void init();
-    iwreqstruct& iwr() const;
+    struct iwreq& iwr() const;
     bool wioctl( int call ) const;
-    bool wioctl( int call, iwreqstruct& ) const;
+    bool wioctl( int call, struct iwreq& ) const;
 
   protected:
-    mutable iwreqstruct _iwr;
+    mutable struct iwreq _iwr;
     QMap<int,int> _channels;
 
   private:
     OChannelHopper* _hopper;
 };
 
 
 /*======================================================================================