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
@@ -185 +185,2 @@ void dumpBytes( const unsigned char* data, int num )
 }
+
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
@@ -130,4 +130,4 @@ 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 );
@@ -154,3 +154,3 @@ ONetworkInterface::ONetworkInterface( QObject* parent, const char* name )
 
-ifreqstruct& ONetworkInterface::ifr() const
+struct ifreq& ONetworkInterface::ifr() const
 {
@@ -174,3 +174,3 @@ void ONetworkInterface::init()
 
-bool ONetworkInterface::ioctl( int call, ifreqstruct& ifreq ) const
+bool ONetworkInterface::ioctl( int call, struct ifreq& ifreq ) const
 {
@@ -379,3 +379,3 @@ OWirelessNetworkInterface::~OWirelessNetworkInterface()
 
-iwreqstruct& OWirelessNetworkInterface::iwr() const
+struct iwreq& OWirelessNetworkInterface::iwr() const
 {
@@ -419,5 +419,2 @@ 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
@@ -427,8 +424,17 @@ void OWirelessNetworkInterface::buildChannelList()
     //ML: _too much_ space. This is damn shitty crap *sigh*
-
-    _iwr.u.data.pointer = (char*) ⦥
-    _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 )
     {
@@ -449,2 +455,17 @@ void OWirelessNetworkInterface::buildChannelList()
     {
+        // <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 );
@@ -456,3 +477,5 @@ void OWirelessNetworkInterface::buildChannelList()
     }
+
     qDebug( "OWirelessNetworkInterface::buildChannelList(): Channel list constructed." );
+    free(buffer);
 }
@@ -507,3 +530,3 @@ void OWirelessNetworkInterface::setChannel( int c ) const
     {
-        memset( &_iwr, 0, sizeof( iwreqstruct ) );
+        memset( &_iwr, 0, sizeof( struct iwreq ) );
         _iwr.u.freq.m = c;
@@ -641,3 +664,3 @@ void OWirelessNetworkInterface::setSSID( const QString& ssid )
 
-bool OWirelessNetworkInterface::wioctl( int call, iwreqstruct& iwreq ) const
+bool OWirelessNetworkInterface::wioctl( int call, struct iwreq& iwreq ) const
 {
@@ -677,3 +700,3 @@ 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;
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
@@ -74,9 +74,2 @@ 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;
-
 /*======================================================================================
@@ -138,3 +131,3 @@ class ONetworkInterface : public QObject
     const int _sfd;
-    mutable ifreqstruct _ifr;
+    mutable ifreq _ifr;
     OMonitoringInterface* _mon;
@@ -142,6 +135,6 @@ class ONetworkInterface : public QObject
   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;
 };
@@ -224,8 +217,8 @@ class OWirelessNetworkInterface : public ONetworkInterface
     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;