QNetworkInterface[unix]: fixup some memcpys

There is an untested config for enabling null-strings, so technically
not supported. But if we ever want to make null mean null
then we should protect against it.

Also drop the explicit template argument for qMin. This means
we use the hetereogeneus version which will promote to
size_t. Which is the type that memcpy expects anyway.

Change-Id: I91e0a3b159b065b76e9e93605ef0e502f41af74f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/src/network/kernel/qnetworkinterface_unix.cpp b/src/network/kernel/qnetworkinterface_unix.cpp
index 7eeba027b6..c0a7d9e00d 100644
--- a/src/network/kernel/qnetworkinterface_unix.cpp
+++ b/src/network/kernel/qnetworkinterface_unix.cpp
@@ -78,7 +78,8 @@ uint QNetworkInterfaceManager::interfaceIndexFromName(const QString &name)
 
     const QByteArray name8bit = name.toLatin1();
     memset(&req, 0, sizeof(ifreq));
-    memcpy(req.ifr_name, name8bit.data(), qMin<int>(name8bit.length() + 1, sizeof(req.ifr_name) - 1));
+    if (!name8bit.isNull())
+        memcpy(req.ifr_name, name8bit.data(), qMin(size_t(name8bit.length()) + 1, sizeof(req.ifr_name) - 1));
 
     uint id = 0;
     if (qt_safe_ioctl(socket, SIOCGIFINDEX, &req) >= 0)
@@ -235,7 +236,8 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
     for ( ; it != names.constEnd(); ++it) {
         ifreq req;
         memset(&req, 0, sizeof(ifreq));
-        memcpy(req.ifr_name, it->constData(), qMin<int>(it->length() + 1, sizeof(req.ifr_name) - 1));
+        if (!it->isNull())
+            memcpy(req.ifr_name, it->constData(), qMin(size_t(it->length()) + 1, sizeof(req.ifr_name) - 1));
 
         QNetworkInterfacePrivate *iface = findInterface(socket, interfaces, req);
 
@@ -246,7 +248,8 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
             iface->name = QString::fromLatin1(req.ifr_name);
 
             // reset the name:
-            memcpy(req.ifr_name, oldName.constData(), qMin<int>(oldName.length() + 1, sizeof(req.ifr_name) - 1));
+            if (!oldName.isNull())
+                memcpy(req.ifr_name, oldName.constData(), qMin(size_t(oldName.length()) + 1, sizeof(req.ifr_name) - 1));
         } else
 #endif
         {