Win32: fix possible crash when listing USB devices.

Make sure to handle if retrieving the device description ends up with a NULL
data buffer pointer. Also switch handling the retrieved string using QString.

Fixes a crash reported in the forums.

Change-Id: I6e95a411308e85656cd78ddcecb1bcee165864d0

1 files changed, 18 insertions, 12 deletions

diff --git a/rbutil/rbutilqt/base/system.cpp b/rbutil/rbutilqt/base/system.cpp
index c36c95b9a1..855d9e3b06 100644
--- a/rbutil/rbutilqt/base/system.cpp
+++ b/rbutil/rbutilqt/base/system.cpp
@@ -432,7 +432,7 @@ QMap<uint32_t, QString> System::listUsbDevices(void)
         DWORD buffersize = 0;
         QString description;
 
-        // get device desriptor first
+        // get device descriptor first
         // for some reason not doing so results in bad things (tm)
         while(!SetupDiGetDeviceRegistryProperty(deviceInfo, &infoData,
             SPDRP_DEVICEDESC, &data, (PBYTE)buffer, buffersize, &buffersize)) {
@@ -445,6 +445,11 @@ QMap<uint32_t, QString> System::listUsbDevices(void)
                 break;
             }
         }
+        if(!buffer) {
+            LOG_WARNING() << "Got no device description"
+                          << "(SetupDiGetDeviceRegistryProperty), item" << i;
+            continue;
+        }
         description = QString::fromWCharArray(buffer);
 
         // now get the hardware id, which contains PID and VID.
@@ -460,18 +465,19 @@ QMap<uint32_t, QString> System::listUsbDevices(void)
             }
         }
 
-        unsigned int vid, pid;
-        // convert buffer text to upper case to avoid depending on the case of
-        // the keys (W7 uses different casing than XP at least).
-        int len = _tcslen(buffer);
-        while(len--) buffer[len] = _totupper(buffer[len]);
-        if(_stscanf(buffer, _TEXT("USB\\VID_%x&PID_%x"), &vid, &pid) == 2) {
-            uint32_t id;
-            id = vid << 16 | pid;
-            usbids.insert(id, description);
-            LOG_INFO("USB VID: %04x, PID: %04x", vid, pid);
+        if(buffer) {
+            // convert buffer text to upper case to avoid depending on the case of
+            // the keys (W7 uses different casing than XP at least).
+            QString data = QString::fromWCharArray(buffer);
+            QRegExp rex("USB\\\\VID_([0-9a-fA-F]{4})&PID_([0-9a-fA-F]{4}).*");
+            if(rex.indexIn(data) >= 0) {
+                uint32_t id;
+                id = rex.cap(1).toUInt(0, 16) << 16 | rex.cap(2).toUInt(0, 16);
+                usbids.insert(id, description);
+                LOG_INFO() << "USB:" << QString("0x%1").arg(id, 8, 16);
+            }
+            free(buffer);
         }
-        if(buffer) free(buffer);
     }
     SetupDiDestroyDeviceInfoList(deviceInfo);