Fix SSID decoding

Allocate sufficient buffer size.

Change-Id: Id2c885d132814553a93b9baa026fa044d667527b
Task-number: QTEE-1038
Reviewed-by: Teemu Holappa <teemu.holappa@theqtcompany.com>

4 files changed, 41 insertions, 39 deletions

diff --git a/src/wifi/qwifimanager.cpp b/src/wifi/qwifimanager.cpp
index 6bace8f..6f733ba 100644
--- a/src/wifi/qwifimanager.cpp
+++ b/src/wifi/qwifimanager.cpp
@@ -68,7 +68,7 @@ void QWifiManagerPrivate::handleAuthenticating(QWifiEvent *event)
     QString ssid = data.mid(data.indexOf(QLatin1String("SSID")) + 6);
     ssid = ssid.left(ssid.lastIndexOf(QLatin1Char('\'')));
 
-    setCurrentSSID(QWifiSupplicant::decodeHexEncoded(ssid));
+    setCurrentSSID(QWifiSupplicant::decodeSsid(ssid));
     updateNetworkState(QWifiManager::Authenticating);
 }
 
@@ -425,7 +425,7 @@ bool QWifiManager::connect(QWifiConfiguration *config)
     const QStringList configuredNetworks = d->call(QStringLiteral("LIST_NETWORKS")).split('\n');
     for (int i = 1; i < configuredNetworks.length(); ++i) {
         const QStringList networkFields = configuredNetworks.at(i).split('\t');
-        const QString ssid = QWifiSupplicant::decodeHexEncoded(networkFields.at(1));
+        const QString ssid = QWifiSupplicant::decodeSsid(networkFields.at(1));
         if (ssid == d->m_currentSSID) {
             id = networkFields.at(0);
             networkKnown = true;
diff --git a/src/wifi/qwifinetworklistmodel.cpp b/src/wifi/qwifinetworklistmodel.cpp
index a1f825f..fa3f7dc 100644
--- a/src/wifi/qwifinetworklistmodel.cpp
+++ b/src/wifi/qwifinetworklistmodel.cpp
@@ -124,7 +124,7 @@ void QWifiNetworkListModel::parseScanResults(const QString &results)
             continue;
         int pos = 0;
 
-        QString ssid = QWifiSupplicant::decodeHexEncoded(info.at(4));
+        QString ssid = QWifiSupplicant::decodeSsid(info.at(4));
         if (ssid.isEmpty())
             continue;
 
diff --git a/src/wifi/qwifisupplicant.cpp b/src/wifi/qwifisupplicant.cpp
index 7b303ed..b2ec497 100644
--- a/src/wifi/qwifisupplicant.cpp
+++ b/src/wifi/qwifisupplicant.cpp
@@ -300,22 +300,32 @@ int QWifiSupplicant::receiveEvent(char *reply, size_t *reply_len)
     return -2;
 }
 
-/*! \internal
- *
-    Decode wpa_supplicant encoded string, see file hostapd/src/utils/common.c
-    in git://w1.fi/hostap.git repository.
+static inline int hex2num(char c)
+{
+    if (c >= '0' && c <= '9')
+        return c - '0';
+    if (c >= 'a' && c <= 'f')
+        return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F')
+        return c - 'A' + 10;
+    return -1;
+}
 
-    For Ascii encoded string, any octet < 32 or > 127 is encoded as a "\\x"
-    followed by the hex representation of the octet. Exception chars are ",
-    \\, \\e, \\n, \\r, \\t which are escaped by a backslash
+static inline int hex2byte(const char *hex)
+{
+    int a, b;
+    a = hex2num(*hex++);
+    if (a < 0)
+        return -1;
+    b = hex2num(*hex++);
+    if (b < 0)
+        return -1;
+    return (a << 4) | b;
+}
 
- */
-QString QWifiSupplicant::decodeHexEncoded(const QString &encoded)
+static inline int printf_decode(char *buf, int maxlen, const char *str)
 {
-    int maxlen = encoded.size() + 1;
-    QByteArray buf;
-    buf.resize(maxlen);
-    const char *pos = encoded.toLocal8Bit().constData();
+    const char *pos = str;
     int len = 0;
     int val;
 
@@ -391,30 +401,24 @@ QString QWifiSupplicant::decodeHexEncoded(const QString &encoded)
     if (maxlen > len)
         buf[len] = '\0';
 
-    return QString::fromUtf8(buf);
+    return len;
 }
 
-int QWifiSupplicant::hex2num(char c)
-{
-    if (c >= '0' && c <= '9')
-        return c - '0';
-    if (c >= 'a' && c <= 'f')
-        return c - 'a' + 10;
-    if (c >= 'A' && c <= 'F')
-        return c - 'A' + 10;
-    return -1;
-}
+/*! \internal
+ *
+    Decode wpa_supplicant encoded string, see file hostapd/src/utils/common.c
+    in git://w1.fi/hostap.git repository.
 
-int QWifiSupplicant::hex2byte(const char *hex)
+    For Ascii encoded string, any octet < 32 or > 127 is encoded as a "\\x"
+    followed by the hex representation of the octet. Exception chars are ",
+    \\, \\e, \\n, \\r, \\t which are escaped by a backslash
+
+ */
+QString QWifiSupplicant::decodeSsid(const QString &encoded)
 {
-    int a, b;
-    a = hex2num(*hex++);
-    if (a < 0)
-        return -1;
-    b = hex2num(*hex++);
-    if (b < 0)
-        return -1;
-    return (a << 4) | b;
+    static char ssid[2048];
+    printf_decode(ssid, sizeof(ssid), encoded.toLatin1().constData());
+    return QString::fromUtf8(ssid);
 }
 
 QT_END_NAMESPACE
diff --git a/src/wifi/qwifisupplicant_p.h b/src/wifi/qwifisupplicant_p.h
index f904925..3b18380 100644
--- a/src/wifi/qwifisupplicant_p.h
+++ b/src/wifi/qwifisupplicant_p.h
@@ -43,12 +43,10 @@ public:
     void closeSupplicantConnection();
     int waitForEvent(char *buf, size_t buflen);
     bool sendCommand(const QString &command, QByteArray *reply);
-    static QString decodeHexEncoded(const QString &encoded);
+    static QString decodeSsid(const QString &encoded);
 
 protected:
     int receiveEvent(char *reply, size_t *reply_len);
-    static int hex2num(char c);
-    static int hex2byte(const char *hex);
 
 private:
     wpa_ctrl *ctrl_conn;