MimeDatabase: Do not crash/assert on invalid mime magic data

Change-Id: I355241e472b1bb379ccc94fdd896c6d894206b0a
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/libs/utils/mimetypes/mimemagicrule.cpp

@@ -233,14 +233,13 @@ QByteArray MimeMagicRule::makePattern(const QByteArray &value)
 }
 
 MimeMagicRule::MimeMagicRule(MimeMagicRule::Type theType,
-                               const QByteArray &theValue,
+                             const QByteArray &theValue,
-                               int theStartPos,
+                             int theStartPos,
-                               int theEndPos,
+                             int theEndPos,
-                               const QByteArray &theMask) :
+                             const QByteArray &theMask,
+                             QString *errorString) :
     d(new MimeMagicRulePrivate)
 {
-    Q_ASSERT(!theValue.isEmpty());
-
     d->type = theType;
     d->value = theValue;
     d->startPos = theStartPos;
@@ -248,10 +247,23 @@ MimeMagicRule::MimeMagicRule(MimeMagicRule::Type theType,
     d->mask = theMask;
     d->matchFunction = 0;
 
+    if (d->value.isEmpty()) {
+        d->type = Invalid;
+        if (errorString)
+            *errorString = QLatin1String("Invalid empty magic rule value");
+        return;
+    }
+
     if (d->type >= Host16 && d->type <= Byte) {
         bool ok;
         d->number = d->value.toUInt(&ok, 0); // autodetect
-        Q_ASSERT(ok);
+        if (!ok) {
+            d->type = Invalid;
+            if (errorString)
+                *errorString = QString::fromLatin1("Invalid magic rule value \"%1\"").arg(
+                        QString::fromLatin1(d->value));
+            return;
+        }
         d->numberMask = !d->mask.isEmpty() ? d->mask.toUInt(&ok, 0) : 0; // autodetect
     }
 
@@ -260,9 +272,23 @@ MimeMagicRule::MimeMagicRule(MimeMagicRule::Type theType,
         d->pattern = makePattern(d->value);
         d->pattern.squeeze();
         if (!d->mask.isEmpty()) {
-            Q_ASSERT(d->mask.size() >= 4 && d->mask.startsWith("0x"));
+            if (d->mask.size() < 4 || !d->mask.startsWith("0x")) {
-            d->mask = QByteArray::fromHex(QByteArray::fromRawData(d->mask.constData() + 2, d->mask.size() - 2));
+                d->type = Invalid;
-            Q_ASSERT(d->mask.size() == d->pattern.size());
+                if (errorString)
+                    *errorString = QString::fromLatin1("Invalid magic rule mask \"%1\"").arg(
+                            QString::fromLatin1(d->mask));
+                return;
+            }
+            const QByteArray &tempMask = QByteArray::fromHex(QByteArray::fromRawData(
+                                                     d->mask.constData() + 2, d->mask.size() - 2));
+            if (tempMask.size() != d->pattern.size()) {
+                d->type = Invalid;
+                if (errorString)
+                    *errorString = QString::fromLatin1("Invalid magic rule mask size \"%1\"").arg(
+                            QString::fromLatin1(d->mask));
+                return;
+            }
+            d->mask = tempMask;
         } else {
             d->mask.fill(char(-1), d->pattern.size());
         }

src/libs/utils/mimetypes/mimemagicrule_p.h

@@ -65,7 +65,8 @@ class QTCREATOR_UTILS_EXPORT MimeMagicRule
 public:
     enum Type { Invalid = 0, String, Host16, Host32, Big16, Big32, Little16, Little32, Byte };
 
-    MimeMagicRule(Type type, const QByteArray &value, int startPos, int endPos, const QByteArray &mask = QByteArray());
+    MimeMagicRule(Type type, const QByteArray &value, int startPos, int endPos,
+                  const QByteArray &mask = QByteArray(), QString *errorString = 0);
     MimeMagicRule(const MimeMagicRule &other);
     ~MimeMagicRule();
 

src/libs/utils/mimetypes/mimetypeparser.cpp

@@ -176,10 +176,6 @@ static bool createMagicMatchRule(const QXmlStreamAttributes &atts,
         return true;
     }
     const QString value = atts.value(QLatin1String(matchValueAttributeC)).toString();
-    if (value.isEmpty()) {
-        *errorMessage = QString::fromLatin1("Empty match value detected.");
-        return false;
-    }
     // Parse for offset as "1" or "1:10"
     int startPos, endPos;
     const QString offsetS = atts.value(QLatin1String(matchOffsetAttributeC)).toString();
@@ -190,8 +186,12 @@ static bool createMagicMatchRule(const QXmlStreamAttributes &atts,
         return false;
     const QString mask = atts.value(QLatin1String(matchMaskAttributeC)).toString();
 
-    rule = new MimeMagicRule(magicType, value.toUtf8(), startPos, endPos, mask.toLatin1());
+    MimeMagicRule *tempRule = new MimeMagicRule(magicType, value.toUtf8(), startPos, endPos,
+                                                mask.toLatin1(), errorMessage);
+    if (!tempRule->isValid())
+        return false;
 
+    rule = tempRule;
     return true;
 }
 #endif