qasn1element: add QAsn1Element::toInteger

This change adds the ability to decode ASN.1 INTEGER fields,
provided they represent a positive number of less than 64-bit.

This is needed for PKCS#12 decoding.

Change-Id: Iafb76f22383278d6773b9e879a8f3ef43c8d2c8f
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>

2 files changed, 25 insertions, 0 deletions

diff --git a/src/network/ssl/qasn1element.cpp b/src/network/ssl/qasn1element.cpp
index d282a02827..cd8ebed501 100644
--- a/src/network/ssl/qasn1element.cpp
+++ b/src/network/ssl/qasn1element.cpp
@@ -242,6 +242,30 @@ QMultiMap<QByteArray, QString> QAsn1Element::toInfo() const
     return info;
 }
 
+qint64 QAsn1Element::toInteger(bool *ok) const
+{
+    if (mType != QAsn1Element::IntegerType || mValue.isEmpty()) {
+        if (ok)
+            *ok = false;
+        return 0;
+    }
+
+    // NOTE: negative numbers are not handled
+    if (mValue.at(0) & 0x80) {
+        if (ok)
+            *ok = false;
+        return 0;
+    }
+
+    qint64 value = mValue.at(0) & 0x7f;
+    for (int i = 1; i < mValue.size(); ++i)
+        value = (value << 8) | quint8(mValue.at(i));
+
+    if (ok)
+        *ok = true;
+    return value;
+}
+
 QVector<QAsn1Element> QAsn1Element::toVector() const
 {
     QVector<QAsn1Element> items;
diff --git a/src/network/ssl/qasn1element_p.h b/src/network/ssl/qasn1element_p.h
index 6b3179ac35..949fd69875 100644
--- a/src/network/ssl/qasn1element_p.h
+++ b/src/network/ssl/qasn1element_p.h
@@ -97,6 +97,7 @@ public:
 
     QDateTime toDateTime() const;
     QMultiMap<QByteArray, QString> toInfo() const;
+    qint64 toInteger(bool *ok = 0) const;
     QVector<QAsn1Element> toVector() const;
     QByteArray toObjectId() const;
     QByteArray toObjectName() const;