rsantanna
commented
3 years ago So, the same happened to me and I just found that the parsing of Priority Rules and Gateways lead to an infinite loop in my case. I'm not an expert in Qt (actually that was my first time debugging a C++ code) but my workaround did work. Here is what I've done to fix. I'll improve the code later to open a PR.
tl;dr: the XML parsing seems to make assumptions that fail. I've added safety checks to guarantee that the parsing occurs as expected.
XML
The gateways section returned in my case looks exactly like this:
...
<gateways>
<cutoff-time>5</cutoff-time>
<internal>
<list>
<entry name="my-vpn-int.example.com">
<description>Internal_Gateway</description>
</entry>
</list>
</internal>
<external>
<list>
<entry name="my-vpn.example.com">
<priority-rule>
<entry name="Any">
<priority>1</priority>
</entry>
</priority-rule>
<priority>1</priority>
<description>External_Gateway</description>
</entry>
</list>
</external>
</gateways>
...Priority Rules
The problem:
This is the original code:
QMap<QString, int> PortalConfigResponse::parsePriorityRules(QXmlStreamReader &xmlReader)
{
PLOGI << "Start parsing the priority rules...";
QMap<QString, int> priorityRules;
while (xmlReader.name() != "priority-rule" || !xmlReader.isEndElement()) {
xmlReader.readNext();
if (xmlReader.name() == "entry" && xmlReader.isStartElement()) {
QString ruleName = xmlReader.attributes().value("name").toString();
// Read the priority tag
xmlReader.readNextStartElement();
int ruleValue = xmlReader.readElementText().toUInt(); // <-- It fails here!
priorityRules.insert(ruleName, ruleValue);
}
}
PLOGI << "Finished parsing the priority rules.";
return priorityRules;
}The method assumes that the tag <priority> comes immediately after <entry>, which in my case is not true. So, it fails at the line marked leading to an QXmlStreamReader::UnexpectedElementError. This cause the xmlReader to stop reading more tokens and since the while loop has no check for errors, it gets stuck and the code doesn't finish.
The workaround:
QMap<QString, int> PortalConfigResponse::parsePriorityRules(QXmlStreamReader &xmlReader)
{
PLOGI << "Start parsing the priority rules...";
QMap<QString, int> priorityRules;
while ((xmlReader.name() != "priority-rule" || !xmlReader.isEndElement()) && !xmlReader.hasError()) {
xmlReader.readNext();
if (xmlReader.name() == "entry" && xmlReader.isStartElement()) {
QString ruleName = xmlReader.attributes().value("name").toString();
// Read the priority tag
while (xmlReader.name() != "priority"){
xmlReader.readNext();
}
//xmlReader.readNextStartElement();
int ruleValue = xmlReader.readElementText().toUInt();
priorityRules.insert(ruleName, ruleValue);
}
}
PLOGI << "Finished parsing the priority rules.";
return priorityRules;
}I put an error check to prevent infinite loop and added a nested while to search for the tag <priority> before calling readElementText().
Gateways
The problem:
This is the original code:
QList<GPGateway> PortalConfigResponse::parseGateways(QXmlStreamReader &xmlReader)
{
PLOGI << "Start parsing the gateways from portal configuration...";
QList<GPGateway> gateways;
while (xmlReader.name() != xmlGateways || !xmlReader.isEndElement()) {
xmlReader.readNext();
// Parse the gateways -> external -> list -> entry
if (xmlReader.name() == "entry" && xmlReader.isStartElement()) {
GPGateway g;
QString address = xmlReader.attributes().value("name").toString();
g.setAddress(address);
g.setPriorityRules(parsePriorityRules(xmlReader));
g.setName(parseGatewayName(xmlReader));
gateways.append(g);
}
}
PLOGI << "Finished parsing the gateways.";
return gateways;
}Here the code executes without problem, but instead of getting the external gateway it takes the internal first and fails to connect since the internal gateway is unreachable.
The (very ugly) workaround:
QList<GPGateway> PortalConfigResponse::parseGateways(QXmlStreamReader &xmlReader)
{
PLOGI << "Start parsing the gateways from portal configuration...";
QList<GPGateway> gateways;
while (xmlReader.name() != "external"){
xmlReader.readNext();
}
while (xmlReader.name() != "list"){
xmlReader.readNext();
}
while (xmlReader.name() != xmlGateways || !xmlReader.isEndElement()) {
xmlReader.readNext();
// Parse the gateways -> external -> list -> entry
if (xmlReader.name() == "entry" && xmlReader.isStartElement()) {
GPGateway g;
QString address = xmlReader.attributes().value("name").toString();
g.setAddress(address);
g.setPriorityRules(parsePriorityRules(xmlReader));
g.setName(parseGatewayName(xmlReader));
gateways.append(g);
}
}
PLOGI << "Finished parsing the gateways.";
return gateways;
}I added two loops before the original one to make sure that the entries read by the method correspond to those of the external list only.
Kind regards,
Rapha
CardboardTurkey
mikedld
betrcode
Hi, gpclient does not connect, but hangs on "Start parsing the priority rules..." Complete log follows
Let me know if you need any more information. Palo Alto firewall is running 10.0.1. But I have seen the same issue on 9.1.4.
BTW, openconnect --protocol=gp works without any issues.
Thanks
/Jo Christian