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strophe / libstrophe

A simple, lightweight C library for writing XMPP clients
http://strophe.im/libstrophe
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Handle missing `<bind>` #224

Closed sjaeckel closed 1 year ago

sjaeckel commented 1 year ago

This patch handles the case where the server sends its list of features, but the <bind> feature is missing. A server doing so is violating RFC6120 (c.f. [0]), but it happened in [1]. Previously we ended up in a segfault, now we terminate the connection.

Reproducing this was done with netcat and profanity:

shell1    $ nc -l -p 5222
profanity $ /connect foo@127.0.0.1 tls disable

-> nc receives: '<?xml version="1.0"?><stream:stream to="127.0.0.1" xml:lang="en" version="1.0" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams">'

nc send: <?xml version="1.0"?>
<stream:stream from="127.0.0.1" id="foobarbaz" lang="en" version="1.0" xmlns:stream="http://etherx.jabber.org/streams">
<features xmlns="http://etherx.jabber.org/streams"><mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl"><mechanism>PLAIN</mechanism></mechanisms></features>

-> nc receives: '<auth mechanism="PLAIN" xmlns="urn:ietf:params:xml:ns:xmpp-sasl">XXXXXXXXXX</auth>'

nc send: <success xmlns="urn:ietf:params:xml:ns:xmpp-sasl"/>

-> nc receives: '<?xml version="1.0"?><stream:stream to="127.0.0.1" xml:lang="en" version="1.0" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams"><stream:stream from="127.0.0.1" id="foobarbaz" lang="en" version="1.0" xmlns:stream="http://etherx.jabber.org/streams">'

nc send: <?xml version="1.0"?>
<stream:stream from="127.0.0.1" id="foobarbaz" lang="en" version="1.0" xmlns:stream="http://etherx.jabber.org/streams">
<features xmlns="http://etherx.jabber.org/streams"/>

-> pre-patch this lead to a segfault of profanity, now the stream gets closed.

[0] https://datatracker.ietf.org/doc/html/rfc6120#section-7.2 [1] https://github.com/profanity-im/profanity/issues/1849