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prosody
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doc/stanza_routing.txt @ 12180:53e0ae770917
util.xml: Do not allow doctypes, comments or processing instructions
Yes. This is as bad as it sounds. CVE pending.
In Prosody itself, this only affects mod_websocket, which uses util.xml
to parse the <open/> frame, thus allowing unauthenticated remote DoS
using Billion Laughs. However, third-party modules using util.xml may
also be affected by this.
This commit installs handlers which disallow the use of doctype
declarations and processing instructions without any escape hatch. It,
by default, also introduces such a handler for comments, however, there
is a way to enable comments nontheless.
This is because util.xml is used to parse human-facing data, where
comments are generally a desirable feature, and also because comments
are generally harmless.
author | Jonas Schäfer <jonas@wielicki.name> |
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date | Mon, 10 Jan 2022 18:23:54 +0100 |
parent | 22:2856dfc1f5cc |
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No 'to' attribute: IQ: Pass to appropriate handler Presence: Broadcast to contacts - if initial presence, also send out presence probes - if probe would be to local user, generate presence stanza for them Message: Route as if it is addressed to the bare JID of the sender To a local host: IQ: Pass to appropriate handler Presence: - Message: Deliver to admin? To local contact: Bare JID: IQ: Pass to appropriate handler Presence: Broadcast to all resources Message: Route to 'best' resource Full JID: IQ: Send to resource Presence: Send to resource Message: Send to resource Full JID but resource not connected: IQ: Return service-unavailable Message: Handle same as if to bare JID Presence: Drop (unless type=subscribe[ed]) To remote contact: Initiate s2s connection if necessary Send stanza across