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construct/matrix/vm_conforms.cc

193 lines
4.6 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2022 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
namespace ircd::m::vm
{
extern m::hookfn<eval &> conform_check_event_id;
extern m::hookfn<eval &> conform_check_origin;
extern m::hookfn<eval &> conform_check_size;
extern m::hookfn<eval &> conform_report;
}
/// Check if event_id is sufficient for the room version.
decltype(ircd::m::vm::conform_check_event_id)
ircd::m::vm::conform_check_event_id
{
{
{ "_site", "vm.conform" }
},
[](const m::event &event, eval &eval)
{
// Don't care about EDU's on this hook
if(!event.event_id)
return;
// Conditions for when we don't care if the event_id conforms. This
// hook only cares if the event_id is sufficient for the version, and
// we don't care about the early matrix versions with mxids here.
const bool unaffected
{
!eval.room_version
|| eval.room_version == "0"
|| eval.room_version == "1"
|| eval.room_version == "2"
};
if(eval.room_version == "3")
if(!event::id::v3::is(event.event_id))
throw error
{
fault::INVALID, "Event ID %s is not sufficient for version 3 room.",
string_view{event.event_id}
};
// note: we check v4 format for all other room versions, including "4"
if(!unaffected && eval.room_version != "3")
if(!event::id::v4::is(event.event_id))
throw error
{
fault::INVALID, "Event ID %s in a version %s room is not a version 4 Event ID.",
string_view{event.event_id},
eval.room_version,
};
}
};
/// Check if an eval with a copts structure (indicating this server is
/// creating the event) has an origin set to !my_host().
decltype(ircd::m::vm::conform_check_origin)
ircd::m::vm::conform_check_origin
{
{
{ "_site", "vm.conform" }
},
[](const m::event &event, eval &eval)
{
if(eval.opts && !eval.opts->conforming)
return;
if(unlikely(eval.copts && !my_host(at<"origin"_>(event))))
throw error
{
fault::INVALID, "Issuing event for origin: %s", at<"origin"_>(event)
};
}
};
/// Check if an event originating from this server exceeds maximum size.
decltype(ircd::m::vm::conform_check_size)
ircd::m::vm::conform_check_size
{
{
{ "_site", "vm.conform" },
},
[](const m::event &event, eval &eval)
{
const size_t &event_size
{
serialized(event)
};
if(event_size > size_t(event::max_size))
throw m::BAD_JSON
{
"Event is %zu bytes which is larger than the maximum %zu bytes",
event_size,
size_t(event::max_size)
};
}
};
/// Generate the conformity report and place the result into the eval. This
/// hook may do some IO to find out if an event is the target of a redaction.
decltype(ircd::m::vm::conform_report)
ircd::m::vm::conform_report
{
{
{ "_site", "vm.conform" }
},
[](const m::event &event, eval &eval)
{
assert(eval.opts);
const auto &opts(*eval.opts);
// When opts.conformed is set the report is already generated
if(opts.conformed)
{
eval.report = opts.report;
return;
}
// Mask of checks to be bypassed
auto non_conform
{
opts.non_conform
};
// This hook is called prior to event_id determination; must be skipped
non_conform.set(event::conforms::INVALID_OR_MISSING_EVENT_ID);
// For internal rooms for now.
if(eval.room_internal)
non_conform.set(event::conforms::MISMATCH_ORIGIN_SENDER);
// Generate the report here.
eval.report = event::conforms
{
event, non_conform.report
};
// When opts.conforming is false a bad report is not an error.
if(!opts.conforming)
return;
const bool allow_redaction
{
// allowed by origin server
eval.report.has(event::conforms::MISMATCH_HASHES)
&& opts.require_content <= 0
&& opts.node_id == json::get<"origin"_>(event)?
true:
// allowed by my server
eval.room_internal?
true:
// allowed by options
non_conform.has(event::conforms::MISMATCH_HASHES)
|| opts.require_content == 0?
true:
// allowed by room auth
event.event_id?
bool(m::redacted(event.event_id)):
// otherwise deny
false
};
auto report
{
eval.report
};
// When allowed, this hook won't throw, but the eval.report will
// still indicate MISMATCH_HASHES.
if(allow_redaction)
report.del(event::conforms::MISMATCH_HASHES);
if(!report.clean())
throw error
{
fault::INVALID, "Non-conforming event: %s",
string(report)
};
}
};