Software / code / prosody
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doc/net.server.lua @ 13801:a5d5fefb8b68 13.0
mod_tls: Enable Prosody's certificate checking for incoming s2s connections (fixes #1916) (thanks Damian, Zash)
Various options in Prosody allow control over the behaviour of the certificate
verification process For example, some deployments choose to allow falling
back to traditional "dialback" authentication (XEP-0220), while others verify
via DANE, hard-coded fingerprints, or other custom plugins.
Implementing this flexibility requires us to override OpenSSL's default
certificate verification, to allow Prosody to verify the certificate itself,
apply custom policies and make decisions based on the outcome.
To enable our custom logic, we have to suppress OpenSSL's default behaviour of
aborting the connection with a TLS alert message. With LuaSec, this can be
achieved by using the verifyext "lsec_continue" flag.
We also need to use the lsec_ignore_purpose flag, because XMPP s2s uses server
certificates as "client" certificates (for mutual TLS verification in outgoing
s2s connections).
Commit 99d2100d2918 moved these settings out of the defaults and into mod_s2s,
because we only really need these changes for s2s, and they should be opt-in,
rather than automatically applied to all TLS services we offer.
That commit was incomplete, because it only added the flags for incoming
direct TLS connections. StartTLS connections are handled by mod_tls, which was
not applying the lsec_* flags. It previously worked because they were already
in the defaults.
This resulted in incoming s2s connections with "invalid" certificates being
aborted early by OpenSSL, even if settings such as `s2s_secure_auth = false`
or DANE were present in the config.
Outgoing s2s connections inherit verify "none" from the defaults, which means
OpenSSL will receive the cert but will not terminate the connection when it is
deemed invalid. This means we don't need lsec_continue there, and we also
don't need lsec_ignore_purpose (because the remote peer is a "server").
Wondering why we can't just use verify "none" for incoming s2s? It's because
in that mode, OpenSSL won't request a certificate from the peer for incoming
connections. Setting verify "peer" is how you ask OpenSSL to request a
certificate from the client, but also what triggers its built-in verification.
| author | Matthew Wild <mwild1@gmail.com> |
|---|---|
| date | Tue, 01 Apr 2025 17:26:56 +0100 |
| parent | 9846:9a0da809ed4a |
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-- Prosody IM -- Copyright (C) 2014,2016 Daurnimator -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. --luacheck: ignore --[[ This file is a template for writing a net.server compatible backend. ]] --[[ Read patterns (also called modes) can be one of: - "*a": Read as much as possible - "*l": Read until end of line ]] --- Handle API local handle_mt = {}; local handle_methods = {}; handle_mt.__index = handle_methods; function handle_methods:set_mode(new_pattern) end function handle_methods:setlistener(listeners) end function handle_methods:setoption(option, value) end function handle_methods:ip() end function handle_methods:starttls(sslctx) end function handle_methods:write(data) end function handle_methods:close() end function handle_methods:pause() end function handle_methods:resume() end --[[ Returns - socket: the socket object underlying this handle ]] function handle_methods:socket() end --[[ Returns - boolean: if an ssl context has been set on this handle ]] function handle_methods:ssl() end --- Listeners API local listeners = {} --[[ connect Called when a client socket has established a connection with it's peer ]] function listeners.onconnect(handle) end --[[ incoming Called when data is received If reading data failed this will be called with `nil, "error message"` ]] function listeners.onincoming(handle, buff, err) end --[[ status Known statuses: - "ssl-handshake-complete" ]] function listeners.onstatus(handle, status) end --[[ disconnect Called when the peer has closed the connection ]] function listeners.ondisconnect(handle) end --[[ drain Called when the handle's write buffer is empty ]] function listeners.ondrain(handle) end --[[ readtimeout Called when a socket inactivity timeout occurs ]] function listeners.onreadtimeout(handle) end --[[ detach: Called when other listeners are going to be removed Allows for clean-up ]] function listeners.ondetach(handle) end --- Top level functions --[[ Returns the syscall level event mechanism in use. Returns: - backend: e.g. "select", "epoll" ]] local function get_backend() end --[[ Starts the event loop. Returns: - "quitting" ]] local function loop() end --[[ Stop a running loop() ]] local function setquitting(quit) end --[[ Links to two handles together, so anything written to one is piped to the other Arguments: - sender, receiver: handles to link - buffersize: maximum #bytes until sender will be locked ]] local function link(sender, receiver, buffersize) end --[[ Binds and listens on the given address and port If `sslctx` is given, the connecting clients will have to negotiate an SSL session Arguments: - address: address to bind to, may be "*" to bind all addresses. will be resolved if it is a string. - port: port to bind (as number) - listeners: a table of listeners - pattern: the read pattern - sslctx: is a valid luasec constructor Returns: - handle - nil, "an error message": on failure (e.g. out of file descriptors) ]] local function addserver(address, port, listeners, pattern, sslctx) end --[[ Binds and listens on the given address and port Mostly the same as addserver but with all optional arguments in a table Arguments: - address: address to bind to, may be "*" to bind all addresses. will be resolved if it is a string. - port: port to bind (as number) - listeners: a table of listeners - config: table of extra settings - read_size: the amount of bytes to read or a read pattern - tls_ctx: is a valid luasec constructor - tls_direct: boolean true for direct TLS, false (or nil) for starttls Returns: - handle - nil, "an error message": on failure (e.g. out of file descriptors) ]] local function listen(address, port, listeners, config) end --[[ Wraps a lua-socket socket client socket in a handle. The socket must be already connected to the remote end. If `sslctx` is given, a SSL session will be negotiated before listeners are called. Arguments: - socket: the lua-socket object to wrap - ip: returned by `handle:ip()` - port: - listeners: a table of listeners - pattern: the read pattern - sslctx: is a valid luasec constructor - typ: the socket type, one of: - "tcp" - "tcp6" - "udp" Returns: - handle, socket - nil, "an error message": on failure (e.g. ) ]] local function wrapclient(socket, ip, serverport, listeners, pattern, sslctx) end --[[ Connects to the given address and port If `sslctx` is given, a SSL session will be negotiated before listeners are called. Arguments: - address: address to connect to. will be resolved if it is a string. - port: port to connect to (as number) - listeners: a table of listeners - pattern: the read pattern - sslctx: is a valid luasec constructor - typ: the socket type, one of: - "tcp" - "tcp6" - "udp" Returns: - handle - nil, "an error message": on failure (e.g. out of file descriptors) ]] local function addclient(address, port, listeners, pattern, sslctx, typ) end --[[ Close all handles ]] local function closeall() end --[[ The callback should be called after `delay` seconds. The callback should be called with the time at the point of firing. If the callback returns a number, it should be called again after that many seconds. Arguments: - delay: number of seconds to wait - callback: function to call. ]] local function add_task(delay, callback) end --[[ Adds a handler for when a signal is fired. Optional to implement callback does not take any arguments Arguments: - signal_id: the signal id (as number) to listen for - handler: callback ]] local function hook_signal(signal_id, handler) end --[[ Adds a low-level FD watcher Arguments: - fd_number: A non-negative integer representing a file descriptor or object with a :getfd() method returning one - on_readable: Optional callback for when the FD is readable - on_writable: Optional callback for when the FD is writable Returns: - net.server handle ]] local function watchfd(fd_number, on_readable, on_writable) end return { get_backend = get_backend; loop = loop; setquitting = setquitting; link = link; addserver = addserver; wrapclient = wrapclient; addclient = addclient; closeall = closeall; hook_signal = hook_signal; watchfd = watchfd; listen = listen; }