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mod_pubsub_post/mod_pubsub_post.lua @ 4651:8231774f5bfd
mod_cloud_notify_encrypted: Ensure body substring remains valid UTF-8
The `body:sub()` call risks splitting the string in the middle of a
multi-byte UTF-8 sequence. This should have been caught by util.stanza
validation, but that would have caused some havoc, at the very least causing
the notification to not be sent.
There have been no reports of this happening. Likely because this module
isn't widely deployed among users with languages that use many longer UTF-8
sequences.
The util.encodings.utf8.valid() function is O(n) where only the last
sequence really needs to be checked, but it's in C and expected to be fast.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sun, 22 Aug 2021 13:22:59 +0200 |
parent | 4552:c87181a98f29 |
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module:depends("http"); local st = require "util.stanza"; local json = require "util.json"; local xml = require "util.xml"; local http = require "net.http"; local uuid_generate = require "util.uuid".generate; local timestamp_generate = require "util.datetime".datetime; local hashes = require "util.hashes"; local from_hex = require "util.hex".from; local hmacs = { sha1 = hashes.hmac_sha1; sha256 = hashes.hmac_sha256; sha384 = hashes.hmac_sha384; sha512 = hashes.hmac_sha512; }; local pubsub_service = module:depends("pubsub").service; local mappings = module:get_option("pubsub_post_mappings", nil); local datamapper; if type(mappings) == "table" then datamapper = require "util.datamapper"; for node, f in pairs(mappings) do if type(f) == "string" then local fh = assert(module:load_resource(f)); mappings[node] = assert(json.parse(fh:read("*a"))); fh:close() end end end local function wrap(node, parsed, raw) if mappings and mappings[node] then return datamapper.unparse(mappings[node], parsed) end return st.stanza("json", { xmlns="urn:xmpp:json:0" }):text(raw); end local error_mapping = { ["forbidden"] = 403; ["item-not-found"] = 404; ["internal-server-error"] = 500; ["conflict"] = 409; }; local function publish_payload(node, actor, item_id, payload) local post_item = st.stanza("item", { xmlns = "http://jabber.org/protocol/pubsub", id = item_id, }) :add_child(payload); local ok, err = pubsub_service:publish(node, actor, item_id, post_item); module:log("debug", ":publish(%q, true, %q, %s) -> %q", node, item_id, payload:top_tag(), err or ""); if not ok then return error_mapping[err] or 500; end return 202; end local function handle_json(node, actor, data) local parsed, err = json.decode(data); if not parsed then return { status_code = 400; body = tostring(err); } end if type(parsed) ~= "table" then return { status_code = 400; body = "object or array expected"; }; end local payload = wrap(node, parsed, data) local item_id = "current"; if payload.attr["http://jabber.org/protocol/pubsub\1id"] then item_id = payload.attr["http://jabber.org/protocol/pubsub\1id"]; payload.attr["http://jabber.org/protocol/pubsub\1id"] = nil; elseif type(parsed.id) == "string" then item_id = parsed.id; end return publish_payload(node, actor, item_id, payload); end local function publish_atom(node, actor, feed) for entry in feed:childtags("entry") do local item_id = entry:get_child_text("id"); if not item_id then item_id = uuid_generate(); entry:tag("id"):text(item_id):up(); end if not entry:get_child_text("published") then entry:tag("published"):text(timestamp_generate()):up(); end local resp = publish_payload(node, actor, item_id, entry); if resp ~= 202 then return resp; end end return 202; end local function handle_xml(node, actor, payload) local xmlpayload, err = xml.parse(payload); if not xmlpayload then module:log("debug", "XML parse error: %s\n%q", err, payload); return { status_code = 400, body = tostring(err) }; end if xmlpayload.attr.xmlns == "http://www.w3.org/2005/Atom" and xmlpayload.name == "feed" then return publish_atom(node, actor, xmlpayload); else return publish_payload(node, actor, "current", xmlpayload); end end local function handle_urlencoded(node, actor, data) local parsed = http.formdecode(data); if type(parsed) ~= "table" then return {status_code = 400; body = "invalid payload"}; end for i = 1, #parsed do parsed[i] = nil; end local payload = wrap(node, parsed, json.encode(parsed)); local item_id = "current"; if payload.attr["http://jabber.org/protocol/pubsub\1id"] then item_id = payload.attr["http://jabber.org/protocol/pubsub\1id"]; payload.attr["http://jabber.org/protocol/pubsub\1id"] = nil; elseif type(parsed.id) == "string" then item_id = parsed.id; end return publish_payload(node, actor, item_id, payload); end local actor_source = module:get_option_string("pubsub_post_actor"); -- COMPAT local default_secret = module:get_option_string("pubsub_post_default_secret"); local actor_secrets = module:get_option("pubsub_post_secrets"); local actors = module:get_option("pubsub_post_actors"); local default_actor = module:get_option_string("pubsub_post_default_actor"); if not default_actor and actor_source == "superuser" then default_actor = true; end local function verify_signature(secret, body, signature) if not signature then return false; end local algo, digest = signature:match("^([^=]+)=(%x+)"); if not algo then return false; end local hmac = hmacs[algo]; if not algo then return false; end return hmac(secret, body) == from_hex(digest); end function handle_POST(event, path) local request = event.request; local content_type = request.headers.content_type or "application/octet-stream"; local actor = actors and actors[path] or default_actor or request.ip; local secret = actor_secrets and actor_secrets[path] or default_secret; module:log("debug", "Handling POST to node %q by %q with %q: \n%s\n", path, actor, content_type, request.body); if secret and not verify_signature(secret, request.body, request.headers.x_hub_signature) then module:log("debug", "Signature validation failed"); return 401; end if not actor then return 401; end if content_type == "application/xml" or content_type:sub(-4) == "+xml" then return handle_xml(path, actor, request.body); elseif content_type == "application/json" or content_type:sub(-5) == "+json" then return handle_json(path, actor, request.body); elseif content_type == "application/x-www-form-urlencoded" then return handle_urlencoded(path, actor, request.body); end module:log("debug", "Unsupported content-type: %q", content_type); return 415; end module:provides("http", { route = { ["POST /*"] = handle_POST; }; }); function module.load() module:log("debug", "Loaded at %s", module:http_url()); end