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# frozen_string_literal: true
# server-server
post '/inbox' do
request.body.rewind # in case someone already read it
@body = request.body.read
halt 400 if @body.empty?
begin
@activity = JSON.parse @body
rescue StandardError
p @body
halt 400
end
halt 501 if @activity['actor'] and @activity['type'] == 'Delete' # deleted actors return 403 => verification error
verify! # unless type == :accept # pixelfed sends unsigned accept activities???
save_activity(@activity, INBOX)
type = @activity['type'].downcase.to_sym
send(type) if %i[create announce follow accept undo].include? type
halt 200
end
# public
get '/.well-known/webfinger' do
halt 404 unless request['resource'] == "acct:#{MENTION}"
send_file(WEBFINGER, type: 'application/jrd+json')
end
get '/pdp8' do
send_file(File.join(PUBLIC_DIR, 'pdp8.json'), type: CONTENT_TYPE)
end
['/following', '/followers'].each do |path|
get path do
send_file(File.join(PUBLIC_DIR, path) + '.json', type: CONTENT_TYPE)
end
end
helpers do
def create
@object ||= @activity['object']
@object = save_object @object, INBOX
return unless @object['inReplyTo']
@object = @object['inReplyTo']
create
end
def announce
create
end
def follow
update_collection FOLLOWERS, @activity['actor']
outbox 'Accept', @activity, [@activity['actor']]
end
def accept
halt 501 unless @activity['object']['type'] == 'Follow'
update_collection FOLLOWING, @activity['object']['object']
end
def undo
halt 501 unless @activity['object']['type'] == 'Follow'
update_collection FOLLOWERS, @activity['object']['actor'], true
end
# https://github.com/mastodon/mastodon/blob/main/app/controllers/concerns/signature_verification.rb
def verify!
# digest
sha256 = OpenSSL::Digest.new('SHA256')
digest = "SHA-256=#{sha256.base64digest(@body)}"
halt 403 unless digest == request.env['HTTP_DIGEST']
# signature
signature_params = {}
request.env['HTTP_SIGNATURE'].split(',').each do |pair|
k, v = pair.split('=')
signature_params[k] = v.gsub('"', '')
end
key_id = signature_params['keyId']
headers = signature_params['headers']
signature = Base64.decode64(signature_params['signature'])
actor = fetch key_id
halt 403 unless actor
key = OpenSSL::PKey::RSA.new(actor['publicKey']['publicKeyPem'])
comparison = headers.split(' ').map do |signed_params_name|
if signed_params_name == '(request-target)'
'(request-target): post /inbox'
elsif signed_params_name == 'content-type'
"#{signed_params_name}: #{request.env['CONTENT_TYPE']}"
else
"#{signed_params_name}: #{request.env["HTTP_#{signed_params_name.upcase}"]}"
end
end.join("\n")
halt 403 unless key.verify(OpenSSL::Digest.new('SHA256'), signature, comparison)
end
def outbox(type, object, recipients)
# send
## https://github.com/mastodon/mastodon/blob/main/app/lib/request.rb
inboxes = []
recipients.uniq.each do |url|
next if [ACTOR, 'https://www.w3.org/ns/activitystreams#Public'].include? url
actor = fetch url
next unless actor
if actor['endpoints'] and actor['endpoints']['sharedInbox']
inboxes << actor['endpoints']['sharedInbox']
elsif actor['inbox']
inboxes << actor['inbox']
end
end
# add date and id, save
activity = save_activity({
'@context' => 'https://www.w3.org/ns/activitystreams',
'type' => type,
'actor' => ACTOR,
'object' => object,
'to' => recipients
}, OUTBOX)
body = activity.to_json
sha256 = OpenSSL::Digest.new('SHA256')
digest = "SHA-256=#{sha256.base64digest(body)}"
keypair = OpenSSL::PKey::RSA.new(File.read('private.pem'))
inboxes.compact.uniq.each do |inbox|
uri = URI(inbox)
httpdate = Time.now.utc.httpdate
string = "(request-target): post #{uri.request_uri}\nhost: #{uri.host}\ndate: #{httpdate}\ndigest: #{digest}\ncontent-type: application/activity+json"
signature = Base64.strict_encode64(keypair.sign(OpenSSL::Digest.new('SHA256'), string))
signed_header = "keyId=\"#{ACTOR}#main-key\",algorithm=\"rsa-sha256\",headers=\"(request-target) host date digest content-type\",signature=\"#{signature}\""
curl(
"-X POST -H 'Content-Type: application/activity+json' -H 'Host: #{uri.host}' -H 'Date: #{httpdate}' -H 'Digest: #{digest}' -H 'Signature: #{signed_header}' -d '#{body}'", inbox
)
end
activity
end
end
|
