nas/app/controllers/concerns/signature_verification.rb
2025-06-02 09:27:08 +00:00

123 lines
4.5 KiB
Ruby

# frozen_string_literal: true
# Implemented according to HTTP signatures (Draft 6)
# <https://tools.ietf.org/html/draft-cavage-http-signatures-06>
module SignatureVerification
extend ActiveSupport::Concern
include DomainControlHelper
EXPIRATION_WINDOW_LIMIT = 12.hours
CLOCK_SKEW_MARGIN = 1.hour
def require_account_signature!
render json: signature_verification_failure_reason, status: signature_verification_failure_code unless signed_request_account
end
def require_actor_signature!
render json: signature_verification_failure_reason, status: signature_verification_failure_code unless signed_request_actor
end
def signed_request?
request.headers['Signature'].present?
end
def signature_key_id
signed_request.key_id
end
private
def signed_request
@signed_request ||= SignedRequest.new(request) if signed_request?
rescue SignatureVerificationError
nil
end
def signature_verification_failure_reason
@signature_verification_failure_reason
end
def signature_verification_failure_code
@signature_verification_failure_code || 401
end
def signed_request_account
signed_request_actor.is_a?(Account) ? signed_request_actor : nil
end
def signed_request_actor
return @signed_request_actor if defined?(@signed_request_actor)
raise Mastodon::SignatureVerificationError, 'Request not signed' unless signed_request?
actor = actor_from_key_id
raise Mastodon::SignatureVerificationError, "Public key not found for key #{signature_key_id}" if actor.nil?
return (@signed_request_actor = actor) if signed_request.verified?(actor)
actor = stoplight_wrapper.run { actor_refresh_key!(actor) }
raise Mastodon::SignatureVerificationError, "Could not refresh public key #{signature_key_id}" if actor.nil?
return (@signed_request_actor = actor) if signed_request.verified?(actor)
fail_with! "Verification failed for #{actor.to_log_human_identifier} #{actor.uri}"
rescue Mastodon::SignatureVerificationError => e
fail_with! e.message
rescue *Mastodon::HTTP_CONNECTION_ERRORS => e
fail_with! "Failed to fetch remote data: #{e.message}"
rescue Mastodon::UnexpectedResponseError
fail_with! 'Failed to fetch remote data (got unexpected reply from server)'
rescue Stoplight::Error::RedLight
fail_with! 'Fetching attempt skipped because of recent connection failure'
end
def fail_with!(message, **options)
Rails.logger.debug { "Signature verification failed: #{message}" }
@signature_verification_failure_reason = { error: message }.merge(options)
@signed_request_actor = nil
end
def actor_from_key_id
key_id = signature_key_id
domain = key_id.start_with?('acct:') ? key_id.split('@').last : key_id
if domain_not_allowed?(domain)
@signature_verification_failure_code = 403
return
end
if key_id.start_with?('acct:')
stoplight_wrapper.run { ResolveAccountService.new.call(key_id.delete_prefix('acct:'), suppress_errors: false) }
elsif !ActivityPub::TagManager.instance.local_uri?(key_id)
account = ActivityPub::TagManager.instance.uri_to_actor(key_id)
account ||= stoplight_wrapper.run { ActivityPub::FetchRemoteKeyService.new.call(key_id, suppress_errors: false) }
account
end
rescue Mastodon::PrivateNetworkAddressError => e
raise Mastodon::SignatureVerificationError, "Requests to private network addresses are disallowed (tried to query #{e.host})"
rescue Mastodon::HostValidationError, ActivityPub::FetchRemoteActorService::Error, ActivityPub::FetchRemoteKeyService::Error, Webfinger::Error => e
raise Mastodon::SignatureVerificationError, e.message
end
def stoplight_wrapper
Stoplight("source:#{request.remote_ip}")
.with_threshold(1)
.with_cool_off_time(5.minutes.seconds)
.with_error_handler { |error, handle| error.is_a?(HTTP::Error) || error.is_a?(OpenSSL::SSL::SSLError) ? handle.call(error) : raise(error) }
end
def actor_refresh_key!(actor)
return if actor.local? || !actor.activitypub?
return actor.refresh! if actor.respond_to?(:refresh!) && actor.possibly_stale?
ActivityPub::FetchRemoteActorService.new.call(actor.uri, only_key: true, suppress_errors: false)
rescue Mastodon::PrivateNetworkAddressError => e
raise Mastodon::SignatureVerificationError, "Requests to private network addresses are disallowed (tried to query #{e.host})"
rescue Mastodon::HostValidationError, ActivityPub::FetchRemoteActorService::Error, Webfinger::Error => e
raise Mastodon::SignatureVerificationError, e.message
end
end