custodian-enqueue ----------------- We open named files from the user to parse tests. The configuration file(s) are currently opened by root, via /etc/service/custodian-enqueue. This should be changed to run as a lower-privileged user. custodian-dequeue ----------------- Two tests pass arguments from the configuration file to the shell: ping http/https The hostname used to ping, and the URL for web-tests, are both passed directly to the shell assuming they match the following regular expression: ^([^\s]+)\s+ So the following configuration file potentially allows a command to be executed by our worker: $(/home/steve/hg/custodian/exploit.sh) must ping otherwise "Owned". http://$(/tmp/exploit.sh)/ must run http with status 200 otherwise "Owned". Given that anybody who can talk to the beanstalkd server can submit JSON-encoded-jobs we cannot rely on catching this solely in the parser. For the moment we've solved the case of the ping-exploitation, because the valid hostnames passed there are [a-z0-9.-]. We've not yet sanitized URLs because that is a harder job. In the case of the ping-test we've done both levels of testing: * Test the hostname is valid priorer to executing the shell. * Ensure the hostname is valid before adding the job to the queue. General ------- We decode arbitrary JSON from the queue. We should sign it, or validate it to will prevent trojan malformed JSON from being added. At the moment we ensure that the job-body we retrieve looks JSON-like, and decodes to a non-empty hash. Problem: We cannot sign the body without giving away our key details. Solution: Read /etc/custodian/salt, and store the checksum of all keys + values with that salt? TODO ---- Anything else? DoS attacks? Steve --