Legend: SPEC!! - Not specified SPEC - Spec not finalized NICK - nick claims ARMA - arma claims - Not done * Top priority . Partially done o Done D Deferred X Abandoned Flag-day changes: (things which are backward incompatible) . remove link key from directories, from connection_t. (just get it from the tls cert) . make onion keys include oaep padding, so you can tell if you decrypted it correctly . add bandwidthrate and bandwidthburst to server descriptor - directories need to say who signed them. - what other pieces of the descriptors need to change? maybe add a section for who's connected to a given router? add a flexible section for reputation info? Bugs: o we call signal(), but we should be calling sigaction() o send socks rejects when things go bad ? o on solaris, need to build with LDFLAGS="-lsocket -lnsl" ./configure o on solaris, we HAVE_UNAME but the uname() call fails? . should maybe make clients exit(1) when bad things happen? e.g. clock skew. o client-side dns cache doesn't appear to be getting populated by 'connected' cells. In fact, the 'connected' cells don't even include the IP. o When it can't resolve any dirservers, it is useless from then on. We should make it reload the RouterFile if it has no dirservers. o Sometimes it picks a middleman node as the exit for a circuit. o if you specify a non-dirserver as exitnode or entrynode, when it makes the first few circuits it hasn't yet fetched the directory, so it warns that it doesn't know the node. o make 'make test' exit(1) if a test fails. . fix buffer unit test so it passes Short-term: - should retry exitpolicy end streams even if the end cell didn't resolve the address for you o add in 'notice' log level X make recommendedversions different for clients and servers. e.g. C0.0.3 vs S0.0.3? o put IP into the descriptor, so clients don't need to resolve things o when you hup, rewrite the router.desc file (and maybe others) - consider handling broken socks4 implementations o improve how it behaves when i remove a line from the approved-routers files - Make tls connections tls_close intentionally - Add '[...truncated]' or similar to truncated log entries (like the directory in connection_dir_process_inbuf()). . Make logs handle it better when writing to them fails. o leave server descriptor out of directory if it's too old o Rename ACI to circID o integrate rep_ok functions, see what breaks - update tor faq o obey SocksBindAddress, ORBindAddress o warn if we're running as root o make connection_flush_buf() more obviously obsolete o let hup reread the config file, eg so we can get new exit policies without restarting o Put recommended_versions in a config entry X use times(2) rather than gettimeofday to measure how long it takes to process a cell o Separate trying to rebuild a circuit because you have none from trying to rebuild a circuit because the current one is stale X Continue reading from socks port even while waiting for connect. o Exit policies o Spec how to write the exit policies o Path selection algorithms o Choose path more incrementally o Let user request first/last node o And disallow certain nodes D Choose path by jurisdiction, etc? o Make relay end cells have failure status and payload attached X let non-approved routers handshake. X Dirserver shouldn't put you in running-routers list if you haven't uploaded a descriptor recently X migrate to using nickname rather than addr:port for routers - migrate to using IPv6 sizes everywhere o Move from onions to ephemeral DH o incremental path building o transition circuit-level sendmes to hop-level sendmes o implement truncate, truncated o move from 192byte DH to 128byte DH, so it isn't so damn slow X exiting from not-last hop X OP logic to decide to extend/truncate a path X make sure exiting from the not-last hop works X logic to find last *open* hop, not last hop, in cpath o Remember address and port when beginning. - Extend by nickname/hostname/something, not by IP. - Need a relay teardown cell, separate from one-way ends. X remove per-connection rate limiting - Make it harder to circumvent bandwidth caps: look at number of bytes sent across sockets, not number sent inside TLS stream. o Audit users of connnection_remove and connection_free outside of main.c; many should use mark_for_close instead. Rendezvous service: o Design and specify protocol o Possible preliminary refactoring: o Should we break circuits up into "circuit-with-cpath" and "circuit-without-cpath"? o We need a way to tag circuits as special-purpose circuits for: o Connecting from Bob's OP to the introduction point o Sending introduction requests from the IPoint to Bob o Connecting from Alice to the rendezvous point for Bob o Connecting from Bob to the rendezvous point for Alice o Waiting at a rendezvous point to be joined o Joined to another circuit at the rendezvous point. (We should also enumerate all the states that these operations can be in.) [NM] o Add circuit metadata [NM] o Code to configure hidden services [NM] 4 hours o Service descriptors o OPs need to maintain identity keys for hidden services [NM] o Code to generate and parse service descriptors [NM] o Advertisement o Generate y.onion hostnames [NM] o Store y.onion hostnames to disk. [NM] o Code to do an HTTP connection over Tor from within Tor [RD] o Publish service descriptors to directory [RD] o Directory accepts and remembers service descriptors, and delivers them as requested o Frontend [RD] o Backend [NM] o Code for OPs to retrieve (and cache?) service descriptors [RD] o Rendezvous o Code as needed to generate and parse all rendezvous-related cell types, and do all handshaking [NM] o ORs implement introduction points o OPs with hidden services establish introduction points o ORs implement rendezvous points o OPs notice y.onion URLs, and: o Retrieve service descriptors o Establish rendezvous points o Send introduction requests to introduction points o Communication o OPs remember which circuits are used for which rendezvous points, and can look up circuits by location-hidden service o OPs send/handle BEGIN cells for location-hidden services o End-to-end communication for location-hidden services o a section in the man pages: how to configure hidden services o let bob use himself as a rendezvous point o let bob choose himself as intro point o let bob replenish his intro points and republish o alice retries introduction and rendezvous a few times? o ORs should not pick themselves while building general circs o should alice ever try to refresh her service desc cache entries? should she expire them after e.g. 15 mins? o race condition: alice has the serverdesc in her cache, she opens the circs, serverdesc expires and is flushed, then she goes to send the intro cell. should serverdesc cache have a last-touched field? are there better fixes? o backward compatibility: when only certain nodes know about rend protocol, how do we deal? have nodes parse the tor version field? force an upgrade? simply be more robust against useless nodes? o should expire rend streams when too much time has passed o should make failed rend/intro circs count toward alice's num_failed circs, to prevent madness when we're offline (But don't count failed rend circs toward Bob's total, or Alice can bork him.) o deal with edge_type in connection_edge.c o retry end for certain reasons (resolvefailed, policyfailed) - preemptively build and start rendezvous circs - preemptively build n-1 hops of intro circs? o (n)ack introduction requests? - cannibalize general circs? D how to set up multiple locations for a hidden service? o make bob publish only established intro circs? o when bob tries to connect to alice's chosen rend point, but can't, but it's not the fault of the last hop in the rend circ, then he should retry? - fix router_get_by_* functions so they can get ourselves too, and audit everything to make sure rend and intro points are just as likely to be us as not. On-going . Better comments for functions! . Go through log messages, reduce confusing error messages. . make the logs include more info (fd, etc) . Unit tests . Update the spec so it matches the code Mid-term: o Refactor: add own routerinfo to routerlist. Right now, only router_get_by_nickname knows about 'this router', as a hack to get circuit_launch_new to do the right thing. - Rotate tls-level connections -- make new ones, expire old ones. So we get actual key rotation, not just symmetric key rotation - And learn to transfer a circuit from one conn to another, so we can empty conns to expire them. o Are there anonymity issues with sequential streamIDs? Sequential circIDs? Eg an attacker can learn how many there have been. The fix is to initialize them randomly rather than at 1. - Look at having smallcells and largecells . Redo scheduler o fix SSL_read bug for buffered records - make round-robining more fair - What happens when a circuit's length is 1? What breaks? . streams / circuits o Implement streams o Rotate circuits after N minutes? X Circuits should expire when circuit->expire triggers NICK . Handle half-open connections o openssh is an application that uses half-open connections o Figure out what causes connections to close, standardize when we mark a connection vs when we tear it down o Look at what ssl does to keep from mutating data streams o Put CPU workers in separate processes o Handle multiple cpu workers (one for each cpu, plus one) o Queue for pending tasks if all workers full o Support the 'process this onion' task D Merge dnsworkers and cpuworkers to some extent o Handle cpuworkers dying . Scrubbing proxies - Find an smtp proxy? - Check the old smtp proxy code o Find an ftp proxy? wget --passive D Wait until there are packet redirectors for Linux . Get socks4a support into Mozilla . Tests o Testing harness/infrastructure D System tests (how?) - Performance tests, so we know when we've improved . webload infrastructure (Bruce) . httperf infrastructure (easy to set up) . oprofile (installed in RH >8.0) NICK . Daemonize and package o Teach it to fork and background . Red Hat spec file o Debian spec file equivalent . Portability . Which .h files are we actually using? . Port to: o Linux o BSD o Solaris o Cygwin . Win32 o OS X - deal with pollhup / reached_eof on all platforms o openssl randomness o inet_ntoa o stdint.h - Make a script to set up a local network on your machine o More flexibility in node addressing D Support IPv6 rather than just 4 o Handle multihomed servers (config variable to set IP) In the distant future: D tunnel tor cell protocol over http, for people who need to do http D better transport than tcp: reliable is necessary, but out-of-order delivery is fine (to some extent). D Load balancing between router twins D Keep track of load over links/nodes, to know who's hosed SPEC!! D Non-clique topologies D Advanced directory servers D Automated reputation management SPEC!! D Figure out how to do threshold directory servers D jurisdiction info in dirserver entries? other info? Older (done) todo stuff: For 0.0.2pre17: o Put a H(K | handshake) into the onionskin response o Make cells 512 bytes o Reduce streamid footprint from 7 bytes to 2 bytes X Check for collisions in streamid (now possible with just 2 bytes), and back up & replace with padding if so o Use the 4 reserved bytes in each cell header to keep 1/5 of a sha1 of the ongoing relay payload (move into stream header) o Move length into the stream header too o Make length 2 bytes D increase DH key length D increase RSA key length D Spec the stream_id stuff. Clarify that nobody on the backward stream should look at stream_id. For 0.0.2pre15: o don't pick exit nodes which will certainly reject all things. o don't pick nodes that the directory says are down o choose randomly from running dirservers, not just first one o install the man page o warn when client-side tries an address/port which no router in the dir accepts. For 0.0.2pre14: o More flexible exit policies (18.*, 18.0.0.0/8) o Work to succeed in the precense of exit policy violation o Replace desired_path_len with opaque path-selection specifier o Client-side DNS caching o Add entries to client DNS cache based on END cells o Remove port from END_REASON_EXITPOLICY cells o Start building new circuits when we get an exit-policy failure. (Defer exiting from the middle of existing circuits or extending existing circuits for later.) o Implement function to check whether a routerinfo_t supports a given exit addr. o Choose the exit node of an in-progress circuit based on pending AP connections. o Choose the exit node _first_, then beginning, then middle nodes. Previous: o Get tor to act like a socks server o socks4, socks4a o socks5 o routers have identity key, link key, onion key. o link key certs are D signed by identity key D not in descriptor o not in config D not on disk o identity and onion keys are in descriptor (and disk) o upon boot, if it doesn't find identity key, generate it and write it. o also write a file with the identity key fingerprint in it o router generates descriptor: flesh out router_get_my_descriptor() o Routers sign descriptors with identity key o routers put version number in descriptor o routers should maybe have `uname -a` in descriptor? o Give nicknames to routers o in config o in descriptors o router posts descriptor o when it boots o every DirFetchPostPeriod seconds D when it changes o change tls stuff so certs don't get written to disk, or read from disk o make directory.c 'thread'safe o dirserver parses descriptor o dirserver checks signature D client checks signature? o dirserver writes directory to file o reads that file upon boot o directory includes all routers, up and down o add "up" line to directory, listing nicknames o instruments ORs to report stats o average cell fullness o average bandwidth used o configure log files. separate log file, separate severities. o what assumptions break if we fclose(0) when we daemonize? o make buffer struct elements opaque outside buffers.c o add log convention to the HACKING file o make 'make install' do the right thing o change binary name to tor o change config files so you look at commandline, else look in /etc/torrc. no cascading. o have an absolute datadir with fixed names for files, and fixed-name keydir under that with fixed names o Move (most of) the router/directory code out of main.c o Simple directory servers o Include key in source; sign directories o Signed directory backend o Document o Integrate o Add versions to code o Have directories list recommended-versions o Include line in directories o Check for presence of line. o Quit if running the wrong version o Command-line option to override quit o Add more information to directory server entries o Exit policies o Clearer bandwidth management o Do we want to remove bandwidth from OR handshakes? o What about OP handshakes? X Move away from openssl o Abstract out crypto calls X Look at nss, others? Just include code? o Use a stronger cipher o aes now, by including the code ourselves X On the fly compression of each stream o Clean up the event loop (optimize and sanitize) o Remove that awful concept of 'roles' o Terminology o Circuits, topics, cells stay named that o 'Connection' gets divided, or renamed, or something? o DNS farm o Distribute queries onto the farm, get answers o Preemptively grow a new worker before he's needed o Prune workers when too many are idle o DNS cache o Clear DNS cache over time D Honor DNS TTL info (how??) o Have strategy when all workers are busy o Keep track of which connections are in dns_wait o Need to cache positives/negatives on the tor side o Keep track of which queries have been asked o Better error handling when o An address doesn't resolve o We have max workers running o Consider taking the master out of the loop? X Implement reply onions o Total rate limiting o Look at OR handshake in more detail o Spec it o Merge OR and OP handshakes o rearrange connection_or so it doesn't suck so much to read D Periodic link key rotation. Spec? o wrap malloc with something that explodes when it fails o Clean up the number of places that get to look at prkey