- tor-dev - lists.torproject.org

The future of Tor client software?
by Steven Engler 21 Feb '23

21 Feb '23

Hi tor-dev, In the past, there were generally two options for supporting Tor in an application. 1. Require the user to install the tor daemon (ex: apt install tor, Tor Expert Bundle, etc) and configure the application to use its SOCKS proxy. 2. Bundle the tor binary with the application (ex: Tor Browser) and have the application use the app-specific tor process as the SOCKS proxy. I'm not clear on how this changes in an Arti world. Arti currently has a Rust Tor client library for applications, and a CLI application to run a SOCKS proxy. Is there any plan to offer an Arti daemon (ex: a systemd service) for clients like with the current tor package? In a future where Arti replaces the Tor client and relay code, or when Arti is recommended for all client-related use cases, will there continue to be a Tor daemon with client support? I see various possibilities for developers who wish to use Tor in their applications: 1. Require users to install/run a Tor system service (whether it's tor or arti). - pros: - shared resource usage (mainly circuits) between applications - familiar to experienced Tor users - cons: - requires an additional installation step for users - easy to break by users (for example changing their SOCKS port) - can't modify the Tor client's configuration (ex: can't enable DNSPort, change SocksPort flags, etc) 2. Bundle tor/arti binaries with the application. - pros: - simple for users (no extra configuration needed) - more control over the Tor client's configuration - cons: - can be brittle (ex: an application is already using port 9150) - resources/circuits are not shared between applications - more work for the application developer (needs to build and bundle the tor binary) - (presumably) slower start-up times since there is no pre-existing pool of pending circuits, and descriptors may be out-of-date 3. Use the arti-client library in the application. - pros: - simple for users (no extra configuration needed) - more control over the Tor client's configuration - easy to use for rust application developers - cons: - likely difficult to use in non-rust applications (writing an ffi for the async arti-client API doesn't sound fun) - resources/circuits are not shared between applications - (presumably) slower start-up times since there is no pre-existing pool of pending circuits, and descriptors may be out-of-date 4. Require users to install/run a Tor transparent proxy or TUN adapter. - pros: - should probably "just work" (ex: no SOCKS port that can change or need to be configured) - cons: - requires an additional installation step for users - can't modify the Tor client's configuration - users likely don't want to proxy all their traffic through Tor - slowdowns due to latency from DNS lookups (RELAY_RESOLVE instead of sending the hostname in the RELAY_BEGIN) - no stream isolation support (maybe?) Are there any guidelines for what method should be used under different circumstances? For example using the arti-client library in an email client seems reasonable since a longer startup time while it builds circuits isn't a big deal. But it might be a bad idea to use the arti-client library in cURL, which would need to build circuits each time curl is invoked in a shell script. - Steve

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Simple tool for mobile remote desktops
by Micah Elizabeth Scott 24 Jan '23

24 Jan '23

Hello, This is an almost trivial utility but I hadn't seen anything quite like it so maybe other folks will find it useful: https://github.com/scanlime/onion-desktop "This is just a toy for now. I wanted to get a feel for the interactive performance of onion services, and it's perhaps sometimes useful if you'd like to share a disposable slice of your computer with a phone when they're both behind NAT. This is a very simple Docker container that runs an xfce4 desktop, novnc, and tor. It will randomly generate a new onion service URL and a VNC password, and show you a tmux with session logs on the left and a big QR code you can scan on the right." Nothing too fancy, just some shell script and Docker and a lot of Debian. The readme has a couple screenshots if you're curious. Cheers, --micah beth

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Proposal 342: Decouple hs_interval and SRV lifetime
by Nick Mathewson 24 Jan '23

24 Jan '23

``` Filename: 342-decouple-hs-interval.md Title: Decoupling hs_interval and SRV lifetime Author: Nick Mathewson Created: 9 January 2023 Status: Draft ``` # Motivation and introduction Tor uses shared random values (SRVs) in the consensus to determine positions of relays within a hash ring. Which shared random value is to be used for a given time period depends upon the time at which that shared random value became valid. But right now, the consensus voting period is closely tied to the shared random value voting cycle: and clients need to understand both of these in order to determine when a shared random value became current. This creates tight coupling between: * The voting schedule * The SRV liveness schedule * The hsdir_interval parameter that determines the length of the an HSDIR index To decouple these values, this proposal describes a forward compatible change to how Tor reports SRVs in consensuses, and how Tor decides which hash ring to use when. ## Reporting SRV timestamps In consensus documents, parties should begin to accept `shared-rand-*-value` lines with an additional argument, in the format of an IsoTimeNospace timestamp (like "1985-10-26T00:00:00"). When present, this timestamp indicates the time at which the given shared random value first became the "current" SRV. Additionally, we define a new consensus method that adds these timestamps to the consensus. We specify that, in the absence of such a timestamp, parties are to assume that the `shared-rand-current-value` SRV became "current" at the first 00:00 UTC on the UTC day of the consensus's valid-after timestamp, and that the `shard-rand-previous-value` SRV became "current" at 00:00 UTC on the previous UTC day. ## Generalizing HSDir index scheduling. Under the current HSDir design, there is one SRV for each time period, and one time period for which each SRV is in use. Decoupling `hsdir_interval` from 24 hours will require that we change this notion slightly. We therefore propose this set of generalized directory behavior rules, which should be equivalent to the current rules under current parameters. The calculation of time periods remains the same (see `rend-spec-v3.txt` section `[TIME PERIODS]`). A single SRV is associated with each time period: specifically, the SRV that was "current" at the start of the time period. There is a separate hash ring associated with each time period and its SRV. Whenever fetching an onion service descriptor, the client uses the hash ring for the time period that contains the start of the liveness interval of the current consensus. Call this the "Consensus" time period. Whenever uploading an onion service descriptor, the service uses _two or three_ hash rings: * The "consensus" time period (see above). * The immediately preceding time period, if the SRV to calculate that hash ring is available in the consensus. * The immediately following time period, if the SRV to calculate that hash ring is available in the consensus. (Under the current parameters, where `hsdir_interval = SRV_interval`, there will never be more than two possible time periods for which the service can qualify.) ## Migration We declare that, for at least the lifetime of the C tor client, we will not make any changes to the voting interval, the SRV interval, or the `hsdir_interval`. As such, we do not need to prioritize implementing these changes in the C client: we can make them in Arti only. ## Issues left unsolved There are likely other lingering issues that would come up if we try to change the voting interval. This proposal does not attempt to solve them. This proposal does not attempt to add flexibility to the SRV voting algorithm itself. Changing `hsdir_interval` would create a flag day where everybody using old and new values of `hsdir_interval` would get different hash rings. We do not try to solve that here. ## Acknowledgments Thanks to David Goulet for explaining all of this stuff to me!

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Tor Bridges and Snowflakes detection attack
by tor＠nullvoid.me 09 Jan '23

09 Jan '23

Hi, https://github.com/scriptzteam/Tor-Bridges-Collector Seems an attacker has found a way to enumerate ~300000 snowflakes and many bridges. I couldn't find any discussion about this in the archive. Thanks,

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Typo in relay metrics (circs_creared)
by Andreas Bollhalder 09 Jan '23

09 Jan '23

Hi I think, there's a typo in the file "src/feature/relay/relay_metrics.c". Shouldn't the word "circs_creared" in the line metrics_format_label("action", "circs_creared")); be read as "circs_cleared"? Andreas PS: Sorry, at the moment I've no clue what would be the correct way to send patches...

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C99 compatibility issue in torsocks
by Florian Weimer 17 Dec '22

17 Dec '22

This patch is needed to avoid an implicit function declaration: diff --git a/src/common/config-file.h b/src/common/config-file.h index 23e1c89d488b789c..e710c202fe099f61 100644 --- a/src/common/config-file.h +++ b/src/common/config-file.h @@ -109,6 +109,7 @@ int conf_file_set_allow_inbound(const char *val, struct configuration *config); int conf_file_set_allow_outbound_localhost(const char *val, struct configuration *config); int conf_file_set_isolate_pid(const char *val, struct configuration *config); +int conf_file_set_enable_ipv6(const char *val, struct configuration *config); int conf_apply_socks_auth(struct configuration *config); I'm not sure where the canonical upstream for this package is, so I'm reporting it here. Fedora is tracking this here: torsocks: Missing declaration in src/common/config-file.h <https://bugzilla.redhat.com/show_bug.cgi?id=2154535> Related to: <https://fedoraproject.org/wiki/Changes/PortingToModernC> <https://fedoraproject.org/wiki/Toolchain/PortingToModernC>

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Applications team no longer updating gitolite repos
by Richard Pospesel 06 Dec '22

06 Dec '22

Hi everyone, With the 12.0 release almost out the door, the applications team will no longer be pushing commits to our git.torproject.org (gitolite) repos. All future code updates will only be pushed to our various gitlab.torproject.org (Gitlab) repos. best, -Richard

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Latest releases missing from changelog
by Michael Rogers 09 Nov '22

09 Nov '22

Hi all, The latest releases (0.4.7.10, 0.4.6.12 and 0.4.5.14) seem to be missing from the changelog: https://gitlab.torproject.org/tpo/core/tor/-/raw/main/ChangeLog Is this file still the right place to look? Cheers, Michael

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Release new version of stem
by Hefee 03 Oct '22

03 Oct '22

Hey, nodens(nodens(a)debian.org) and me are currently packaging the new version of onionshare for Debian and stumbled over the dependency cepa[1], what is a fork of stem. After digging deeper into it, I found out, that the main reason why they do so is the support for Client Auth v3 onions[2]. I really would like not to package a fork of stem, if possible. That's why I ask, when it is planed to release a new version of stem? It hasn't seen any release since 2019 and there are a lot of changes in master branch too. Maybe you can just release the current state of the maint branch, that is actually what is released as cepa 1.8.3. I some how need to solve this till January, when Debian is freezing (not accepting new versions). Regards hefee [1] https://github.com/onionshare/cepa [2] https://github.com/torproject/stem/commit/ 2f3bbf64b4ce3b63160a3c56b15748ba626de4a0

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Blacklist all domains, whitelist .onion,.exit
by nyxnor 21 Sep '22

21 Sep '22

Hello. I am trying to make a tor only allow traffic through onion services and exit nodes. I would like to blacklist all domains first, as that is simple and does not need to be updated, then whitelist all onions and exits. Reason: I am hosting an onion service, but I don't want any client traffic comming from that machine. I've played with MapAddress, VirtualAddrNetworkIPV4, AutomapHostsOnResolve, AutomaptHostsSuffixes, but nothing seems to work as intended above. MapAddress *=127.0.0.1 does not report invalid conf, but the controller reports it is using invalid sytax because "*" be source or target. I tricked the controller with MapAddress *.*=127.0.0.1, as every domain has a dot, the controller didn't report syntax error and this option is actually ignored. If the above worked, then the next option would be the whitelisting: MapAddress *.onion VIRTUAL_IP Or possibly the AutomapHostsOnResolve 1 and AutomapHostsSuffixes .exit,.onion would handle that part hopefully. I did the lazy way, the antivirus way, I downloaded the IANA TLD domain list and used basic string manipulation to make: MapAddress *.${domain} 127.0.0.1 And yes, as you may think, the list is huge that has to be on its own included conf file, and also prone to be outdated every time a new TLD is created. But it works, in a dumb and prone to mistakes, it works. Can this be done better? Not antivirus way of all is permitted, some known items are blocked. I would prefer all is blocked and some items are permitted. The real objective was to block all non .onion and .exit targets coming from a client, that the controller reports with SOURCE_ADDR, but I didn't find an option to MapAddress per client or anything similar to that do manipulate addresses per client source, so that is why I started doing this for all tor traffic, which is not what I really want, but controlling targets per client.

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