From: Daira Hopwood Date: Sat, 22 Aug 2015 12:20:45 +0000 (+0100) Subject: Rename tor.rst to anonymity-configuration.rst. X-Git-Url: https://git.rkrishnan.org/nxhtml.html?a=commitdiff_plain;h=300a88cbc3fad71672d76a04dd36be6d729a0082;p=tahoe-lafs%2Ftahoe-lafs.git Rename tor.rst to anonymity-configuration.rst. Signed-off-by: Daira Hopwood --- diff --git a/docs/anonymity-configuration.rst b/docs/anonymity-configuration.rst new file mode 100644 index 00000000..e5a113b8 --- /dev/null +++ b/docs/anonymity-configuration.rst @@ -0,0 +1,345 @@ +.. -*- coding: utf-8-with-signature; fill-column: 77 -*- + +====================================================== +Using Tahoe-LAFS with an anonymizing network: Tor, I2P +====================================================== + +1. `Use cases`_ +2. `Native Tor integration for Tahoe-LAFS`_ +3. `Software Dependencies`_ +4. `Configuration`_ +5. `Performance and security issues of Tor Hidden Services`_ +6. `Torsocks: the old way of configuring Tahoe-LAFS to use Tor`_ + +Use cases +========= + +Tor is an anonymizing network used to help hide the identity of internet +clients and servers. Please see the Tor Project's website for more information: +https://www.torproject.org/ + +Informative description about what i2p is... here. + + +There are three potential use-cases for Tahoe-LAFS on the client side: + +1. User does not care to protect their anonymity or to connect to anonymous + storage servers. This document is not useful to you... so stop reading. + +2. User does not care to protect their anonymity but they wish to connect to + Tahoe-LAFS storage servers which are accessbile only via Tor Hidden Services or I2P. + (For Tor users this means only use Tor if the endpoint string has a .onion address.) + +3. User wishes to always use an anonymizing network (Tor, I2P) to protect their anonymity when + connecting to Tahoe-LAFS storage grids (whether or not the storage servers + are anonymous). + + +For Tahoe-LAFS storage servers there are three use-cases: + +1. Storage server operator does not care to protect their own anonymity + nor to help the clients protect theirs. Stop reading this document + and run your Tahoe-LAFS storage server using publicly routed TCP/IP. + +2. The operator does not require anonymity for the storage server, but + they want it to be available over both publicly routed TCP/IP and + through an anonymizing network (I2P, Tor Hidden Services). One possible reason to do this is + because being reachable through an anonymizing network is a convenient + way to bypass NAT or firewall that prevents publicly routed TCP/IP + connections to your server. Another is that making your storage + server reachable through an anonymizing network can provide better + protection for your clients who themselves use that anonymizing network to protect their + anonymity. + + See this Tor Project page for more information about Tor Hidden Services: + https://www.torproject.org/docs/hidden-services.html.en + + See this I2P Project page for more information about I2P: + https://... + +3. The operator wishes to protect their anonymity by making their + Tahoe server accessible only via Tor Hidden Services. + + + +Native Tor integration for Tahoe-LAFS +===================================== + +Native Tor integration for Tahoe-LAFS utilizes the Twisted endpoints API:: +* https://twistedmatrix.com/documents/current/core/howto/endpoints.html + +Twisted's endpoint parser plugin system is extensible via installing additional +Twisted packages. The native Tor integration for Tahoe-LAFS uses +endpoint and parser plugins from the txsocksx and txtorcon modules. +Although the Twisted endpoint API is very flexible it is missing a feature so that +servers can be written in an endpoint agnostic style. We've opened a Twisted trac +ticket for this feature here:: +* https://twistedmatrix.com/trac/ticket/7603 + +Once this ticket is resolved then an additional changes can be made to Foolscap +so that it's server side API is completely endpoint agnostic which will allow +users to easily to use Tahoe-LAFS with many protocols on the server side. + +txsocksx will try to use the system tor's SOCKS port if available; +attempts are made on ports 9050 and 9151. Currently the maintainer of txsocksx +has not merged in our code for the Tor client endpoint. We'll use +this branch until the Tor endpoint code is merged upstream:: +* https://github.com/david415/txsocksx/tree/endpoint_parsers_retry_socks + +txtorcon will use the system tor control port to configure Tor Hidden Services +pending resolution of tor trac ticket 11291:: +* https://trac.torproject.org/projects/tor/ticket/11291 + +See also Tahoe-LAFS Tor related tickets #1010 and #517. + + + +Software Dependencies +===================== + +* Tor (tor) must be installed. See here: + https://www.torproject.org/docs/installguide.html.en + +* The "Tor-friendly" branch of txsocksx must be installed + ( Once this is merged then you can use upstream txsocksx; + https://github.com/habnabit/txsocksx/pull/8 ) :: + + pip install git+https://github.com/david415/txsocksx.git + +* txtorcon must be installed :: + + pip install txtorcon + +Once these software dependencies are installed and the Tahoe-LAFS node +is restarted, then no further configuration is necessary for "unsafe" +Tor connectivity to other Tahoe-LAFS nodes (client use-case 2 from `Use cases`_, above). + +In order to implement client use-case 3 or server use-cases 2 or 3, further +configuration is necessary. + + +Configuration +============= + +``[node]`` +``anonymize = (boolean, optional)`` + +This specifies two changes in behavior: + 1. Transform all non-Tor client endpoints into Tor client endpoints. + 2. Force ``tub.location`` to be set to "safe" values. + +This option is **critical** to preserving the client's anonymity (client +use-case 3 from `Use cases`_, above). It is also necessary to +preserve a server's anonymity (server use-case 3). + +When ``anonymize`` is set to ``true`` then ``tub.location`` does not need +to be specified... and it is an error to specify a ``tub.location`` value +that contains anything other than "UNREACHABLE" or a Tor Hidden Service +Twisted endpoint descriptor string. + +If server use-case 2 from `Use cases`_ above is desired then you can set +``tub.location`` to a Tor Hidden Service endpoint string AND "AUTODETECT" +like this:: + tub.location = "AUTODETECT,onion:80:hiddenServiceDir=/var/lib/tor/my_service" + +It is an error to specify a ``tub.location`` value that contains "AUTODETECT" +when ``anonymize`` is also set to ``true``. + +Operators of Tahoe-LAFS storage servers wishing to protect the identity of their +storage server should set ``anonymize`` to ``true`` and specify a +Tor Hidden Service endpoint descriptor string for the ``tub.location`` +value in the ``tahoe.cfg`` like this:: + tub.location = "onion:80:hiddenServiceDir=/var/lib/tor/my_service" + +Setting this configuration option is necessary for Server use-cases 2 and 3 +(from `Use cases`_, above). + + +Performance and security issues of Tor Hidden Services +====================================================== + +If you are running a server which does not itself need to be +anonymous, should you make it reachable as a Tor Hidden Service or +not? Or should you make it reachable *both* as a Tor Hidden Service +and as a publicly traceable TCP/IP server? + +There are several trade-offs effected by this decision. + +NAT/Firewall penetration +------------------------ + +Making a server be reachable as a Tor Hidden Service makes it +reachable even if there are NATs or firewalls preventing direct TCP/IP +connections to the server. + +Anonymity +--------- + +Making a Tahoe-LAFS server accessible *only* via Tor Hidden Services +can be used to guarantee that the Tahoe-LAFS clients use Tor to +connect. This prevents misconfigured clients from accidentally +de-anonymizing themselves by connecting to your server through the +traceable Internet. + +Also, interaction, through Tor, with a Tor Hidden Service may be more +protected from network traffic analysis than interaction, through Tor, +with a publicly traceable TCP/IP server. + +**XXX is there a document maintained by Tor developers which substantiates or refutes this belief? +If so we need to link to it. If not, then maybe we should explain more here why we think this?** + +Performance +----------- + +A client connecting to a Tahoe-LAFS server through Tor incurs +substantially higher latency and sometimes worse throughput than the +same client connecting to the same server over a normal traceable +TCP/IP connection. + +A client connecting to a Tahoe-LAFS server which is a Tor Hidden +Service incurs much more latency and probably worse throughput. + +Positive and negative effects on other Tor users +------------------------------------------------ + +Sending your Tahoe-LAFS traffic over Tor adds cover traffic for other +Tor users who are also transmitting bulk data. So that is good for +them -- increasing their anonymity. + +However, it makes the performance of other Tor users' interactive +sessions -- e.g. ssh sessions -- much worse. This is because Tor +doesn't currently have any prioritization or quality-of-service +features, so someone else's ssh keystrokes may have to wait in line +while your bulk file contents get transmitted. The added delay might +make other people's interactive sessions unusable. + +Both of these effects are doubled if you upload or download files to a +Tor Hidden Service, as compared to if you upload or download files +over Tor to a publicly traceable TCP/IP server. + + +Native I2P Integration for Tahoe-LAFS +===================================== + +Really cool and interesting description of how the I2p integration works... + + +Software Dependencies +===================== + +I2p software deps here + + +Configuration +============= + +informative configuration info for i2p users + + +Performance and security issues of I2p (if applicable) +====================================================== + +i2p info here + + +Torsocks: the old way of configuring Tahoe-LAFS to use Tor +========================================================== + +Before the native Tor integration for Tahoe-LAFS, users would use Torsocks. +Please see these pages for more information about Torsocks:: +* https://code.google.com/p/torsocks/ +* https://trac.torproject.org/projects/tor/wiki/doc/torsocks +* https://github.com/dgoulet/torsocks/ + + +Starting And Stopping +--------------------- + +Assuming you have your Tahoe-LAFS node directory placed in **~/.tahoe**, +use Torsocks to start Tahoe like this:: + usewithtor tahoe start + +Likewise if restarting, then with Torsocks like this:: + usewithtor tahoe restart + +After Tahoe is started, additional Tahoe commandline commands will not +need to be executed with Torsocks because the Tahoe gateway long running +process handles all the network connectivity. + + +Configuration +------------- + +Before Tahoe-LAFS had native Tor integration it would deanonymize the user if a +``tub.location`` value is not set. This is because Tahoe-LAFS at that time +defaulted to autodetecting the external IP interface and announced that IP +address to the server. + +Tahoe-LAFS + Torsocks client configuration:: + +* Run a node using ``torsocks``, in client-only mode (i.e. we can + make outbound connections, but other nodes will not be able to connect + to us). The literal '``client.fakelocation``' will not resolve, but will + serve as a reminder to human observers that this node cannot be reached. + "Don't call us.. we'll call you":: + + tub.port = 8098 + tub.location = client.fakelocation:0 + + +Tahoe-LAFS + Torsocks storage server configuration:: + +* Run a node behind a Tor proxy, and make the server available as a Tor + "hidden service". (This assumes that other clients are running their + node with ``torsocks``, such that they are prepared to connect to a + ``.onion`` address.) The hidden service must first be configured in + Tor, by giving it a local port number and then obtaining a ``.onion`` + name, using something in the ``torrc`` file like:: + + HiddenServiceDir /var/lib/tor/hidden_services/tahoe + HiddenServicePort 29212 127.0.0.1:8098 + + once Tor is restarted, the ``.onion`` hostname will be in + ``/var/lib/tor/hidden_services/tahoe/hostname``. Then set up your + ``tahoe.cfg`` like:: + + tub.port = 8098 + tub.location = ualhejtq2p7ohfbb.onion:29212 + +**Troubleshooting** + +On some NetBSD systems, torsocks may segfault:: + + $ torsocks telnet www.google.com 80 + Segmentation fault (core dumped) + +and backtraces show looping libc and syscalls:: + + #7198 0xbbbda26e in *__socket30 (domain=2, type=1, protocol=6) at socket.c:64 + #7199 0xbb84baf9 in socket () from /usr/lib/libc.so.12 + #7200 0xbbbda19b in tsocks_socket (domain=2, type=1, protocol=6) at socket.c:56 + #7201 0xbbbda26e in *__socket30 (domain=2, type=1, protocol=6) at socket.c:64 + #7202 0xbb84baf9 in socket () from /usr/lib/libc.so.12 + [...etc...] + +This has to do with the nature of the torsocks socket() call wrapper being unaware +of NetBSD's internal binary backwards compatibility. + +Information on a the first parts of a solution patch can be found in a tor-dev +thread here from Thomas Klausner: + +* https://lists.torproject.org/pipermail/tor-dev/2013-November/005741.html + +As of this writing, torsocks still exists in the pkgsrc wip tree here: + +* http://pkgsrc.se/wip/torsocks + +but the NetBSD-specific patches have been merged upstream into torsocks as of commitid 6adfba809267d9c217906d6974468db22293ab9b: + +* https://gitweb.torproject.org/torsocks.git/commit/6adfba809267d9c217906d6974468db22293ab9b + + +Legacy I2P Tahoe-LAFS Configuration +=================================== + +legacy i2p info here diff --git a/docs/tor.rst b/docs/tor.rst deleted file mode 100644 index b7238f2d..00000000 --- a/docs/tor.rst +++ /dev/null @@ -1,310 +0,0 @@ -.. -*- coding: utf-8-with-signature; fill-column: 77 -*- - -========================= -Using Tahoe-LAFS with Tor -========================= - -1. `Use cases`_ -2. `Native Tor integration for Tahoe-LAFS`_ -3. `Software Dependencies`_ -4. `Configuration`_ -5. `Performance and security issues of Tor Hidden Services`_ -6. `Torsocks: the old way of configuring Tahoe-LAFS to use Tor`_ - -Use cases -========= - -Tor is an anonymizing network used to help hide the identity of internet -clients and servers. Please see the Tor Project's website for more information: -https://www.torproject.org/ - - -There are three potential use-cases for Tahoe-LAFS on the client side: - -1. User does not care to protect their anonymity or to connect to anonymous - storage servers. This document is not useful to you... so stop reading. - -2. User does not care to protect their anonymity but they wish to connect to - Tahoe-LAFS storage servers which are accessbile only via Tor Hidden Services. - -3. User wishes to always use Tor to protect their anonymity when - connecting to Tahoe-LAFS storage grids (whether or not the storage servers - are Tor Hidden Services) [*]. - - -For Tahoe-LAFS storage servers there are three use-cases: - -1. Storage server operator does not care to protect their own anonymity - nor to help the clients protect theirs. Stop reading this document - and run your Tahoe-LAFS storage server using publicly routed TCP/IP. - -2. The operator does not require anonymity for his storage server, but - he wants it to be available over both publicly routed TCP/IP and - through Tor Hidden Services. One possible reason to do this is - because being reachable through Tor Hidden Services is a convenient - way to bypass NAT or firewall that prevents publicly routed TCP/IP - connections to your server. Another is that making your storage - server reachable through Tor Hidden Services can provide better - protection for your clients who themselves use Tor to protect their - anonymity [*]. - - See this Tor Project page for more information about Tor Hidden Services: - https://www.torproject.org/docs/hidden-services.html.en - -3. The operator wishes to protect their anonymity by making their - Tahoe server accessible only via Tor Hidden Services. - - - -Native Tor integration for Tahoe-LAFS -===================================== - -Native Tor integration for Tahoe-LAFS utilizes the Twisted endpoints API:: -* https://twistedmatrix.com/documents/current/core/howto/endpoints.html - -Twisted's endpoint parser plugin system is extensible via installing additional -Twisted packages. The native Tor integration for Tahoe-LAFS uses -endpoint and parser plugins from the txsocksx and txtorcon modules. -Although the Twisted endpoint API is very flexible it is missing a feature so that -servers can be written in an endpoint agnostic style. We've opened a Twisted trac -ticket for this feature here:: -* https://twistedmatrix.com/trac/ticket/7603 - -Once this ticket is resolved then an additional changes can be made to Foolscap -so that it's server side API is completely endpoint agnostic which will allow -users to easily to use Tahoe-LAFS with many protocols on the server side. - -txsocksx will try to use the system tor's SOCKS port if available; -attempts are made on ports 9050 and 9151. Currently the maintainer of txsocksx -has not merged in our code for the Tor client endpoint. We'll use -this branch until the Tor endpoint code is merged upstream:: -* https://github.com/david415/txsocksx/tree/endpoint_parsers_retry_socks - -txtorcon will use the system tor control port to configure Tor Hidden Services -pending resolution of tor trac ticket 11291:: -* https://trac.torproject.org/projects/tor/ticket/11291 - -See also Tahoe-LAFS Tor related tickets #1010 and #517. - - - -Software Dependencies -===================== - -* Tor (tor) must be installed. See here: - https://www.torproject.org/docs/installguide.html.en - -* The "Tor-friendly" branch of txsocksx must be installed - ( Once this is merged then you can use upstream txsocksx; - https://github.com/habnabit/txsocksx/pull/8 ) :: - - pip install git+https://github.com/david415/txsocksx.git - -* txtorcon must be installed :: - - pip install txtorcon - -Once these software dependencies are installed and the Tahoe-LAFS node -is restarted, then no further configuration is necessary for "unsafe" -Tor connectivity to other Tahoe-LAFS nodes (client use-case 2 from `Use cases`_, above). - -In order to implement client use-case 3 or server use-cases 2 or 3, further -configuration is necessary. - - -Configuration -============= - -``[node]`` -``anonymize = (boolean, optional)`` - -This specifies two changes in behavior: - 1. Transform all non-Tor client endpoints into Tor client endpoints. - 2. Force ``tub.location`` to be set to "safe" values. - -This option is **critical** to preserving the client's anonymity (client -use-case 3 from `Use cases`_, above). It is also necessary to -preserve a server's anonymity (server use-case 3). - -When ``anonymize`` is set to ``true`` then ``tub.location`` does not need -to be specified... and it is an error to specify a ``tub.location`` value -that contains anything other than "UNREACHABLE" or a Tor Hidden Service -Twisted endpoint descriptor string. - -If server use-case 2 from `Use cases`_ above is desired then you can set -``tub.location`` to a Tor Hidden Service endpoint string AND "AUTODETECT" -like this:: - tub.location = "AUTODETECT,onion:80:hiddenServiceDir=/var/lib/tor/my_service" - -It is an error to specify a ``tub.location`` value that contains "AUTODETECT" -when ``anonymize`` is also set to ``true``. - -Operators of Tahoe-LAFS storage servers wishing to protect the identity of their -storage server should set ``anonymize`` to ``true`` and specify a -Tor Hidden Service endpoint descriptor string for the ``tub.location`` -value in the ``tahoe.cfg`` like this:: - tub.location = "onion:80:hiddenServiceDir=/var/lib/tor/my_service" - -Setting this configuration option is necessary for Server use-cases 2 and 3 -(from `Use cases`_, above). - - -Performance and security issues of Tor Hidden Services -====================================================== - -If you are running a server which does not itself need to be -anonymous, should you make it reachable as a Tor Hidden Service or -not? Or should you make it reachable *both* as a Tor Hidden Service -and as a publicly traceable TCP/IP server? - -There are several trade-offs effected by this decision. - -NAT/Firewall penetration ------------------------- - -Making a server be reachable as a Tor Hidden Service makes it -reachable even if there are NATs or firewalls preventing direct TCP/IP -connections to the server. - -Anonymity ---------- - -Making a Tahoe-LAFS server accessible *only* via Tor Hidden Services -can be used to guarantee that the Tahoe-LAFS clients use Tor to -connect. This prevents misconfigured clients from accidentally -de-anonymizing themselves by connecting to your server through the -traceable Internet. - -Also, interaction, through Tor, with a Tor Hidden Service may be more -protected from network traffic analysis than interaction, through Tor, -with a publicly traceable TCP/IP server. - -**XXX is there a document maintained by Tor developers which substantiates or refutes this belief? -If so we need to link to it. If not, then maybe we should explain more here why we think this?** - -Performance ------------ - -A client connecting to a Tahoe-LAFS server through Tor incurs -substantially higher latency and sometimes worse throughput than the -same client connecting to the same server over a normal traceable -TCP/IP connection. - -A client connecting to a Tahoe-LAFS server which is a Tor Hidden -Service incurs much more latency and probably worse throughput. - -Positive and negative effects on other Tor users ------------------------------------------------- - -Sending your Tahoe-LAFS traffic over Tor adds cover traffic for other -Tor users who are also transmitting bulk data. So that is good for -them -- increasing their anonymity. - -However, it makes the performance of other Tor users' interactive -sessions -- e.g. ssh sessions -- much worse. This is because Tor -doesn't currently have any prioritization or quality-of-service -features, so someone else's ssh keystrokes may have to wait in line -while your bulk file contents get transmitted. The added delay might -make other people's interactive sessions unusable. - -Both of these effects are doubled if you upload or download files to a -Tor Hidden Service, as compared to if you upload or download files -over Tor to a publicly traceable TCP/IP server. - - - -Torsocks: the old way of configuring Tahoe-LAFS to use Tor -========================================================== - -Before the native Tor integration for Tahoe-LAFS, users would use Torsocks. -Please see these pages for more information about Torsocks:: -* https://code.google.com/p/torsocks/ -* https://trac.torproject.org/projects/tor/wiki/doc/torsocks -* https://github.com/dgoulet/torsocks/ - - -Starting And Stopping ---------------------- - -Assuming you have your Tahoe-LAFS node directory placed in **~/.tahoe**, -use Torsocks to start Tahoe like this:: - usewithtor tahoe start - -Likewise if restarting, then with Torsocks like this:: - usewithtor tahoe restart - -After Tahoe is started, additional Tahoe commandline commands will not -need to be executed with Torsocks because the Tahoe gateway long running -process handles all the network connectivity. - - -Configuration -------------- - -Before Tahoe-LAFS had native Tor integration it would deanonymize the user if a -``tub.location`` value is not set. This is because Tahoe-LAFS at that time -defaulted to autodetecting the external IP interface and announced that IP -address to the server. - -Tahoe-LAFS + Torsocks client configuration:: - -* Run a node using ``torsocks``, in client-only mode (i.e. we can - make outbound connections, but other nodes will not be able to connect - to us). The literal '``client.fakelocation``' will not resolve, but will - serve as a reminder to human observers that this node cannot be reached. - "Don't call us.. we'll call you":: - - tub.port = 8098 - tub.location = client.fakelocation:0 - - -Tahoe-LAFS + Torsocks storage server configuration:: - -* Run a node behind a Tor proxy, and make the server available as a Tor - "hidden service". (This assumes that other clients are running their - node with ``torsocks``, such that they are prepared to connect to a - ``.onion`` address.) The hidden service must first be configured in - Tor, by giving it a local port number and then obtaining a ``.onion`` - name, using something in the ``torrc`` file like:: - - HiddenServiceDir /var/lib/tor/hidden_services/tahoe - HiddenServicePort 29212 127.0.0.1:8098 - - once Tor is restarted, the ``.onion`` hostname will be in - ``/var/lib/tor/hidden_services/tahoe/hostname``. Then set up your - ``tahoe.cfg`` like:: - - tub.port = 8098 - tub.location = ualhejtq2p7ohfbb.onion:29212 - -**Troubleshooting** - -On some NetBSD systems, torsocks may segfault:: - - $ torsocks telnet www.google.com 80 - Segmentation fault (core dumped) - -and backtraces show looping libc and syscalls:: - - #7198 0xbbbda26e in *__socket30 (domain=2, type=1, protocol=6) at socket.c:64 - #7199 0xbb84baf9 in socket () from /usr/lib/libc.so.12 - #7200 0xbbbda19b in tsocks_socket (domain=2, type=1, protocol=6) at socket.c:56 - #7201 0xbbbda26e in *__socket30 (domain=2, type=1, protocol=6) at socket.c:64 - #7202 0xbb84baf9 in socket () from /usr/lib/libc.so.12 - [...etc...] - -This has to do with the nature of the torsocks socket() call wrapper being unaware -of NetBSD's internal binary backwards compatibility. - -Information on a the first parts of a solution patch can be found in a tor-dev -thread here from Thomas Klausner: - -* https://lists.torproject.org/pipermail/tor-dev/2013-November/005741.html - -As of this writing, torsocks still exists in the pkgsrc wip tree here: - -* http://pkgsrc.se/wip/torsocks - -but the NetBSD-specific patches have been merged upstream into torsocks as of commitid 6adfba809267d9c217906d6974468db22293ab9b: - -* https://gitweb.torproject.org/torsocks.git/commit/6adfba809267d9c217906d6974468db22293ab9b