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@@ -124,6 +124,229 @@ Changes in version 0.2.3.6-alpha - 2011-10-26 should help prevent mistakes in the future. Fixes bug 3512. +Changes in version 0.2.2.34 - 2011-10-26 + Tor 0.2.2.34 fixes a critical anonymity vulnerability where an attacker + can deanonymize Tor users. Everybody should upgrade. + + The attack relies on four components: 1) Clients reuse their TLS cert + when talking to different relays, so relays can recognize a user by + the identity key in her cert. 2) An attacker who knows the client's + identity key can probe each guard relay to see if that identity key + is connected to that guard relay right now. 3) A variety of active + attacks in the literature (starting from "Low-Cost Traffic Analysis + of Tor" by Murdoch and Danezis in 2005) allow a malicious website to + discover the guard relays that a Tor user visiting the website is using. + 4) Clients typically pick three guards at random, so the set of guards + for a given user could well be a unique fingerprint for her. This + release fixes components #1 and #2, which is enough to block the attack; + the other two remain as open research problems. Special thanks to + "frosty_un" for reporting the issue to us! + + Clients should upgrade so they are no longer recognizable by the TLS + certs they present. Relays should upgrade so they no longer allow a + remote attacker to probe them to test whether unpatched clients are + currently connected to them. + + This release also fixes several vulnerabilities that allow an attacker + to enumerate bridge relays. Some bridge enumeration attacks still + remain; see for example proposal 188. + + o Privacy/anonymity fixes (clients): + - Clients and bridges no longer send TLS certificate chains on + outgoing OR connections. Previously, each client or bridge + would use the same cert chain for all outgoing OR connections + for up to 24 hours, which allowed any relay that the client or + bridge contacted to determine which entry guards it is using. + Fixes CVE-2011-2768. Bugfix on 0.0.9pre5; found by "frosty_un". + - If a relay receives a CREATE_FAST cell on a TLS connection, it + no longer considers that connection as suitable for satisfying a + circuit EXTEND request. Now relays can protect clients from the + CVE-2011-2768 issue even if the clients haven't upgraded yet. + - Directory authorities no longer assign the Guard flag to relays + that haven't upgraded to the above "refuse EXTEND requests + to client connections" fix. Now directory authorities can + protect clients from the CVE-2011-2768 issue even if neither + the clients nor the relays have upgraded yet. There's a new + "GiveGuardFlagTo_CVE_2011_2768_VulnerableRelays" config option + to let us transition smoothly, else tomorrow there would be no + guard relays. + + o Privacy/anonymity fixes (bridge enumeration): + - Bridge relays now do their directory fetches inside Tor TLS + connections, like all the other clients do, rather than connecting + directly to the DirPort like public relays do. Removes another + avenue for enumerating bridges. Fixes bug 4115; bugfix on 0.2.0.35. + - Bridges relays now build circuits for themselves in a more similar + way to how clients build them. Removes another avenue for + enumerating bridges. Fixes bug 4124; bugfix on 0.2.0.3-alpha, + when bridges were introduced. + - Bridges now refuse CREATE or CREATE_FAST cells on OR connections + that they initiated. Relays could distinguish incoming bridge + connections from client connections, creating another avenue for + enumerating bridges. Fixes CVE-2011-2769. Bugfix on 0.2.0.3-alpha. + Found by "frosty_un". + + o Major bugfixes: + - Fix a crash bug when changing node restrictions while a DNS lookup + is in-progress. Fixes bug 4259; bugfix on 0.2.2.25-alpha. Bugfix + by "Tey'". + - Don't launch a useless circuit after failing to use one of a + hidden service's introduction points. Previously, we would + launch a new introduction circuit, but not set the hidden service + which that circuit was intended to connect to, so it would never + actually be used. A different piece of code would then create a + new introduction circuit correctly. Bug reported by katmagic and + found by Sebastian Hahn. Bugfix on 0.2.1.13-alpha; fixes bug 4212. + + o Minor bugfixes: + - Change an integer overflow check in the OpenBSD_Malloc code so + that GCC is less likely to eliminate it as impossible. Patch + from Mansour Moufid. Fixes bug 4059. + - When a hidden service turns an extra service-side introduction + circuit into a general-purpose circuit, free the rend_data and + intro_key fields first, so we won't leak memory if the circuit + is cannibalized for use as another service-side introduction + circuit. Bugfix on 0.2.1.7-alpha; fixes bug 4251. + - Bridges now skip DNS self-tests, to act a little more stealthily. + Fixes bug 4201; bugfix on 0.2.0.3-alpha, which first introduced + bridges. Patch by "warms0x". + - Fix internal bug-checking logic that was supposed to catch + failures in digest generation so that it will fail more robustly + if we ask for a nonexistent algorithm. Found by Coverity Scan. + Bugfix on 0.2.2.1-alpha; fixes Coverity CID 479. + - Report any failure in init_keys() calls launched because our + IP address has changed. Spotted by Coverity Scan. Bugfix on + 0.1.1.4-alpha; fixes CID 484. + + o Minor bugfixes (log messages and documentation): + - Remove a confusing dollar sign from the example fingerprint in the + man page, and also make the example fingerprint a valid one. Fixes + bug 4309; bugfix on 0.2.1.3-alpha. + - The next version of Windows will be called Windows 8, and it has + a major version of 6, minor version of 2. Correctly identify that + version instead of calling it "Very recent version". Resolves + ticket 4153; reported by funkstar. + - Downgrade log messages about circuit timeout calibration from + "notice" to "info": they don't require or suggest any human + intervention. Patch from Tom Lowenthal. Fixes bug 4063; + bugfix on 0.2.2.14-alpha. + + o Minor features: + - Turn on directory request statistics by default and include them in + extra-info descriptors. Don't break if we have no GeoIP database. + Backported from 0.2.3.1-alpha; implements ticket 3951. + - Update to the October 4 2011 Maxmind GeoLite Country database. + + +Changes in version 0.2.1.31 - 2011-10-26 + Tor 0.2.1.31 backports important security and privacy fixes for + oldstable. This release is intended only for package maintainers and + others who cannot use the 0.2.2 stable series. All others should be + using Tor 0.2.2.x or newer. + + o Security fixes (also included in 0.2.2.x): + - Replace all potentially sensitive memory comparison operations + with versions whose runtime does not depend on the data being + compared. This will help resist a class of attacks where an + adversary can use variations in timing information to learn + sensitive data. Fix for one case of bug 3122. (Safe memcmp + implementation by Robert Ransom based partially on code by DJB.) + - Fix an assert in parsing router descriptors containing IPv6 + addresses. This one took down the directory authorities when + somebody tried some experimental code. Bugfix on 0.2.1.3-alpha. + + o Privacy/anonymity fixes (also included in 0.2.2.x): + - Clients and bridges no longer send TLS certificate chains on + outgoing OR connections. Previously, each client or bridge + would use the same cert chain for all outgoing OR connections + for up to 24 hours, which allowed any relay that the client or + bridge contacted to determine which entry guards it is using. + Fixes CVE-2011-2768. Bugfix on 0.0.9pre5; found by frosty_un. + - If a relay receives a CREATE_FAST cell on a TLS connection, it + no longer considers that connection as suitable for satisfying a + circuit EXTEND request. Now relays can protect clients from the + CVE-2011-2768 issue even if the clients haven't upgraded yet. + - Bridges now refuse CREATE or CREATE_FAST cells on OR connections + that they initiated. Relays could distinguish incoming bridge + connections from client connections, creating another avenue for + enumerating bridges. Fixes CVE-2011-2769. Bugfix on 0.2.0.3-alpha. + Found by "frosty_un". + - When receiving a hidden service descriptor, check that it is for + the hidden service we wanted. Previously, Tor would store any + hidden service descriptors that a directory gave it, whether it + wanted them or not. This wouldn't have let an attacker impersonate + a hidden service, but it did let directories pre-seed a client + with descriptors that it didn't want. Bugfix on 0.0.6. + - Avoid linkability based on cached hidden service descriptors: forget + all hidden service descriptors cached as a client when processing a + SIGNAL NEWNYM command. Fixes bug 3000; bugfix on 0.0.6. + - Make the bridge directory authority refuse to answer directory + requests for "all" descriptors. It used to include bridge + descriptors in its answer, which was a major information leak. + Found by "piebeer". Bugfix on 0.2.0.3-alpha. + - Don't attach new streams to old rendezvous circuits after SIGNAL + NEWNYM. Previously, we would keep using an existing rendezvous + circuit if it remained open (i.e. if it were kept open by a + long-lived stream, or if a new stream were attached to it before + Tor could notice that it was old and no longer in use). Bugfix on + 0.1.1.15-rc; fixes bug 3375. + + o Minor bugfixes (also included in 0.2.2.x): + - When we restart our relay, we might get a successful connection + from the outside before we've started our reachability tests, + triggering a warning: "ORPort found reachable, but I have no + routerinfo yet. Failing to inform controller of success." This + bug was harmless unless Tor is running under a controller + like Vidalia, in which case the controller would never get a + REACHABILITY_SUCCEEDED status event. Bugfix on 0.1.2.6-alpha; + fixes bug 1172. + - Build correctly on OSX with zlib 1.2.4 and higher with all warnings + enabled. Fixes bug 1526. + - Remove undocumented option "-F" from tor-resolve: it hasn't done + anything since 0.2.1.16-rc. + - Avoid signed/unsigned comparisons by making SIZE_T_CEILING unsigned. + None of the cases where we did this before were wrong, but by making + this change we avoid warnings. Fixes bug 2475; bugfix on 0.2.1.28. + - Fix a rare crash bug that could occur when a client was configured + with a large number of bridges. Fixes bug 2629; bugfix on + 0.2.1.2-alpha. Bugfix by trac user "shitlei". + - Correct the warning displayed when a rendezvous descriptor exceeds + the maximum size. Fixes bug 2750; bugfix on 0.2.1.5-alpha. Found by + John Brooks. + - Fix an uncommon assertion failure when running with DNSPort under + heavy load. Fixes bug 2933; bugfix on 0.2.0.1-alpha. + - When warning about missing zlib development packages during compile, + give the correct package names. Bugfix on 0.2.0.1-alpha. + - Require that introduction point keys and onion keys have public + exponent 65537. Bugfix on 0.2.0.10-alpha. + - Do not crash when our configuration file becomes unreadable, for + example due to a permissions change, between when we start up + and when a controller calls SAVECONF. Fixes bug 3135; bugfix + on 0.0.9pre6. + - Fix warnings from GCC 4.6's "-Wunused-but-set-variable" option. + Fixes bug 3208. + - Always NUL-terminate the sun_path field of a sockaddr_un before + passing it to the kernel. (Not a security issue: kernels are + smart enough to reject bad sockaddr_uns.) Found by Coverity; + CID #428. Bugfix on Tor 0.2.0.3-alpha. + - Don't stack-allocate the list of supplementary GIDs when we're + about to log them. Stack-allocating NGROUPS_MAX gid_t elements + could take up to 256K, which is way too much stack. Found by + Coverity; CID #450. Bugfix on 0.2.1.7-alpha. + + o Minor bugfixes (only in 0.2.1.x): + - Resume using micro-version numbers in 0.2.1.x: our Debian packages + rely on them. Bugfix on 0.2.1.30. + - Use git revisions instead of svn revisions when generating our + micro-version numbers. Bugfix on 0.2.1.15-rc; fixes bug 2402. + + o Minor features (also included in 0.2.2.x): + - Adjust the expiration time on our SSL session certificates to + better match SSL certs seen in the wild. Resolves ticket 4014. + - Allow nameservers with IPv6 address. Resolves bug 2574. + - Update to the October 4 2011 Maxmind GeoLite Country database. + + Changes in version 0.2.3.5-alpha - 2011-09-28 Tor 0.2.3.5-alpha fixes two bugs that make it possible to enumerate bridge relays; fixes an assertion error that many users started hitting |