[tor-commits] [tor/release-0.2.2] add a release blurb
arma at torproject.org
arma at torproject.org
Thu Oct 27 23:52:31 UTC 2011
commit 135ad197aead90adac887201fc99ec537c03e40a
Author: Roger Dingledine <arma at torproject.org>
Date: Wed Oct 26 20:20:43 2011 -0400
add a release blurb
---
ChangeLog | 32 +++++++++++++++-
ReleaseNotes | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 144 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 80b48d3..2c20536 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,31 @@
Changes in version 0.2.2.34 - 2011-10-26
- o Privacy/anonymity fixes:
+ 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
@@ -18,6 +44,8 @@ Changes in version 0.2.2.34 - 2011-10-26
"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
@@ -27,7 +55,7 @@ Changes in version 0.2.2.34 - 2011-10-26
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
+ 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".
diff --git a/ReleaseNotes b/ReleaseNotes
index a04bfae..8e3a60b 100644
--- a/ReleaseNotes
+++ b/ReleaseNotes
@@ -3,6 +3,120 @@ This document summarizes new features and bugfixes in each stable release
of Tor. If you want to see more detailed descriptions of the changes in
each development snapshot, see the ChangeLog file.
+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 0.2.2.33 - 2011-09-13
Tor 0.2.2.33 fixes several bugs, and includes a slight tweak to Tor's
TLS handshake that makes relays and bridges that run this new version
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