From 4c06c619faceb5d158a725d97fda45cadb2cf9c9 Mon Sep 17 00:00:00 2001 From: Nick Mathewson Date: Tue, 18 May 2021 08:40:09 -0400 Subject: Use a more secure hash function for the circuitmux hashtable. Fixes bug 40931; bugfix on 0.2.4.4-alpha. Also tracked as TROVE-2021-005. This issue was reported by Jann Horn from Google's Project Zero. --- changes/bug40391 | 9 +++++++++ 1 file changed, 9 insertions(+) create mode 100644 changes/bug40391 (limited to 'changes') diff --git a/changes/bug40391 b/changes/bug40391 new file mode 100644 index 0000000000..e3c186275f --- /dev/null +++ b/changes/bug40391 @@ -0,0 +1,9 @@ + o Major bugfixes (security): + - Resist a hashtable-based CPU denial-of-service attack against + relays. Previously we used a naive unkeyed hash function to look up + circuits in a circuitmux object. An attacker could exploit this to + construct circuits with chosen circuit IDs in order to try to create + collisions and make the hash table inefficient. Now we use a SipHash + construction for this hash table instead. Fixes bug 40391; bugfix on + 0.2.4.4-alpha. This issue is also tracked as TROVE-2021-005. + Reported by Jann Horn from Google's Project Zero. -- cgit v1.2.3-54-g00ecf