commit 691c7171878371f98c4b0a32992f7d9ed9b1ac74 Author: David Goulet dgoulet@torproject.org Date: Fri Jan 15 12:54:07 2021 -0500

Revert "IPv6 sybil: consider addresses in the same /64 to be equal."

This reverts commit d07f17f67685d75fec8a851b3ae3d157c1e31aa3.

We don't want to consider an entire routable IPv6 network as sybil if more than 2 relays happen to be on it. For path selection it is very important but not for selecting relays in the consensus.

Fixes #40243 --- changes/ticket40243 | 4 ++++ src/feature/dirauth/dirvote.c | 3 +-- 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/changes/ticket40243 b/changes/ticket40243 new file mode 100644 index 0000000000..548ec95ab4 --- /dev/null +++ b/changes/ticket40243 @@ -0,0 +1,4 @@ + o Major bugfixes (authority, IPv6): + - Do not consider multiple relays in the same IPv6 network to be sybils. + Sybils are selected based on the /128 now, not the /64. Fixes bug 40243; + bugfix on 0.4.5.1-alpha. diff --git a/src/feature/dirauth/dirvote.c b/src/feature/dirauth/dirvote.c index a1f9bb28ae..6824af815f 100644 --- a/src/feature/dirauth/dirvote.c +++ b/src/feature/dirauth/dirvote.c @@ -4219,8 +4219,7 @@ compare_routerinfo_addrs_by_family(const routerinfo_t *a, { const tor_addr_t *addr1 = (family==AF_INET) ? &a->ipv4_addr : &a->ipv6_addr; const tor_addr_t *addr2 = (family==AF_INET) ? &b->ipv4_addr : &b->ipv6_addr; - const int maskbits = (family==AF_INET) ? 32 : 64; - return tor_addr_compare_masked(addr1, addr2, maskbits, CMP_EXACT); + return tor_addr_compare(addr1, addr2, CMP_EXACT); }

/** Helper for sorting: compares two ipv4 routerinfos first by ipv4 address,