commit dd68d596cdf68999c0cb4c0caf594d8580eaba40 Author: Nick Mathewson nickm@torproject.org Date: Tue Jan 31 16:09:49 2012 -0500

Set IPV6_V6ONLY on listener sockets bound to IPv6 addresses.

If we don't do this, [::] can be interpreted to mean all v4 and all v6 addresses. Found by dcf. Fixes bug 4760. See RFC 3493 section 5.3 for more info. --- changes/bug4760 | 4 ++++ src/or/connection.c | 19 +++++++++++++++++++ 2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/changes/bug4760 b/changes/bug4760 new file mode 100644 index 0000000..ea8d16e --- /dev/null +++ b/changes/bug4760 @@ -0,0 +1,4 @@ + o Minor bugfixes: + - When binding to an IPv6 address, set the IPV6_V6ONLY socket + option, so that the IP stack doesn't decide to use it for IPv4 + too. Fixes bug 4760; bugfix on 0.2.3.9-alpha. diff --git a/src/or/connection.c b/src/or/connection.c index bf65e8e..06a7562 100644 --- a/src/or/connection.c +++ b/src/or/connection.c @@ -902,6 +902,25 @@ connection_listener_new(const struct sockaddr *listensockaddr,

make_socket_reuseable(s);

+#ifdef IPV6_V6ONLY + if (listensockaddr->sa_family == AF_INET6) { +#ifdef _WIN32 + /* In Redmond, this kind of thing passes for standards-conformance. */ + DWORD one = 1; +#else + int one = 1; +#endif + /* We need to set IPV6_V6ONLY so that this socket can't get used for + * IPv4 connections. */ + if (setsockopt(s,IPPROTO_IPV6, IPV6_V6ONLY, (void*)&one, sizeof(one))<0) { + int e = tor_socket_errno(s); + log_warn(LD_NET, "Error setting IPV6_V6ONLY flag: %s", + tor_socket_strerror(e)); + /* Keep going; probably not harmful. */ + } + } +#endif + if (bind(s,listensockaddr,socklen) < 0) { const char *helpfulhint = ""; int e = tor_socket_errno(s);