commit 97f7efa9e3316e4e8970a87a1ee53fd4fd0075d8 Author: Nick Mathewson nickm@torproject.org Date: Tue Sep 10 11:07:25 2019 -0400
pf: when extracting an IPv6 address, make sure we got an IPv6 address
Our code assumes that when we're configured to get IPv6 addresses out of a TRANS_PF transparent proxy connection, we actually will. But we didn't check that, and so FreeBSD started warning us about a potential NULL pointer dereference.
Fixes part of bug 31687; bugfix on 0.2.3.4-alpha when this code was added. --- changes/ticket31687_2 | 5 +++++ src/core/or/connection_edge.c | 7 +++++-- 2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/changes/ticket31687_2 b/changes/ticket31687_2 new file mode 100644 index 000000000..eadc69827 --- /dev/null +++ b/changes/ticket31687_2 @@ -0,0 +1,5 @@ + o Minor bugfixes (FreeBSD, PF-based proxy, IPv6): + - When extracting an IPv6 address from a PF-based proxy, verify + that we are actually configured to receive an IPv6 address, + and log an internal error if not. Fixes part of bug 31687; + bugfix on 0.2.3.4-alpha. diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c index e4b3455d1..7cc67d7f5 100644 --- a/src/core/or/connection_edge.c +++ b/src/core/or/connection_edge.c @@ -2547,8 +2547,11 @@ destination_from_pf(entry_connection_t *conn, socks_request_t *req) } else if (proxy_sa->sa_family == AF_INET6) { struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)proxy_sa; pnl.af = AF_INET6; - memcpy(&pnl.saddr.v6, tor_addr_to_in6(&ENTRY_TO_CONN(conn)->addr), - sizeof(struct in6_addr)); + const struct in6_addr *dest_in6 = + tor_addr_to_in6(&ENTRY_TO_CONN(conn)->addr); + if (BUG(!dest_in6)) + return -1; + memcpy(&pnl.saddr.v6, dest_in6, sizeof(struct in6_addr)); pnl.sport = htons(ENTRY_TO_CONN(conn)->port); memcpy(&pnl.daddr.v6, &sin6->sin6_addr, sizeof(struct in6_addr)); pnl.dport = sin6->sin6_port;