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.
This commit is contained in:
Nick Mathewson 2019-09-10 11:07:25 -04:00
parent 51475aee57
commit 97f7efa9e3
2 changed files with 10 additions and 2 deletions

5
changes/ticket31687_2 Normal file
View File

@ -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.

View File

@ -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;