[Pkg-gnupg-commit] [gnupg2] 52/185: dirmngr: Implement querying nameservers over IPv6.
Daniel Kahn Gillmor
dkg at fifthhorseman.net
Mon Aug 7 11:55:19 UTC 2017
This is an automated email from the git hooks/post-receive script.
dkg pushed a commit to branch experimental
in repository gnupg2.
commit 15d2a009931f44a60b9df6325f837add208459d6
Author: Justus Winter <justus at g10code.com>
Date: Tue Jun 13 11:33:06 2017 +0200
dirmngr: Implement querying nameservers over IPv6.
* dirmngr/dns.c (dns_so_check): Reinitialize sockets on address family
mismatch.
(enum dns_res_state): New states for querying over IPv6.
(dns_res_exec): Implement the new states by copying and modifying the
IPv4 variants. Branch to their respective counterparts if the current
list of resolvers using the current address family is exhausted.
--
This allows dirmngr to resolve names on systems where the nameservers
are only reachable via IPv6.
GnuPG-bug-id: 2990
Signed-off-by: Justus Winter <justus at g10code.com>
---
dirmngr/dns.c | 180 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 179 insertions(+), 1 deletion(-)
diff --git a/dirmngr/dns.c b/dirmngr/dns.c
index c660cf5..a89411b 100644
--- a/dirmngr/dns.c
+++ b/dirmngr/dns.c
@@ -7583,6 +7583,22 @@ int dns_so_check(struct dns_socket *so) {
retry:
switch (so->state) {
case DNS_SO_UDP_INIT:
+ if (so->remote.ss_family != so->local.ss_family) {
+ /* Family mismatch. Reinitialize. */
+ if ((error = dns_so_closefd(so, &so->udp)))
+ goto error;
+ if ((error = dns_so_closefd(so, &so->tcp)))
+ goto error;
+
+ /* If the user supplied an interface
+ statement, that is gone now. Sorry. */
+ memset(&so->local, 0, sizeof so->local);
+ so->local.ss_family = so->remote.ss_family;
+
+ if (-1 == (so->udp = dns_socket((struct sockaddr *)&so->local, SOCK_DGRAM, &error)))
+ goto error;
+ }
+
so->state++;
case DNS_SO_UDP_CONN:
error = dns_connect(so->udp, (struct sockaddr *)&so->remote, dns_sa_len(&so->remote));
@@ -7621,6 +7637,19 @@ retry:
so->state++;
case DNS_SO_TCP_INIT:
+ if (so->remote.ss_family != so->local.ss_family) {
+ /* Family mismatch. Reinitialize. */
+ if ((error = dns_so_closefd(so, &so->udp)))
+ goto error;
+ if ((error = dns_so_closefd(so, &so->tcp)))
+ goto error;
+
+ /* If the user supplied an interface
+ statement, that is gone now. Sorry. */
+ memset(&so->local, 0, sizeof so->local);
+ so->local.ss_family = so->remote.ss_family;
+ }
+
if (dns_so_tcp_keep(so)) {
so->state = DNS_SO_TCP_SEND;
@@ -8072,6 +8101,8 @@ enum dns_res_state {
DNS_R_RESOLV1_NS, /* Epilog: Inspect answer */
DNS_R_FOREACH_A,
DNS_R_QUERY_A,
+ DNS_R_FOREACH_AAAA,
+ DNS_R_QUERY_AAAA,
DNS_R_CNAME0_A,
DNS_R_CNAME1_A,
@@ -8731,8 +8762,22 @@ exec:
F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
if (!dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
- if (!dns_rr_i_count(&F->hints_j))
+ if (!dns_rr_i_count(&F->hints_j)) {
+ /* Check if we have in fact servers
+ with an IPv6 address. */
+ dns_rr_i_init(&F->hints_j, F->hints);
+ F->hints_j.name = u.ns.host;
+ F->hints_j.type = DNS_T_AAAA;
+ F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
+ if (dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
+ /* We do. Reinitialize
+ iterator and handle it. */
+ dns_rr_i_init(&F->hints_j, F->hints);
+ dgoto(R->sp, DNS_R_FOREACH_AAAA);
+ }
+
dgoto(R->sp, DNS_R_RESOLV0_NS);
+ }
dgoto(R->sp, DNS_R_FOREACH_NS);
}
@@ -8833,6 +8878,139 @@ exec:
/* XXX: Should we copy F->answer to R->nodata? */
dgoto(R->sp, DNS_R_FOREACH_A);
+ case DNS_R_FOREACH_AAAA: {
+ struct dns_aaaa aaaa;
+ struct sockaddr_in6 sin6;
+
+ /*
+ * NOTE: Iterator initialized in DNS_R_FOREACH_NS because
+ * this state is re-entrant, but we need to reset
+ * .name to a valid pointer each time.
+ */
+ if ((error = dns_ns_parse(&u.ns, &F->hints_ns, F->hints)))
+ goto error;
+
+ F->hints_j.name = u.ns.host;
+ F->hints_j.type = DNS_T_AAAA;
+ F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
+
+ if (!dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
+ if (!dns_rr_i_count(&F->hints_j)) {
+ /* Check if we have in fact servers
+ with an IPv4 address. */
+ dns_rr_i_init(&F->hints_j, F->hints);
+ F->hints_j.name = u.ns.host;
+ F->hints_j.type = DNS_T_A;
+ F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
+ if (dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
+ /* We do. Reinitialize
+ iterator and handle it. */
+ dns_rr_i_init(&F->hints_j, F->hints);
+ dgoto(R->sp, DNS_R_FOREACH_A);
+ }
+
+ dgoto(R->sp, DNS_R_RESOLV0_NS);
+ }
+
+ dgoto(R->sp, DNS_R_FOREACH_NS);
+ }
+
+ if ((error = dns_aaaa_parse(&aaaa, &rr, F->hints)))
+ goto error;
+
+ memset(&sin6, '\0', sizeof sin6); /* NB: silence valgrind */
+ sin6.sin6_family = AF_INET6;
+ sin6.sin6_addr = aaaa.addr;
+ if (R->sp == 0)
+ sin6.sin6_port = dns_hints_port(R->hints, AF_INET, &sin6.sin6_addr);
+ else
+ sin6.sin6_port = htons(53);
+
+ if (DNS_DEBUG) {
+ char addr[INET6_ADDRSTRLEN + 1];
+ dns_aaaa_print(addr, sizeof addr, &aaaa);
+ dns_header(F->query)->qid = dns_so_mkqid(&R->so);
+ DNS_SHOW(F->query, "ASKING: %s/%s @ DEPTH: %u)", u.ns.host, addr, R->sp);
+ }
+
+ dns_trace_setcname(R->trace, u.ns.host, (struct sockaddr *)&sin6);
+
+ if ((error = dns_so_submit(&R->so, F->query, (struct sockaddr *)&sin6)))
+ goto error;
+
+ F->state++;
+ }
+ case DNS_R_QUERY_AAAA:
+ if (dns_so_elapsed(&R->so) >= dns_resconf_timeout(R->resconf))
+ dgoto(R->sp, DNS_R_FOREACH_AAAA);
+
+ if ((error = dns_so_check(&R->so)))
+ goto error;
+
+ if (!dns_p_setptr(&F->answer, dns_so_fetch(&R->so, &error)))
+ goto error;
+
+ if (DNS_DEBUG) {
+ DNS_SHOW(F->answer, "ANSWER @ DEPTH: %u)", R->sp);
+ }
+
+ if (dns_p_rcode(F->answer) == DNS_RC_FORMERR ||
+ dns_p_rcode(F->answer) == DNS_RC_NOTIMP ||
+ dns_p_rcode(F->answer) == DNS_RC_BADVERS) {
+ /* Temporarily disable EDNS0 and try again. */
+ if (F->qflags & DNS_Q_EDNS0) {
+ F->qflags &= ~DNS_Q_EDNS0;
+ if ((error = dns_q_remake(&F->query, F->qflags)))
+ goto error;
+
+ dgoto(R->sp, DNS_R_FOREACH_AAAA);
+ }
+ }
+
+ if ((error = dns_rr_parse(&rr, 12, F->query)))
+ goto error;
+
+ if (!(len = dns_d_expand(u.name, sizeof u.name, rr.dn.p, F->query, &error)))
+ goto error;
+ else if (len >= sizeof u.name)
+ goto toolong;
+
+ dns_rr_foreach(&rr, F->answer, .section = DNS_S_AN, .name = u.name, .type = rr.type) {
+ dgoto(R->sp, DNS_R_FINISH); /* Found */
+ }
+
+ dns_rr_foreach(&rr, F->answer, .section = DNS_S_AN, .name = u.name, .type = DNS_T_CNAME) {
+ F->ans_cname = rr;
+
+ dgoto(R->sp, DNS_R_CNAME0_A);
+ }
+
+ /*
+ * XXX: The condition here should probably check whether
+ * R->sp == 0, because DNS_R_SEARCH runs regardless of
+ * options.recurse. See DNS_R_BIND.
+ */
+ if (!R->resconf->options.recurse) {
+ /* Make first answer our tentative answer */
+ if (!R->nodata)
+ dns_p_movptr(&R->nodata, &F->answer);
+
+ dgoto(R->sp, DNS_R_SEARCH);
+ }
+
+ dns_rr_foreach(&rr, F->answer, .section = DNS_S_NS, .type = DNS_T_NS) {
+ dns_p_movptr(&F->hints, &F->answer);
+
+ dgoto(R->sp, DNS_R_ITERATE);
+ }
+
+ /* XXX: Should this go further up? */
+ if (dns_header(F->answer)->aa)
+ dgoto(R->sp, DNS_R_FINISH);
+
+ /* XXX: Should we copy F->answer to R->nodata? */
+
+ dgoto(R->sp, DNS_R_FOREACH_AAAA);
case DNS_R_CNAME0_A:
if (&F[1] >= endof(R->stack))
dgoto(R->sp, DNS_R_FINISH);
--
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