security-and-privacy/gnupg
security-and-privacy/gnupg
1
0
Fork 0
mirror of git://git.gnupg.org/gnupg.git synced 2024-12-22 10:19:57 +01:00
Code Activity

dirmngr: Implement querying nameservers over IPv6.

Browse Source 
* 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@g10code.com>
This commit is contained in:
Justus Winter 2017-06-13 11:33:06 +02:00
parent e80925171d
commit 15d2a00993
No known key found for this signature in database
GPG Key ID: DD1A52F9DA8C9020
1 changed files with 179 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

180
dirmngr/dns.c
View File

@ -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);