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Diffstat (limited to 'src/resolve/resolved-dns-scope.c')
-rw-r--r--src/resolve/resolved-dns-scope.c278
1 files changed, 177 insertions, 101 deletions
diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c
index 09e6872d26..8a52d66fad 100644
--- a/src/resolve/resolved-dns-scope.c
+++ b/src/resolve/resolved-dns-scope.c
@@ -30,6 +30,7 @@
#include "random-util.h"
#include "resolved-dns-scope.h"
#include "resolved-llmnr.h"
+#include "resolved-mdns.h"
#include "socket-util.h"
#include "strv.h"
@@ -56,9 +57,25 @@ int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int
s->family = family;
s->resend_timeout = MULTICAST_RESEND_TIMEOUT_MIN_USEC;
+ s->dnssec_mode = _DNSSEC_MODE_INVALID;
+
+ if (protocol == DNS_PROTOCOL_DNS) {
+ /* Copy DNSSEC mode from the link if it is set there,
+ * otherwise take the manager's DNSSEC mode. Note that
+ * we copy this only at scope creation time, and do
+ * not update it from the on, even if the setting
+ * changes. */
+
+ if (l)
+ s->dnssec_mode = link_get_dnssec_mode(l);
+ else
+ s->dnssec_mode = manager_get_dnssec_mode(m);
+ }
+
LIST_PREPEND(scopes, m->dns_scopes, s);
dns_scope_llmnr_membership(s, true);
+ dns_scope_mdns_membership(s, true);
log_debug("New scope on link %s, protocol %s, family %s", l ? l->name : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family));
@@ -79,7 +96,8 @@ static void dns_scope_abort_transactions(DnsScope *s) {
* freed while we still look at it */
t->block_gc++;
- dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
+ if (DNS_TRANSACTION_IS_LIVE(t->state))
+ dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
t->block_gc--;
dns_transaction_free(t);
@@ -95,6 +113,7 @@ DnsScope* dns_scope_free(DnsScope *s) {
log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->name : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family));
dns_scope_llmnr_membership(s, false);
+ dns_scope_mdns_membership(s, false);
dns_scope_abort_transactions(s);
while (s->query_candidates)
@@ -158,18 +177,15 @@ void dns_scope_packet_lost(DnsScope *s, usec_t usec) {
s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC);
}
-int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
+static int dns_scope_emit_one(DnsScope *s, int fd, DnsPacket *p) {
union in_addr_union addr;
int ifindex = 0, r;
int family;
- uint16_t port;
uint32_t mtu;
- size_t saved_size = 0;
assert(s);
assert(p);
assert(p->protocol == s->protocol);
- assert((s->protocol == DNS_PROTOCOL_DNS) != (fd < 0));
if (s->link) {
mtu = s->link->mtu;
@@ -178,30 +194,13 @@ int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
mtu = manager_find_mtu(s->manager);
switch (s->protocol) {
+
case DNS_PROTOCOL_DNS:
- assert(server);
+ assert(fd >= 0);
if (DNS_PACKET_QDCOUNT(p) > 1)
return -EOPNOTSUPP;
- if (server->possible_features >= DNS_SERVER_FEATURE_LEVEL_EDNS0) {
- bool edns_do;
- size_t packet_size;
-
- edns_do = server->possible_features >= DNS_SERVER_FEATURE_LEVEL_DO;
-
- if (server->possible_features >= DNS_SERVER_FEATURE_LEVEL_LARGE)
- packet_size = DNS_PACKET_UNICAST_SIZE_LARGE_MAX;
- else
- packet_size = server->received_udp_packet_max;
-
- r = dns_packet_append_opt_rr(p, packet_size, edns_do, &saved_size);
- if (r < 0)
- return r;
-
- DNS_PACKET_HEADER(p)->arcount = htobe16(be16toh(DNS_PACKET_HEADER(p)->arcount) + 1);
- }
-
if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
return -EMSGSIZE;
@@ -212,15 +211,11 @@ int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
if (r < 0)
return r;
- if (saved_size > 0) {
- dns_packet_truncate(p, saved_size);
-
- DNS_PACKET_HEADER(p)->arcount = htobe16(be16toh(DNS_PACKET_HEADER(p)->arcount) - 1);
- }
-
break;
case DNS_PROTOCOL_LLMNR:
+ assert(fd < 0);
+
if (DNS_PACKET_QDCOUNT(p) > 1)
return -EOPNOTSUPP;
@@ -228,7 +223,6 @@ int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
return -EBUSY;
family = s->family;
- port = LLMNR_PORT;
if (family == AF_INET) {
addr.in = LLMNR_MULTICAST_IPV4_ADDRESS;
@@ -241,7 +235,32 @@ int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
if (fd < 0)
return fd;
- r = manager_send(s->manager, fd, ifindex, family, &addr, port, p);
+ r = manager_send(s->manager, fd, ifindex, family, &addr, LLMNR_PORT, p);
+ if (r < 0)
+ return r;
+
+ break;
+
+ case DNS_PROTOCOL_MDNS:
+ assert(fd < 0);
+
+ if (!ratelimit_test(&s->ratelimit))
+ return -EBUSY;
+
+ family = s->family;
+
+ if (family == AF_INET) {
+ addr.in = MDNS_MULTICAST_IPV4_ADDRESS;
+ fd = manager_mdns_ipv4_fd(s->manager);
+ } else if (family == AF_INET6) {
+ addr.in6 = MDNS_MULTICAST_IPV6_ADDRESS;
+ fd = manager_mdns_ipv6_fd(s->manager);
+ } else
+ return -EAFNOSUPPORT;
+ if (fd < 0)
+ return fd;
+
+ r = manager_send(s->manager, fd, ifindex, family, &addr, MDNS_PORT, p);
if (r < 0)
return r;
@@ -254,8 +273,39 @@ int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
return 1;
}
-static int dns_scope_socket(DnsScope *s, int type, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
- DnsServer *srv = NULL;
+int dns_scope_emit_udp(DnsScope *s, int fd, DnsPacket *p) {
+ int r;
+
+ assert(s);
+ assert(p);
+ assert(p->protocol == s->protocol);
+ assert((s->protocol == DNS_PROTOCOL_DNS) == (fd >= 0));
+
+ do {
+ /* If there are multiple linked packets, set the TC bit in all but the last of them */
+ if (p->more) {
+ assert(p->protocol == DNS_PROTOCOL_MDNS);
+ dns_packet_set_flags(p, true, true);
+ }
+
+ r = dns_scope_emit_one(s, fd, p);
+ if (r < 0)
+ return r;
+
+ p = p->more;
+ } while (p);
+
+ return 0;
+}
+
+static int dns_scope_socket(
+ DnsScope *s,
+ int type,
+ int family,
+ const union in_addr_union *address,
+ DnsServer *server,
+ uint16_t port) {
+
_cleanup_close_ int fd = -1;
union sockaddr_union sa = {};
socklen_t salen;
@@ -263,31 +313,27 @@ static int dns_scope_socket(DnsScope *s, int type, int family, const union in_ad
int ret, r;
assert(s);
- assert((family == AF_UNSPEC) == !address);
-
- if (family == AF_UNSPEC) {
- srv = dns_scope_get_dns_server(s);
- if (!srv)
- return -ESRCH;
-
- srv->possible_features = dns_server_possible_features(srv);
- if (type == SOCK_DGRAM && srv->possible_features < DNS_SERVER_FEATURE_LEVEL_UDP)
- return -EAGAIN;
+ if (server) {
+ assert(family == AF_UNSPEC);
+ assert(!address);
- sa.sa.sa_family = srv->family;
- if (srv->family == AF_INET) {
+ sa.sa.sa_family = server->family;
+ if (server->family == AF_INET) {
sa.in.sin_port = htobe16(port);
- sa.in.sin_addr = srv->address.in;
+ sa.in.sin_addr = server->address.in;
salen = sizeof(sa.in);
- } else if (srv->family == AF_INET6) {
+ } else if (server->family == AF_INET6) {
sa.in6.sin6_port = htobe16(port);
- sa.in6.sin6_addr = srv->address.in6;
+ sa.in6.sin6_addr = server->address.in6;
sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
salen = sizeof(sa.in6);
} else
return -EAFNOSUPPORT;
} else {
+ assert(family != AF_UNSPEC);
+ assert(address);
+
sa.sa.sa_family = family;
if (family == AF_INET) {
@@ -345,21 +391,18 @@ static int dns_scope_socket(DnsScope *s, int type, int family, const union in_ad
if (r < 0 && errno != EINPROGRESS)
return -errno;
- if (server)
- *server = srv;
-
ret = fd;
fd = -1;
return ret;
}
-int dns_scope_udp_dns_socket(DnsScope *s, DnsServer **server) {
- return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, 53, server);
+int dns_scope_socket_udp(DnsScope *s, DnsServer *server, uint16_t port) {
+ return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, server, port);
}
-int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
- return dns_scope_socket(s, SOCK_STREAM, family, address, port, server);
+int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port) {
+ return dns_scope_socket(s, SOCK_STREAM, family, address, server, port);
}
DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) {
@@ -368,13 +411,14 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
assert(s);
assert(domain);
- if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex))
- return DNS_SCOPE_NO;
+ /* Checks if the specified domain is something to look up on
+ * this scope. Note that this accepts non-qualified hostnames,
+ * i.e. those without any search path prefixed yet. */
- if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family) & flags) == 0)
+ if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex))
return DNS_SCOPE_NO;
- if (dns_name_is_root(domain))
+ if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family, 0) & flags) == 0)
return DNS_SCOPE_NO;
/* Never resolve any loopback hostname or IP address via DNS,
@@ -385,6 +429,16 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
dns_name_equal(domain, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
return DNS_SCOPE_NO;
+ /* Never respond to some of the domains listed in RFC6303 */
+ if (dns_name_endswith(domain, "0.in-addr.arpa") > 0 ||
+ dns_name_equal(domain, "255.255.255.255.in-addr.arpa") > 0 ||
+ dns_name_equal(domain, "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
+ return DNS_SCOPE_NO;
+
+ /* Never respond to some of the domains listed in RFC6761 */
+ if (dns_name_endswith(domain, "invalid") > 0)
+ return DNS_SCOPE_NO;
+
/* Always honour search domains for routing queries. Note that
* we return DNS_SCOPE_YES here, rather than just
* DNS_SCOPE_MAYBE, which means wildcard scopes won't be
@@ -397,10 +451,16 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
case DNS_PROTOCOL_DNS:
- if ((!dns_name_is_single_label(domain) ||
- (!(flags & SD_RESOLVED_NO_SEARCH) && dns_scope_has_search_domains(s))) &&
- dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
- dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0)
+ /* Exclude link-local IP ranges */
+ if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
+ dns_name_endswith(domain, "8.e.f.ip6.arpa") == 0 &&
+ dns_name_endswith(domain, "9.e.f.ip6.arpa") == 0 &&
+ dns_name_endswith(domain, "a.e.f.ip6.arpa") == 0 &&
+ dns_name_endswith(domain, "b.e.f.ip6.arpa") == 0 &&
+ /* If networks use .local in their private setups, they are supposed to also add .local to their search
+ * domains, which we already checked above. Otherwise, we consider .local specific to mDNS and won't
+ * send such queries ordinary DNS servers. */
+ dns_name_endswith(domain, "local") == 0)
return DNS_SCOPE_MAYBE;
return DNS_SCOPE_NO;
@@ -434,8 +494,27 @@ int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) {
assert(s);
assert(key);
- if (s->protocol == DNS_PROTOCOL_DNS)
- return true;
+ /* Check if it makes sense to resolve the specified key on
+ * this scope. Note that this call assumes as fully qualified
+ * name, i.e. the search suffixes already appended. */
+
+ if (s->protocol == DNS_PROTOCOL_DNS) {
+
+ /* On classic DNS, looking up non-address RRs is always
+ * fine. (Specifically, we want to permit looking up
+ * DNSKEY and DS records on the root and top-level
+ * domains.) */
+ if (!dns_resource_key_is_address(key))
+ return true;
+
+ /* However, we refuse to look up A and AAAA RRs on the
+ * root and single-label domains, under the assumption
+ * that those should be resolved via LLMNR or search
+ * path only, and should not be leaked onto the
+ * internet. */
+ return !(dns_name_is_single_label(DNS_RESOURCE_KEY_NAME(key)) ||
+ dns_name_is_root(DNS_RESOURCE_KEY_NAME(key)));
+ }
/* On mDNS and LLMNR, send A and AAAA queries only on the
* respective scopes */
@@ -449,19 +528,15 @@ int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) {
return true;
}
-int dns_scope_llmnr_membership(DnsScope *s, bool b) {
+static int dns_scope_multicast_membership(DnsScope *s, bool b, struct in_addr in, struct in6_addr in6) {
int fd;
assert(s);
-
- if (s->protocol != DNS_PROTOCOL_LLMNR)
- return 0;
-
assert(s->link);
if (s->family == AF_INET) {
struct ip_mreqn mreqn = {
- .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS,
+ .imr_multiaddr = in,
.imr_ifindex = s->link->ifindex,
};
@@ -480,7 +555,7 @@ int dns_scope_llmnr_membership(DnsScope *s, bool b) {
} else if (s->family == AF_INET6) {
struct ipv6_mreq mreq = {
- .ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS,
+ .ipv6mr_multiaddr = in6,
.ipv6mr_interface = s->link->ifindex,
};
@@ -499,6 +574,22 @@ int dns_scope_llmnr_membership(DnsScope *s, bool b) {
return 0;
}
+int dns_scope_llmnr_membership(DnsScope *s, bool b) {
+
+ if (s->protocol != DNS_PROTOCOL_LLMNR)
+ return 0;
+
+ return dns_scope_multicast_membership(s, b, LLMNR_MULTICAST_IPV4_ADDRESS, LLMNR_MULTICAST_IPV6_ADDRESS);
+}
+
+int dns_scope_mdns_membership(DnsScope *s, bool b) {
+
+ if (s->protocol != DNS_PROTOCOL_MDNS)
+ return 0;
+
+ return dns_scope_multicast_membership(s, b, MDNS_MULTICAST_IPV4_ADDRESS, MDNS_MULTICAST_IPV6_ADDRESS);
+}
+
static int dns_scope_make_reply_packet(
DnsScope *s,
uint16_t id,
@@ -549,7 +640,7 @@ static int dns_scope_make_reply_packet(
if (answer) {
for (i = 0; i < answer->n_rrs; i++) {
- r = dns_packet_append_rr(p, answer->items[i].rr, NULL);
+ r = dns_packet_append_rr(p, answer->items[i].rr, NULL, NULL);
if (r < 0)
return r;
}
@@ -559,7 +650,7 @@ static int dns_scope_make_reply_packet(
if (soa) {
for (i = 0; i < soa->n_rrs; i++) {
- r = dns_packet_append_rr(p, soa->items[i].rr, NULL);
+ r = dns_packet_append_rr(p, soa->items[i].rr, NULL, NULL);
if (r < 0)
return r;
}
@@ -692,7 +783,7 @@ DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsResourceKey *key,
/* Refuse reusing transactions that completed based on cached
* data instead of a real packet, if that's requested. */
if (!cache_ok &&
- IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) &&
+ IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_RCODE_FAILURE) &&
t->answer_source != DNS_TRANSACTION_NETWORK)
return NULL;
@@ -725,7 +816,11 @@ static int dns_scope_make_conflict_packet(
0 /* (ad) */,
0 /* (cd) */,
0));
- random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t));
+
+ /* For mDNS, the transaction ID should always be 0 */
+ if (s->protocol != DNS_PROTOCOL_MDNS)
+ random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t));
+
DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
DNS_PACKET_HEADER(p)->arcount = htobe16(1);
@@ -733,7 +828,7 @@ static int dns_scope_make_conflict_packet(
if (r < 0)
return r;
- r = dns_packet_append_rr(p, rr, NULL);
+ r = dns_packet_append_rr(p, rr, NULL, NULL);
if (r < 0)
return r;
@@ -766,7 +861,7 @@ static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata
return 0;
}
- r = dns_scope_emit(scope, -1, NULL, p);
+ r = dns_scope_emit_udp(scope, -1, p);
if (r < 0)
log_debug_errno(r, "Failed to send conflict packet: %m");
}
@@ -815,6 +910,8 @@ int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
if (r < 0)
return log_debug_errno(r, "Failed to add conflict dispatch event: %m");
+ (void) sd_event_source_set_description(scope->conflict_event_source, "scope-conflict");
+
return 0;
}
@@ -901,34 +998,13 @@ void dns_scope_dump(DnsScope *s, FILE *f) {
DnsSearchDomain *dns_scope_get_search_domains(DnsScope *s) {
assert(s);
- /* Returns the list of *local* search domains -- not the
- * global ones. */
-
if (s->protocol != DNS_PROTOCOL_DNS)
return NULL;
if (s->link)
return s->link->search_domains;
- return NULL;
-}
-
-bool dns_scope_has_search_domains(DnsScope *s) {
- assert(s);
-
- /* Tests if there are *any* search domains suitable for this
- * scope. This means either local or global ones */
-
- if (s->protocol != DNS_PROTOCOL_DNS)
- return false;
-
- if (s->manager->search_domains)
- return true;
-
- if (s->link && s->link->search_domains)
- return true;
-
- return false;
+ return s->manager->search_domains;
}
bool dns_scope_name_needs_search_domain(DnsScope *s, const char *name) {
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2025-01-20 18:31:33 +0000