diff options
Diffstat (limited to 'src/resolve')
36 files changed, 2246 insertions, 167 deletions
diff --git a/src/resolve/dns-type.c b/src/resolve/dns-type.c index 78d9d5733f..aaf5ed62c1 100644 --- a/src/resolve/dns-type.c +++ b/src/resolve/dns-type.c @@ -96,6 +96,15 @@ bool dns_type_is_valid_query(uint16_t type) { DNS_TYPE_RRSIG); } +bool dns_type_is_zone_transer(uint16_t type) { + + /* Zone transfers, either normal or incremental */ + + return IN_SET(type, + DNS_TYPE_AXFR, + DNS_TYPE_IXFR); +} + bool dns_type_is_valid_rr(uint16_t type) { /* The types valid as RR in packets (but not necessarily diff --git a/src/resolve/dns-type.h b/src/resolve/dns-type.h index 7b79d29d7e..e675fe4ea3 100644 --- a/src/resolve/dns-type.h +++ b/src/resolve/dns-type.h @@ -136,6 +136,7 @@ bool dns_type_is_obsolete(uint16_t type); bool dns_type_may_wildcard(uint16_t type); bool dns_type_apex_only(uint16_t type); bool dns_type_needs_authentication(uint16_t type); +bool dns_type_is_zone_transer(uint16_t type); int dns_type_to_af(uint16_t type); bool dns_class_is_pseudo(uint16_t class); diff --git a/src/resolve/resolv.conf b/src/resolve/resolv.conf new file mode 100644 index 0000000000..b8034d6829 --- /dev/null +++ b/src/resolve/resolv.conf @@ -0,0 +1,11 @@ +# This is a static resolv.conf file for connecting local clients to +# systemd-resolved via its DNS stub listener on 127.0.0.53. +# +# Third party programs must not access this file directly, but only through the +# symlink at /etc/resolv.conf. To manage resolv.conf(5) in a different way, +# replace this symlink by a static file or a different symlink. +# +# See systemd-resolved.service(8) for details about the supported modes of +# operation for /etc/resolv.conf. + +nameserver 127.0.0.53 diff --git a/src/resolve/resolve-tool.c b/src/resolve/resolve-tool.c index 2cb2e42b23..4e1e916669 100644 --- a/src/resolve/resolve-tool.c +++ b/src/resolve/resolve-tool.c @@ -21,17 +21,21 @@ #include <net/if.h> #include "sd-bus.h" +#include "sd-netlink.h" #include "af-list.h" #include "alloc-util.h" #include "bus-error.h" #include "bus-util.h" #include "escape.h" -#include "in-addr-util.h" #include "gcrypt-util.h" +#include "in-addr-util.h" +#include "netlink-util.h" +#include "pager.h" #include "parse-util.h" #include "resolved-def.h" #include "resolved-dns-packet.h" +#include "strv.h" #include "terminal-util.h" #define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC) @@ -42,6 +46,7 @@ static uint16_t arg_type = 0; static uint16_t arg_class = 0; static bool arg_legend = true; static uint64_t arg_flags = 0; +static bool arg_no_pager = false; typedef enum ServiceFamily { SERVICE_FAMILY_TCP, @@ -67,6 +72,7 @@ static enum { MODE_STATISTICS, MODE_RESET_STATISTICS, MODE_FLUSH_CACHES, + MODE_STATUS, } arg_mode = MODE_RESOLVE_HOST; static ServiceFamily service_family_from_string(const char *s) { @@ -1031,6 +1037,472 @@ static int flush_caches(sd_bus *bus) { return 0; } +static int map_link_dns_servers(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { + char ***l = userdata; + int r; + + assert(bus); + assert(member); + assert(m); + assert(l); + + r = sd_bus_message_enter_container(m, 'a', "(iay)"); + if (r < 0) + return r; + + for (;;) { + const void *a; + char *pretty; + int family; + size_t sz; + + r = sd_bus_message_enter_container(m, 'r', "iay"); + if (r < 0) + return r; + if (r == 0) + break; + + r = sd_bus_message_read(m, "i", &family); + if (r < 0) + return r; + + r = sd_bus_message_read_array(m, 'y', &a, &sz); + if (r < 0) + return r; + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + if (!IN_SET(family, AF_INET, AF_INET6)) { + log_debug("Unexpected family, ignoring."); + continue; + } + + if (sz != FAMILY_ADDRESS_SIZE(family)) { + log_debug("Address size mismatch, ignoring."); + continue; + } + + r = in_addr_to_string(family, a, &pretty); + if (r < 0) + return r; + + r = strv_consume(l, pretty); + if (r < 0) + return r; + } + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + return 0; +} + +static int map_link_domains(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { + char ***l = userdata; + int r; + + assert(bus); + assert(member); + assert(m); + assert(l); + + r = sd_bus_message_enter_container(m, 'a', "(sb)"); + if (r < 0) + return r; + + for (;;) { + const char *domain; + int route_only; + char *pretty; + + r = sd_bus_message_read(m, "(sb)", &domain, &route_only); + if (r < 0) + return r; + if (r == 0) + break; + + if (route_only) + pretty = strappend("~", domain); + else + pretty = strdup(domain); + if (!pretty) + return -ENOMEM; + + r = strv_consume(l, pretty); + if (r < 0) + return r; + } + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + return 0; +} + +static int status_ifindex(sd_bus *bus, int ifindex, const char *name, bool *empty_line) { + + struct link_info { + uint64_t scopes_mask; + char *llmnr; + char *mdns; + char *dnssec; + char **dns; + char **domains; + char **ntas; + int dnssec_supported; + } link_info = {}; + + static const struct bus_properties_map property_map[] = { + { "ScopesMask", "t", NULL, offsetof(struct link_info, scopes_mask) }, + { "DNS", "a(iay)", map_link_dns_servers, offsetof(struct link_info, dns) }, + { "Domains", "a(sb)", map_link_domains, offsetof(struct link_info, domains) }, + { "LLMNR", "s", NULL, offsetof(struct link_info, llmnr) }, + { "MulticastDNS", "s", NULL, offsetof(struct link_info, mdns) }, + { "DNSSEC", "s", NULL, offsetof(struct link_info, dnssec) }, + { "DNSSECNegativeTrustAnchors", "as", NULL, offsetof(struct link_info, ntas) }, + { "DNSSECSupported", "b", NULL, offsetof(struct link_info, dnssec_supported) }, + {} + }; + + _cleanup_free_ char *ifi = NULL, *p = NULL; + char ifname[IF_NAMESIZE] = ""; + char **i; + int r; + + assert(bus); + assert(ifindex > 0); + assert(empty_line); + + if (!name) { + if (!if_indextoname(ifindex, ifname)) + return log_error_errno(errno, "Failed to resolve interface name for %i: %m", ifindex); + + name = ifname; + } + + if (asprintf(&ifi, "%i", ifindex) < 0) + return log_oom(); + + r = sd_bus_path_encode("/org/freedesktop/resolve1/link", ifi, &p); + if (r < 0) + return log_oom(); + + r = bus_map_all_properties(bus, + "org.freedesktop.resolve1", + p, + property_map, + &link_info); + if (r < 0) { + log_error_errno(r, "Failed to get link data for %i: %m", ifindex); + goto finish; + } + + pager_open(arg_no_pager, false); + + if (*empty_line) + fputc('\n', stdout); + + printf("%sLink %i (%s)%s\n", + ansi_highlight(), ifindex, name, ansi_normal()); + + if (link_info.scopes_mask == 0) + printf(" Current Scopes: none\n"); + else + printf(" Current Scopes:%s%s%s%s%s\n", + link_info.scopes_mask & SD_RESOLVED_DNS ? " DNS" : "", + link_info.scopes_mask & SD_RESOLVED_LLMNR_IPV4 ? " LLMNR/IPv4" : "", + link_info.scopes_mask & SD_RESOLVED_LLMNR_IPV6 ? " LLMNR/IPv6" : "", + link_info.scopes_mask & SD_RESOLVED_MDNS_IPV4 ? " mDNS/IPv4" : "", + link_info.scopes_mask & SD_RESOLVED_MDNS_IPV6 ? " mDNS/IPv6" : ""); + + printf(" LLMNR setting: %s\n" + "MulticastDNS setting: %s\n" + " DNSSEC setting: %s\n" + " DNSSEC supported: %s\n", + strna(link_info.llmnr), + strna(link_info.mdns), + strna(link_info.dnssec), + yes_no(link_info.dnssec_supported)); + + STRV_FOREACH(i, link_info.dns) { + printf(" %s %s\n", + i == link_info.dns ? "DNS Server:" : " ", + *i); + } + + STRV_FOREACH(i, link_info.domains) { + printf(" %s %s\n", + i == link_info.domains ? "DNS Domain:" : " ", + *i); + } + + STRV_FOREACH(i, link_info.ntas) { + printf(" %s %s\n", + i == link_info.ntas ? "DNSSEC NTA:" : " ", + *i); + } + + *empty_line = true; + + r = 0; + +finish: + strv_free(link_info.dns); + strv_free(link_info.domains); + free(link_info.llmnr); + free(link_info.mdns); + free(link_info.dnssec); + strv_free(link_info.ntas); + return r; +} + +static int map_global_dns_servers(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { + char ***l = userdata; + int r; + + assert(bus); + assert(member); + assert(m); + assert(l); + + r = sd_bus_message_enter_container(m, 'a', "(iiay)"); + if (r < 0) + return r; + + for (;;) { + const void *a; + char *pretty; + int family, ifindex; + size_t sz; + + r = sd_bus_message_enter_container(m, 'r', "iiay"); + if (r < 0) + return r; + if (r == 0) + break; + + r = sd_bus_message_read(m, "ii", &ifindex, &family); + if (r < 0) + return r; + + r = sd_bus_message_read_array(m, 'y', &a, &sz); + if (r < 0) + return r; + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + if (ifindex != 0) /* only show the global ones here */ + continue; + + if (!IN_SET(family, AF_INET, AF_INET6)) { + log_debug("Unexpected family, ignoring."); + continue; + } + + if (sz != FAMILY_ADDRESS_SIZE(family)) { + log_debug("Address size mismatch, ignoring."); + continue; + } + + r = in_addr_to_string(family, a, &pretty); + if (r < 0) + return r; + + r = strv_consume(l, pretty); + if (r < 0) + return r; + } + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + return 0; +} + +static int map_global_domains(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { + char ***l = userdata; + int r; + + assert(bus); + assert(member); + assert(m); + assert(l); + + r = sd_bus_message_enter_container(m, 'a', "(isb)"); + if (r < 0) + return r; + + for (;;) { + const char *domain; + int route_only, ifindex; + char *pretty; + + r = sd_bus_message_read(m, "(isb)", &ifindex, &domain, &route_only); + if (r < 0) + return r; + if (r == 0) + break; + + if (ifindex != 0) /* only show the global ones here */ + continue; + + if (route_only) + pretty = strappend("~", domain); + else + pretty = strdup(domain); + if (!pretty) + return -ENOMEM; + + r = strv_consume(l, pretty); + if (r < 0) + return r; + } + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + return 0; +} + +static int status_global(sd_bus *bus, bool *empty_line) { + + struct global_info { + char **dns; + char **domains; + char **ntas; + } global_info = {}; + + static const struct bus_properties_map property_map[] = { + { "DNS", "a(iiay)", map_global_dns_servers, offsetof(struct global_info, dns) }, + { "Domains", "a(isb)", map_global_domains, offsetof(struct global_info, domains) }, + { "DNSSECNegativeTrustAnchors", "as", NULL, offsetof(struct global_info, ntas) }, + {} + }; + + char **i; + int r; + + assert(bus); + assert(empty_line); + + r = bus_map_all_properties(bus, + "org.freedesktop.resolve1", + "/org/freedesktop/resolve1", + property_map, + &global_info); + if (r < 0) { + log_error_errno(r, "Failed to get global data: %m"); + goto finish; + } + + if (strv_isempty(global_info.dns) && strv_isempty(global_info.domains) && strv_isempty(global_info.ntas)) { + r = 0; + goto finish; + } + + pager_open(arg_no_pager, false); + + printf("%sGlobal%s\n", ansi_highlight(), ansi_normal()); + STRV_FOREACH(i, global_info.dns) { + printf(" %s %s\n", + i == global_info.dns ? "DNS Server:" : " ", + *i); + } + + STRV_FOREACH(i, global_info.domains) { + printf(" %s %s\n", + i == global_info.domains ? "DNS Domain:" : " ", + *i); + } + + strv_sort(global_info.ntas); + STRV_FOREACH(i, global_info.ntas) { + printf(" %s %s\n", + i == global_info.ntas ? "DNSSEC NTA:" : " ", + *i); + } + + *empty_line = true; + + r = 0; + +finish: + strv_free(global_info.dns); + strv_free(global_info.domains); + strv_free(global_info.ntas); + + return r; +} + +static int status_all(sd_bus *bus) { + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL; + _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL; + sd_netlink_message *i; + bool empty_line = true; + int r; + + assert(bus); + + r = status_global(bus, &empty_line); + if (r < 0) + return r; + + r = sd_netlink_open(&rtnl); + if (r < 0) + return log_error_errno(r, "Failed to connect to netlink: %m"); + + r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, 0); + if (r < 0) + return rtnl_log_create_error(r); + + r = sd_netlink_message_request_dump(req, true); + if (r < 0) + return rtnl_log_create_error(r); + + r = sd_netlink_call(rtnl, req, 0, &reply); + if (r < 0) + return log_error_errno(r, "Failed to enumerate links: %m"); + + r = 0; + for (i = reply; i; i = sd_netlink_message_next(i)) { + const char *name; + int ifindex, q; + uint16_t type; + + q = sd_netlink_message_get_type(i, &type); + if (q < 0) + return rtnl_log_parse_error(q); + + if (type != RTM_NEWLINK) + continue; + + q = sd_rtnl_message_link_get_ifindex(i, &ifindex); + if (q < 0) + return rtnl_log_parse_error(q); + + if (ifindex == LOOPBACK_IFINDEX) + continue; + + q = sd_netlink_message_read_string(i, IFLA_IFNAME, &name); + if (q < 0) + return rtnl_log_parse_error(q); + + q = status_ifindex(bus, ifindex, name, &empty_line); + if (q < 0 && r >= 0) + r = q; + } + + return r; +} + static void help_protocol_types(void) { if (arg_legend) puts("Known protocol types:"); @@ -1038,8 +1510,8 @@ static void help_protocol_types(void) { } static void help_dns_types(void) { - int i; const char *t; + int i; if (arg_legend) puts("Known DNS RR types:"); @@ -1051,8 +1523,8 @@ static void help_dns_types(void) { } static void help_dns_classes(void) { - int i; const char *t; + int i; if (arg_legend) puts("Known DNS RR classes:"); @@ -1073,6 +1545,7 @@ static void help(void) { "Resolve domain names, IPv4 and IPv6 addresses, DNS resource records, and services.\n\n" " -h --help Show this help\n" " --version Show package version\n" + " --no-pager Do not pipe output into a pager\n" " -4 Resolve IPv4 addresses\n" " -6 Resolve IPv6 addresses\n" " -i --interface=INTERFACE Look on interface\n" @@ -1091,6 +1564,7 @@ static void help(void) { " --legend=BOOL Print headers and additional info (default: yes)\n" " --statistics Show resolver statistics\n" " --reset-statistics Reset resolver statistics\n" + " --status Show link and server status\n" " --flush-caches Flush all local DNS caches\n" , program_invocation_short_name); } @@ -1109,7 +1583,9 @@ static int parse_argv(int argc, char *argv[]) { ARG_SEARCH, ARG_STATISTICS, ARG_RESET_STATISTICS, + ARG_STATUS, ARG_FLUSH_CACHES, + ARG_NO_PAGER, }; static const struct option options[] = { @@ -1130,7 +1606,9 @@ static int parse_argv(int argc, char *argv[]) { { "search", required_argument, NULL, ARG_SEARCH }, { "statistics", no_argument, NULL, ARG_STATISTICS, }, { "reset-statistics", no_argument, NULL, ARG_RESET_STATISTICS }, + { "status", no_argument, NULL, ARG_STATUS }, { "flush-caches", no_argument, NULL, ARG_FLUSH_CACHES }, + { "no-pager", no_argument, NULL, ARG_NO_PAGER }, {} }; @@ -1308,6 +1786,14 @@ static int parse_argv(int argc, char *argv[]) { arg_mode = MODE_FLUSH_CACHES; break; + case ARG_STATUS: + arg_mode = MODE_STATUS; + break; + + case ARG_NO_PAGER: + arg_no_pager = true; + break; + case '?': return -EINVAL; @@ -1484,8 +1970,38 @@ int main(int argc, char **argv) { r = flush_caches(bus); break; + + case MODE_STATUS: + + if (argc > optind) { + char **ifname; + bool empty_line = false; + + r = 0; + STRV_FOREACH(ifname, argv + optind) { + int ifindex, q; + + q = parse_ifindex(argv[optind], &ifindex); + if (q < 0) { + ifindex = if_nametoindex(argv[optind]); + if (ifindex <= 0) { + log_error_errno(errno, "Failed to resolve interface name: %s", argv[optind]); + continue; + } + } + + q = status_ifindex(bus, ifindex, NULL, &empty_line); + if (q < 0 && r >= 0) + r = q; + } + } else + r = status_all(bus); + + break; } finish: + pager_close(); + return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE; } diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c index f08c6c0637..2ca65e6953 100644 --- a/src/resolve/resolved-bus.c +++ b/src/resolve/resolved-bus.c @@ -647,6 +647,8 @@ static int bus_method_resolve_record(sd_bus_message *message, void *userdata, sd if (!dns_type_is_valid_query(type)) return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Specified resource record type %" PRIu16 " may not be used in a query.", type); + if (dns_type_is_zone_transer(type)) + return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Zone transfers not permitted via this programming interface."); if (dns_type_is_obsolete(type)) return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Specified DNS resource record type %" PRIu16 " is obsolete.", type); @@ -670,6 +672,10 @@ static int bus_method_resolve_record(sd_bus_message *message, void *userdata, sd if (r < 0) return r; + /* Let's request that the TTL is fixed up for locally cached entries, after all we return it in the wire format + * blob */ + q->clamp_ttl = true; + q->request = sd_bus_message_ref(message); q->complete = bus_method_resolve_record_complete; @@ -1414,6 +1420,36 @@ static int bus_property_get_dnssec_supported( return sd_bus_message_append(reply, "b", manager_dnssec_supported(m)); } +static int bus_property_get_ntas( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + const char *domain; + Iterator i; + int r; + + assert(reply); + assert(m); + + r = sd_bus_message_open_container(reply, 'a', "s"); + if (r < 0) + return r; + + SET_FOREACH(domain, m->trust_anchor.negative_by_name, i) { + r = sd_bus_message_append(reply, "s", domain); + if (r < 0) + return r; + } + + return sd_bus_message_close_container(reply); +} + static int bus_method_reset_statistics(sd_bus_message *message, void *userdata, sd_bus_error *error) { Manager *m = userdata; DnsScope *s; @@ -1540,6 +1576,7 @@ static const sd_bus_vtable resolve_vtable[] = { SD_BUS_PROPERTY("CacheStatistics", "(ttt)", bus_property_get_cache_statistics, 0, 0), SD_BUS_PROPERTY("DNSSECStatistics", "(tttt)", bus_property_get_dnssec_statistics, 0, 0), SD_BUS_PROPERTY("DNSSECSupported", "b", bus_property_get_dnssec_supported, 0, 0), + SD_BUS_PROPERTY("DNSSECNegativeTrustAnchors", "as", bus_property_get_ntas, 0, 0), SD_BUS_METHOD("ResolveHostname", "isit", "a(iiay)st", bus_method_resolve_hostname, SD_BUS_VTABLE_UNPRIVILEGED), SD_BUS_METHOD("ResolveAddress", "iiayt", "a(is)t", bus_method_resolve_address, SD_BUS_VTABLE_UNPRIVILEGED), diff --git a/src/resolve/resolved-conf.c b/src/resolve/resolved-conf.c index fecf7ecccf..dd233e7c4a 100644 --- a/src/resolve/resolved-conf.c +++ b/src/resolve/resolved-conf.c @@ -37,6 +37,10 @@ int manager_add_dns_server_by_string(Manager *m, DnsServerType type, const char if (r < 0) return r; + /* Silently filter out 0.0.0.0 and 127.0.0.53 (our own stub DNS listener) */ + if (!dns_server_address_valid(family, &address)) + return 0; + /* Filter out duplicates */ s = dns_server_find(manager_get_first_dns_server(m, type), family, &address, ifindex); if (s) { diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h index b2b86d1772..4a92bd1150 100644 --- a/src/resolve/resolved-dns-answer.h +++ b/src/resolve/resolved-dns-answer.h @@ -87,6 +87,10 @@ static inline unsigned dns_answer_size(DnsAnswer *a) { return a ? a->n_rrs : 0; } +static inline bool dns_answer_isempty(DnsAnswer *a) { + return dns_answer_size(a) <= 0; +} + void dns_answer_dump(DnsAnswer *answer, FILE *f); DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref); diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c index ba937107b6..87f7c21d03 100644 --- a/src/resolve/resolved-dns-cache.c +++ b/src/resolve/resolved-dns-cache.c @@ -790,7 +790,7 @@ static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, D return NULL; } -int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **ret, bool *authenticated) { +int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, bool clamp_ttl, int *rcode, DnsAnswer **ret, bool *authenticated) { _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; char key_str[DNS_RESOURCE_KEY_STRING_MAX]; unsigned n = 0; @@ -798,6 +798,7 @@ int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **r bool nxdomain = false; DnsCacheItem *j, *first, *nsec = NULL; bool have_authenticated = false, have_non_authenticated = false; + usec_t current; assert(c); assert(key); @@ -892,11 +893,24 @@ int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **r if (!answer) return -ENOMEM; + if (clamp_ttl) + current = now(clock_boottime_or_monotonic()); + LIST_FOREACH(by_key, j, first) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + if (!j->rr) continue; - r = dns_answer_add(answer, j->rr, j->ifindex, j->authenticated ? DNS_ANSWER_AUTHENTICATED : 0); + if (clamp_ttl) { + rr = dns_resource_record_ref(j->rr); + + r = dns_resource_record_clamp_ttl(&rr, LESS_BY(j->until, current) / USEC_PER_SEC); + if (r < 0) + return r; + } + + r = dns_answer_add(answer, rr ?: j->rr, j->ifindex, j->authenticated ? DNS_ANSWER_AUTHENTICATED : 0); if (r < 0) return r; } diff --git a/src/resolve/resolved-dns-cache.h b/src/resolve/resolved-dns-cache.h index 2293718e86..22a7c17377 100644 --- a/src/resolve/resolved-dns-cache.h +++ b/src/resolve/resolved-dns-cache.h @@ -40,7 +40,7 @@ void dns_cache_flush(DnsCache *c); void dns_cache_prune(DnsCache *c); int dns_cache_put(DnsCache *c, DnsResourceKey *key, int rcode, DnsAnswer *answer, bool authenticated, uint32_t nsec_ttl, usec_t timestamp, int owner_family, const union in_addr_union *owner_address); -int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **answer, bool *authenticated); +int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, bool clamp_ttl, int *rcode, DnsAnswer **answer, bool *authenticated); int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address); diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c index b7907bb511..ea0be56d98 100644 --- a/src/resolve/resolved-dns-packet.c +++ b/src/resolve/resolved-dns-packet.c @@ -264,6 +264,7 @@ int dns_packet_validate_query(DnsPacket *p) { switch (p->protocol) { case DNS_PROTOCOL_LLMNR: + case DNS_PROTOCOL_DNS: /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */ if (DNS_PACKET_QDCOUNT(p) != 1) return -EBADMSG; @@ -676,13 +677,15 @@ fail: } /* Append the OPT pseudo-RR described in RFC6891 */ -int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start) { +int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, int rcode, size_t *start) { size_t saved_size; int r; assert(p); /* we must never advertise supported packet size smaller than the legacy max */ assert(max_udp_size >= DNS_PACKET_UNICAST_SIZE_MAX); + assert(rcode >= 0); + assert(rcode <= _DNS_RCODE_MAX); if (p->opt_start != (size_t) -1) return -EBUSY; @@ -701,13 +704,13 @@ int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, si if (r < 0) goto fail; - /* maximum udp packet that can be received */ + /* class: maximum udp packet that can be received */ r = dns_packet_append_uint16(p, max_udp_size, NULL); if (r < 0) goto fail; /* extended RCODE and VERSION */ - r = dns_packet_append_uint16(p, 0, NULL); + r = dns_packet_append_uint16(p, ((uint16_t) rcode & 0x0FF0) << 4, NULL); if (r < 0) goto fail; @@ -717,9 +720,8 @@ int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, si goto fail; /* RDLENGTH */ - - if (edns0_do) { - /* If DO is on, also append RFC6975 Algorithm data */ + if (edns0_do & !DNS_PACKET_QR(p)) { + /* If DO is on and this is not a reply, also append RFC6975 Algorithm data */ static const uint8_t rfc6975[] = { @@ -750,7 +752,6 @@ int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, si r = dns_packet_append_blob(p, rfc6975, sizeof(rfc6975), NULL); } else r = dns_packet_append_uint16(p, 0, NULL); - if (r < 0) goto fail; @@ -791,6 +792,7 @@ int dns_packet_truncate_opt(DnsPacket *p) { } int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) { + size_t saved_size, rdlength_offset, end, rdlength, rds; int r; @@ -1134,6 +1136,36 @@ fail: return r; } +int dns_packet_append_question(DnsPacket *p, DnsQuestion *q) { + DnsResourceKey *key; + int r; + + assert(p); + + DNS_QUESTION_FOREACH(key, q) { + r = dns_packet_append_key(p, key, NULL); + if (r < 0) + return r; + } + + return 0; +} + +int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a) { + DnsResourceRecord *rr; + int r; + + assert(p); + + DNS_ANSWER_FOREACH(rr, a) { + r = dns_packet_append_rr(p, rr, NULL, NULL); + if (r < 0) + return r; + } + + return 0; +} + int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) { assert(p); @@ -2029,8 +2061,10 @@ static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) { assert(rr->key->type == DNS_TYPE_OPT); /* Check that the version is 0 */ - if (((rr->ttl >> 16) & UINT32_C(0xFF)) != 0) - return false; + if (((rr->ttl >> 16) & UINT32_C(0xFF)) != 0) { + *rfc6975 = false; + return true; /* if it's not version 0, it's OK, but we will ignore the OPT field contents */ + } p = rr->opt.data; l = rr->opt.data_size; @@ -2153,16 +2187,27 @@ int dns_packet_extract(DnsPacket *p) { continue; } - if (has_rfc6975) { - /* If the OPT RR contains RFC6975 algorithm data, then this is indication that - * the server just copied the OPT it got from us (which contained that data) - * back into the reply. If so, then it doesn't properly support EDNS, as - * RFC6975 makes it very clear that the algorithm data should only be contained - * in questions, never in replies. Crappy Belkin routers copy the OPT data for - * example, hence let's detect this so that we downgrade early. */ - log_debug("OPT RR contained RFC6975 data, ignoring."); - bad_opt = true; - continue; + if (DNS_PACKET_QR(p)) { + /* Additional checks for responses */ + + if (!DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(rr)) { + /* If this is a reply and we don't know the EDNS version then something + * is weird... */ + log_debug("EDNS version newer that our request, bad server."); + return -EBADMSG; + } + + if (has_rfc6975) { + /* If the OPT RR contains RFC6975 algorithm data, then this is indication that + * the server just copied the OPT it got from us (which contained that data) + * back into the reply. If so, then it doesn't properly support EDNS, as + * RFC6975 makes it very clear that the algorithm data should only be contained + * in questions, never in replies. Crappy Belkin routers copy the OPT data for + * example, hence let's detect this so that we downgrade early. */ + log_debug("OPT RR contained RFC6975 data, ignoring."); + bad_opt = true; + continue; + } } p->opt = dns_resource_record_ref(rr); diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h index 416335d0a2..7b7d4e14c9 100644 --- a/src/resolve/resolved-dns-packet.h +++ b/src/resolve/resolved-dns-packet.h @@ -118,6 +118,8 @@ static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) { #define DNS_PACKET_AD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 5) & 1) #define DNS_PACKET_CD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 4) & 1) +#define DNS_PACKET_FLAG_TC (UINT16_C(1) << 9) + static inline uint16_t DNS_PACKET_RCODE(DnsPacket *p) { uint16_t rcode; @@ -126,7 +128,34 @@ static inline uint16_t DNS_PACKET_RCODE(DnsPacket *p) { else rcode = 0; - return rcode | (be16toh(DNS_PACKET_HEADER(p)->flags) & 15); + return rcode | (be16toh(DNS_PACKET_HEADER(p)->flags) & 0xF); +} + +static inline uint16_t DNS_PACKET_PAYLOAD_SIZE_MAX(DnsPacket *p) { + + /* Returns the advertised maximum datagram size for replies, or the DNS default if there's nothing defined. */ + + if (p->opt) + return MAX(DNS_PACKET_UNICAST_SIZE_MAX, p->opt->key->class); + + return DNS_PACKET_UNICAST_SIZE_MAX; +} + +static inline bool DNS_PACKET_DO(DnsPacket *p) { + if (!p->opt) + return false; + + return !!(p->opt->ttl & (1U << 15)); +} + +static inline bool DNS_PACKET_VERSION_SUPPORTED(DnsPacket *p) { + /* Returns true if this packet is in a version we support. Which means either non-EDNS or EDNS(0), but not EDNS + * of any newer versions */ + + if (!p->opt) + return true; + + return DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(p->opt); } /* LLMNR defines some bits differently */ @@ -182,7 +211,9 @@ int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, bool canonica int dns_packet_append_name(DnsPacket *p, const char *name, bool allow_compression, bool canonical_candidate, size_t *start); int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, size_t *start); int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start); -int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start); +int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, int rcode, size_t *start); +int dns_packet_append_question(DnsPacket *p, DnsQuestion *q); +int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a); void dns_packet_truncate(DnsPacket *p, size_t sz); int dns_packet_truncate_opt(DnsPacket *p); @@ -232,7 +263,8 @@ enum { DNS_RCODE_BADNAME = 20, DNS_RCODE_BADALG = 21, DNS_RCODE_BADTRUNC = 22, - _DNS_RCODE_MAX_DEFINED + _DNS_RCODE_MAX_DEFINED, + _DNS_RCODE_MAX = 4095 /* 4 bit rcode in the header plus 8 bit rcode in OPT, makes 12 bit */ }; const char* dns_rcode_to_string(int i) _const_; diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c index ea04e58d61..c8af5579f0 100644 --- a/src/resolve/resolved-dns-query.c +++ b/src/resolve/resolved-dns-query.c @@ -154,6 +154,7 @@ static int dns_query_candidate_add_transaction(DnsQueryCandidate *c, DnsResource goto gc; } + t->clamp_ttl = c->query->clamp_ttl; return 1; gc: @@ -403,6 +404,16 @@ DnsQuery *dns_query_free(DnsQuery *q) { sd_bus_message_unref(q->request); sd_bus_track_unref(q->bus_track); + dns_packet_unref(q->request_dns_packet); + + if (q->request_dns_stream) { + /* Detach the stream from our query, in case something else keeps a reference to it. */ + q->request_dns_stream->complete = NULL; + q->request_dns_stream->on_packet = NULL; + q->request_dns_stream->query = NULL; + dns_stream_unref(q->request_dns_stream); + } + free(q->request_address_string); if (q->manager) { @@ -420,7 +431,8 @@ int dns_query_new( DnsQuery **ret, DnsQuestion *question_utf8, DnsQuestion *question_idna, - int ifindex, uint64_t flags) { + int ifindex, + uint64_t flags) { _cleanup_(dns_query_freep) DnsQuery *q = NULL; DnsResourceKey *key; diff --git a/src/resolve/resolved-dns-query.h b/src/resolve/resolved-dns-query.h index c2ac02f68b..49a35b846b 100644 --- a/src/resolve/resolved-dns-query.h +++ b/src/resolve/resolved-dns-query.h @@ -71,6 +71,10 @@ struct DnsQuery { * family */ bool suppress_unroutable_family; + + /* If true, the RR TTLs of the answer will be clamped by their current left validity in the cache */ + bool clamp_ttl; + DnsTransactionState state; unsigned n_cname_redirects; @@ -95,6 +99,10 @@ struct DnsQuery { unsigned block_all_complete; char *request_address_string; + /* DNS stub information */ + DnsPacket *request_dns_packet; + DnsStream *request_dns_stream; + /* Completion callback */ void (*complete)(DnsQuery* q); unsigned block_ready; diff --git a/src/resolve/resolved-dns-question.h b/src/resolve/resolved-dns-question.h index ea41478975..a9a1863b1e 100644 --- a/src/resolve/resolved-dns-question.h +++ b/src/resolve/resolved-dns-question.h @@ -56,6 +56,10 @@ static inline unsigned dns_question_size(DnsQuestion *q) { return q ? q->n_keys : 0; } +static inline bool dns_question_isempty(DnsQuestion *q) { + return dns_question_size(q) <= 0; +} + DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQuestion*, dns_question_unref); #define _DNS_QUESTION_FOREACH(u, key, q) \ diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c index 6a29a93a26..5687588a7d 100644 --- a/src/resolve/resolved-dns-rr.c +++ b/src/resolve/resolved-dns-rr.c @@ -1532,6 +1532,232 @@ const struct hash_ops dns_resource_record_hash_ops = { .compare = dns_resource_record_compare_func, }; +DnsResourceRecord *dns_resource_record_copy(DnsResourceRecord *rr) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *copy = NULL; + DnsResourceRecord *t; + + assert(rr); + + copy = dns_resource_record_new(rr->key); + if (!copy) + return NULL; + + copy->ttl = rr->ttl; + copy->expiry = rr->expiry; + copy->n_skip_labels_signer = rr->n_skip_labels_signer; + copy->n_skip_labels_source = rr->n_skip_labels_source; + copy->unparseable = rr->unparseable; + + switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) { + + case DNS_TYPE_SRV: + copy->srv.priority = rr->srv.priority; + copy->srv.weight = rr->srv.weight; + copy->srv.port = rr->srv.port; + copy->srv.name = strdup(rr->srv.name); + if (!copy->srv.name) + return NULL; + break; + + case DNS_TYPE_PTR: + case DNS_TYPE_NS: + case DNS_TYPE_CNAME: + case DNS_TYPE_DNAME: + copy->ptr.name = strdup(rr->ptr.name); + if (!copy->ptr.name) + return NULL; + break; + + case DNS_TYPE_HINFO: + copy->hinfo.cpu = strdup(rr->hinfo.cpu); + if (!copy->hinfo.cpu) + return NULL; + + copy->hinfo.os = strdup(rr->hinfo.os); + if(!copy->hinfo.os) + return NULL; + break; + + case DNS_TYPE_TXT: + case DNS_TYPE_SPF: + copy->txt.items = dns_txt_item_copy(rr->txt.items); + if (!copy->txt.items) + return NULL; + break; + + case DNS_TYPE_A: + copy->a = rr->a; + break; + + case DNS_TYPE_AAAA: + copy->aaaa = rr->aaaa; + break; + + case DNS_TYPE_SOA: + copy->soa.mname = strdup(rr->soa.mname); + if (!copy->soa.mname) + return NULL; + copy->soa.rname = strdup(rr->soa.rname); + if (!copy->soa.rname) + return NULL; + copy->soa.serial = rr->soa.serial; + copy->soa.refresh = rr->soa.refresh; + copy->soa.retry = rr->soa.retry; + copy->soa.expire = rr->soa.expire; + copy->soa.minimum = rr->soa.minimum; + break; + + case DNS_TYPE_MX: + copy->mx.priority = rr->mx.priority; + copy->mx.exchange = strdup(rr->mx.exchange); + if (!copy->mx.exchange) + return NULL; + break; + + case DNS_TYPE_LOC: + copy->loc = rr->loc; + break; + + case DNS_TYPE_SSHFP: + copy->sshfp.algorithm = rr->sshfp.algorithm; + copy->sshfp.fptype = rr->sshfp.fptype; + copy->sshfp.fingerprint = memdup(rr->sshfp.fingerprint, rr->sshfp.fingerprint_size); + if (!copy->sshfp.fingerprint) + return NULL; + copy->sshfp.fingerprint_size = rr->sshfp.fingerprint_size; + break; + + case DNS_TYPE_DNSKEY: + copy->dnskey.flags = rr->dnskey.flags; + copy->dnskey.protocol = rr->dnskey.protocol; + copy->dnskey.algorithm = rr->dnskey.algorithm; + copy->dnskey.key = memdup(rr->dnskey.key, rr->dnskey.key_size); + if (!copy->dnskey.key) + return NULL; + copy->dnskey.key_size = rr->dnskey.key_size; + break; + + case DNS_TYPE_RRSIG: + copy->rrsig.type_covered = rr->rrsig.type_covered; + copy->rrsig.algorithm = rr->rrsig.algorithm; + copy->rrsig.labels = rr->rrsig.labels; + copy->rrsig.original_ttl = rr->rrsig.original_ttl; + copy->rrsig.expiration = rr->rrsig.expiration; + copy->rrsig.inception = rr->rrsig.inception; + copy->rrsig.key_tag = rr->rrsig.key_tag; + copy->rrsig.signer = strdup(rr->rrsig.signer); + if (!copy->rrsig.signer) + return NULL; + copy->rrsig.signature = memdup(rr->rrsig.signature, rr->rrsig.signature_size); + if (!copy->rrsig.signature) + return NULL; + copy->rrsig.signature_size = rr->rrsig.signature_size; + break; + + case DNS_TYPE_NSEC: + copy->nsec.next_domain_name = strdup(rr->nsec.next_domain_name); + if (!copy->nsec.next_domain_name) + return NULL; + copy->nsec.types = bitmap_copy(rr->nsec.types); + if (!copy->nsec.types) + return NULL; + break; + + case DNS_TYPE_DS: + copy->ds.key_tag = rr->ds.key_tag; + copy->ds.algorithm = rr->ds.algorithm; + copy->ds.digest_type = rr->ds.digest_type; + copy->ds.digest = memdup(rr->ds.digest, rr->ds.digest_size); + if (!copy->ds.digest) + return NULL; + copy->ds.digest_size = rr->ds.digest_size; + break; + + case DNS_TYPE_NSEC3: + copy->nsec3.algorithm = rr->nsec3.algorithm; + copy->nsec3.flags = rr->nsec3.flags; + copy->nsec3.iterations = rr->nsec3.iterations; + copy->nsec3.salt = memdup(rr->nsec3.salt, rr->nsec3.salt_size); + if (!copy->nsec3.salt) + return NULL; + copy->nsec3.salt_size = rr->nsec3.salt_size; + copy->nsec3.next_hashed_name = memdup(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size); + if (!copy->nsec3.next_hashed_name_size) + return NULL; + copy->nsec3.next_hashed_name_size = rr->nsec3.next_hashed_name_size; + copy->nsec3.types = bitmap_copy(rr->nsec3.types); + if (!copy->nsec3.types) + return NULL; + break; + + case DNS_TYPE_TLSA: + copy->tlsa.cert_usage = rr->tlsa.cert_usage; + copy->tlsa.selector = rr->tlsa.selector; + copy->tlsa.matching_type = rr->tlsa.matching_type; + copy->tlsa.data = memdup(rr->tlsa.data, rr->tlsa.data_size); + if (!copy->tlsa.data) + return NULL; + copy->tlsa.data_size = rr->tlsa.data_size; + break; + + case DNS_TYPE_CAA: + copy->caa.flags = rr->caa.flags; + copy->caa.tag = strdup(rr->caa.tag); + if (!copy->caa.tag) + return NULL; + copy->caa.value = memdup(rr->caa.value, rr->caa.value_size); + if (!copy->caa.value) + return NULL; + copy->caa.value_size = rr->caa.value_size; + break; + + case DNS_TYPE_OPT: + default: + copy->generic.data = memdup(rr->generic.data, rr->generic.data_size); + if (!copy->generic.data) + return NULL; + copy->generic.data_size = rr->generic.data_size; + break; + } + + t = copy; + copy = NULL; + + return t; +} + +int dns_resource_record_clamp_ttl(DnsResourceRecord **rr, uint32_t max_ttl) { + DnsResourceRecord *old_rr, *new_rr; + uint32_t new_ttl; + + assert(rr); + old_rr = *rr; + + if (old_rr->key->type == DNS_TYPE_OPT) + return -EINVAL; + + new_ttl = MIN(old_rr->ttl, max_ttl); + if (new_ttl == old_rr->ttl) + return 0; + + if (old_rr->n_ref == 1) { + /* Patch in place */ + old_rr->ttl = new_ttl; + return 1; + } + + new_rr = dns_resource_record_copy(old_rr); + if (!new_rr) + return -ENOMEM; + + new_rr->ttl = new_ttl; + + dns_resource_record_unref(*rr); + *rr = new_rr; + + return 1; +} + DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i) { DnsTxtItem *n; @@ -1564,6 +1790,25 @@ bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b) { return dns_txt_item_equal(a->items_next, b->items_next); } +DnsTxtItem *dns_txt_item_copy(DnsTxtItem *first) { + DnsTxtItem *i, *copy = NULL, *end = NULL; + + LIST_FOREACH(items, i, first) { + DnsTxtItem *j; + + j = memdup(i, offsetof(DnsTxtItem, data) + i->length + 1); + if (!j) { + dns_txt_item_free_all(copy); + return NULL; + } + + LIST_INSERT_AFTER(items, copy, end, j); + end = j; + } + + return copy; +} + static const char* const dnssec_algorithm_table[_DNSSEC_ALGORITHM_MAX_DEFINED] = { /* Mnemonics as listed on https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml */ [DNSSEC_ALGORITHM_RSAMD5] = "RSAMD5", diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h index 020a2abd77..42d39a1251 100644 --- a/src/resolve/resolved-dns-rr.h +++ b/src/resolve/resolved-dns-rr.h @@ -282,6 +282,13 @@ static inline size_t DNS_RESOURCE_RECORD_RDATA_SIZE(DnsResourceRecord *rr) { return rr->wire_format_size - rr->wire_format_rdata_offset; } +static inline uint8_t DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(DnsResourceRecord *rr) { + assert(rr); + assert(rr->key->type == DNS_TYPE_OPT); + + return ((rr->ttl >> 16) & 0xFF) == 0; +} + DnsResourceKey* dns_resource_key_new(uint16_t class, uint16_t type, const char *name); DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const DnsResourceRecord *cname); int dns_resource_key_new_append_suffix(DnsResourceKey **ret, DnsResourceKey *key, char *name); @@ -318,6 +325,7 @@ int dns_resource_record_new_reverse(DnsResourceRecord **ret, int family, const u int dns_resource_record_new_address(DnsResourceRecord **ret, int family, const union in_addr_union *address, const char *name); int dns_resource_record_equal(const DnsResourceRecord *a, const DnsResourceRecord *b); const char* dns_resource_record_to_string(DnsResourceRecord *rr); +DnsResourceRecord *dns_resource_record_copy(DnsResourceRecord *rr); DEFINE_TRIVIAL_CLEANUP_FUNC(DnsResourceRecord*, dns_resource_record_unref); int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical); @@ -327,8 +335,11 @@ int dns_resource_record_source(DnsResourceRecord *rr, const char **ret); int dns_resource_record_is_signer(DnsResourceRecord *rr, const char *zone); int dns_resource_record_is_synthetic(DnsResourceRecord *rr); +int dns_resource_record_clamp_ttl(DnsResourceRecord **rr, uint32_t max_ttl); + DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i); bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b); +DnsTxtItem *dns_txt_item_copy(DnsTxtItem *i); void dns_resource_record_hash_func(const void *i, struct siphash *state); diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c index 9d484d0a48..ed0c6aa105 100644 --- a/src/resolve/resolved-dns-scope.c +++ b/src/resolve/resolved-dns-scope.c @@ -232,7 +232,7 @@ static int dns_scope_emit_one(DnsScope *s, int fd, DnsPacket *p) { if (fd < 0) return fd; - r = manager_send(s->manager, fd, ifindex, family, &addr, LLMNR_PORT, p); + r = manager_send(s->manager, fd, ifindex, family, &addr, LLMNR_PORT, NULL, p); if (r < 0) return r; @@ -257,7 +257,7 @@ static int dns_scope_emit_one(DnsScope *s, int fd, DnsPacket *p) { if (fd < 0) return fd; - r = manager_send(s->manager, fd, ifindex, family, &addr, MDNS_PORT, p); + r = manager_send(s->manager, fd, ifindex, family, &addr, MDNS_PORT, NULL, p); if (r < 0) return r; @@ -578,6 +578,7 @@ static int dns_scope_multicast_membership(DnsScope *s, bool b, struct in_addr in } int dns_scope_llmnr_membership(DnsScope *s, bool b) { + assert(s); if (s->protocol != DNS_PROTOCOL_LLMNR) return 0; @@ -586,6 +587,7 @@ int dns_scope_llmnr_membership(DnsScope *s, bool b) { } int dns_scope_mdns_membership(DnsScope *s, bool b) { + assert(s); if (s->protocol != DNS_PROTOCOL_MDNS) return 0; @@ -604,15 +606,14 @@ static int dns_scope_make_reply_packet( DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; - unsigned i; int r; assert(s); assert(ret); - if ((!q || q->n_keys <= 0) - && (!answer || answer->n_rrs <= 0) - && (!soa || soa->n_rrs <= 0)) + if (dns_question_isempty(q) && + dns_answer_isempty(answer) && + dns_answer_isempty(soa)) return -EINVAL; r = dns_packet_new(&p, s->protocol, 0); @@ -631,35 +632,20 @@ static int dns_scope_make_reply_packet( 0 /* (cd) */, rcode)); - if (q) { - for (i = 0; i < q->n_keys; i++) { - r = dns_packet_append_key(p, q->keys[i], NULL); - if (r < 0) - return r; - } - - DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys); - } - - if (answer) { - for (i = 0; i < answer->n_rrs; i++) { - r = dns_packet_append_rr(p, answer->items[i].rr, NULL, NULL); - if (r < 0) - return r; - } - - DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs); - } + r = dns_packet_append_question(p, q); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); - if (soa) { - for (i = 0; i < soa->n_rrs; i++) { - r = dns_packet_append_rr(p, soa->items[i].rr, NULL, NULL); - if (r < 0) - return r; - } + r = dns_packet_append_answer(p, answer); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->ancount = htobe16(dns_answer_size(answer)); - DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs); - } + r = dns_packet_append_answer(p, soa); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->arcount = htobe16(dns_answer_size(soa)); *ret = p; p = NULL; @@ -668,25 +654,25 @@ static int dns_scope_make_reply_packet( } static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) { - unsigned n; + DnsResourceRecord *rr; + DnsResourceKey *key; assert(s); assert(p); - if (p->question) - for (n = 0; n < p->question->n_keys; n++) - dns_zone_verify_conflicts(&s->zone, p->question->keys[n]); - if (p->answer) - for (n = 0; n < p->answer->n_rrs; n++) - dns_zone_verify_conflicts(&s->zone, p->answer->items[n].rr->key); + DNS_QUESTION_FOREACH(key, p->question) + dns_zone_verify_conflicts(&s->zone, key); + + DNS_ANSWER_FOREACH(rr, p->answer) + dns_zone_verify_conflicts(&s->zone, rr->key); } void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { - _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; + _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; DnsResourceKey *key = NULL; bool tentative = false; - int r, fd; + int r; assert(s); assert(p); @@ -708,7 +694,7 @@ void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { r = dns_packet_extract(p); if (r < 0) { - log_debug_errno(r, "Failed to extract resources from incoming packet: %m"); + log_debug_errno(r, "Failed to extract resource records from incoming packet: %m"); return; } @@ -718,7 +704,7 @@ void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { return; } - assert(p->question->n_keys == 1); + assert(dns_question_size(p->question) == 1); key = p->question->keys[0]; r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative); @@ -738,9 +724,21 @@ void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { return; } - if (stream) + if (stream) { r = dns_stream_write_packet(stream, reply); - else { + if (r < 0) { + log_debug_errno(r, "Failed to enqueue reply packet: %m"); + return; + } + + /* Let's take an extra reference on this stream, so that it stays around after returning. The reference + * will be dangling until the stream is disconnected, and the default completion handler of the stream + * will then unref the stream and destroy it */ + if (DNS_STREAM_QUEUED(stream)) + dns_stream_ref(stream); + } else { + int fd; + if (!ratelimit_test(&s->ratelimit)) return; @@ -762,12 +760,11 @@ void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { * verified uniqueness for all records. Also see RFC * 4795, Section 2.7 */ - r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply); - } - - if (r < 0) { - log_debug_errno(r, "Failed to send reply packet: %m"); - return; + r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, NULL, reply); + if (r < 0) { + log_debug_errno(r, "Failed to send reply packet: %m"); + return; + } } } diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c index a9decf1158..9b7b471600 100644 --- a/src/resolve/resolved-dns-server.c +++ b/src/resolve/resolved-dns-server.c @@ -21,6 +21,7 @@ #include "alloc-util.h" #include "resolved-dns-server.h" +#include "resolved-dns-stub.h" #include "resolved-resolv-conf.h" #include "siphash24.h" #include "string-table.h" @@ -513,7 +514,7 @@ int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeature else packet_size = server->received_udp_packet_max; - return dns_packet_append_opt(packet, packet_size, edns_do, NULL); + return dns_packet_append_opt(packet, packet_size, edns_do, 0, NULL); } int dns_server_ifindex(const DnsServer *s) { @@ -746,6 +747,19 @@ void manager_next_dns_server(Manager *m) { manager_set_dns_server(m, m->dns_servers); } +bool dns_server_address_valid(int family, const union in_addr_union *sa) { + + /* Refuses the 0 IP addresses as well as 127.0.0.53 (which is our own DNS stub) */ + + if (in_addr_is_null(family, sa)) + return false; + + if (family == AF_INET && sa->in.s_addr == htobe32(INADDR_DNS_STUB)) + return false; + + return true; +} + static const char* const dns_server_type_table[_DNS_SERVER_TYPE_MAX] = { [DNS_SERVER_SYSTEM] = "system", [DNS_SERVER_FALLBACK] = "fallback", diff --git a/src/resolve/resolved-dns-server.h b/src/resolve/resolved-dns-server.h index 03ed85b3b9..c1732faffd 100644 --- a/src/resolve/resolved-dns-server.h +++ b/src/resolve/resolved-dns-server.h @@ -140,6 +140,8 @@ DnsServer *manager_set_dns_server(Manager *m, DnsServer *s); DnsServer *manager_get_dns_server(Manager *m); void manager_next_dns_server(Manager *m); +bool dns_server_address_valid(int family, const union in_addr_union *sa); + DEFINE_TRIVIAL_CLEANUP_FUNC(DnsServer*, dns_server_unref); extern const struct hash_ops dns_server_hash_ops; diff --git a/src/resolve/resolved-dns-stream.c b/src/resolve/resolved-dns-stream.c index a1040aeff4..dd0e0b90e3 100644 --- a/src/resolve/resolved-dns-stream.c +++ b/src/resolve/resolved-dns-stream.c @@ -56,8 +56,8 @@ static int dns_stream_complete(DnsStream *s, int error) { if (s->complete) s->complete(s, error); - else - dns_stream_free(s); + else /* the default action if no completion function is set is to close the stream */ + dns_stream_unref(s); return 0; } @@ -323,10 +323,16 @@ static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *use return 0; } -DnsStream *dns_stream_free(DnsStream *s) { +DnsStream *dns_stream_unref(DnsStream *s) { if (!s) return NULL; + assert(s->n_ref > 0); + s->n_ref--; + + if (s->n_ref > 0) + return NULL; + dns_stream_stop(s); if (s->manager) { @@ -339,13 +345,23 @@ DnsStream *dns_stream_free(DnsStream *s) { free(s); - return 0; + return NULL; } -DEFINE_TRIVIAL_CLEANUP_FUNC(DnsStream*, dns_stream_free); +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsStream*, dns_stream_unref); + +DnsStream *dns_stream_ref(DnsStream *s) { + if (!s) + return NULL; + + assert(s->n_ref > 0); + s->n_ref++; + + return s; +} int dns_stream_new(Manager *m, DnsStream **ret, DnsProtocol protocol, int fd) { - _cleanup_(dns_stream_freep) DnsStream *s = NULL; + _cleanup_(dns_stream_unrefp) DnsStream *s = NULL; int r; assert(m); @@ -358,6 +374,7 @@ int dns_stream_new(Manager *m, DnsStream **ret, DnsProtocol protocol, int fd) { if (!s) return -ENOMEM; + s->n_ref = 1; s->fd = -1; s->protocol = protocol; diff --git a/src/resolve/resolved-dns-stream.h b/src/resolve/resolved-dns-stream.h index 5ccc842249..e6569678fa 100644 --- a/src/resolve/resolved-dns-stream.h +++ b/src/resolve/resolved-dns-stream.h @@ -26,8 +26,16 @@ typedef struct DnsStream DnsStream; #include "resolved-dns-packet.h" #include "resolved-dns-transaction.h" +/* Streams are used by three subsystems: + * + * 1. The normal transaction logic when doing a DNS or LLMNR lookup via TCP + * 2. The LLMNR logic when accepting a TCP-based lookup + * 3. The DNS stub logic when accepting a TCP-based lookup + */ + struct DnsStream { Manager *manager; + int n_ref; DnsProtocol protocol; @@ -50,12 +58,23 @@ struct DnsStream { int (*on_packet)(DnsStream *s); int (*complete)(DnsStream *s, int error); - DnsTransaction *transaction; + DnsTransaction *transaction; /* when used by the transaction logic */ + DnsQuery *query; /* when used by the DNS stub logic */ LIST_FIELDS(DnsStream, streams); }; int dns_stream_new(Manager *m, DnsStream **s, DnsProtocol protocol, int fd); -DnsStream *dns_stream_free(DnsStream *s); +DnsStream *dns_stream_unref(DnsStream *s); +DnsStream *dns_stream_ref(DnsStream *s); int dns_stream_write_packet(DnsStream *s, DnsPacket *p); + +static inline bool DNS_STREAM_QUEUED(DnsStream *s) { + assert(s); + + if (s->fd < 0) /* already stopped? */ + return false; + + return !!s->write_packet; +} diff --git a/src/resolve/resolved-dns-stub.c b/src/resolve/resolved-dns-stub.c new file mode 100644 index 0000000000..d263cedcd9 --- /dev/null +++ b/src/resolve/resolved-dns-stub.c @@ -0,0 +1,572 @@ +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "fd-util.h" +#include "resolved-dns-stub.h" +#include "socket-util.h" + +/* The MTU of the loopback device is 64K on Linux, advertise that as maximum datagram size, but subtract the Ethernet, + * IP and UDP header sizes */ +#define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U) + +static int dns_stub_make_reply_packet( + uint16_t id, + int rcode, + DnsQuestion *q, + DnsAnswer *answer, + bool add_opt, /* add an OPT RR to this packet */ + bool edns0_do, /* set the EDNS0 DNSSEC OK bit */ + bool ad, /* set the DNSSEC authenticated data bit */ + DnsPacket **ret) { + + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + DnsResourceRecord *rr; + unsigned c = 0; + int r; + + /* Note that we don't bother with any additional RRs, as this is stub is for local lookups only, and hence + * roundtrips aren't expensive. */ + + r = dns_packet_new(&p, DNS_PROTOCOL_DNS, 0); + if (r < 0) + return r; + + /* If the client didn't do EDNS, clamp the rcode to 4 bit */ + if (!add_opt && rcode > 0xF) + rcode = DNS_RCODE_SERVFAIL; + + DNS_PACKET_HEADER(p)->id = id; + DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( + 1 /* qr */, + 0 /* opcode */, + 0 /* aa */, + 0 /* tc */, + 1 /* rd */, + 1 /* ra */, + ad /* ad */, + 0 /* cd */, + rcode)); + + r = dns_packet_append_question(p, q); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); + + DNS_ANSWER_FOREACH(rr, answer) { + r = dns_question_matches_rr(q, rr, NULL); + if (r < 0) + return r; + if (r > 0) + goto add; + + r = dns_question_matches_cname_or_dname(q, rr, NULL); + if (r < 0) + return r; + if (r > 0) + goto add; + + continue; + add: + r = dns_packet_append_rr(p, rr, NULL, NULL); + if (r < 0) + return r; + + c++; + } + DNS_PACKET_HEADER(p)->ancount = htobe16(c); + + if (add_opt) { + r = dns_packet_append_opt(p, ADVERTISE_DATAGRAM_SIZE_MAX, edns0_do, rcode, NULL); + if (r < 0) + return r; + } + + *ret = p; + p = NULL; + + return 0; +} + +static void dns_stub_detach_stream(DnsStream *s) { + assert(s); + + s->complete = NULL; + s->on_packet = NULL; + s->query = NULL; +} + +static int dns_stub_send(Manager *m, DnsStream *s, DnsPacket *p, DnsPacket *reply) { + int r; + + assert(m); + assert(p); + assert(reply); + + if (s) + r = dns_stream_write_packet(s, reply); + else { + int fd; + + /* Truncate the message to the right size */ + if (reply->size > DNS_PACKET_PAYLOAD_SIZE_MAX(p)) { + dns_packet_truncate(reply, DNS_PACKET_UNICAST_SIZE_MAX); + DNS_PACKET_HEADER(reply)->flags = htobe16(be16toh(DNS_PACKET_HEADER(reply)->flags) | DNS_PACKET_FLAG_TC); + } + + fd = manager_dns_stub_udp_fd(m); + if (fd < 0) + return log_debug_errno(fd, "Failed to get reply socket: %m"); + + /* Note that it is essential here that we explicitly choose the source IP address for this packet. This + * is because otherwise the kernel will choose it automatically based on the routing table and will + * thus pick 127.0.0.1 rather than 127.0.0.53. */ + + r = manager_send(m, fd, LOOPBACK_IFINDEX, p->family, &p->sender, p->sender_port, &p->destination, reply); + } + if (r < 0) + return log_debug_errno(r, "Failed to send reply packet: %m"); + + return 0; +} + +static int dns_stub_send_failure(Manager *m, DnsStream *s, DnsPacket *p, int rcode) { + _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; + int r; + + assert(m); + assert(p); + + r = dns_stub_make_reply_packet(DNS_PACKET_ID(p), rcode, p->question, NULL, !!p->opt, DNS_PACKET_DO(p), false, &reply); + if (r < 0) + return log_debug_errno(r, "Failed to build failure packet: %m"); + + return dns_stub_send(m, s, p, reply); +} + +static void dns_stub_query_complete(DnsQuery *q) { + int r; + + assert(q); + assert(q->request_dns_packet); + + switch (q->state) { + + case DNS_TRANSACTION_SUCCESS: { + _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; + + r = dns_stub_make_reply_packet( + DNS_PACKET_ID(q->request_dns_packet), + q->answer_rcode, + q->question_idna, + q->answer, + !!q->request_dns_packet->opt, + DNS_PACKET_DO(q->request_dns_packet), + DNS_PACKET_DO(q->request_dns_packet) && q->answer_authenticated, + &reply); + if (r < 0) { + log_debug_errno(r, "Failed to build reply packet: %m"); + break; + } + + (void) dns_stub_send(q->manager, q->request_dns_stream, q->request_dns_packet, reply); + break; + } + + case DNS_TRANSACTION_RCODE_FAILURE: + (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, q->answer_rcode); + break; + + case DNS_TRANSACTION_NOT_FOUND: + (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_NXDOMAIN); + break; + + case DNS_TRANSACTION_TIMEOUT: + case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: + /* Propagate a timeout as a no packet, i.e. that the client also gets a timeout */ + break; + + case DNS_TRANSACTION_NO_SERVERS: + case DNS_TRANSACTION_INVALID_REPLY: + case DNS_TRANSACTION_ERRNO: + case DNS_TRANSACTION_ABORTED: + case DNS_TRANSACTION_DNSSEC_FAILED: + case DNS_TRANSACTION_NO_TRUST_ANCHOR: + case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: + case DNS_TRANSACTION_NETWORK_DOWN: + (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_SERVFAIL); + break; + + case DNS_TRANSACTION_NULL: + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + default: + assert_not_reached("Impossible state"); + } + + /* If there's a packet to write set, let's leave the stream around */ + if (q->request_dns_stream && DNS_STREAM_QUEUED(q->request_dns_stream)) { + + /* Detach the stream from our query (make it an orphan), but do not drop the reference to it. The + * default completion action of the stream will drop the reference. */ + + dns_stub_detach_stream(q->request_dns_stream); + q->request_dns_stream = NULL; + } + + dns_query_free(q); +} + +static int dns_stub_stream_complete(DnsStream *s, int error) { + assert(s); + + log_debug_errno(error, "DNS TCP connection terminated, destroying query: %m"); + + assert(s->query); + dns_query_free(s->query); + + return 0; +} + +static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) { + DnsQuery *q = NULL; + int r; + + assert(m); + assert(p); + assert(p->protocol == DNS_PROTOCOL_DNS); + + /* Takes ownership of the *s stream object */ + + if (in_addr_is_localhost(p->family, &p->sender) <= 0 || + in_addr_is_localhost(p->family, &p->destination) <= 0) { + log_error("Got packet on unexpected IP range, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL); + goto fail; + } + + r = dns_packet_extract(p); + if (r < 0) { + log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m"); + dns_stub_send_failure(m, s, p, DNS_RCODE_FORMERR); + goto fail; + } + + if (!DNS_PACKET_VERSION_SUPPORTED(p)) { + log_debug("Got EDNS OPT field with unsupported version number."); + dns_stub_send_failure(m, s, p, DNS_RCODE_BADVERS); + goto fail; + } + + if (dns_type_is_obsolete(p->question->keys[0]->type)) { + log_debug("Got message with obsolete key type, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP); + goto fail; + } + + if (dns_type_is_zone_transer(p->question->keys[0]->type)) { + log_debug("Got request for zone transfer, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP); + goto fail; + } + + if (!DNS_PACKET_RD(p)) { + /* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */ + log_debug("Got request with recursion disabled, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_REFUSED); + goto fail; + } + + if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) { + log_debug("Got request with DNSSEC CD bit set, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP); + goto fail; + } + + r = dns_query_new(m, &q, p->question, p->question, 0, SD_RESOLVED_PROTOCOLS_ALL|SD_RESOLVED_NO_SEARCH|SD_RESOLVED_NO_CNAME); + if (r < 0) { + log_error_errno(r, "Failed to generate query object: %m"); + dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL); + goto fail; + } + + /* Request that the TTL is corrected by the cached time for this lookup, so that we return vaguely useful TTLs */ + q->clamp_ttl = true; + + q->request_dns_packet = dns_packet_ref(p); + q->request_dns_stream = dns_stream_ref(s); /* make sure the stream stays around until we can send a reply through it */ + q->complete = dns_stub_query_complete; + + if (s) { + s->on_packet = NULL; + s->complete = dns_stub_stream_complete; + s->query = q; + } + + r = dns_query_go(q); + if (r < 0) { + log_error_errno(r, "Failed to start query: %m"); + dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL); + goto fail; + } + + log_info("Processing query..."); + return; + +fail: + if (s && DNS_STREAM_QUEUED(s)) + dns_stub_detach_stream(s); + + dns_query_free(q); +} + +static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + Manager *m = userdata; + int r; + + r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); + if (r <= 0) + return r; + + if (dns_packet_validate_query(p) > 0) { + log_debug("Got DNS stub UDP query packet for id %u", DNS_PACKET_ID(p)); + + dns_stub_process_query(m, NULL, p); + } else + log_debug("Invalid DNS stub UDP packet, ignoring."); + + return 0; +} + +int manager_dns_stub_udp_fd(Manager *m) { + static const int one = 1; + + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(53), + .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), + }; + + int r; + + if (m->dns_stub_udp_fd >= 0) + return m->dns_stub_udp_fd; + + m->dns_stub_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->dns_stub_udp_fd < 0) + return -errno; + + r = setsockopt(m->dns_stub_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->dns_stub_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->dns_stub_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* Make sure no traffic from outside the local host can leak to onto this socket */ + r = setsockopt(m->dns_stub_udp_fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->dns_stub_udp_fd, &sa.sa, sizeof(sa.in)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->dns_stub_udp_event_source, m->dns_stub_udp_fd, EPOLLIN, on_dns_stub_packet, m); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(m->dns_stub_udp_event_source, "dns-stub-udp"); + + return m->dns_stub_udp_fd; + +fail: + m->dns_stub_udp_fd = safe_close(m->dns_stub_udp_fd); + return r; +} + +static int on_dns_stub_stream_packet(DnsStream *s) { + assert(s); + assert(s->read_packet); + + if (dns_packet_validate_query(s->read_packet) > 0) { + log_debug("Got DNS stub TCP query packet for id %u", DNS_PACKET_ID(s->read_packet)); + + dns_stub_process_query(s->manager, s, s->read_packet); + } else + log_debug("Invalid DNS stub TCP packet, ignoring."); + + /* Drop the reference to the stream. Either a query was created and added its own reference to the stream now, + * or that didn't happen in which case we want to free the stream */ + dns_stream_unref(s); + + return 0; +} + +static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + DnsStream *stream; + Manager *m = userdata; + int cfd, r; + + cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); + if (cfd < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + return -errno; + } + + r = dns_stream_new(m, &stream, DNS_PROTOCOL_DNS, cfd); + if (r < 0) { + safe_close(cfd); + return r; + } + + stream->on_packet = on_dns_stub_stream_packet; + + /* We let the reference to the stream dangling here, it will either be dropped by the default "complete" action + * of the stream, or by our packet callback, or when the manager is shut down. */ + + return 0; +} + +int manager_dns_stub_tcp_fd(Manager *m) { + static const int one = 1; + + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), + .in.sin_port = htobe16(53), + }; + + int r; + + if (m->dns_stub_tcp_fd >= 0) + return m->dns_stub_tcp_fd; + + m->dns_stub_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->dns_stub_tcp_fd < 0) + return -errno; + + r = setsockopt(m->dns_stub_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->dns_stub_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->dns_stub_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->dns_stub_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* Make sure no traffic from outside the local host can leak to onto this socket */ + r = setsockopt(m->dns_stub_tcp_fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->dns_stub_tcp_fd, &sa.sa, sizeof(sa.in)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = listen(m->dns_stub_tcp_fd, SOMAXCONN); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->dns_stub_tcp_event_source, m->dns_stub_tcp_fd, EPOLLIN, on_dns_stub_stream, m); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(m->dns_stub_tcp_event_source, "dns-stub-tcp"); + + return m->dns_stub_tcp_fd; + +fail: + m->dns_stub_tcp_fd = safe_close(m->dns_stub_tcp_fd); + return r; +} + +int manager_dns_stub_start(Manager *m) { + int r; + + assert(m); + + r = manager_dns_stub_udp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + r = manager_dns_stub_tcp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + return 0; + +eaddrinuse: + log_warning("Another process is already listening on 127.0.0.53:53. Turning off local DNS stub support."); + manager_dns_stub_stop(m); + + return 0; +} + +void manager_dns_stub_stop(Manager *m) { + assert(m); + + m->dns_stub_udp_event_source = sd_event_source_unref(m->dns_stub_udp_event_source); + m->dns_stub_tcp_event_source = sd_event_source_unref(m->dns_stub_tcp_event_source); + + m->dns_stub_udp_fd = safe_close(m->dns_stub_udp_fd); + m->dns_stub_tcp_fd = safe_close(m->dns_stub_tcp_fd); +} diff --git a/src/resolve/resolved-dns-stub.h b/src/resolve/resolved-dns-stub.h new file mode 100644 index 0000000000..fce4d25ede --- /dev/null +++ b/src/resolve/resolved-dns-stub.h @@ -0,0 +1,31 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "resolved-manager.h" + +/* 127.0.0.53 in native endian */ +#define INADDR_DNS_STUB ((in_addr_t) 0x7f000035U) + +int manager_dns_stub_udp_fd(Manager *m); +int manager_dns_stub_tcp_fd(Manager *m); + +void manager_dns_stub_stop(Manager *m); +int manager_dns_stub_start(Manager *m); diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 2b1a32b8fb..d455b6b1fa 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -60,7 +60,14 @@ static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { static void dns_transaction_close_connection(DnsTransaction *t) { assert(t); - t->stream = dns_stream_free(t->stream); + if (t->stream) { + /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */ + t->stream->complete = NULL; + t->stream->on_packet = NULL; + t->stream->transaction = NULL; + t->stream = dns_stream_unref(t->stream); + } + t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); t->dns_udp_fd = safe_close(t->dns_udp_fd); } @@ -462,7 +469,7 @@ static int on_stream_complete(DnsStream *s, int error) { t = s->transaction; p = dns_packet_ref(s->read_packet); - t->stream = dns_stream_free(t->stream); + dns_transaction_close_connection(t); if (ERRNO_IS_DISCONNECT(error)) { usec_t usec; @@ -574,7 +581,7 @@ static int dns_transaction_open_tcp(DnsTransaction *t) { r = dns_stream_write_packet(t->stream, t->sent); if (r < 0) { - t->stream = dns_stream_free(t->stream); + t->stream = dns_stream_unref(t->stream); return r; } @@ -601,6 +608,10 @@ static void dns_transaction_cache_answer(DnsTransaction *t) { if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) return; + /* Caching disabled? */ + if (!t->scope->manager->enable_cache) + return; + /* We never cache if this packet is from the local host, under * the assumption that a locally running DNS server would * cache this anyway, and probably knows better when to flush @@ -1313,7 +1324,7 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { /* Let's then prune all outdated entries */ dns_cache_prune(&t->scope->cache); - r = dns_cache_lookup(&t->scope->cache, t->key, &t->answer_rcode, &t->answer, &t->answer_authenticated); + r = dns_cache_lookup(&t->scope->cache, t->key, t->clamp_ttl, &t->answer_rcode, &t->answer, &t->answer_authenticated); if (r < 0) return r; if (r > 0) { diff --git a/src/resolve/resolved-dns-transaction.h b/src/resolve/resolved-dns-transaction.h index bc1529d621..96b066845d 100644 --- a/src/resolve/resolved-dns-transaction.h +++ b/src/resolve/resolved-dns-transaction.h @@ -74,6 +74,8 @@ struct DnsTransaction { bool initial_jitter_scheduled:1; bool initial_jitter_elapsed:1; + bool clamp_ttl:1; + DnsPacket *sent, *received; DnsAnswer *answer; diff --git a/src/resolve/resolved-gperf.gperf b/src/resolve/resolved-gperf.gperf index 82f26215df..2fd56bce26 100644 --- a/src/resolve/resolved-gperf.gperf +++ b/src/resolve/resolved-gperf.gperf @@ -19,3 +19,4 @@ Resolve.FallbackDNS, config_parse_dns_servers, DNS_SERVER_FALLBACK, 0 Resolve.Domains, config_parse_search_domains, 0, 0 Resolve.LLMNR, config_parse_resolve_support, 0, offsetof(Manager, llmnr_support) Resolve.DNSSEC, config_parse_dnssec_mode, 0, offsetof(Manager, dnssec_mode) +Resolve.Cache, config_parse_bool, 0, offsetof(Manager, enable_cache) diff --git a/src/resolve/resolved-link-bus.c b/src/resolve/resolved-link-bus.c index bfb87d78e7..364812250f 100644 --- a/src/resolve/resolved-link-bus.c +++ b/src/resolve/resolved-link-bus.c @@ -28,7 +28,23 @@ #include "strv.h" static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_resolve_support, resolve_support, ResolveSupport); -static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_dnssec_mode, dnssec_mode, DnssecMode); + +static int property_get_dnssec_mode( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + + assert(reply); + assert(l); + + return sd_bus_message_append(reply, "s", dnssec_mode_to_string(link_get_dnssec_mode(l))); +} static int property_get_dns( sd_bus *bus, @@ -214,6 +230,9 @@ int bus_link_method_set_dns_servers(sd_bus_message *message, void *userdata, sd_ if (sz != FAMILY_ADDRESS_SIZE(family)) return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid address size"); + if (!dns_server_address_valid(family, d)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid DNS server address"); + r = sd_bus_message_exit_container(message); if (r < 0) return r; @@ -249,6 +268,7 @@ int bus_link_method_set_dns_servers(sd_bus_message *message, void *userdata, sd_ dns_server_unlink_marked(l->dns_servers); link_allocate_scopes(l); + (void) link_save_user(l); (void) manager_write_resolv_conf(l->manager); return sd_bus_reply_method_return(message, NULL); @@ -330,6 +350,7 @@ int bus_link_method_set_domains(sd_bus_message *message, void *userdata, sd_bus_ dns_search_domain_unlink_marked(l->search_domains); + (void) link_save_user(l); (void) manager_write_resolv_conf(l->manager); return sd_bus_reply_method_return(message, NULL); @@ -368,6 +389,8 @@ int bus_link_method_set_llmnr(sd_bus_message *message, void *userdata, sd_bus_er link_allocate_scopes(l); link_add_rrs(l, false); + (void) link_save_user(l); + return sd_bus_reply_method_return(message, NULL); } @@ -400,6 +423,8 @@ int bus_link_method_set_mdns(sd_bus_message *message, void *userdata, sd_bus_err link_allocate_scopes(l); link_add_rrs(l, false); + (void) link_save_user(l); + return sd_bus_reply_method_return(message, NULL); } @@ -430,6 +455,8 @@ int bus_link_method_set_dnssec(sd_bus_message *message, void *userdata, sd_bus_e link_set_dnssec_mode(l, mode); + (void) link_save_user(l); + return sd_bus_reply_method_return(message, NULL); } @@ -473,6 +500,8 @@ int bus_link_method_set_dnssec_negative_trust_anchors(sd_bus_message *message, v l->dnssec_negative_trust_anchors = ns; ns = NULL; + (void) link_save_user(l); + return sd_bus_reply_method_return(message, NULL); } @@ -491,6 +520,7 @@ int bus_link_method_revert(sd_bus_message *message, void *userdata, sd_bus_error link_allocate_scopes(l); link_add_rrs(l, false); + (void) link_save_user(l); (void) manager_write_resolv_conf(l->manager); return sd_bus_reply_method_return(message, NULL); @@ -504,7 +534,7 @@ const sd_bus_vtable link_vtable[] = { SD_BUS_PROPERTY("Domains", "a(sb)", property_get_domains, 0, 0), SD_BUS_PROPERTY("LLMNR", "s", property_get_resolve_support, offsetof(Link, llmnr_support), 0), SD_BUS_PROPERTY("MulticastDNS", "s", property_get_resolve_support, offsetof(Link, mdns_support), 0), - SD_BUS_PROPERTY("DNSSEC", "s", property_get_dnssec_mode, offsetof(Link, dnssec_mode), 0), + SD_BUS_PROPERTY("DNSSEC", "s", property_get_dnssec_mode, 0, 0), SD_BUS_PROPERTY("DNSSECNegativeTrustAnchors", "as", property_get_ntas, 0, 0), SD_BUS_PROPERTY("DNSSECSupported", "b", property_get_dnssec_supported, 0, 0), diff --git a/src/resolve/resolved-link.c b/src/resolve/resolved-link.c index b189c21920..ea4a007139 100644 --- a/src/resolve/resolved-link.c +++ b/src/resolve/resolved-link.c @@ -22,7 +22,10 @@ #include "sd-network.h" #include "alloc-util.h" +#include "fd-util.h" +#include "fileio.h" #include "missing.h" +#include "mkdir.h" #include "parse-util.h" #include "resolved-link.h" #include "string-util.h" @@ -49,6 +52,9 @@ int link_new(Manager *m, Link **ret, int ifindex) { l->dnssec_mode = _DNSSEC_MODE_INVALID; l->operstate = IF_OPER_UNKNOWN; + if (asprintf(&l->state_file, "/run/systemd/resolve/netif/%i", ifindex) < 0) + return -ENOMEM; + r = hashmap_put(m->links, INT_TO_PTR(ifindex), l); if (r < 0) return r; @@ -93,6 +99,8 @@ Link *link_free(Link *l) { dns_scope_free(l->mdns_ipv4_scope); dns_scope_free(l->mdns_ipv6_scope); + free(l->state_file); + free(l); return NULL; } @@ -165,7 +173,7 @@ void link_add_rrs(Link *l, bool force_remove) { link_address_add_rrs(a, force_remove); } -int link_update_rtnl(Link *l, sd_netlink_message *m) { +int link_process_rtnl(Link *l, sd_netlink_message *m) { const char *n = NULL; int r; @@ -190,6 +198,27 @@ int link_update_rtnl(Link *l, sd_netlink_message *m) { return 0; } +static int link_update_dns_server_one(Link *l, const char *name) { + union in_addr_union a; + DnsServer *s; + int family, r; + + assert(l); + assert(name); + + r = in_addr_from_string_auto(name, &family, &a); + if (r < 0) + return r; + + s = dns_server_find(l->dns_servers, family, &a, 0); + if (s) { + dns_server_move_back_and_unmark(s); + return 0; + } + + return dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, family, &a, 0); +} + static int link_update_dns_servers(Link *l) { _cleanup_strv_free_ char **nameservers = NULL; char **nameserver; @@ -208,22 +237,9 @@ static int link_update_dns_servers(Link *l) { dns_server_mark_all(l->dns_servers); STRV_FOREACH(nameserver, nameservers) { - union in_addr_union a; - DnsServer *s; - int family; - - r = in_addr_from_string_auto(*nameserver, &family, &a); + r = link_update_dns_server_one(l, *nameserver); if (r < 0) goto clear; - - s = dns_server_find(l->dns_servers, family, &a, 0); - if (s) - dns_server_move_back_and_unmark(s); - else { - r = dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, family, &a, 0); - if (r < 0) - goto clear; - } } dns_server_unlink_marked(l->dns_servers); @@ -341,7 +357,6 @@ clear: static int link_update_dnssec_negative_trust_anchors(Link *l) { _cleanup_strv_free_ char **ntas = NULL; _cleanup_set_free_free_ Set *ns = NULL; - char **i; int r; assert(l); @@ -358,11 +373,9 @@ static int link_update_dnssec_negative_trust_anchors(Link *l) { if (!ns) return -ENOMEM; - STRV_FOREACH(i, ntas) { - r = set_put_strdup(ns, *i); - if (r < 0) - return r; - } + r = set_put_strdupv(ns, ntas); + if (r < 0) + return r; set_free_free(l->dnssec_negative_trust_anchors); l->dnssec_negative_trust_anchors = ns; @@ -379,6 +392,9 @@ static int link_update_search_domain_one(Link *l, const char *name, bool route_o DnsSearchDomain *d; int r; + assert(l); + assert(name); + r = dns_search_domain_find(l->search_domains, name, &d); if (r < 0) return r; @@ -439,7 +455,7 @@ clear: return r; } -static int link_is_unmanaged(Link *l) { +static int link_is_managed(Link *l) { _cleanup_free_ char *state = NULL; int r; @@ -447,11 +463,11 @@ static int link_is_unmanaged(Link *l) { r = sd_network_link_get_setup_state(l->ifindex, &state); if (r == -ENODATA) - return 1; + return 0; if (r < 0) return r; - return STR_IN_SET(state, "pending", "unmanaged"); + return !STR_IN_SET(state, "pending", "unmanaged"); } static void link_read_settings(Link *l) { @@ -461,12 +477,12 @@ static void link_read_settings(Link *l) { /* Read settings from networkd, except when networkd is not managing this interface. */ - r = link_is_unmanaged(l); + r = link_is_managed(l); if (r < 0) { log_warning_errno(r, "Failed to determine whether interface %s is managed: %m", l->name); return; } - if (r > 0) { + if (r == 0) { /* If this link used to be managed, but is now unmanaged, flush all our settings — but only once. */ if (l->is_managed) @@ -503,10 +519,11 @@ static void link_read_settings(Link *l) { log_warning_errno(r, "Failed to read search domains for interface %s, ignoring: %m", l->name); } -int link_update_monitor(Link *l) { +int link_update(Link *l) { assert(l); link_read_settings(l); + link_load_user(l); link_allocate_scopes(l); link_add_rrs(l, false); @@ -838,3 +855,261 @@ bool link_address_relevant(LinkAddress *a, bool local_multicast) { return true; } + +static bool link_needs_save(Link *l) { + assert(l); + + /* Returns true if any of the settings where set different from the default */ + + if (l->is_managed) + return false; + + if (l->llmnr_support != RESOLVE_SUPPORT_YES || + l->mdns_support != RESOLVE_SUPPORT_NO || + l->dnssec_mode != _DNSSEC_MODE_INVALID) + return true; + + if (l->dns_servers || + l->search_domains) + return true; + + if (!set_isempty(l->dnssec_negative_trust_anchors)) + return true; + + return false; +} + +int link_save_user(Link *l) { + _cleanup_free_ char *temp_path = NULL; + _cleanup_fclose_ FILE *f = NULL; + const char *v; + int r; + + assert(l); + assert(l->state_file); + + if (!link_needs_save(l)) { + (void) unlink(l->state_file); + return 0; + } + + r = mkdir_parents(l->state_file, 0700); + if (r < 0) + goto fail; + + r = fopen_temporary(l->state_file, &f, &temp_path); + if (r < 0) + goto fail; + + fputs("# This is private data. Do not parse.\n", f); + + v = resolve_support_to_string(l->llmnr_support); + if (v) + fprintf(f, "LLMNR=%s\n", v); + + v = resolve_support_to_string(l->mdns_support); + if (v) + fprintf(f, "MDNS=%s\n", v); + + v = dnssec_mode_to_string(l->dnssec_mode); + if (v) + fprintf(f, "DNSSEC=%s\n", v); + + if (l->dns_servers) { + DnsServer *server; + + fputs("SERVERS=", f); + LIST_FOREACH(servers, server, l->dns_servers) { + + if (server != l->dns_servers) + fputc(' ', f); + + v = dns_server_string(server); + if (!v) { + r = -ENOMEM; + goto fail; + } + + fputs(v, f); + } + fputc('\n', f); + } + + if (l->search_domains) { + DnsSearchDomain *domain; + + fputs("DOMAINS=", f); + LIST_FOREACH(domains, domain, l->search_domains) { + + if (domain != l->search_domains) + fputc(' ', f); + + if (domain->route_only) + fputc('~', f); + + fputs(DNS_SEARCH_DOMAIN_NAME(domain), f); + } + fputc('\n', f); + } + + if (!set_isempty(l->dnssec_negative_trust_anchors)) { + bool space = false; + Iterator i; + char *nta; + + fputs("NTAS=", f); + SET_FOREACH(nta, l->dnssec_negative_trust_anchors, i) { + + if (space) + fputc(' ', f); + + fputs(nta, f); + space = true; + } + fputc('\n', f); + } + + r = fflush_and_check(f); + if (r < 0) + goto fail; + + if (rename(temp_path, l->state_file) < 0) { + r = -errno; + goto fail; + } + + return 0; + +fail: + (void) unlink(l->state_file); + + if (temp_path) + (void) unlink(temp_path); + + return log_error_errno(r, "Failed to save link data %s: %m", l->state_file); +} + +int link_load_user(Link *l) { + _cleanup_free_ char + *llmnr = NULL, + *mdns = NULL, + *dnssec = NULL, + *servers = NULL, + *domains = NULL, + *ntas = NULL; + + ResolveSupport s; + int r; + + assert(l); + assert(l->state_file); + + /* Try to load only a single time */ + if (l->loaded) + return 0; + l->loaded = true; + + if (l->is_managed) + return 0; /* if the device is managed, then networkd is our configuration source, not the bus API */ + + r = parse_env_file(l->state_file, NEWLINE, + "LLMNR", &llmnr, + "MDNS", &mdns, + "DNSSEC", &dnssec, + "SERVERS", &servers, + "DOMAINS", &domains, + "NTAS", &ntas, + NULL); + if (r == -ENOENT) + return 0; + if (r < 0) + goto fail; + + link_flush_settings(l); + + /* If we can't recognize the LLMNR or MDNS setting we don't override the default */ + s = resolve_support_from_string(llmnr); + if (s >= 0) + l->llmnr_support = s; + + s = resolve_support_from_string(mdns); + if (s >= 0) + l->mdns_support = s; + + /* If we can't recognize the DNSSEC setting, then set it to invalid, so that the daemon default is used. */ + l->dnssec_mode = dnssec_mode_from_string(dnssec); + + if (servers) { + const char *p = servers; + + for (;;) { + _cleanup_free_ char *word = NULL; + + r = extract_first_word(&p, &word, NULL, 0); + if (r < 0) + goto fail; + if (r == 0) + break; + + r = link_update_dns_server_one(l, word); + if (r < 0) { + log_debug_errno(r, "Failed to load DNS server '%s', ignoring: %m", word); + continue; + } + } + } + + if (domains) { + const char *p = domains; + + for (;;) { + _cleanup_free_ char *word = NULL; + const char *n; + bool is_route; + + r = extract_first_word(&p, &word, NULL, 0); + if (r < 0) + goto fail; + if (r == 0) + break; + + is_route = word[0] == '~'; + n = is_route ? word + 1 : word; + + r = link_update_search_domain_one(l, n, is_route); + if (r < 0) { + log_debug_errno(r, "Failed to load search domain '%s', ignoring: %m", word); + continue; + } + } + } + + if (ntas) { + _cleanup_set_free_free_ Set *ns = NULL; + + ns = set_new(&dns_name_hash_ops); + if (!ns) { + r = -ENOMEM; + goto fail; + } + + r = set_put_strsplit(ns, ntas, NULL, 0); + if (r < 0) + goto fail; + + l->dnssec_negative_trust_anchors = ns; + ns = NULL; + } + + return 0; + +fail: + return log_error_errno(r, "Failed to load link data %s: %m", l->state_file); +} + +void link_remove_user(Link *l) { + assert(l); + assert(l->state_file); + + (void) unlink(l->state_file); +} diff --git a/src/resolve/resolved-link.h b/src/resolve/resolved-link.h index f534c12824..6a2343f9f7 100644 --- a/src/resolve/resolved-link.h +++ b/src/resolve/resolved-link.h @@ -81,12 +81,15 @@ struct Link { char name[IF_NAMESIZE]; uint32_t mtu; uint8_t operstate; + + bool loaded; + char *state_file; }; int link_new(Manager *m, Link **ret, int ifindex); Link *link_free(Link *l); -int link_update_rtnl(Link *l, sd_netlink_message *m); -int link_update_monitor(Link *l); +int link_process_rtnl(Link *l, sd_netlink_message *m); +int link_update(Link *l); bool link_relevant(Link *l, int family, bool local_multicast); LinkAddress* link_find_address(Link *l, int family, const union in_addr_union *in_addr); void link_add_rrs(Link *l, bool force_remove); @@ -102,6 +105,10 @@ void link_next_dns_server(Link *l); DnssecMode link_get_dnssec_mode(Link *l); bool link_dnssec_supported(Link *l); +int link_save_user(Link *l); +int link_load_user(Link *l); +void link_remove_user(Link *l); + int link_address_new(Link *l, LinkAddress **ret, int family, const union in_addr_union *in_addr); LinkAddress *link_address_free(LinkAddress *a); int link_address_update_rtnl(LinkAddress *a, sd_netlink_message *m); diff --git a/src/resolve/resolved-llmnr.c b/src/resolve/resolved-llmnr.c index 8b1d71a3eb..3516af58ee 100644 --- a/src/resolve/resolved-llmnr.c +++ b/src/resolve/resolved-llmnr.c @@ -91,18 +91,19 @@ static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *u DnsScope *scope; int r; + assert(s); + assert(fd >= 0); + assert(m); + r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p); if (r <= 0) return r; scope = manager_find_scope(m, p); - if (!scope) { + if (!scope) log_warning("Got LLMNR UDP packet on unknown scope. Ignoring."); - return 0; - } - - if (dns_packet_validate_reply(p) > 0) { - log_debug("Got LLMNR reply packet for id %u", DNS_PACKET_ID(p)); + else if (dns_packet_validate_reply(p) > 0) { + log_debug("Got LLMNR UDP reply packet for id %u", DNS_PACKET_ID(p)); dns_scope_check_conflicts(scope, p); @@ -111,7 +112,7 @@ static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *u dns_transaction_process_reply(t, p); } else if (dns_packet_validate_query(p) > 0) { - log_debug("Got LLMNR query packet for id %u", DNS_PACKET_ID(p)); + log_debug("Got LLMNR UDP query packet for id %u", DNS_PACKET_ID(p)); dns_scope_process_query(scope, NULL, p); } else @@ -283,25 +284,19 @@ static int on_llmnr_stream_packet(DnsStream *s) { DnsScope *scope; assert(s); + assert(s->read_packet); scope = manager_find_scope(s->manager, s->read_packet); - if (!scope) { + if (!scope) log_warning("Got LLMNR TCP packet on unknown scope. Ignoring."); - return 0; - } - - if (dns_packet_validate_query(s->read_packet) > 0) { - log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet)); + else if (dns_packet_validate_query(s->read_packet) > 0) { + log_debug("Got LLMNR TCP query packet for id %u", DNS_PACKET_ID(s->read_packet)); dns_scope_process_query(scope, s, s->read_packet); - - /* If no reply packet was set, we free the stream */ - if (s->write_packet) - return 0; } else - log_debug("Invalid LLMNR TCP packet."); + log_debug("Invalid LLMNR TCP packet, ignoring."); - dns_stream_free(s); + dns_stream_unref(s); return 0; } diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index 23101cb760..add463b6a9 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -23,6 +23,7 @@ #include "af-list.h" #include "alloc-util.h" +#include "dirent-util.h" #include "dns-domain.h" #include "fd-util.h" #include "fileio-label.h" @@ -35,6 +36,7 @@ #include "random-util.h" #include "resolved-bus.h" #include "resolved-conf.h" +#include "resolved-dns-stub.h" #include "resolved-etc-hosts.h" #include "resolved-llmnr.h" #include "resolved-manager.h" @@ -78,11 +80,11 @@ static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void * goto fail; } - r = link_update_rtnl(l, mm); + r = link_process_rtnl(l, mm); if (r < 0) goto fail; - r = link_update_monitor(l); + r = link_update(l); if (r < 0) goto fail; @@ -95,6 +97,7 @@ static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void * case RTM_DELLINK: if (l) { log_debug("Removing link %i/%s", l->ifindex, l->name); + link_remove_user(l); link_free(l); } @@ -279,7 +282,7 @@ static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void * sd_network_monitor_flush(m->network_monitor); HASHMAP_FOREACH(l, m->links, i) { - r = link_update_monitor(l); + r = link_update(l); if (r < 0) log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex); } @@ -491,11 +494,13 @@ int manager_new(Manager **ret) { m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1; m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1; m->mdns_ipv4_fd = m->mdns_ipv6_fd = -1; + m->dns_stub_udp_fd = m->dns_stub_tcp_fd = -1; m->hostname_fd = -1; m->llmnr_support = RESOLVE_SUPPORT_YES; m->mdns_support = RESOLVE_SUPPORT_NO; m->dnssec_mode = DEFAULT_DNSSEC_MODE; + m->enable_cache = true; m->read_resolv_conf = true; m->need_builtin_fallbacks = true; m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY; @@ -540,6 +545,8 @@ int manager_new(Manager **ret) { (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m); (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m); + manager_cleanup_saved_user(m); + *ret = m; m = NULL; @@ -551,6 +558,10 @@ int manager_start(Manager *m) { assert(m); + r = manager_dns_stub_start(m); + if (r < 0) + return r; + r = manager_llmnr_start(m); if (r < 0) return r; @@ -580,6 +591,11 @@ Manager *manager_free(Manager *m) { dns_scope_free(m->unicast_scope); + /* At this point only orphaned streams should remain. All others should have been freed already by their + * owners */ + while (m->dns_streams) + dns_stream_unref(m->dns_streams); + hashmap_free(m->links); hashmap_free(m->dns_transactions); @@ -591,6 +607,7 @@ Manager *manager_free(Manager *m) { manager_llmnr_stop(m); manager_mdns_stop(m); + manager_dns_stub_stop(m); sd_bus_slot_unref(m->prepare_for_sleep_slot); sd_event_source_unref(m->bus_retry_event_source); @@ -805,7 +822,14 @@ int manager_write(Manager *m, int fd, DnsPacket *p) { return 0; } -static int manager_ipv4_send(Manager *m, int fd, int ifindex, const struct in_addr *addr, uint16_t port, DnsPacket *p) { +static int manager_ipv4_send( + Manager *m, + int fd, + int ifindex, + const struct in_addr *destination, + uint16_t port, + const struct in_addr *source, + DnsPacket *p) { union sockaddr_union sa = { .in.sin_family = AF_INET, }; @@ -818,14 +842,14 @@ static int manager_ipv4_send(Manager *m, int fd, int ifindex, const struct in_ad assert(m); assert(fd >= 0); - assert(addr); + assert(destination); assert(port > 0); assert(p); iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; - sa.in.sin_addr = *addr; + sa.in.sin_addr = *destination; sa.in.sin_port = htobe16(port), mh.msg_iov = &iov; @@ -849,12 +873,23 @@ static int manager_ipv4_send(Manager *m, int fd, int ifindex, const struct in_ad pi = (struct in_pktinfo*) CMSG_DATA(cmsg); pi->ipi_ifindex = ifindex; + + if (source) + pi->ipi_spec_dst = *source; } return sendmsg_loop(fd, &mh, 0); } -static int manager_ipv6_send(Manager *m, int fd, int ifindex, const struct in6_addr *addr, uint16_t port, DnsPacket *p) { +static int manager_ipv6_send( + Manager *m, + int fd, + int ifindex, + const struct in6_addr *destination, + uint16_t port, + const struct in6_addr *source, + DnsPacket *p) { + union sockaddr_union sa = { .in6.sin6_family = AF_INET6, }; @@ -867,14 +902,14 @@ static int manager_ipv6_send(Manager *m, int fd, int ifindex, const struct in6_a assert(m); assert(fd >= 0); - assert(addr); + assert(destination); assert(port > 0); assert(p); iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; - sa.in6.sin6_addr = *addr; + sa.in6.sin6_addr = *destination; sa.in6.sin6_port = htobe16(port), sa.in6.sin6_scope_id = ifindex; @@ -899,24 +934,36 @@ static int manager_ipv6_send(Manager *m, int fd, int ifindex, const struct in6_a pi = (struct in6_pktinfo*) CMSG_DATA(cmsg); pi->ipi6_ifindex = ifindex; + + if (source) + pi->ipi6_addr = *source; } return sendmsg_loop(fd, &mh, 0); } -int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *addr, uint16_t port, DnsPacket *p) { +int manager_send( + Manager *m, + int fd, + int ifindex, + int family, + const union in_addr_union *destination, + uint16_t port, + const union in_addr_union *source, + DnsPacket *p) { + assert(m); assert(fd >= 0); - assert(addr); + assert(destination); assert(port > 0); assert(p); log_debug("Sending %s packet with id %" PRIu16 " on interface %i/%s.", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family)); if (family == AF_INET) - return manager_ipv4_send(m, fd, ifindex, &addr->in, port, p); + return manager_ipv4_send(m, fd, ifindex, &destination->in, port, &source->in, p); if (family == AF_INET6) - return manager_ipv6_send(m, fd, ifindex, &addr->in6, port, p); + return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, &source->in6, p); return -EAFNOSUPPORT; } @@ -1153,7 +1200,7 @@ int manager_compile_dns_servers(Manager *m, OrderedSet **dns) { return 0; } -int manager_compile_search_domains(Manager *m, OrderedSet **domains) { +int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) { DnsSearchDomain *d; Iterator i; Link *l; @@ -1167,6 +1214,11 @@ int manager_compile_search_domains(Manager *m, OrderedSet **domains) { return r; LIST_FOREACH(domains, d, m->search_domains) { + + if (filter_route >= 0 && + d->route_only != !!filter_route) + continue; + r = ordered_set_put(*domains, d->name); if (r == -EEXIST) continue; @@ -1177,6 +1229,11 @@ int manager_compile_search_domains(Manager *m, OrderedSet **domains) { HASHMAP_FOREACH(l, m->links, i) { LIST_FOREACH(domains, d, l->search_domains) { + + if (filter_route >= 0 && + d->route_only != !!filter_route) + continue; + r = ordered_set_put(*domains, d->name); if (r == -EEXIST) continue; @@ -1259,3 +1316,58 @@ void manager_flush_caches(Manager *m) { log_info("Flushed all caches."); } + +void manager_cleanup_saved_user(Manager *m) { + _cleanup_closedir_ DIR *d = NULL; + struct dirent *de; + int r; + + assert(m); + + /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface + * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can + * be restarted without losing this data. */ + + d = opendir("/run/systemd/resolve/netif/"); + if (!d) { + if (errno == ENOENT) + return; + + log_warning_errno(errno, "Failed to open interface directory: %m"); + return; + } + + FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) { + _cleanup_free_ char *p = NULL; + int ifindex; + Link *l; + + if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG)) + continue; + + if (STR_IN_SET(de->d_name, ".", "..")) + continue; + + r = parse_ifindex(de->d_name, &ifindex); + if (r < 0) /* Probably some temporary file from a previous run. Delete it */ + goto rm; + + l = hashmap_get(m->links, INT_TO_PTR(ifindex)); + if (!l) /* link vanished */ + goto rm; + + if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */ + goto rm; + + continue; + + rm: + p = strappend("/run/systemd/resolve/netif/", de->d_name); + if (!p) { + log_oom(); + return; + } + + (void) unlink(p); + } +} diff --git a/src/resolve/resolved-manager.h b/src/resolve/resolved-manager.h index ef71202ef9..deebd8e484 100644 --- a/src/resolve/resolved-manager.h +++ b/src/resolve/resolved-manager.h @@ -46,6 +46,7 @@ struct Manager { ResolveSupport llmnr_support; ResolveSupport mdns_support; DnssecMode dnssec_mode; + bool enable_cache; /* Network */ Hashmap *links; @@ -72,7 +73,6 @@ struct Manager { LIST_HEAD(DnsSearchDomain, search_domains); unsigned n_search_domains; - bool permit_domain_search; bool need_builtin_fallbacks:1; @@ -129,6 +129,13 @@ struct Manager { Set* etc_hosts_by_address; Hashmap* etc_hosts_by_name; usec_t etc_hosts_last, etc_hosts_mtime; + + /* Local DNS stub on 127.0.0.53:53 */ + int dns_stub_udp_fd; + int dns_stub_tcp_fd; + + sd_event_source *dns_stub_udp_event_source; + sd_event_source *dns_stub_tcp_event_source; }; /* Manager */ @@ -141,7 +148,7 @@ int manager_start(Manager *m); uint32_t manager_find_mtu(Manager *m); int manager_write(Manager *m, int fd, DnsPacket *p); -int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *addr, uint16_t port, DnsPacket *p); +int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *destination, uint16_t port, const union in_addr_union *source, DnsPacket *p); int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret); int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr); @@ -162,7 +169,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free); int manager_is_own_hostname(Manager *m, const char *name); int manager_compile_dns_servers(Manager *m, OrderedSet **servers); -int manager_compile_search_domains(Manager *m, OrderedSet **domains); +int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route); DnssecMode manager_get_dnssec_mode(Manager *m); bool manager_dnssec_supported(Manager *m); @@ -172,3 +179,5 @@ void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResource bool manager_routable(Manager *m, int family); void manager_flush_caches(Manager *m); + +void manager_cleanup_saved_user(Manager *m); diff --git a/src/resolve/resolved-resolv-conf.c b/src/resolve/resolved-resolv-conf.c index ae17aef3ab..31b25ca50f 100644 --- a/src/resolve/resolved-resolv-conf.c +++ b/src/resolve/resolved-resolv-conf.c @@ -194,10 +194,13 @@ static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *doma Iterator i; fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n" - "# Third party programs must not access this file directly, but\n" - "# only through the symlink at /etc/resolv.conf. To manage\n" - "# resolv.conf(5) in a different way, replace the symlink by a\n" - "# static file or a different symlink.\n\n", f); + "# This is a dynamic resolv.conf file for connecting local clients directly to\n" + "# all known DNS servers.\n#\n" + "# Third party programs must not access this file directly, but only through the\n" + "# symlink at /etc/resolv.conf. To manage resolv.conf(5) in a different way,\n" + "# replace this symlink by a static file or a different symlink.\n#\n" + "# See systemd-resolved.service(8) for details about the supported modes of\n" + "# operation for /etc/resolv.conf.\n\n", f); if (ordered_set_isempty(dns)) fputs("# No DNS servers known.\n", f); @@ -232,7 +235,7 @@ int manager_write_resolv_conf(Manager *m) { if (r < 0) return log_warning_errno(r, "Failed to compile list of DNS servers: %m"); - r = manager_compile_search_domains(m, &domains); + r = manager_compile_search_domains(m, &domains, false); if (r < 0) return log_warning_errno(r, "Failed to compile list of search domains: %m"); diff --git a/src/resolve/resolved.c b/src/resolve/resolved.c index 3a47b82d8a..deb75f9ae5 100644 --- a/src/resolve/resolved.c +++ b/src/resolve/resolved.c @@ -67,7 +67,11 @@ int main(int argc, char *argv[]) { goto finish; } - r = drop_privileges(uid, gid, 0); + /* Drop privileges, but keep three caps. Note that we drop those too, later on (see below) */ + r = drop_privileges(uid, gid, + (UINT64_C(1) << CAP_NET_RAW)| /* needed for SO_BINDTODEVICE */ + (UINT64_C(1) << CAP_NET_BIND_SERVICE)| /* needed to bind on port 53 */ + (UINT64_C(1) << CAP_SETPCAP) /* needed in order to drop the caps later */); if (r < 0) goto finish; @@ -88,6 +92,13 @@ int main(int argc, char *argv[]) { /* Write finish default resolv.conf to avoid a dangling symlink */ (void) manager_write_resolv_conf(m); + /* Let's drop the remaining caps now */ + r = capability_bounding_set_drop(0, true); + if (r < 0) { + log_error_errno(r, "Failed to drop remaining caps: %m"); + goto finish; + } + sd_notify(false, "READY=1\n" "STATUS=Processing requests..."); diff --git a/src/resolve/resolved.conf.in b/src/resolve/resolved.conf.in index a288588924..3bd8389c88 100644 --- a/src/resolve/resolved.conf.in +++ b/src/resolve/resolved.conf.in @@ -17,3 +17,4 @@ #Domains= #LLMNR=yes #DNSSEC=@DEFAULT_DNSSEC_MODE@ +#Cache=yes diff --git a/src/resolve/test-dns-packet.c b/src/resolve/test-dns-packet.c index 41e5c1caa5..956b155872 100644 --- a/src/resolve/test-dns-packet.c +++ b/src/resolve/test-dns-packet.c @@ -33,6 +33,19 @@ #define HASH_KEY SD_ID128_MAKE(d3,1e,48,90,4b,fa,4c,fe,af,9d,d5,a1,d7,2e,8a,b1) +static void verify_rr_copy(DnsResourceRecord *rr) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *copy = NULL; + const char *a, *b; + + assert_se(copy = dns_resource_record_copy(rr)); + assert_se(dns_resource_record_equal(copy, rr) > 0); + + assert_se(a = dns_resource_record_to_string(rr)); + assert_se(b = dns_resource_record_to_string(copy)); + + assert_se(streq(a, b)); +} + static uint64_t hash(DnsResourceRecord *rr) { struct siphash state; @@ -66,6 +79,8 @@ static void test_packet_from_file(const char* filename, bool canonical) { assert_se(dns_packet_append_blob(p, data + offset + 8, packet_size, NULL) >= 0); assert_se(dns_packet_read_rr(p, &rr, NULL, NULL) >= 0); + verify_rr_copy(rr); + s = dns_resource_record_to_string(rr); assert_se(s); puts(s); @@ -78,6 +93,8 @@ static void test_packet_from_file(const char* filename, bool canonical) { assert_se(dns_packet_append_blob(p2, rr->wire_format, rr->wire_format_size, NULL) >= 0); assert_se(dns_packet_read_rr(p2, &rr2, NULL, NULL) >= 0); + verify_rr_copy(rr); + s2 = dns_resource_record_to_string(rr); assert_se(s2); assert_se(streq(s, s2)); |