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-rw-r--r--src/resolve/resolved-conf.c603
1 files changed, 603 insertions, 0 deletions
diff --git a/src/resolve/resolved-conf.c b/src/resolve/resolved-conf.c
new file mode 100644
index 0000000..2f08ed0
--- /dev/null
+++ b/src/resolve/resolved-conf.c
@@ -0,0 +1,603 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "conf-parser.h"
+#include "constants.h"
+#include "creds-util.h"
+#include "dns-domain.h"
+#include "extract-word.h"
+#include "hexdecoct.h"
+#include "parse-util.h"
+#include "proc-cmdline.h"
+#include "resolved-conf.h"
+#include "resolved-dns-search-domain.h"
+#include "resolved-dns-stub.h"
+#include "resolved-dnssd.h"
+#include "resolved-manager.h"
+#include "socket-netlink.h"
+#include "specifier.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "utf8.h"
+
+DEFINE_CONFIG_PARSE_ENUM(config_parse_dns_stub_listener_mode, dns_stub_listener_mode, DnsStubListenerMode, "Failed to parse DNS stub listener mode setting");
+
+static int manager_add_dns_server_by_string(Manager *m, DnsServerType type, const char *word) {
+ _cleanup_free_ char *server_name = NULL;
+ union in_addr_union address;
+ int family, r, ifindex = 0;
+ uint16_t port;
+ DnsServer *s;
+
+ assert(m);
+ assert(word);
+
+ r = in_addr_port_ifindex_name_from_string_auto(word, &family, &address, &port, &ifindex, &server_name);
+ if (r < 0)
+ return r;
+
+ /* Silently filter out 0.0.0.0, 127.0.0.53, 127.0.0.54 (our own stub DNS listener) */
+ if (!dns_server_address_valid(family, &address))
+ return 0;
+
+ /* By default, the port number is determined with the transaction feature level.
+ * See dns_transaction_port() and dns_server_port(). */
+ if (IN_SET(port, 53, 853))
+ port = 0;
+
+ /* Filter out duplicates */
+ s = dns_server_find(manager_get_first_dns_server(m, type), family, &address, port, ifindex, server_name);
+ if (s) {
+ /* Drop the marker. This is used to find the servers that ceased to exist, see
+ * manager_mark_dns_servers() and manager_flush_marked_dns_servers(). */
+ dns_server_move_back_and_unmark(s);
+ return 0;
+ }
+
+ return dns_server_new(m, NULL, type, NULL, family, &address, port, ifindex, server_name);
+}
+
+int manager_parse_dns_server_string_and_warn(Manager *m, DnsServerType type, const char *string) {
+ int r;
+
+ assert(m);
+ assert(string);
+
+ for (;;) {
+ _cleanup_free_ char *word = NULL;
+
+ r = extract_first_word(&string, &word, NULL, 0);
+ if (r <= 0)
+ return r;
+
+ r = manager_add_dns_server_by_string(m, type, word);
+ if (r < 0)
+ log_warning_errno(r, "Failed to add DNS server address '%s', ignoring: %m", word);
+ }
+}
+
+static int manager_add_search_domain_by_string(Manager *m, const char *domain) {
+ DnsSearchDomain *d;
+ bool route_only;
+ int r;
+
+ assert(m);
+ assert(domain);
+
+ route_only = *domain == '~';
+ if (route_only)
+ domain++;
+
+ if (dns_name_is_root(domain) || streq(domain, "*")) {
+ route_only = true;
+ domain = ".";
+ }
+
+ r = dns_search_domain_find(m->search_domains, domain, &d);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ dns_search_domain_move_back_and_unmark(d);
+ else {
+ r = dns_search_domain_new(m, &d, DNS_SEARCH_DOMAIN_SYSTEM, NULL, domain);
+ if (r < 0)
+ return r;
+ }
+
+ d->route_only = route_only;
+ return 0;
+}
+
+int manager_parse_search_domains_and_warn(Manager *m, const char *string) {
+ int r;
+
+ assert(m);
+ assert(string);
+
+ for (;;) {
+ _cleanup_free_ char *word = NULL;
+
+ r = extract_first_word(&string, &word, NULL, EXTRACT_UNQUOTE);
+ if (r <= 0)
+ return r;
+
+ r = manager_add_search_domain_by_string(m, word);
+ if (r < 0)
+ log_warning_errno(r, "Failed to add search domain '%s', ignoring: %m", word);
+ }
+}
+
+int config_parse_dns_servers(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ Manager *m = ASSERT_PTR(userdata);
+ int r;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+
+ if (isempty(rvalue))
+ /* Empty assignment means clear the list */
+ dns_server_unlink_all(manager_get_first_dns_server(m, ltype));
+ else {
+ /* Otherwise, add to the list */
+ r = manager_parse_dns_server_string_and_warn(m, ltype, rvalue);
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r,
+ "Failed to parse DNS server string '%s', ignoring.", rvalue);
+ return 0;
+ }
+ }
+
+ /* If we have a manual setting, then we stop reading
+ * /etc/resolv.conf */
+ if (ltype == DNS_SERVER_SYSTEM)
+ m->read_resolv_conf = false;
+ if (ltype == DNS_SERVER_FALLBACK)
+ m->need_builtin_fallbacks = false;
+
+ return 0;
+}
+
+int config_parse_search_domains(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ Manager *m = ASSERT_PTR(userdata);
+ int r;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+
+ if (isempty(rvalue))
+ /* Empty assignment means clear the list */
+ dns_search_domain_unlink_all(m->search_domains);
+ else {
+ /* Otherwise, add to the list */
+ r = manager_parse_search_domains_and_warn(m, rvalue);
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r,
+ "Failed to parse search domains string '%s', ignoring.", rvalue);
+ return 0;
+ }
+ }
+
+ /* If we have a manual setting, then we stop reading
+ * /etc/resolv.conf */
+ m->read_resolv_conf = false;
+
+ return 0;
+}
+
+int config_parse_dnssd_service_name(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ static const Specifier specifier_table[] = {
+ { 'a', specifier_architecture, NULL },
+ { 'b', specifier_boot_id, NULL },
+ { 'B', specifier_os_build_id, NULL },
+ { 'H', specifier_hostname, NULL }, /* We will use specifier_dnssd_hostname(). */
+ { 'm', specifier_machine_id, NULL },
+ { 'o', specifier_os_id, NULL },
+ { 'v', specifier_kernel_release, NULL },
+ { 'w', specifier_os_version_id, NULL },
+ { 'W', specifier_os_variant_id, NULL },
+ {}
+ };
+ DnssdService *s = ASSERT_PTR(userdata);
+ _cleanup_free_ char *name = NULL;
+ int r;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+
+ if (isempty(rvalue)) {
+ s->name_template = mfree(s->name_template);
+ return 0;
+ }
+
+ r = specifier_printf(rvalue, DNS_LABEL_MAX, specifier_table, NULL, NULL, &name);
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r,
+ "Invalid service instance name template '%s', ignoring assignment: %m", rvalue);
+ return 0;
+ }
+
+ if (!dns_service_name_is_valid(name)) {
+ log_syntax(unit, LOG_WARNING, filename, line, 0,
+ "Service instance name template '%s' renders to invalid name '%s'. Ignoring assignment.",
+ rvalue, name);
+ return 0;
+ }
+
+ return free_and_strdup_warn(&s->name_template, rvalue);
+}
+
+int config_parse_dnssd_service_type(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ DnssdService *s = ASSERT_PTR(userdata);
+ int r;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+
+ if (isempty(rvalue)) {
+ s->type = mfree(s->type);
+ return 0;
+ }
+
+ if (!dnssd_srv_type_is_valid(rvalue)) {
+ log_syntax(unit, LOG_WARNING, filename, line, 0, "Service type is invalid. Ignoring.");
+ return 0;
+ }
+
+ r = free_and_strdup(&s->type, rvalue);
+ if (r < 0)
+ return log_oom();
+
+ return 0;
+}
+
+int config_parse_dnssd_txt(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ _cleanup_(dnssd_txtdata_freep) DnssdTxtData *txt_data = NULL;
+ DnssdService *s = ASSERT_PTR(userdata);
+ DnsTxtItem *last = NULL;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+
+ if (isempty(rvalue)) {
+ /* Flush out collected items */
+ s->txt_data_items = dnssd_txtdata_free_all(s->txt_data_items);
+ return 0;
+ }
+
+ txt_data = new0(DnssdTxtData, 1);
+ if (!txt_data)
+ return log_oom();
+
+ for (;;) {
+ _cleanup_free_ char *word = NULL, *key = NULL, *value = NULL;
+ _cleanup_free_ void *decoded = NULL;
+ size_t length = 0;
+ DnsTxtItem *i;
+ int r;
+
+ r = extract_first_word(&rvalue, &word, NULL,
+ EXTRACT_UNQUOTE|EXTRACT_CUNESCAPE|EXTRACT_UNESCAPE_RELAX);
+ if (r == 0)
+ break;
+ if (r == -ENOMEM)
+ return log_oom();
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r, "Invalid syntax, ignoring: %s", rvalue);
+ return 0;
+ }
+
+ r = split_pair(word, "=", &key, &value);
+ if (r == -ENOMEM)
+ return log_oom();
+ if (r == -EINVAL)
+ key = TAKE_PTR(word);
+
+ if (!ascii_is_valid(key)) {
+ log_syntax(unit, LOG_WARNING, filename, line, 0, "Invalid key, ignoring: %s", key);
+ continue;
+ }
+
+ switch (ltype) {
+
+ case DNS_TXT_ITEM_DATA:
+ if (value) {
+ r = unbase64mem(value, strlen(value), &decoded, &length);
+ if (r == -ENOMEM)
+ return log_oom();
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r,
+ "Invalid base64 encoding, ignoring: %s", value);
+ continue;
+ }
+ }
+
+ r = dnssd_txt_item_new_from_data(key, decoded, length, &i);
+ if (r < 0)
+ return log_oom();
+ break;
+
+ case DNS_TXT_ITEM_TEXT:
+ r = dnssd_txt_item_new_from_string(key, value, &i);
+ if (r < 0)
+ return log_oom();
+ break;
+
+ default:
+ assert_not_reached();
+ }
+
+ LIST_INSERT_AFTER(items, txt_data->txts, last, i);
+ last = i;
+ }
+
+ if (txt_data->txts) {
+ LIST_PREPEND(items, s->txt_data_items, txt_data);
+ TAKE_PTR(txt_data);
+ }
+
+ return 0;
+}
+
+int config_parse_dns_stub_listener_extra(
+ const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ _cleanup_free_ DnsStubListenerExtra *stub = NULL;
+ Manager *m = userdata;
+ const char *p;
+ int r;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+ assert(data);
+
+ if (isempty(rvalue)) {
+ m->dns_extra_stub_listeners = ordered_set_free(m->dns_extra_stub_listeners);
+ return 0;
+ }
+
+ r = dns_stub_listener_extra_new(m, &stub);
+ if (r < 0)
+ return log_oom();
+
+ p = startswith(rvalue, "udp:");
+ if (p)
+ stub->mode = DNS_STUB_LISTENER_UDP;
+ else {
+ p = startswith(rvalue, "tcp:");
+ if (p)
+ stub->mode = DNS_STUB_LISTENER_TCP;
+ else {
+ stub->mode = DNS_STUB_LISTENER_YES;
+ p = rvalue;
+ }
+ }
+
+ r = in_addr_port_ifindex_name_from_string_auto(p, &stub->family, &stub->address, &stub->port, NULL, NULL);
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r,
+ "Failed to parse address in %s=%s, ignoring assignment: %m",
+ lvalue, rvalue);
+ return 0;
+ }
+
+ r = ordered_set_ensure_put(&m->dns_extra_stub_listeners, &dns_stub_listener_extra_hash_ops, stub);
+ if (r == -ENOMEM)
+ return log_oom();
+ if (r < 0) {
+ log_syntax(unit, LOG_WARNING, filename, line, r,
+ "Failed to store %s=%s, ignoring assignment: %m", lvalue, rvalue);
+ return 0;
+ }
+
+ TAKE_PTR(stub);
+
+ return 0;
+}
+
+static void read_credentials(Manager *m) {
+ _cleanup_free_ char *dns = NULL, *domains = NULL;
+ int r;
+
+ assert(m);
+
+ /* Hmm, if we aren't supposed to read /etc/resolv.conf because the DNS settings were already
+ * configured explicitly in our config file, we don't want to honour credentials either */
+ if (!m->read_resolv_conf)
+ return;
+
+ r = read_credential_strings_many("network.dns", &dns,
+ "network.search_domains", &domains);
+ if (r < 0)
+ log_warning_errno(r, "Failed to read credentials, ignoring: %m");
+
+ if (dns) {
+ r = manager_parse_dns_server_string_and_warn(m, DNS_SERVER_SYSTEM, dns);
+ if (r < 0)
+ log_warning_errno(r, "Failed to parse credential network.dns '%s', ignoring.", dns);
+
+ m->read_resolv_conf = false;
+ }
+
+ if (domains) {
+ r = manager_parse_search_domains_and_warn(m, domains);
+ if (r < 0)
+ log_warning_errno(r, "Failed to parse credential network.search_domains '%s', ignoring.", domains);
+
+ m->read_resolv_conf = false;
+ }
+}
+
+struct ProcCmdlineInfo {
+ Manager *manager;
+
+ /* If there's a setting configured via /proc/cmdline we want to reset the configured lists, but only
+ * once, so that multiple nameserver= or domain= settings can be specified on the kernel command line
+ * and will be combined. These booleans will be set once we erase the list once. */
+ bool dns_server_unlinked;
+ bool search_domain_unlinked;
+};
+
+static int proc_cmdline_callback(const char *key, const char *value, void *data) {
+ struct ProcCmdlineInfo *info = ASSERT_PTR(data);
+ int r;
+
+ assert(key);
+ assert(info->manager);
+
+ /* The kernel command line option names are chosen to be compatible with what various tools already
+ * interpret, for example dracut and SUSE Linux. */
+
+ if (streq(key, "nameserver")) {
+
+ if (proc_cmdline_value_missing(key, value))
+ return 0;
+
+ if (!info->dns_server_unlinked) {
+ /* The kernel command line overrides any prior configuration */
+ dns_server_unlink_all(manager_get_first_dns_server(info->manager, DNS_SERVER_SYSTEM));
+ info->dns_server_unlinked = true;
+ }
+
+ r = manager_parse_dns_server_string_and_warn(info->manager, DNS_SERVER_SYSTEM, value);
+ if (r < 0)
+ log_warning_errno(r, "Failed to parse DNS server string '%s', ignoring.", value);
+
+ info->manager->read_resolv_conf = false;
+
+ } else if (streq(key, "domain")) {
+
+ if (proc_cmdline_value_missing(key, value))
+ return 0;
+
+ if (!info->search_domain_unlinked) {
+ dns_search_domain_unlink_all(info->manager->search_domains);
+ info->search_domain_unlinked = true;
+ }
+
+ r = manager_parse_search_domains_and_warn(info->manager, value);
+ if (r < 0)
+ log_warning_errno(r, "Failed to parse credential provided search domain string '%s', ignoring.", value);
+
+ info->manager->read_resolv_conf = false;
+ }
+
+ return 0;
+}
+
+static void read_proc_cmdline(Manager *m) {
+ int r;
+
+ assert(m);
+
+ r = proc_cmdline_parse(proc_cmdline_callback, &(struct ProcCmdlineInfo) { .manager = m }, 0);
+ if (r < 0)
+ log_warning_errno(r, "Failed to read kernel command line, ignoring: %m");
+}
+
+int manager_parse_config_file(Manager *m) {
+ int r;
+
+ assert(m);
+
+ r = config_parse_config_file("resolved.conf", "Resolve\0",
+ config_item_perf_lookup, resolved_gperf_lookup,
+ CONFIG_PARSE_WARN, m);
+ if (r < 0)
+ return r;
+
+ read_credentials(m); /* credentials are only used when nothing is explicitly configured … */
+ read_proc_cmdline(m); /* … but kernel command line overrides local configuration. */
+
+ if (m->need_builtin_fallbacks) {
+ r = manager_parse_dns_server_string_and_warn(m, DNS_SERVER_FALLBACK, DNS_SERVERS);
+ if (r < 0)
+ return r;
+ }
+
+#if !HAVE_OPENSSL_OR_GCRYPT
+ if (m->dnssec_mode != DNSSEC_NO) {
+ log_warning("DNSSEC option cannot be enabled or set to allow-downgrade when systemd-resolved is built without a cryptographic library. Turning off DNSSEC support.");
+ m->dnssec_mode = DNSSEC_NO;
+ }
+#endif
+
+#if !ENABLE_DNS_OVER_TLS
+ if (m->dns_over_tls_mode != DNS_OVER_TLS_NO) {
+ log_warning("DNS-over-TLS option cannot be enabled or set to opportunistic when systemd-resolved is built without DNS-over-TLS support. Turning off DNS-over-TLS support.");
+ m->dns_over_tls_mode = DNS_OVER_TLS_NO;
+ }
+#endif
+ return 0;
+
+}
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