/* SPDX-License-Identifier: LGPL-2.1+ */
-/***
- This file is part of systemd.
-
- Copyright 2014 Tom Gundersen <teg@jklm.no>
-
- 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 <resolv.h>
-#include <stdio_ext.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
#include "alloc-util.h"
#include "dns-domain.h"
#include "fd-util.h"
-#include "fileio-label.h"
#include "fileio.h"
#include "ordered-set.h"
#include "resolved-conf.h"
#include "resolved-resolv-conf.h"
#include "string-util.h"
#include "strv.h"
+#include "tmpfile-util-label.h"
/* A resolv.conf file containing the DNS server and domain data we learnt from uplink, i.e. the full uplink data */
#define PRIVATE_UPLINK_RESOLV_CONF "/run/systemd/resolve/resolv.conf"
/* A resolv.conf file containing the domain data we learnt from uplink, but our own DNS server address. */
#define PRIVATE_STUB_RESOLV_CONF "/run/systemd/resolve/stub-resolv.conf"
-/* A static resolv.conf file containing no domains, but only our own DNS sever address */
+/* A static resolv.conf file containing no domains, but only our own DNS server address */
#define PRIVATE_STATIC_RESOLV_CONF ROOTLIBEXECDIR "/resolv.conf"
+int manager_check_resolv_conf(const Manager *m) {
+ const char *path;
+ struct stat st;
+ int r;
+
+ assert(m);
+
+ /* This warns only when our stub listener is disabled and /etc/resolv.conf is a symlink to
+ * PRIVATE_STATIC_RESOLV_CONF or PRIVATE_STUB_RESOLV_CONF. */
+
+ if (m->dns_stub_listener_mode != DNS_STUB_LISTENER_NO)
+ return 0;
+
+ r = stat("/etc/resolv.conf", &st);
+ if (r < 0) {
+ if (errno == ENOENT)
+ return 0;
+
+ return log_warning_errno(errno, "Failed to stat /etc/resolv.conf: %m");
+ }
+
+ FOREACH_STRING(path,
+ PRIVATE_STUB_RESOLV_CONF,
+ PRIVATE_STATIC_RESOLV_CONF) {
+
+ struct stat own;
+
+ /* Is it symlinked to our own uplink file? */
+ if (stat(path, &own) >= 0 &&
+ st.st_dev == own.st_dev &&
+ st.st_ino == own.st_ino) {
+ log_warning("DNSStubListener= is disabled, but /etc/resolv.conf is a symlink to %s "
+ "which expects DNSStubListener= to be enabled.", path);
+ return -EOPNOTSUPP;
+ }
+ }
+
+ return 0;
+}
+
static bool file_is_our_own(const struct stat *st) {
const char *path;
int manager_read_resolv_conf(Manager *m) {
_cleanup_fclose_ FILE *f = NULL;
struct stat st;
- char line[LINE_MAX];
+ unsigned n = 0;
int r;
assert(m);
dns_server_mark_all(m->dns_servers);
dns_search_domain_mark_all(m->search_domains);
- FOREACH_LINE(line, f, r = -errno; goto clear) {
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
const char *a;
char *l;
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0) {
+ log_error_errno(r, "Failed to read /etc/resolv.conf: %m");
+ goto clear;
+ }
+ if (r == 0)
+ break;
+
+ n++;
+
l = strstrip(line);
- if (IN_SET(*l, '#', ';'))
+ if (IN_SET(*l, '#', ';', 0))
continue;
a = first_word(l, "nameserver");
if (r < 0)
log_warning_errno(r, "Failed to parse search domain string '%s', ignoring.", a);
}
+
+ log_syntax(NULL, LOG_DEBUG, "/etc/resolv.conf", n, 0, "Ignoring resolv.conf line: %s", l);
}
m->resolv_conf_mtime = timespec_load(&st.st_mtim);
}
static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) {
+ DnsScope *scope;
+
assert(s);
assert(f);
assert(count);
if (!dns_server_string(s)) {
- log_warning("Our of memory, or invalid DNS address. Ignoring server.");
+ log_warning("Out of memory, or invalid DNS address. Ignoring server.");
return;
}
- /* Check if the DNS server is limited to particular domains;
- * resolv.conf does not have a syntax to express that, so it must not
- * appear as a global name server to avoid routing unrelated domains to
- * it (which is a privacy violation, will most probably fail anyway,
- * and adds unnecessary load) */
- if (dns_server_limited_domains(s)) {
- log_debug("DNS server %s has route-only domains, not using as global name server", dns_server_string(s));
+ /* Check if the scope this DNS server belongs to is suitable as 'default' route for lookups; resolv.conf does
+ * not have a syntax to express that, so it must not appear as a global name server to avoid routing unrelated
+ * domains to it (which is a privacy violation, will most probably fail anyway, and adds unnecessary load) */
+ scope = dns_server_scope(s);
+ if (scope && !dns_scope_is_default_route(scope)) {
+ log_debug("Scope of DNS server %s has only route-only domains, not using as global name server", dns_server_string(s));
return;
}
"# internal DNS stub resolver of systemd-resolved. This file lists all\n"
"# configured search domains.\n"
"#\n"
- "# Run \"systemd-resolve --status\" to see details about the uplink DNS servers\n"
+ "# Run \"resolvectl status\" to see details about the uplink DNS servers\n"
"# currently in use.\n"
"#\n"
"# Third party programs must not access this file directly, but only through the\n"
"# See man:systemd-resolved.service(8) for details about the supported modes of\n"
"# operation for /etc/resolv.conf.\n"
"\n"
- "nameserver 127.0.0.53\n", f);
+ "nameserver 127.0.0.53\n"
+ "options edns0\n", f);
if (!ordered_set_isempty(domains))
write_resolv_conf_search(domains, f);
if (r < 0)
return log_warning_errno(r, "Failed to open private resolv.conf file for writing: %m");
- (void) __fsetlocking(f_uplink, FSETLOCKING_BYCALLER);
(void) fchmod(fileno(f_uplink), 0644);
r = fopen_temporary_label(PRIVATE_STUB_RESOLV_CONF, PRIVATE_STUB_RESOLV_CONF, &f_stub, &temp_path_stub);
if (r < 0)
return log_warning_errno(r, "Failed to open private stub-resolv.conf file for writing: %m");
- (void) __fsetlocking(f_stub, FSETLOCKING_BYCALLER);
(void) fchmod(fileno(f_stub), 0644);
r = write_uplink_resolv_conf_contents(f_uplink, dns, domains);
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