resolve: lift limits on search domains count or length

glibc 2.26 lifted restrictions on search domains count or length to
unlimited. This has also been backported to 2.17 in some distributions (RHEL 7
and derivatives). Other softwares may have their own limits for search domains,
but we should not restrict what is written out any more.

https://sourceware.org/legacy-ml/libc-announce/2017/msg00001.html

diff --git a/src/resolve/resolved-resolv-conf.c b/src/resolve/resolved-resolv-conf.c
index c6f48d6d8856ed7b5333fa0667c01602ad69b881..befd8d794910f38beefc7ec61b4a4f159dcdf49f 100644 (file)
--- a/src/resolve/resolved-resolv-conf.c
+++ b/src/resolve/resolved-resolv-conf.c
@@ -231,7 +231,6 @@ static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) {
 static void write_resolv_conf_search(
                 OrderedSet *domains,
                 FILE *f) {
-        unsigned length = 0, count = 0;
         Iterator i;
         char *domain;
 
@@ -241,15 +240,6 @@ static void write_resolv_conf_search(
         fputs("search", f);
 
         ORDERED_SET_FOREACH(domain, domains, i) {
-                if (++count > MAXDNSRCH) {
-                        fputs("\n# Too many search domains configured, remaining ones ignored.", f);
-                        break;
-                }
-                length += strlen(domain) + 1;
-                if (length > 256) {
-                        fputs("\n# Total length of all search domains is too long, remaining ones ignored.", f);
-                        break;
-                }
                 fputc(' ', f);
                 fputs(domain, f);
         }

diff --git a/test/networkd-test.py b/test/networkd-test.py
index b225694819447cc06023d7ba7422275ab98a04f1..140561d25d9973e1b3466acc72d2efa4f19a48c5 100755 (executable)
--- a/test/networkd-test.py
+++ b/test/networkd-test.py
@@ -917,40 +917,7 @@ Domains= one two three four five six seven eight nine ten''')
             if ' one' in contents:
                 break
             time.sleep(0.1)
-        self.assertRegex(contents, 'search .*one two three four')
-        self.assertNotIn('seven\n', contents)
-        self.assertIn('# Too many search domains configured, remaining ones ignored.\n', contents)
-
-    def test_search_domains_too_long(self):
-
-        # we don't use this interface for this test
-        self.if_router = None
-
-        name_prefix = 'a' * 60
-
-        self.write_network('test.netdev', '''\
-[NetDev]
-Name=dummy0
-Kind=dummy
-MACAddress=12:34:56:78:9a:bc''')
-        self.write_network('test.network', '''\
-[Match]
-Name=dummy0
-[Network]
-Address=192.168.42.100/24
-DNS=192.168.42.1
-Domains={p}0 {p}1 {p}2 {p}3 {p}4'''.format(p=name_prefix))
-
-        self.start_unit('systemd-networkd')
-
-        for timeout in range(50):
-            with open(RESOLV_CONF) as f:
-                contents = f.read()
-            if ' one' in contents:
-                break
-            time.sleep(0.1)
-        self.assertRegex(contents, 'search .*{p}0 {p}1 {p}2'.format(p=name_prefix))
-        self.assertIn('# Total length of all search domains is too long, remaining ones ignored.', contents)
+        self.assertRegex(contents, 'search .*one two three four five six seven eight nine ten')
 
     def test_dropin(self):
         # we don't use this interface for this test