From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 13 Oct 2025 09:34:24 +0000 (+0200)
Subject: dns-domain: make dns_name_change_suffix() work with an empty/null suffix
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e5dc5821ff8852241d3842da95694a3a9433cfbf;p=thirdparty%2Fsystemd.git

dns-domain: make dns_name_change_suffix() work with an empty/null suffix
---

diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c
index c9788989d83..d45fbc63438 100644
--- a/src/shared/dns-domain.c
+++ b/src/shared/dns-domain.c
@@ -27,7 +27,12 @@ int dns_label_unescape(const char **name, char *dest, size_t sz, DNSLabelFlags f
         int r = 0;
 
         assert(name);
-        assert(*name);
+
+        if (isempty(*name)) {
+                if (dest && sz >= 1)
+                        dest[0] = 0;
+                return 0;
+        }
 
         n = *name;
         d = dest;
@@ -649,12 +654,10 @@ int dns_name_change_suffix(const char *name, const char *old_suffix, const char
         int r, q;
 
         assert(name);
-        assert(old_suffix);
-        assert(new_suffix);
         assert(ret);
 
         n = name;
-        s = old_suffix;
+        s = strempty(old_suffix);
 
         for (;;) {
                 char ln[DNS_LABEL_MAX+1], ls[DNS_LABEL_MAX+1];
diff --git a/src/test/test-dns-domain.c b/src/test/test-dns-domain.c
index f1d11305c1d..ae73725c8ee 100644
--- a/src/test/test-dns-domain.c
+++ b/src/test/test-dns-domain.c
@@ -654,6 +654,9 @@ TEST(dns_name_change_suffix) {
         test_dns_name_change_suffix_one("", "", "piff.paff", 1, "piff.paff");
         test_dns_name_change_suffix_one("", "", "", 1, ".");
         test_dns_name_change_suffix_one("a", "b", "c", 0, NULL);
+        test_dns_name_change_suffix_one("wau.wau", "wau", NULL, 1, "wau");
+        test_dns_name_change_suffix_one("wau.wau", NULL, "wau", 1, "wau.wau.wau");
+        test_dns_name_change_suffix_one("wau.wau", NULL, NULL, 1, "wau.wau");
 }
 
 static void test_dns_name_suffix_one(const char *name, unsigned n_labels, const char *result, int ret) {