From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Thu, 24 Apr 2025 00:49:50 +0000 (+0900)
Subject: resolvectl: skip reading remaining elements when an invalid address is specified
X-Git-Tag: v258-rc1~745^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=06a5d24d78d9bc24028300ae82ba0ab8cd8363d6;p=thirdparty%2Fsystemd.git

resolvectl: skip reading remaining elements when an invalid address is specified

Previous code assumed that both family and address are read when
-EINVAL, hence the following read of port and name could succeed.

Let's drop the assumption, and skip reading remaining elements.

No functional change, just refactoring and preparation for later change.
---

diff --git a/src/resolve/resolvectl.c b/src/resolve/resolvectl.c
index fa6ace9bec2..f517d149dd1 100644
--- a/src/resolve/resolvectl.c
+++ b/src/resolve/resolvectl.c
@@ -1366,7 +1366,7 @@ static int read_dns_server_one(sd_bus_message *m, ReadDNSFlag flags, char **ret)
         union in_addr_union a;
         const char *name = NULL;
         int32_t ifindex = 0;
-        int family, r, k;
+        int family, r;
         uint16_t port = 0;
 
         assert(m);
@@ -1386,9 +1386,30 @@ static int read_dns_server_one(sd_bus_message *m, ReadDNSFlag flags, char **ret)
                         return r;
         }
 
-        k = bus_message_read_in_addr_auto(m, &error, &family, &a);
-        if (k < 0 && !sd_bus_error_has_name(&error, SD_BUS_ERROR_INVALID_ARGS))
-                return k;
+        r = bus_message_read_in_addr_auto(m, &error, &family, &a);
+        if (r < 0) {
+                if (sd_bus_error_has_name(&error, SD_BUS_ERROR_INVALID_ARGS)) {
+                        /* CurrentDNSServer provides AF_UNSPEC when no current server assigned. */
+                        log_debug("Invalid DNS server, ignoring: %s", bus_error_message(&error, r));
+
+                        for (;;) {
+                                r = sd_bus_message_skip(m, NULL);
+                                if (r == -ENXIO) /* End of the container */
+                                        break;
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+
+                        *ret = NULL;
+                        return 1;
+                }
+
+                return r;
+        }
 
         if (FLAGS_SET(flags, READ_DNS_EXTENDED)) {
                 r = sd_bus_message_read(m, "q", &port);
@@ -1404,12 +1425,6 @@ static int read_dns_server_one(sd_bus_message *m, ReadDNSFlag flags, char **ret)
         if (r < 0)
                 return r;
 
-        if (k < 0) {
-                log_debug("Invalid DNS server, ignoring: %s", bus_error_message(&error, k));
-                *ret = NULL;
-                return 1;
-        }
-
         if (FLAGS_SET(flags, READ_DNS_ONLY_GLOBAL) && ifindex > 0 && ifindex != LOOPBACK_IFINDEX) {
                 /* This one has an (non-loopback) ifindex set, and we were told to suppress those. Hence do so. */
                 *ret = NULL;