sd-dhcp-client: fix busy loop reading zero sized DHCP UDP packets. (#3299)

diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 3846cf74760c8c4cba01bd1ec440d2f85afad1d8..123169832ced34e271e98b32b93348d27399179f 100644 (file)
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -1636,6 +1636,9 @@ static int client_receive_message_udp(
         if (buflen < 0)
                 return buflen;
 
+        if (buflen == 0)
+                buflen = 1;
+
         message = malloc0(buflen);
         if (!message)
                 return -ENOMEM;