- Fix similar code in auth_zone synth cname to add the extra checks.

diff --git a/doc/Changelog b/doc/Changelog
index 59541fa34237b7707d66517917f8c9ca0584909f..67f89849d44eb4dc4c28403ee15ae648124496b3 100644 (file)
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -5,6 +5,7 @@
          to correct RFC number.
        - Fix Assert Causing DoS in synth_cname(),
          reported by X41 D-Sec.
+       - Fix similar code in auth_zone synth cname to add the extra checks.
 
 2 December 2019: Wouter
        - Merge pull request #122 from he32: In tcp_callback_writer(),

diff --git a/services/authzone.c b/services/authzone.c
index b59a7334cb876f272ecafe3d495eeae700cb7326..7d806d9d59d06d9400c8b901669f7b040dbd1864 100644 (file)
--- a/services/authzone.c
+++ b/services/authzone.c
@@ -2380,6 +2380,10 @@ create_synth_cname(uint8_t* qname, size_t qname_len, struct regional* region,
                return 0; /* rdatalen in DNAME rdata is malformed */
        if(dname_valid(dtarg, dtarglen) != dtarglen)
                return 0; /* DNAME RR has malformed rdata */
+       if(qname_len == 0)
+               return 0; /* too short */
+       if(qname_len <= node->namelen)
+               return 0; /* qname too short for dname removal */
 
        /* synthesize a CNAME */
        newlen = synth_cname_buf(qname, qname_len, node->namelen,