Check that the message is non NULL in dns_dt_parse

It was possible to dereference a NULL pointer in dns_dt_parse
if it was reading a malformed DNSTAP file.  This would could
cause dnstap-read to exit.  This has been fixed.

diff --git a/lib/dns/dnstap.c b/lib/dns/dnstap.c
index 29a5882512c2ca7dcd4da4237d5d3c940c95cb26..5d2468ffa5a20e522884445d0f20a668dc1f6ebd 100644 (file)
--- a/lib/dns/dnstap.c
+++ b/lib/dns/dnstap.c
@@ -1036,6 +1036,10 @@ dns_dt_parse(isc_mem_t *mctx, isc_region_t *src, dns_dtdata_t **destp) {
 
        m = frame->message;
 
+       if (m == NULL) {
+               CLEANUP(DNS_R_BADDNSTAP);
+       }
+
        /* Message type */
        switch (m->type) {
        case DNSTAP__MESSAGE__TYPE__AUTH_QUERY: