X25: Check that record is all ASCII digits

diff --git a/lib/dns/rdata/generic/x25_19.c b/lib/dns/rdata/generic/x25_19.c
index 4c536214786ce4e3d5f9ce7af5b46c359d72cb12..93f99c8dc657cfaf30909bb3468722107995c0a3 100644 (file)
--- a/lib/dns/rdata/generic/x25_19.c
+++ b/lib/dns/rdata/generic/x25_19.c
@@ -59,6 +59,7 @@ totext_x25(ARGS_TOTEXT) {
 static inline isc_result_t
 fromwire_x25(ARGS_FROMWIRE) {
        isc_region_t sr;
+       unsigned int i;
 
        REQUIRE(type == dns_rdatatype_x25);
 
@@ -68,9 +69,14 @@ fromwire_x25(ARGS_FROMWIRE) {
        UNUSED(options);
 
        isc_buffer_activeregion(source, &sr);
-       if (sr.length < 5) {
+       if (sr.length < 5 || sr.base[0] != (sr.length - 1)) {
                return (DNS_R_FORMERR);
        }
+       for (i = 1; i < sr.length; i++) {
+               if (sr.base[i] < 0x30 || sr.base[i] > 0x39) {
+                       return (DNS_R_FORMERR);
+               }
+       }
        return (txt_fromwire(source, target));
 }