just left-pad with zeros on cast from "too small" octet values

diff --git a/src/lib/util/value.c b/src/lib/util/value.c
index 3ffa5bd8b83e387e7416792b958e631332e798d8..6fee0295454a7dec5ee5fe2b75ccb3f0be8068d9 100644 (file)
--- a/src/lib/util/value.c
+++ b/src/lib/util/value.c
@@ -2112,17 +2112,9 @@ static int fr_value_box_fixed_size_from_octets(fr_value_box_t *dst,
                                              fr_type_t dst_type, fr_dict_attr_t const *dst_enumv,
                                              fr_value_box_t const *src)
 {
-       if (!fr_type_is_fixed_size(dst_type)) if (!fr_cond_assert(false)) return -1;
+       uint8_t *ptr;
 
-       if (src->vb_length < network_min_size(dst_type)) {
-               fr_strerror_printf("Invalid cast from %s to %s.  Source is length %zd is smaller than "
-                                  "destination type size %zd",
-                                  fr_type_to_str(src->type),
-                                  fr_type_to_str(dst_type),
-                                  src->vb_length,
-                                  network_min_size(dst_type));
-               return -1;
-       }
+       if (!fr_type_is_fixed_size(dst_type)) if (!fr_cond_assert(false)) return -1;
 
        if (src->vb_length > network_max_size(dst_type)) {
                fr_strerror_printf("Invalid cast from %s to %s.  Source length %zd is greater than "
@@ -2136,11 +2128,25 @@ static int fr_value_box_fixed_size_from_octets(fr_value_box_t *dst,
 
        fr_value_box_init(dst, dst_type, dst_enumv, src->tainted);
 
+       /*
+        *      No data to copy means just reset it to zero.
+        */
+       if (!src->vb_length) return 0;
+
+       ptr = (uint8_t *) &dst->datum;
+
+       /*
+        *      If the source is too small, just left-fill with zeroes.
+        */
+       if (src->vb_length < network_min_size(dst_type)) {
+               ptr += network_min_size(dst_type) - src->vb_length;
+       }
+
        /*
         *      Copy the raw octets into the datum of a value_box
         *      inverting bytesex for uint32s (if LE).
         */
-       memcpy(&dst->datum, src->vb_octets, fr_value_box_field_sizes[dst_type]);
+       memcpy(ptr, src->vb_octets, src->vb_length);
        fr_value_box_hton(dst, dst);
 
        return 0;