OSS-FUZZ: Fix reported errors

src/coap_asn1.c

@@ -72,7 +72,7 @@ asn1_tag_c(const uint8_t **ptr, size_t *plen, int *constructed, int *cls) {
     tag = (tag << 7) + (byte & 0x7F);
     (*plen)--;
     (*ptr)++;
-    if (*plen == 0)
+    if (*plen == 0 || (uint32_t)tag > (INT_MAX >> 7))
       return COAP_ASN1_FAIL;
     byte = (**ptr);
   }

src/coap_subscribe.c

@@ -477,11 +477,11 @@ coap_op_observe_load_disk(coap_context_t *ctx) {
       if (!coap_op_observe_write(fp_new, observe_key, e_proto, e_listen_addr,
                                  s_addr_info, raw_packet, oscore_info))
         goto fail;
-      coap_delete_bin_const(raw_packet);
-      raw_packet = NULL;
-      coap_delete_bin_const(oscore_info);
-      oscore_info = NULL;
     }
+    coap_delete_bin_const(raw_packet);
+    raw_packet = NULL;
+    coap_delete_bin_const(oscore_info);
+    oscore_info = NULL;
   }
   coap_delete_bin_const(raw_packet);
   raw_packet = NULL;