lib: in ykpiv_transfer_data() handle overflow by exiting

this is detected and printed, but we never exit the function

Thanks to Eric Sesterhenn of x41 D-Sec for reporting this issue to us.

lib/ykpiv.c

@@ -562,8 +562,12 @@ ykpiv_rc ykpiv_transfer_data(ykpiv_state *state, const unsigned char *templ,
       goto Cleanup;
     }
     if(*out_len + recv_len - 2 > max_out) {
+      if(state->verbose) {
         fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *out_len + recv_len - 2, max_out);
       }
+      res = YKPIV_SIZE_ERROR;
+      goto Cleanup;
+    }
     if(out_data) {
       memcpy(out_data, data, recv_len - 2);
       out_data += recv_len - 2;