- sum_len = sum_end(file_sum);
- /* If we had a read error, send a bad checksum. */
- if (buf && buf->status != 0)
- file_sum[0]++;
+ if (sum_end(sender_file_sum) != checksum_len)
+ overflow_exit("checksum_len"); /* Impossible... */
+
+ /* If we had a read error, send a bad checksum. We use all bits
+ * off as long as the checksum doesn't happen to be that, in
+ * which case we turn the last 0 bit into a 1. */
+ if (buf && buf->status != 0) {
+ int i;
+ for (i = 0; i < checksum_len && sender_file_sum[i] == 0; i++) {}
+ memset(sender_file_sum, 0, checksum_len);
+ if (i == checksum_len)
+ sender_file_sum[i-1]++;
+ }