- * one or more of the lower eight bits of |good| will be cleared. We
- * AND the bottom 8 bits together and duplicate the result to all the
- * bits. */
- good &= good >> 4;
- good &= good >> 2;
- good &= good >> 1;
- good <<= sizeof(good)*8-1;
- good = DUPLICATE_MSB_TO_ALL(good);
-
- rec->length -= good & (padding_length+1);
-
- /* We can always safely skip the explicit IV. We check at the beginning
- * of this function that the record has at least enough space for the
- * IV, MAC and padding length byte. (These can be checked in
- * non-constant time because it's all public information.) So, if the
- * padding was invalid, then we didn't change |rec->length| and this is
- * safe. If the padding was valid then we know that we have at least
- * overhead+padding_length bytes of space and so this is still safe
- * because overhead accounts for the explicit IV. */
- if (has_explicit_iv)
- {
- rec->data += block_size;
- rec->input += block_size;
- rec->length -= block_size;
- rec->orig_len -= block_size;
- }
+ * one or more of the lower eight bits of |good| will be cleared.
+ */
+ good = constant_time_eq(0xff, good & 0xff);
+ padding_length = good & (padding_length+1);
+ rec->length -= padding_length;
+ rec->type |= padding_length<<8; /* kludge: pass padding length */