parser: validate buffer reallocation

Signed-off-by: Eduardo Silva <[email protected]>

src/flb_parser_decoder.c

@@ -519,15 +519,18 @@ int flb_parser_decoder_do(struct mk_list *decoders,
  * We got a match: 'key name' == 'decoder field name', validate
  * that we have enough space in our temporal buffer.
  */
- if (flb_sds_alloc(dec->buffer) < v.via.str.size) {
+ if (flb_sds_alloc(dec->buffer) < flb_sds_alloc(data_sds)) {
  /* Increase buffer size */
- size_t diff = (v.via.str.size - flb_sds_alloc(dec->buffer));
+ size_t diff;
+ diff = (flb_sds_alloc(data_sds) - flb_sds_alloc(dec->buffer));
  tmp_sds = flb_sds_increase(dec->buffer, diff);
  if (!tmp_sds) {
  flb_errno();
  break;
  }
- dec->buffer = tmp_sds;
+ if (tmp_sds != dec->buffer) {
+ dec->buffer = tmp_sds;
+ }
  }
 
  /* Process decoder rules */