BUG #13764: function ghstore_consistent() returns a wrong value if var "strategy" contains an unsupported number

The following bug has been logged on the website:

Bug reference: 13764
Logged by: Zhang Yan
Email address: rucsoftsec(at)163(dot)com
PostgreSQL version: 9.4.5
Operating system: Linux Mint 15
Description:

function ghstore_consistent() computes the consistency and return a bool
value. It first computes the value of variable "strategy". It second
executes different branches of the code depending of different value of
variable "straregy". When the value of variable"strategy" is an unsupported
strategy number, function ghstore_consistent() will executes the code in
line 584. It means function ghstore_consistent() fails, but the value of
variable "res" is "true" which will be returned in line 586. Therefore, does
it need to assign "false" to variable "res" after line 584?
the related code snippets in ghstore_consistent() are as following:
483 Datum
484 ghstore_consistent(PG_FUNCTION_ARGS)
485 {
486 GISTTYPE *entry = (GISTTYPE *) DatumGetPointer(((GISTENTRY *)
PG_GETARG_POINTER(0))->key);
487 StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
488
489 /* Oid subtype = PG_GETARG_OID(3); */
490 bool *recheck = (bool *) PG_GETARG_POINTER(4);
491 bool res = true;
492 BITVECP sign;
493
494 /* All cases served by this function are inexact */
495 *recheck = true;
496
497 if (ISALLTRUE(entry))
498 PG_RETURN_BOOL(true);
499
500 sign = GETSIGN(entry);
501
502 if (strategy == HStoreContainsStrategyNumber ||
503 strategy == HStoreOldContainsStrategyNumber)
504 {
505 HStore *query = PG_GETARG_HS(1);
506 HEntry *qe = ARRPTR(query);
507 char *qv = STRPTR(query);
508 int count = HS_COUNT(query);
509 int i;
510
511 for (i = 0; res && i < count; ++i)
512 {
513 int crc = crc32_sz((char *)
HS_KEY(qe, qv, i), HS_KEYLEN(qe, i));
514
515 if (GETBIT(sign, HASHVAL(crc)))
516 {
517 if (!HS_VALISNULL(qe, i))
518 {
519 crc = crc32_sz((char *)
HS_VAL(qe, qv, i), HS_VALLEN(qe, i));
520 if (!GETBIT(sign,
HASHVAL(crc)))
521 res = false;
522 }
523 }
524 else
525 res = false;
526 }
527 }
528 else if (strategy == HStoreExistsStrategyNumber)
529 {
530 text *query = PG_GETARG_TEXT_PP(1);
531 int crc =
crc32_sz(VARDATA_ANY(query), VARSIZE_ANY_EXHDR(query));
532
533 res = (GETBIT(sign, HASHVAL(crc))) ? true : false;
534 }
535 else if (strategy == HStoreExistsAllStrategyNumber)
536 {
537 ArrayType *query = PG_GETARG_ARRAYTYPE_P(1);
538 Datum *key_datums;
539 bool *key_nulls;
540 int key_count;
541 int i;
542
543 deconstruct_array(query,
544 TEXTOID, -1, false,
'i',
545 &key_datums,
&key_nulls, &key_count);
546
547 for (i = 0; res && i < key_count; ++i)
548 {
549 int crc;
550
551 if (key_nulls[i])
552 continue;
553 crc = crc32_sz(VARDATA(key_datums[i]),
VARSIZE(key_datums[i]) - VARHDRSZ);
554 if (!(GETBIT(sign, HASHVAL(crc))))
555 res = FALSE;
556 }
557 }
558 else if (strategy == HStoreExistsAnyStrategyNumber)
559 {
560 ArrayType *query = PG_GETARG_ARRAYTYPE_P(1);
561 Datum *key_datums;
562 bool *key_nulls;
563 int key_count;
564 int i;
565
566 deconstruct_array(query,
567 TEXTOID, -1, false,
'i',
568 &key_datums,
&key_nulls, &key_count);
569
570 res = FALSE;
571
572 for (i = 0; !res && i < key_count; ++i)
573 {
574 int crc;
575
576 if (key_nulls[i])
577 continue;
578 crc = crc32_sz(VARDATA(key_datums[i]),
VARSIZE(key_datums[i]) - VARHDRSZ);
579 if (GETBIT(sign, HASHVAL(crc)))
580 res = TRUE;
581 }
582 }
583 else
584 elog(ERROR, "Unsupported strategy number: %d",
strategy);
585
586 PG_RETURN_BOOL(res);
587 }