Operands don't affect result (CONSTANT_EXPRESSION_RESULT) (src/backend/utils/adt/jsonfuncs.c)

From: Ranier Vilela <ranier(dot)vf(at)gmail(dot)com>
To: Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Operands don't affect result (CONSTANT_EXPRESSION_RESULT) (src/backend/utils/adt/jsonfuncs.c)
Date: 2021-02-10 23:42:45
Message-ID: CAEudQAqge3QfzoBRhe59QrB_5g+NmQUj2QpzqZ9Nc7QepXGAEw@mail.gmail.com
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Hi,

Per Coverity.

The use of type "long" is problematic with Windows 64bits.
Long type on Windows 64bits is 32 bits.

See at:
https://docs.microsoft.com/pt-br/cpp/cpp/data-type-ranges?view=msvc-160

*long* 4 *long int*, *signed long int* -2.147.483.648 a 2.147.483.647
Therefore long never be > INT_MAX at Windows 64 bits.

Thus lindex is always false in this expression:
if (errno != 0 || badp == c || *badp != '\0' || lindex > INT_MAX || lindex
< INT_MIN)

Patch suggestion to fix this.

diff --git a/src/backend/utils/adt/jsonfuncs.c
b/src/backend/utils/adt/jsonfuncs.c
index 215a10f16e..54b0eded76 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -1675,7 +1675,7 @@ push_path(JsonbParseState **st, int level, Datum
*path_elems,
* end, the access index must be normalized by level.
*/
enum jbvType *tpath = palloc0((path_len - level) * sizeof(enum jbvType));
- long lindex;
+ int64 lindex;
JsonbValue newkey;

/*

regards,
Ranier Vilela

Attachment Content-Type Size
jsonfuncs.patch application/octet-stream 482 bytes

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