Re: Avoid overflow with simplehash

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От Ranier Vilela
Тема Re: Avoid overflow with simplehash
Дата
Msg-id CAEudQAp27pPfDkbwM5A1btAqtR6yZWbiN4h1206edV-ZvyTURw@mail.gmail.com
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Ответ на Re: Avoid overflow with simplehash  (Daniel Gustafsson <daniel@yesql.se>)
Ответы Re: Avoid overflow with simplehash
Re: Avoid overflow with simplehash
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Em qui., 6 de jul. de 2023 às 11:37, Daniel Gustafsson <daniel@yesql.se> escreveu:
> On 6 Jul 2023, at 16:28, Ranier Vilela <ranier.vf@gmail.com> wrote:

> The function SH_START_ITERATE can trigger some overflow.
>
> See:
> typedef struct SH_ITERATOR
> {
> uint32 cur; /* current element */
> uint32 end;
> bool done; /* iterator exhausted? */
> } SH_ITERATOR;
>
> The cur field is uint32 size and currently can be stored a uint64,
> which obviously does not fit.

-       Assert(startelem < SH_MAX_SIZE);
+       Assert(startelem < PG_UINT32_MAX);

I mighe be missing something, but from skimming the current code, SH_MAX_SIZE
is currently defined as:

#define SH_MAX_SIZE (((uint64) PG_UINT32_MAX) + 1)
This is Assert, that is, in production this test is not done.

See the comments:
"Search for the first empty element."

If the empty element is not found, startelem has PG_UINT64_MAX value,
which do not fit in uint32.

Can you see this?

regards,
Ranier Vilela

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