Re: pg_dump / copy bugs with "big lines" ?

Daniel Verite wrote:

> My tests are OK too but I see an issue with the code in
> enlargeStringInfo(), regarding integer overflow.
> The bit of comment that says:
>
> Note we are assuming here that limit <= INT_MAX/2, else the above
> loop could overflow.
>
> is obsolete, it's now INT_MAX instead of INT_MAX/2.

I would keep this comment but use UINT_MAX/2 instead.

> There's a related problem here:
> newlen = 2 * str->maxlen;
> while (needed > newlen)
> newlen = 2 * newlen;
> str->maxlen is an int going up to INT_MAX so [2 * str->maxlen] now
> *will* overflow when [str->maxlen > INT_MAX/2].
> Eventually it somehow works because of this:
> if (newlen > limit)
> newlen = limit;
> but newlen is wonky (when resulting from int overflow)
> before being brought back to limit.

Yeah, you're right. We also need to cast "needed" to Size in the while
test; and the repalloc_huge() call no longer needs a cast.

I propose the attached.

Not sure if we also need to cast the assignment to str->maxlen in the
last line.

--
Álvaro Herrera https://www.2ndQuadrant.com/
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