Re: BUG #17839: Heap-buffer overflow on float8_to_char with invalid template - Mailing list pgsql-bugs

From Thiago Nunes
Subject Re: BUG #17839: Heap-buffer overflow on float8_to_char with invalid template
Date
Msg-id CANf6e1+LSX4EMER08f2rSQ+MSMUzAtVfKXFpiBRAdRmk2L-uQQ@mail.gmail.com
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In response to Re: BUG #17839: Heap-buffer overflow on float8_to_char with invalid template  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-bugs
Got it, I thought that since we were filling the string with #s there, we should reposition the zero_end.

I will wait for your patch then, thanks for looking into it!

Cheers,

On Wed, Mar 15, 2023 at 12:45 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Thiago Nunes <thiagotnunes@gmail.com> writes:
> I think your solution deals with all the cases, but I would like to point
> out how I fixed it locally. I recalculated Num.zero_end after this line (
> https://github.com/postgres/postgres/blob/REL_15_2/src/backend/utils/adt/formatting.c#L6716
> ):

> ```
> Num.zero_end = Num.pre + Num.post;
> ```

Hmm ... that seems a bit ad-hoc, because as far as I understand this
code, zero_end is supposed to track where is the last '0' format
character.  That shouldn't change just because we decided that the
data value overflowed.

                        regards, tom lane

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