Re: BUG #17839: Heap-buffer overflow on float8_to_char with invalid template

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