On Tue, May 29, 2018 at 02:00:26AM +0800, Herbert Xu wrote:
> On Mon, May 28, 2018 at 12:22:00AM +0800, Herbert Xu wrote:
> > The minus sign generated from arithmetic expansion is currently
> > unquoted which causes anomalies when the result is used in where
> > the quoting matters.
> > This patch fixes it by explicitly calling memtodest for the minus
> > sign.
> > Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
> This was buggy. Here is an update.
> ---8<---
> The minus sign generated from arithmetic expansion is currently
> unquoted which causes anomalies when the result is used in where
> the quoting matters.
> This patch fixes it by explicitly calling memtodest for the minus
> sign.
> Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
> diff --git a/src/expand.c b/src/expand.c
> index 7a51766..7ed1bc0 100644
> --- a/src/expand.c
> +++ b/src/expand.c
> @@ -490,7 +490,14 @@ expari(int flag)
> result = arith(p + 1);
> popstackmark(&sm);
>
> - len = cvtnum(result);
> + len = 0;
> + if (result < 0) {
> + memtodest("-", 1, flag);
> + result = -result;
This negation overflows if result is INTMAX_MIN, leading to undefined
behaviour. Perhaps leave the memtodest call but use STADJUST to remove
the minus sign itself, leaving only the CTLESC or nothing.
> + len++;
> + }
> +
> + len += cvtnum(result);
>
> if (likely(!(flag & EXP_QUOTED)))
> recordregion(begoff, begoff + len, 0);
--
Jilles Tjoelker
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