On Wed, May 05, 2021 at 09:34:15PM +0000, Guilherme Janczak wrote:
> The expression "s + strlen(s) - 1" can create a pointer to one before
> *s if strlen(s) is 0.
>
> ---
> util.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/util.c b/util.c
> index bdba718..c97f491 100644
> --- a/util.c
> +++ b/util.c
> @@ -59,9 +59,13 @@ skip(char *s, char c) {
> static void
> trim(char *s) {
> char *e;
> -
> - e = s + strlen(s) - 1;
> - while(isspace(*e) && e > s)
Hi,
Thanks for the patch. It seems indeed to read out-of-bounds 1 byte before the
buffer if the input is empty.
I think if the condition is reversed then it is fine:
> - while(isspace(*e) && e > s)
to:
> - while(e > s && isspace(*e))
I'll apply this and a few small changes tomorrow.
> - e--;
> - *(e + 1) = '\0';
> +
> + e = s + strlen(s);
> + while (e > s) {
> + if (!isspace(*--e)) {
> + e++;
> + *e = '\0';
> + break;
> + }
> + }
> }
> --
> 2.31.1
>
>
--
Kind regards,
Hiltjo
