Re: [musl] [PATCH] fix avoidable segfault in catclose

[Rich Felker <dalias@libc.org>]

On Thu, Jan 25, 2024 at 08:09:49AM +0100, Ismael Luceno wrote:
> catclose may be called with an invalid argument, particularly -1 may be
> returned by catopen if there's an error.
> 
> Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
> ---
>  src/locale/catclose.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/src/locale/catclose.c b/src/locale/catclose.c
> index 54e24dd2163b..af959a58dfb5 100644
> --- a/src/locale/catclose.c
> +++ b/src/locale/catclose.c
> @@ -8,6 +8,8 @@
>  
>  int catclose (nl_catd catd)
>  {
> +	if (catd == (nl_catd)-1)
> +		return -1;
>  	char *map = (char *)catd;
>  	munmap(map, V(map+8)+20);
>  	return 0;
> -- 
> 2.43.0

Generally in musl, we prefer to trap on UB rather than allowing
forward progress, especially when the natural default action without
special casing it is to trap.

Rich