[vlc-devel] [PATCH] control: rc: avoid stringop-truncation warning

[Alexandre Janniaux]

Hi,

There should be no functional differences as the null character is
forced in the end of the path. Copying one meaningful character less
would happend as soon as the path is already too long, and otherwise
only the strncpy null character is expected to be truncated, but is
ensured by the code following.

The documentation state that sun_path should contain a null-terminated
pathname so it doesn't look wrong to enforce the last \0 byte too. Am
I missing something?

I hope I'm clear enough,

Regards,
--
Alexandre Janniaux
Videolabs

On Mon, Jan 20, 2020 at 03:29:43PM +0200, Rémi Denis-Courmont wrote:
> On second consideration, chopping the path is not correct behaviour. This patch is concealing the bug highlighted by the warning rather than fixing it IMO.
>
> Better drop the feature altogether as I dot think anyone's using it.
>
> Le 20 janvier 2020 09:38:46 GMT+02:00, "Rémi Denis-Courmont" <remi at remlab.net> a écrit :
> >OK, though I'd suggest removing Unix socket support entirely as the old
> >RC "protocol" is not suitable for programmatic usage.
> >
> >Le 19 janvier 2020 17:39:27 GMT+02:00, Alexandre Janniaux
> ><ajanni at videolabs.io> a écrit :
> >>Fortify enabled implies a warning if we use strncpy with a length
> >equal
> >>to the buffer size. As we fill the last item with a null character, we
> >>can use length-1 instead as well.
> >>---
> >> modules/control/rc.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >>diff --git a/modules/control/rc.c b/modules/control/rc.c
> >>index cd85602d59..dc37d352ad 100644
> >>--- a/modules/control/rc.c
> >>+++ b/modules/control/rc.c
> >>@@ -1730,7 +1730,7 @@ static int Activate( vlc_object_t *p_this )
> >>         }
> >>
> >>         addr.sun_family = AF_LOCAL;
> >>-        strncpy( addr.sun_path, psz_unix_path, sizeof( addr.sun_path
> >)
> >>);
> >>+        strncpy( addr.sun_path, psz_unix_path, sizeof( addr.sun_path
> >)
> >>- 1 );
> >>         addr.sun_path[sizeof( addr.sun_path ) - 1] = '\0';
> >>
> >>         if (bind (i_socket, (struct sockaddr *)&addr, sizeof (addr))
> >>--
> >>2.25.0
> >>
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> --
> Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez excuser ma brièveté.

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