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

[Rémi Denis-Courmont]

Hi,

The point is that the warning points to a real problem with the implementation, which the patch does not fix. And as a general rule, I'm against removing warnings without fixing the real problem.

Le 20 janvier 2020 15:51:03 GMT+02:00, Alexandre Janniaux <ajanni at videolabs.io> a écrit :
>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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>excuser
>> >ma brièveté.
>>
>> --
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