[vlc-devel] [PATCH 1/2] dvdnav: Limit user information about insufficient permissions

[Rémi Denis-Courmont]

Le perjantaina 1. toukokuuta 2020, 13.58.21 EEST david.fuhrmann at gmail.com a 
écrit :
> From: David Fuhrmann <dfuhrmann at videolan.org>
> 
> The mentioned security setting is only relevant for accessing
> RAW block devices (/dev/xxx), which is one of the main use cases
> for this module (accessing an optical drive).
> It is not relevant for file or folder access.
> 
> Therefore limit the dialog to only show it in this case.
> dvdnav does not provide a way to get the underlying error back
> to this module, therefore the path is probed again to ensure
> that the actual failure was EPERM.
> ---
>  modules/access/dvdnav.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/modules/access/dvdnav.c b/modules/access/dvdnav.c
> index f082f1021b..558103eae3 100644
> --- a/modules/access/dvdnav.c
> +++ b/modules/access/dvdnav.c
> @@ -377,10 +377,23 @@ static int AccessDemuxOpen ( vlc_object_t *p_this )
>          msg_Warn( p_demux, "cannot open DVD (%s)", psz_file);
> 
>  #ifdef __APPLE__
> -        vlc_dialog_display_error( p_demux, _("Problem accessing a system
> resource"), -            _("Potentially, macOS blocks access to your disc.
> "
> -              "Please open \"System Preferences\" -> \"Security & Privacy\"
> " -              "and allow VLC to access your external media in \"Files
> and Folders\" section."));
> +        /* This is only relevant when accessing
> RAW block devices */
> +        if( forced && !strncasecmp( psz_file,
> "/dev/", 5) )

That's a very dubious way to identify device nodes.

> +        {
> +            int fd = vlc_open( psz_file, O_RDONLY | O_NONBLOCK );
> +            bool permissionError = ( fd == -1 && errno == EPERM );
> +            if( fd != -1 )
> +                vlc_close( fd );

And this reinvents access for no obvious reasons.

> +
> +            if( permissionError )
> +            {
> +                msg_Err( p_demux, "Path %s cannot be opened due to
> unsufficient permissions", psz_file ); +               
> vlc_dialog_display_error( p_demux, _("Problem accessing a system
> resource"), +                                         _("Potentially, macOS
> blocks access to your disc. " +                                          
> "Please open \"System Preferences\" -> \"Security & Privacy\" " +          
>                                 "and allow VLC to access your external
> media in \"Files and Folders\" section.")); +            }
> +        }
>  #endif
>          goto bailout;
>      }

-- 
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