Re: [PATCH v2 2/3] sysfs: Only accept read/write permissions for file attributes
From: Greg Kroah-Hartman
Date: Thu Mar 12 2015 - 06:02:01 EST
On Wed, Mar 11, 2015 at 02:22:10PM -0400, Vivien Didelot wrote:
> For sysfs file attributes, only read and write permissions make sense.
> Mask provided attribute permissions accordingly and send a warning
> to the console if invalid permission bits are set.
> This patch is originally from Guenter  and includes the fixup
> explained in the thread, that is printing permissions in octal format
> and limiting the scope of attributes to SYSFS_PREALLOC | 0664.
>  https://lkml.org/lkml/2015/1/19/599
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
> fs/sysfs/group.c | 6 ++++++
> 1 file changed, 6 insertions(+)
> diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
> index 3fdccd9..b400c04 100644
> --- a/fs/sysfs/group.c
> +++ b/fs/sysfs/group.c
> @@ -55,6 +55,12 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
> if (!mode)
> + WARN(mode & ~(SYSFS_PREALLOC | 0664),
> + "Attribute %s: Invalid permissions 0%o\n",
> + (*attr)->name, mode);
> + mode &= SYSFS_PREALLOC | 0664;
How does a "normal" boot look with this warning in place? There still
seem to be a number of files in sysfs that might trigger this.
Also, we have a build-time warning if a sysfs file is this type of
attribute, shouldn't we just rely on that instead of this run-time
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