On 03/12/2015 03:01 AM, Greg Kroah-Hartman wrote:
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 [1] 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.
[1] https://lkml.org/lkml/2015/1/19/599
Cc: Guenter Roeck <[email protected]>
Signed-off-by: Vivien Didelot <[email protected]>
---
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)
continue;
}
+
+ 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.
I was under the impression that they all were addressed, but I may have
missed some pattern(s). Can you point me to an example, by any chance ?
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
warning?
The mode value can be returned from an is_visible function, and even if not
there is no guarantee that the build-time warning triggers (attribute lists
can be generated manually, for example).
Thanks,
Guenter
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