On Sun, 2014-03-16 at 22:00 -0700, Joe Perches wrote:
> On Mon, 2014-03-17 at 14:25 +1030, Rusty Russell wrote:
> 
> > Erk, our tests are insufficient.  Testbuilding an allmodconfig with this
> > now:
> 
> Good idea.
> 
> > diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> []
> > @@ -188,6 +188,9 @@ struct kparam_array
> >     /* Default value instead of permissions? */                     \
> >     static int __param_perm_check_##name __attribute__((unused)) =  \
> >     BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
> > +   /* User perms >= group perms >= other perms. */                 \
> > +   + BUILD_BUG_ON_ZERO(((perm) >> 6) < (((perm) >> 3) & 7))        \
> > +   + BUILD_BUG_ON_ZERO((((perm) >> 3) & 7) < ((perm) & 7))         \
> >     + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);   \
> >     static const char __param_str_##name[] = prefix #name;          \
> >     static struct kernel_param __moduleparam_const __param_##name   \
> 
> It might make sense to separate this octal permissions
> test into a new macro for other checks in macros like
> CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2.
> 
> Maybe something like:
> 
> #define VERIFY_OCTAL_PERMISSIONS(perm)                                        
> \
>       static int __param_perm_check_##name __attribute__((unused)) =  \
>       BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
>       /* User perms >= group perms >= other perms. */                 \
>       + BUILD_BUG_ON_ZERO(((perm) >> 6) < (((perm) >> 3) & 7))        \
>       + BUILD_BUG_ON_ZERO((((perm) >> 3) & 7) < ((perm) & 7));        \

Maybe this is better:

#define VERIFY_OCTAL_PERMISSIONS(perms)                                 \
({                                                                      \
        if (__builtin_constant_p(perms)) {                              \
                BUILD_BUG_ON((perms) < 0);                              \
                BUILD_BUG_ON((perms) > 0777);                           \
                /* User perms >= group perms >= other perms */          \
                BUILD_BUG_ON(((perms) >> 6) < (((perms) >> 3) & 7));    \
                BUILD_BUG_ON((((perms) >> 3) & 7) < ((perms) & 7));     \
        }                                                               \
        ;                                                               \
})


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