Re: [PATCH] Compile-time check re world-writeable module params

[Jan Engelhardt <jengelh@linux01.gwdg.de>]

>One of mistakes module_param() user can make is to supply default value
>of module parameter as the last argument. module_param() accepts
>permissions instead. If default value is, say, 3 (-------wx), parameter
>becomes world-writeable.
>
>First version of this check (only "& 2" part) directly caught 4 out of 7
>places during my last grep.

It could probably do "& 0013" or "& ~664", because -x seems quite 
useless in module parameters. That would also catch perm<0 and 
perm>0777.

> #define __module_param_call(prefix, name, set, get, arg, perm)		\
>+	/* Default value instead of permissions? */			\
>+	static int __param_perm_check_##name __attribute__((unused)) =	\
>+	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2));	\
> 	static char __param_str_##name[] = prefix #name;		\
> 	static struct kernel_param const __param_##name			\
> 	__attribute_used__						\


	-`J'
-- 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/