Re: [PATCH V2 01/10] Add secure_modules() call

From: Josh Boyer
Date: Thu Aug 29 2013 - 11:01:58 EST


On Mon, Aug 19, 2013 at 01:26:02PM -0400, Matthew Garrett wrote:
> Provide a single call to allow kernel code to determine whether the system
> has been configured to either disable module loading entirely or to load
> only modules signed with a trusted key.
>
> Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
> ---
> include/linux/module.h | 7 +++++++
> kernel/module.c | 9 +++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 46f1ea0..0c266b2 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -509,6 +509,8 @@ int unregister_module_notifier(struct notifier_block * nb);
>
> extern void print_modules(void);
>
> +extern bool secure_modules(void);
> +
> #else /* !CONFIG_MODULES... */
>
> /* Given an address, look for it in the exception tables. */
> @@ -619,6 +621,11 @@ static inline int unregister_module_notifier(struct notifier_block * nb)
> static inline void print_modules(void)
> {
> }
> +
> +static inline bool secure_modules(void)
> +{
> + return false;
> +}
> #endif /* CONFIG_MODULES */
>
> #ifdef CONFIG_SYSFS
> diff --git a/kernel/module.c b/kernel/module.c
> index 2069158..801021e 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3852,3 +3852,12 @@ void module_layout(struct module *mod,
> }
> EXPORT_SYMBOL(module_layout);
> #endif
> +
> +bool secure_modules(void)
> +{
> +#ifdef CONFIG_MODULE_SIG
> + return (sig_enforce || modules_disabled);
> +#else
> + return modules_disabled;
> +#endif
> +}

Needs an EXPORT_SYMBOL/EXPORT_SYMBOL_GPL here, or the patches to drivers
later in the series will fail to link.

josh
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