module: export module signature enforcement status (fda784e5) · Commits · 戴 / test

A static variable sig_enforce is used as status var to indicate the real value of CONFIG_MODULE_SIG_FORCE, once this one is set the var will hold true, but if the CONFIG is not set the status var will hold whatever value is present in the module.sig_enforce kernel cmdline param: true when =1 and false when =0 or not present. Considering this cmdline param take place over the CONFIG value when it's not set, other places in the kernel could misbehave since they would have only the CONFIG_MODULE_SIG_FORCE value to rely on. Exporting this status var allows the kernel to rely in the effective value of module signature enforcement, being it from CONFIG value or cmdline param. Signed-off-by:

Bruno E. O. Meneguele <brdeoliv@redhat.com> Signed-off-by:

Mimi Zohar <zohar@linux.vnet.ibm.com>

include/linux/module.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -639,6 +639,8 @@ static inline bool is_livepatch_module(struct module *mod)
		}
		#endif /* CONFIG_LIVEPATCH */

		bool is_module_sig_enforced(void);

		#else /* !CONFIG_MODULES... */

		static inline struct module *__module_address(unsigned long addr)
		@@ -753,6 +755,11 @@ static inline bool module_requested_async_probing(struct module *module)
		return false;
		}

		static inline bool is_module_sig_enforced(void)
		{
		return false;
		}

		#endif /* CONFIG_MODULES */

		#ifdef CONFIG_SYSFS

kernel/module.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -278,6 +278,16 @@ static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
		module_param(sig_enforce, bool_enable_only, 0644);
		#endif /* !CONFIG_MODULE_SIG_FORCE */

		/*
		* Export sig_enforce kernel cmdline parameter to allow other subsystems rely
		* on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
		*/
		bool is_module_sig_enforced(void)
		{
		return sig_enforce;
		}
		EXPORT_SYMBOL(is_module_sig_enforced);

		/* Block module loading/unloading? */
		int modules_disabled = 0;
		core_param(nomodule, modules_disabled, bint, 0);

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