[PATCH v2 7/8] kernel/module.c: avoid ifdefs for sig_enforce declaration

From: Luis R. Rodriguez
Date: Wed Apr 22 2015 - 18:12:49 EST


From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>

There's no need to require an ifdef over the declaration
of sig_enforce as IS_ENABLED() can be used. While at it,
there's no harm in exposing this kernel parameter outside of
CONFIG_MODULE_SIG as it'd be a no-op on non module sig
kernels.

Now, technically we should in theory be able to remove
the #ifdef'ery over the declaration of the module parameter
as we are also trusting the bool_enable_only code for
CONFIG_MODULE_SIG kernels but for now remain paranoid
and keep it.

With time if no one can put a bullet through bool_enable_only
and if there are no technical requirements over not exposing
CONFIG_MODULE_SIG_FORCE with the measures in place by
bool_enable_only we could remove this last ifdef.

Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: cocci@xxxxxxxxxxxxxxx
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
---
kernel/module.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 43a1ef3..9e51b37 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -105,15 +105,10 @@ static LIST_HEAD(modules);
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */

-#ifdef CONFIG_MODULE_SIG
-#ifdef CONFIG_MODULE_SIG_FORCE
-static bool sig_enforce = true;
-#else
-static bool sig_enforce = false;
-
+static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
+#ifndef CONFIG_MODULE_SIG_FORCE
module_param(sig_enforce, bool_enable_only, 0644);
#endif /* !CONFIG_MODULE_SIG_FORCE */
-#endif /* CONFIG_MODULE_SIG */

/* Block module loading/unloading? */
int modules_disabled = 0;
--
2.3.2.209.gd67f9d5.dirty

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