module: limit enabling module.sig_enforce

0c18f29a · Mimi Zohar <[email protected]> · 2021-06-22 13:36:41 +02:00

Irrespective as to whether CONFIG_MODULE_SIG is configured, specifying
"module.sig_enforce=1" on the boot command line sets "sig_enforce".
Only allow "sig_enforce" to be set when CONFIG_MODULE_SIG is configured.

This patch makes the presence of /sys/module/module/parameters/sig_enforce
dependent on CONFIG_MODULE_SIG=y.

Fixes: fda784e50aac ("module: export module signature enforcement status")
Reported-by: Nayna Jain <[email protected]>
Tested-by: Mimi Zohar <[email protected]>
Tested-by: Jessica Yu <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>
Signed-off-by: Jessica Yu <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: 0c18f29aae7ce3dadd26d8ee3505d07cc982df75
Parents: a96bfed6

Changes

1 files changed · +9 −5

File	Status	Add	Del	Content
kernel/module.c	modified	+9	−5	View file

kernel/module.c

View file

diff --git a/kernel/module.c b/kernel/module.c
index 7e78dfa..927d46c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -266,9 +266,18 @@ static void module_assert_mutex_or_preempt(void)
 #endif
 }
 
+#ifdef CONFIG_MODULE_SIG
 static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
 module_param(sig_enforce, bool_enable_only, 0644);
 
+void set_module_sig_enforced(void)
+{
+	sig_enforce = true;
+}
+#else
+#define sig_enforce false
+#endif
+
 /*
  * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
  * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
@@ -279,11 +288,6 @@ bool is_module_sig_enforced(void)
 }
 EXPORT_SYMBOL(is_module_sig_enforced);
 
-void set_module_sig_enforced(void)
-{
-	sig_enforce = true;
-}
-
 /* Block module loading/unloading? */
 int modules_disabled = 0;
 core_param(nomodule, modules_disabled, bint, 0);