stackleak: Allow runtime disabling of kernel stack erasing
Introduce CONFIG_STACKLEAK_RUNTIME_DISABLE option, which provides
'stack_erasing' sysctl. It can be used in runtime to control kernel
stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index cc02050..3ae223f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -91,7 +91,9 @@
#ifdef CONFIG_CHR_DEV_SG
#include <scsi/sg.h>
#endif
-
+#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
+#include <linux/stackleak.h>
+#endif
#ifdef CONFIG_LOCKUP_DETECTOR
#include <linux/nmi.h>
#endif
@@ -1233,6 +1235,17 @@ static struct ctl_table kern_table[] = {
.extra2 = &one,
},
#endif
+#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
+ {
+ .procname = "stack_erasing",
+ .data = NULL,
+ .maxlen = sizeof(int),
+ .mode = 0600,
+ .proc_handler = stack_erasing_sysctl,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+#endif
{ }
};