[PATCH 7/8] configs/hardening: Enable CONFIG_STACKLEAK

[Kees Cook]

Since we can wipe the stack with both Clang and GCC plugins, enable this
for the "hardening.config" for wider testing.

Signed-off-by: Kees Cook <kees at kernel.org>
---
Cc: "Gustavo A. R. Silva" <gustavoars at kernel.org>
Cc: <linux-hardening at vger.kernel.org>
---
 kernel/configs/hardening.config | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config
index dd7c32fb5ac1..3da00926b4eb 100644
--- a/kernel/configs/hardening.config
+++ b/kernel/configs/hardening.config
@@ -63,6 +63,9 @@ CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
 # Initialize all stack variables to zero on function entry.
 CONFIG_INIT_STACK_ALL_ZERO=y
 
+# Wipe kernel stack after syscall completion to reduce stale data lifetime.
+CONFIG_STACKLEAK=y
+
 # Wipe RAM at reboot via EFI. For more details, see:
 # https://trustedcomputinggroup.org/resource/pc-client-work-group-platform-reset-attack-mitigation-specification/
 # https://bugzilla.redhat.com/show_bug.cgi?id=1532058
-- 
2.34.1