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

From: Kees Cook <kees@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <kees@kernel.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-hardening@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Marco Elver <elver@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nicolas Schier <nicolas.schier@linux.dev>,
	Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	kasan-dev@googlegroups.com, linux-doc@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH 7/8] configs/hardening: Enable CONFIG_STACKLEAK
Date: Wed,  7 May 2025 11:16:13 -0700	[thread overview]
Message-ID: <20250507181615.1947159-7-kees@kernel.org> (raw)
In-Reply-To: <20250507180852.work.231-kees@kernel.org>

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@kernel.org>
---
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: <linux-hardening@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

