From:   Eric Biggers <ebiggers@kernel.org>
To:     linux-hardening@vger.kernel.org, Kees Cook <keescook@chromium.org>
Cc:     llvm@lists.linux.dev, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: [PATCH] randstruct: temporarily disable clang support
Date:   Fri,  3 Feb 2023 11:42:01 -0800
Message-Id: <20230203194201.92015-1-ebiggers@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Eric Biggers <ebiggers@google.com>

Randstruct with clang is currently unsafe to use in any clang release
that supports it, due to a clang bug that is causing miscompilations:
"-frandomize-layout-seed inconsistently randomizes all-function-pointers
structs" (https://github.com/llvm/llvm-project/issues/60349).  Disable
it temporarily until the bug is fixed and the fix is released in a clang
version that can be checked for.

Fixes: 035f7f87b729 ("randstruct: Enable Clang support")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 security/Kconfig.hardening | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index 53baa95cb644..aad16187148c 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -280,7 +280,8 @@ config ZERO_CALL_USED_REGS
 endmenu
 
 config CC_HAS_RANDSTRUCT
-	def_bool $(cc-option,-frandomize-layout-seed-file=/dev/null)
+	# Temporarily disabled due to https://github.com/llvm/llvm-project/issues/60349
+	def_bool n
 
 choice
 	prompt "Randomize layout of sensitive kernel structures"

base-commit: 7b753a909f426f2789d9db6f357c3d59180a9354
-- 
2.39.1