path: root/scripts/gcc-plugins/Kconfig
diff options
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-12-06 09:32:57 +0100
committerKees Cook <keescook@chromium.org>2018-12-12 13:20:07 -0800
commit189af4657186da08a2e79fb8e906cfd82b2ccddc (patch)
treeaef1d1ec51997c0baf5f415ad71a7929ac049746 /scripts/gcc-plugins/Kconfig
parentLinux 4.20-rc2 (diff)
ARM: smp: add support for per-task stack canaries
On ARM, we currently only change the value of the stack canary when switching tasks if the kernel was built for UP. On SMP kernels, this is impossible since the stack canary value is obtained via a global symbol reference, which means a) all running tasks on all CPUs must use the same value b) we can only modify the value when no kernel stack frames are live on any CPU, which is effectively never. So instead, use a GCC plugin to add a RTL pass that replaces each reference to the address of the __stack_chk_guard symbol with an expression that produces the address of the 'stack_canary' field that is added to struct thread_info. This way, each task will use its own randomized value. Cc: Russell King <linux@armlinux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Emese Revfy <re.emese@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Laura Abbott <labbott@redhat.com> Cc: kernel-hardening@lists.openwall.com Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'scripts/gcc-plugins/Kconfig')
1 files changed, 4 insertions, 0 deletions
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index 0d5c799688f0..d45f7f36b859 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -190,4 +190,8 @@ config STACKLEAK_RUNTIME_DISABLE
runtime to control kernel stack erasing for kernels built with
+ bool
+ depends on GCC_PLUGINS && ARM