diff mbox series

[v3,07/16] lkdtm: Disable UNSET_SMEP with CFI

Message ID 20210914191045.2234020-8-samitolvanen@google.com (mailing list archive)
State Superseded
Headers show
Series x86: Add support for Clang CFI | expand

Commit Message

Sami Tolvanen Sept. 14, 2021, 7:10 p.m. UTC 
Disable the UNSET_SMEP test when CONFIG_CFI_CLANG is enabled as
jumping to a call gadget would always trip CFI instead.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 drivers/misc/lkdtm/bugs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kees Cook Sept. 14, 2021, 7:30 p.m. UTC | #1 
On Tue, Sep 14, 2021 at 12:10:36PM -0700, Sami Tolvanen wrote:
> Disable the UNSET_SMEP test when CONFIG_CFI_CLANG is enabled as
> jumping to a call gadget would always trip CFI instead.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Yeah, (thankfully) this test can't work sanely under CFI.

Acked-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 4282b625200f..6e8677852262 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -367,7 +367,7 @@  void lkdtm_STACK_GUARD_PAGE_TRAILING(void)
 
 void lkdtm_UNSET_SMEP(void)
 {
-#if IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_UML)
+#if IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_UML) && !IS_ENABLED(CONFIG_CFI_CLANG)
 #define MOV_CR4_DEPTH	64
 	void (*direct_write_cr4)(unsigned long val);
 	unsigned char *insn;