lkdtm: Make arch-specific tests always available
I'd like arch-specific tests to XFAIL when on a mismatched architecture
so that we can more easily compare test coverage across all systems.
Lacking kernel configs or CPU features count as a FAIL, not an XFAIL.
Additionally fixes a build failure under 32-bit UML.
Fixes: b09511c253e5 ("lkdtm: Add a DOUBLE_FAULT crash type on x86")
Fixes: cea23efb4de2 ("lkdtm/bugs: Make double-fault test always available")
Fixes: 6cb6982f42cb ("lkdtm: arm64: test kernel pointer authentication")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200625203704.317097-5-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 08c7028..1033880 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -13,7 +13,7 @@
#include <linux/uaccess.h>
#include <linux/slab.h>
-#ifdef CONFIG_X86_32
+#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
#include <asm/desc.h>
#endif
@@ -418,7 +418,7 @@ void lkdtm_UNSET_SMEP(void)
void lkdtm_DOUBLE_FAULT(void)
{
-#ifdef CONFIG_X86_32
+#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML)
/*
* Trigger #DF by setting the stack limit to zero. This clobbers
* a GDT TLS slot, which is okay because the current task will die
@@ -453,38 +453,42 @@ void lkdtm_DOUBLE_FAULT(void)
#endif
}
-#ifdef CONFIG_ARM64_PTR_AUTH
+#ifdef CONFIG_ARM64
static noinline void change_pac_parameters(void)
{
- /* Reset the keys of current task */
- ptrauth_thread_init_kernel(current);
- ptrauth_thread_switch_kernel(current);
+ if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH)) {
+ /* Reset the keys of current task */
+ ptrauth_thread_init_kernel(current);
+ ptrauth_thread_switch_kernel(current);
+ }
}
+#endif
-#define CORRUPT_PAC_ITERATE 10
noinline void lkdtm_CORRUPT_PAC(void)
{
+#ifdef CONFIG_ARM64
+#define CORRUPT_PAC_ITERATE 10
int i;
+ if (!IS_ENABLED(CONFIG_ARM64_PTR_AUTH))
+ pr_err("FAIL: kernel not built with CONFIG_ARM64_PTR_AUTH\n");
+
if (!system_supports_address_auth()) {
- pr_err("FAIL: arm64 pointer authentication feature not present\n");
+ pr_err("FAIL: CPU lacks pointer authentication feature\n");
return;
}
- pr_info("Change the PAC parameters to force function return failure\n");
+ pr_info("changing PAC parameters to force function return failure...\n");
/*
- * Pac is a hash value computed from input keys, return address and
+ * PAC is a hash value computed from input keys, return address and
* stack pointer. As pac has fewer bits so there is a chance of
* collision, so iterate few times to reduce the collision probability.
*/
for (i = 0; i < CORRUPT_PAC_ITERATE; i++)
change_pac_parameters();
- pr_err("FAIL: %s test failed. Kernel may be unstable from here\n", __func__);
-}
-#else /* !CONFIG_ARM64_PTR_AUTH */
-noinline void lkdtm_CORRUPT_PAC(void)
-{
- pr_err("FAIL: arm64 pointer authentication config disabled\n");
-}
+ pr_err("FAIL: survived PAC changes! Kernel may be unstable from here\n");
+#else
+ pr_err("XFAIL: this test is arm64-only\n");
#endif
+}
