[PATCH v5 34/39] x86/shstk: Wire in shadow stack interface

Rick Edgecombe
2023-01-19T21:43:30Z

The kernel now has the main shadow stack functionality to support
applications. Wire in the WRSS and shadow stack enable/disable functions
into the existing shadow stack API skeleton.

Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---

v4:
- Remove "CET" references

v2:
- Split from other patches

arch/x86/kernel/shstk.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
index 71dbb49b93cd..07142e6f05f6 100644
--- a/arch/x86/kernel/shstk.c
+++ b/arch/x86/kernel/shstk.c
@@ -465,9 +465,17 @@ long shstk_prctl(struct task_struct *task, int option, unsigned long features)
return -EINVAL;

if (option == ARCH_SHSTK_DISABLE) {
+ if (features & ARCH_SHSTK_WRSS)
+ return wrss_control(false);
+ if (features & ARCH_SHSTK_SHSTK)
+ return shstk_disable();
return -EINVAL;
}

/* Handle ARCH_SHSTK_ENABLE */
+ if (features & ARCH_SHSTK_SHSTK)
+ return shstk_setup();
+ if (features & ARCH_SHSTK_WRSS)
+ return wrss_control(true);
return -EINVAL;
}
--
2.17.1