[tip: x86/shstk] x86/shstk: Wire in shadow stack interface

From: tip-bot2 for Rick Edgecombe
Date: Wed Aug 02 2023 - 18:19:51 EST


The following commit has been merged into the x86/shstk branch of tip:

Commit-ID: 488af8ea7131185c1adcbb0b52da2b6800429ecb
Gitweb: https://git.kernel.org/tip/488af8ea7131185c1adcbb0b52da2b6800429ecb
Author: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
AuthorDate: Mon, 12 Jun 2023 17:11:03 -07:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Wed, 02 Aug 2023 15:01:51 -07:00

x86/shstk: Wire in shadow stack interface

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.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Tested-by: Pengfei Xu <pengfei.xu@xxxxxxxxx>
Tested-by: John Allen <john.allen@xxxxxxx>
Tested-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20230613001108.3040476-38-rick.p.edgecombe%40intel.com
---
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 ea0bf11..d723cdc 100644
--- a/arch/x86/kernel/shstk.c
+++ b/arch/x86/kernel/shstk.c
@@ -502,9 +502,17 @@ 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;
}