From: Rick Edgecombe <rick.p.edgecombe@intel.com>
To: x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@kernel.org>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H . J . Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
Weijiang Yang <weijiang.yang@intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
John Allen <john.allen@amd.com>,
kcc@google.com, eranian@google.com, rppt@kernel.org,
jamorris@linux.microsoft.com, dethoma@microsoft.com,
akpm@linux-foundation.org, Andrew.Cooper3@citrix.com,
christina.schimpe@intel.com, david@redhat.com,
debug@rivosinc.com
Cc: rick.p.edgecombe@intel.com
Subject: [PATCH v6 28/41] x86: Introduce userspace API for shadow stack
Date: Sat, 18 Feb 2023 13:14:20 -0800 [thread overview]
Message-ID: <20230218211433.26859-29-rick.p.edgecombe@intel.com> (raw)
In-Reply-To: <20230218211433.26859-1-rick.p.edgecombe@intel.com>
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Add three new arch_prctl() handles:
- ARCH_SHSTK_ENABLE/DISABLE enables or disables the specified
feature. Returns 0 on success or an error.
- ARCH_SHSTK_LOCK prevents future disabling or enabling of the
specified feature. Returns 0 on success or an error
The features are handled per-thread and inherited over fork(2)/clone(2),
but reset on exec().
This is preparation patch. It does not implement any features.
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: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
[tweaked with feedback from tglx]
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
v4:
- Remove references to CET and replace with shadow stack (Peterz)
v3:
- Move shstk.c Makefile changes earlier (Kees)
- Add #ifdef around features_locked and features (Kees)
- Encapsulate features reset earlier in reset_thread_features() so
features and features_locked are not referenced in code that would be
compiled !CONFIG_X86_USER_SHADOW_STACK. (Kees)
- Fix typo in commit log (Kees)
- Switch arch_prctl() numbers to avoid conflict with LAM
v2:
- Only allow one enable/disable per call (tglx)
- Return error code like a normal arch_prctl() (Alexander Potapenko)
- Make CET only (tglx)
---
arch/x86/include/asm/processor.h | 6 +++++
arch/x86/include/asm/shstk.h | 21 +++++++++++++++
arch/x86/include/uapi/asm/prctl.h | 6 +++++
arch/x86/kernel/Makefile | 2 ++
arch/x86/kernel/process_64.c | 7 ++++-
arch/x86/kernel/shstk.c | 44 +++++++++++++++++++++++++++++++
6 files changed, 85 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/include/asm/shstk.h
create mode 100644 arch/x86/kernel/shstk.c
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 8d73004e4cac..bd16e012b3e9 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -28,6 +28,7 @@ struct vm86;
#include <asm/unwind_hints.h>
#include <asm/vmxfeatures.h>
#include <asm/vdso/processor.h>
+#include <asm/shstk.h>
#include <linux/personality.h>
#include <linux/cache.h>
@@ -475,6 +476,11 @@ struct thread_struct {
*/
u32 pkru;
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+ unsigned long features;
+ unsigned long features_locked;
+#endif
+
/* Floating point and extended processor state */
struct fpu fpu;
/*
diff --git a/arch/x86/include/asm/shstk.h b/arch/x86/include/asm/shstk.h
new file mode 100644
index 000000000000..ec753809f074
--- /dev/null
+++ b/arch/x86/include/asm/shstk.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SHSTK_H
+#define _ASM_X86_SHSTK_H
+
+#ifndef __ASSEMBLY__
+#include <linux/types.h>
+
+struct task_struct;
+
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+long shstk_prctl(struct task_struct *task, int option, unsigned long features);
+void reset_thread_features(void);
+#else
+static inline long shstk_prctl(struct task_struct *task, int option,
+ unsigned long arg2) { return -EINVAL; }
+static inline void reset_thread_features(void) {}
+#endif /* CONFIG_X86_USER_SHADOW_STACK */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_X86_SHSTK_H */
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index 500b96e71f18..b2b3b7200b2d 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -20,4 +20,10 @@
#define ARCH_MAP_VDSO_32 0x2002
#define ARCH_MAP_VDSO_64 0x2003
+/* Don't use 0x3001-0x3004 because of old glibcs */
+
+#define ARCH_SHSTK_ENABLE 0x5001
+#define ARCH_SHSTK_DISABLE 0x5002
+#define ARCH_SHSTK_LOCK 0x5003
+
#endif /* _ASM_X86_PRCTL_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 92446f1dedd7..b366641703e3 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -146,6 +146,8 @@ obj-$(CONFIG_CALL_THUNKS) += callthunks.o
obj-$(CONFIG_X86_CET) += cet.o
+obj-$(CONFIG_X86_USER_SHADOW_STACK) += shstk.o
+
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4e34b3b68ebd..71094c8a305f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -514,6 +514,8 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip,
load_gs_index(__USER_DS);
}
+ reset_thread_features();
+
loadsegment(fs, 0);
loadsegment(es, _ds);
loadsegment(ds, _ds);
@@ -830,7 +832,10 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
case ARCH_MAP_VDSO_64:
return prctl_map_vdso(&vdso_image_64, arg2);
#endif
-
+ case ARCH_SHSTK_ENABLE:
+ case ARCH_SHSTK_DISABLE:
+ case ARCH_SHSTK_LOCK:
+ return shstk_prctl(task, option, arg2);
default:
ret = -EINVAL;
break;
diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
new file mode 100644
index 000000000000..41ed6552e0a5
--- /dev/null
+++ b/arch/x86/kernel/shstk.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * shstk.c - Intel shadow stack support
+ *
+ * Copyright (c) 2021, Intel Corporation.
+ * Yu-cheng Yu <yu-cheng.yu@intel.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/bitops.h>
+#include <asm/prctl.h>
+
+void reset_thread_features(void)
+{
+ current->thread.features = 0;
+ current->thread.features_locked = 0;
+}
+
+long shstk_prctl(struct task_struct *task, int option, unsigned long features)
+{
+ if (option == ARCH_SHSTK_LOCK) {
+ task->thread.features_locked |= features;
+ return 0;
+ }
+
+ /* Don't allow via ptrace */
+ if (task != current)
+ return -EINVAL;
+
+ /* Do not allow to change locked features */
+ if (features & task->thread.features_locked)
+ return -EPERM;
+
+ /* Only support enabling/disabling one feature at a time. */
+ if (hweight_long(features) > 1)
+ return -EINVAL;
+
+ if (option == ARCH_SHSTK_DISABLE) {
+ return -EINVAL;
+ }
+
+ /* Handle ARCH_SHSTK_ENABLE */
+ return -EINVAL;
+}
--
2.17.1
next prev parent reply other threads:[~2023-02-18 21:21 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-18 21:13 [PATCH v6 00/41] Shadow stacks for userspace Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 01/41] Documentation/x86: Add CET shadow stack description Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 02/41] x86/shstk: Add Kconfig option for shadow stack Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 03/41] x86/cpufeatures: Add CPU feature flags for shadow stacks Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 04/41] x86/cpufeatures: Enable CET CR4 bit for shadow stack Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 05/41] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 06/41] x86/fpu: Add helper for modifying xstate Rick Edgecombe
2023-02-18 21:13 ` [PATCH v6 07/41] x86: Move control protection handler to separate file Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 08/41] x86/shstk: Add user control-protection fault handler Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 09/41] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 10/41] x86/mm: Move pmd_write(), pud_write() up in the file Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 11/41] mm: Introduce pte_mkwrite_kernel() Rick Edgecombe
2023-02-19 20:38 ` Kees Cook
2023-02-20 11:17 ` David Hildenbrand
2023-02-20 11:19 ` David Hildenbrand
2023-03-01 15:39 ` Deepak Gupta
2023-02-18 21:14 ` [PATCH v6 12/41] s390/mm: Introduce pmd_mkwrite_kernel() Rick Edgecombe
2023-02-19 20:39 ` Kees Cook
2023-02-20 11:21 ` David Hildenbrand
2023-02-23 12:14 ` Heiko Carstens
2023-02-23 17:59 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 13/41] mm: Make pte_mkwrite() take a VMA Rick Edgecombe
2023-02-19 20:40 ` Kees Cook
2023-02-20 1:00 ` Michael Ellerman
2023-02-20 21:24 ` Edgecombe, Rick P
2023-02-20 11:23 ` David Hildenbrand
2023-02-20 22:56 ` Edgecombe, Rick P
2023-03-01 15:41 ` Deepak Gupta
2023-02-18 21:14 ` [PATCH v6 14/41] x86/mm: Introduce _PAGE_SAVED_DIRTY Rick Edgecombe
2023-02-20 11:32 ` David Hildenbrand
2023-02-20 21:38 ` Edgecombe, Rick P
2023-02-21 8:38 ` David Hildenbrand
2023-02-21 20:08 ` Edgecombe, Rick P
2023-02-21 20:13 ` Dave Hansen
2023-02-22 1:02 ` Edgecombe, Rick P
2023-02-22 9:05 ` David Hildenbrand
2023-02-22 17:23 ` Dave Hansen
2023-02-22 17:27 ` David Hildenbrand
2023-02-22 17:42 ` Kees Cook
2023-02-22 17:54 ` Dave Hansen
2023-02-22 19:39 ` Kees Cook
2023-02-18 21:14 ` [PATCH v6 15/41] x86/mm: Update ptep/pmdp_set_wrprotect() for _PAGE_SAVED_DIRTY Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 16/41] x86/mm: Start actually marking _PAGE_SAVED_DIRTY Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 17/41] mm: Move VM_UFFD_MINOR_BIT from 37 to 38 Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 18/41] mm: Introduce VM_SHADOW_STACK for shadow stack memory Rick Edgecombe
2023-02-20 12:56 ` David Hildenbrand
2023-02-20 22:08 ` Edgecombe, Rick P
2023-02-21 8:34 ` David Hildenbrand
2023-02-22 22:13 ` Deepak Gupta
2023-02-18 21:14 ` [PATCH v6 19/41] x86/mm: Check shadow stack page fault errors Rick Edgecombe
2023-02-20 12:57 ` David Hildenbrand
2023-02-22 23:07 ` Edgecombe, Rick P
2023-02-23 12:55 ` David Hildenbrand
2023-02-18 21:14 ` [PATCH v6 20/41] x86/mm: Teach pte_mkwrite() about stack memory Rick Edgecombe
2023-02-19 20:41 ` Kees Cook
2023-02-20 22:52 ` Edgecombe, Rick P
2023-03-01 15:42 ` Deepak Gupta
2023-02-18 21:14 ` [PATCH v6 21/41] mm: Add guard pages around a shadow stack Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 22/41] mm/mmap: Add shadow stack pages to memory accounting Rick Edgecombe
2023-02-20 12:58 ` David Hildenbrand
2023-02-20 22:44 ` Edgecombe, Rick P
2023-02-21 8:31 ` David Hildenbrand
2023-02-22 0:06 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 23/41] mm: Re-introduce vm_flags to do_mmap() Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 24/41] mm: Don't allow write GUPs to shadow stack memory Rick Edgecombe
2023-02-21 8:42 ` David Hildenbrand
2023-02-21 20:02 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 25/41] x86/mm: Introduce MAP_ABOVE4G Rick Edgecombe
2023-02-19 20:43 ` Kees Cook
2023-02-20 22:38 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 26/41] mm: Warn on shadow stack memory in wrong vma Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 27/41] x86/mm: Warn if create Write=0,Dirty=1 with raw prot Rick Edgecombe
2023-02-19 20:45 ` Kees Cook
2023-02-20 22:32 ` Edgecombe, Rick P
2023-02-18 21:14 ` Rick Edgecombe [this message]
2023-02-24 12:20 ` [PATCH v6 28/41] x86: Introduce userspace API for shadow stack Borislav Petkov
2023-02-24 18:37 ` Edgecombe, Rick P
2023-02-28 10:58 ` Borislav Petkov
2023-02-28 22:35 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 29/41] x86/shstk: Add user-mode shadow stack support Rick Edgecombe
2023-02-24 12:22 ` Borislav Petkov
2023-02-24 18:25 ` Edgecombe, Rick P
2023-02-24 18:33 ` Borislav Petkov
2023-02-18 21:14 ` [PATCH v6 30/41] x86/shstk: Handle thread shadow stack Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 31/41] x86/shstk: Introduce routines modifying shstk Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 32/41] x86/shstk: Handle signals for shadow stack Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 33/41] x86/shstk: Introduce map_shadow_stack syscall Rick Edgecombe
2023-02-23 0:03 ` Deepak Gupta
2023-02-23 1:11 ` Edgecombe, Rick P
2023-02-23 21:20 ` Deepak Gupta
2023-02-23 23:42 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 34/41] x86/shstk: Support WRSS for userspace Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 35/41] x86: Expose thread features in /proc/$PID/status Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 36/41] x86/shstk: Wire in shadow stack interface Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 37/41] selftests/x86: Add shadow stack test Rick Edgecombe
2023-02-19 20:47 ` Kees Cook
2023-02-21 8:48 ` David Hildenbrand
2023-02-21 20:02 ` Edgecombe, Rick P
2023-02-23 13:47 ` Borislav Petkov
2023-02-23 17:54 ` Edgecombe, Rick P
2023-02-24 11:45 ` Borislav Petkov
2023-02-24 18:39 ` Edgecombe, Rick P
2023-02-18 21:14 ` [PATCH v6 38/41] x86/fpu: Add helper for initing features Rick Edgecombe
2023-02-19 20:48 ` Kees Cook
2023-02-18 21:14 ` [PATCH v6 39/41] x86: Add PTRACE interface for shadow stack Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 40/41] x86/shstk: Add ARCH_SHSTK_UNLOCK Rick Edgecombe
2023-02-18 21:14 ` [PATCH v6 41/41] x86/shstk: Add ARCH_SHSTK_STATUS Rick Edgecombe
2023-02-20 3:42 ` [PATCH v6 00/41] Shadow stacks for userspace Kees Cook
2023-02-20 22:54 ` Edgecombe, Rick P
2023-02-20 6:50 ` Mike Rapoport
2023-02-20 21:23 ` Edgecombe, Rick P
2023-02-20 20:22 ` John Allen
2023-02-21 2:38 ` Pengfei Xu
2023-02-22 19:28 ` Borislav Petkov
2023-02-22 19:31 ` Edgecombe, Rick P
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