From: Yu-cheng Yu <yu-cheng.yu@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>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v10 26/26] x86/cet/shstk: Add arch_prctl functions for shadow stack
Date: Wed, 29 Apr 2020 15:07:32 -0700 [thread overview]
Message-ID: <20200429220732.31602-27-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20200429220732.31602-1-yu-cheng.yu@intel.com>
arch_prctl(ARCH_X86_CET_STATUS, u64 *args)
Get CET feature status.
The parameter 'args' is a pointer to a user buffer. The kernel returns
the following information:
*args = shadow stack/IBT status
*(args + 1) = shadow stack base address
*(args + 2) = shadow stack size
arch_prctl(ARCH_X86_CET_DISABLE, u64 features)
Disable CET features specified in 'features'. Return -EPERM if CET is
locked.
arch_prctl(ARCH_X86_CET_LOCK)
Lock in CET features.
arch_prctl(ARCH_X86_CET_ALLOC_SHSTK, u64 *args)
Allocate a new shadow stack.
The parameter 'args' is a pointer to a user buffer containing the
desired size to allocate. The kernel returns the allocated shadow
stack address in *args.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
v10:
- Verify CET is enabled before handling arch_prctl.
- Change input parameters from unsigned long to u64, to make it clear they
are 64-bit.
arch/x86/include/asm/cet.h | 4 ++
arch/x86/include/uapi/asm/prctl.h | 5 ++
arch/x86/kernel/Makefile | 2 +-
arch/x86/kernel/cet.c | 29 +++++++++++
arch/x86/kernel/cet_prctl.c | 87 +++++++++++++++++++++++++++++++
arch/x86/kernel/process.c | 4 +-
6 files changed, 128 insertions(+), 3 deletions(-)
create mode 100644 arch/x86/kernel/cet_prctl.c
diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h
index 71dc92acd2f2..99e6e741d28c 100644
--- a/arch/x86/include/asm/cet.h
+++ b/arch/x86/include/asm/cet.h
@@ -14,16 +14,20 @@ struct sc_ext;
struct cet_status {
unsigned long shstk_base;
unsigned long shstk_size;
+ unsigned int locked:1;
};
#ifdef CONFIG_X86_INTEL_CET
+int prctl_cet(int option, u64 arg2);
int cet_setup_shstk(void);
int cet_setup_thread_shstk(struct task_struct *p);
+int cet_alloc_shstk(unsigned long *arg);
void cet_disable_free_shstk(struct task_struct *p);
int cet_verify_rstor_token(bool ia32, unsigned long ssp, unsigned long *new_ssp);
void cet_restore_signal(struct sc_ext *sc);
int cet_setup_signal(bool ia32, unsigned long rstor, struct sc_ext *sc);
#else
+static inline int prctl_cet(int option, u64 arg2) { return -EINVAL; }
static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; }
static inline void cet_disable_free_shstk(struct task_struct *p) {}
static inline void cet_restore_signal(struct sc_ext *sc) { return; }
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index 5a6aac9fa41f..d962f0ec9ccf 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -14,4 +14,9 @@
#define ARCH_MAP_VDSO_32 0x2002
#define ARCH_MAP_VDSO_64 0x2003
+#define ARCH_X86_CET_STATUS 0x3001
+#define ARCH_X86_CET_DISABLE 0x3002
+#define ARCH_X86_CET_LOCK 0x3003
+#define ARCH_X86_CET_ALLOC_SHSTK 0x3004
+
#endif /* _ASM_X86_PRCTL_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index e9cc2551573b..0b621e2afbdc 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -144,7 +144,7 @@ obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o
obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
-obj-$(CONFIG_X86_INTEL_CET) += cet.o
+obj-$(CONFIG_X86_INTEL_CET) += cet.o cet_prctl.o
###
# 64 bit specific files
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 121552047b86..c1b9b540c03e 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -145,6 +145,35 @@ static int create_rstor_token(bool ia32, unsigned long ssp,
return 0;
}
+int cet_alloc_shstk(unsigned long *arg)
+{
+ unsigned long len = *arg;
+ unsigned long addr;
+ unsigned long token;
+ unsigned long ssp;
+
+ addr = alloc_shstk(round_up(len, PAGE_SIZE));
+
+ if (IS_ERR((void *)addr))
+ return PTR_ERR((void *)addr);
+
+ /* Restore token is 8 bytes and aligned to 8 bytes */
+ ssp = addr + len;
+ token = ssp;
+
+ if (!in_ia32_syscall())
+ token |= TOKEN_MODE_64;
+ ssp -= 8;
+
+ if (write_user_shstk_64(ssp, token)) {
+ vm_munmap(addr, len);
+ return -EINVAL;
+ }
+
+ *arg = addr;
+ return 0;
+}
+
int cet_setup_shstk(void)
{
unsigned long addr, size;
diff --git a/arch/x86/kernel/cet_prctl.c b/arch/x86/kernel/cet_prctl.c
new file mode 100644
index 000000000000..0139c48f2215
--- /dev/null
+++ b/arch/x86/kernel/cet_prctl.c
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/errno.h>
+#include <linux/uaccess.h>
+#include <linux/prctl.h>
+#include <linux/compat.h>
+#include <linux/mman.h>
+#include <linux/elfcore.h>
+#include <asm/processor.h>
+#include <asm/prctl.h>
+#include <asm/cet.h>
+
+/* See Documentation/x86/intel_cet.rst. */
+
+static int handle_get_status(u64 arg2)
+{
+ struct cet_status *cet = ¤t->thread.cet;
+ u64 buf[3] = {0, 0, 0};
+
+ if (cet->shstk_size) {
+ buf[0] |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
+ buf[1] = (u64)cet->shstk_base;
+ buf[2] = (u64)cet->shstk_size;
+ }
+
+ return copy_to_user((u64 __user *)arg2, buf, sizeof(buf));
+}
+
+static int handle_alloc_shstk(u64 arg2)
+{
+ int err = 0;
+ unsigned long arg;
+ unsigned long addr = 0;
+ unsigned long size = 0;
+
+ if (get_user(arg, (unsigned long __user *)arg2))
+ return -EFAULT;
+
+ size = arg;
+ err = cet_alloc_shstk(&arg);
+ if (err)
+ return err;
+
+ addr = arg;
+ if (put_user((u64)addr, (u64 __user *)arg2)) {
+ vm_munmap(addr, size);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+int prctl_cet(int option, u64 arg2)
+{
+ struct cet_status *cet;
+
+ if (!IS_ENABLED(CONFIG_X86_INTEL_CET))
+ return -EINVAL;
+
+ if (option == ARCH_X86_CET_STATUS)
+ return handle_get_status(arg2);
+
+ if (!static_cpu_has(X86_FEATURE_SHSTK))
+ return -EINVAL;
+
+ cet = ¤t->thread.cet;
+
+ switch (option) {
+ case ARCH_X86_CET_DISABLE:
+ if (cet->locked)
+ return -EPERM;
+ if (arg2 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)
+ cet_disable_free_shstk(current);
+
+ return 0;
+
+ case ARCH_X86_CET_LOCK:
+ cet->locked = 1;
+ return 0;
+
+ case ARCH_X86_CET_ALLOC_SHSTK:
+ return handle_alloc_shstk(arg2);
+
+ default:
+ return -EINVAL;
+ }
+}
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ef1c2b8086a2..de6773dd6a16 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -996,7 +996,7 @@ long do_arch_prctl_common(struct task_struct *task, int option,
return get_cpuid_mode();
case ARCH_SET_CPUID:
return set_cpuid_mode(task, cpuid_enabled);
+ default:
+ return prctl_cet(option, cpuid_enabled);
}
-
- return -EINVAL;
}
--
2.21.0
next prev parent reply other threads:[~2020-04-29 22:09 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 22:07 [PATCH v10 00/26] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 01/26] Documentation/x86: Add CET description Yu-cheng Yu
2020-04-29 22:53 ` Dave Hansen
2020-04-29 23:02 ` Yu-cheng Yu
2020-05-12 23:20 ` Yu-cheng Yu
2020-05-15 18:39 ` Dave Hansen
2020-05-15 21:33 ` Yu-cheng Yu
2020-05-15 22:43 ` Dave Hansen
2020-05-15 23:29 ` Yu-cheng Yu
2020-05-15 23:56 ` Dave Hansen
2020-05-16 2:51 ` H.J. Lu
2020-05-17 23:09 ` Dave Hansen
2020-05-16 2:53 ` Yu-cheng Yu
2020-05-18 13:41 ` Dave Hansen
2020-05-18 14:01 ` H.J. Lu
2020-05-18 14:26 ` Dave Hansen
2020-05-18 14:21 ` Yu-cheng Yu
2020-05-18 23:47 ` Yu-cheng Yu
2020-05-19 0:38 ` Dave Hansen
2020-05-19 1:35 ` Andy Lutomirski
2020-05-20 1:04 ` Andy Lutomirski
2020-05-29 2:08 ` Yu-cheng Yu
2020-05-16 0:13 ` Andrew Cooper
2020-05-16 2:37 ` H.J. Lu
2020-05-16 14:09 ` Andrew Cooper
2020-05-22 16:49 ` Peter Zijlstra
2020-05-22 17:48 ` Andrew Cooper
2020-04-29 22:07 ` [PATCH v10 02/26] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 03/26] x86/fpu/xstate: Introduce CET MSR XSAVES supervisor states Yu-cheng Yu
2020-07-23 16:10 ` Sean Christopherson
2020-07-23 16:21 ` Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 04/26] x86/cet: Add control-protection fault handler Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Yu-cheng Yu
2020-05-07 15:55 ` Dave Hansen
2020-05-07 16:59 ` Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 06/26] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 07/26] x86/mm: Remove _PAGE_DIRTY_HW from kernel RO pages Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 08/26] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 09/26] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 10/26] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 11/26] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY_HW to _PAGE_COW Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 12/26] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 13/26] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 14/26] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 15/26] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 16/26] mm: Add guard pages around a shadow stack Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 17/26] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 18/26] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 19/26] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 20/26] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 21/26] ELF: UAPI and Kconfig additions for ELF program properties Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 22/26] ELF: Add ELF program property parsing support Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 23/26] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 24/26] x86/cet/shstk: ELF header parsing for shadow stack Yu-cheng Yu
2020-04-29 22:07 ` [PATCH v10 25/26] x86/cet/shstk: Handle thread " Yu-cheng Yu
2020-04-29 22:07 ` Yu-cheng Yu [this message]
2020-05-21 22:42 ` [PATCH v10 26/26] x86/cet/shstk: Add arch_prctl functions for " Kees Cook
2020-05-22 17:17 ` Yu-cheng Yu
2020-05-22 17:29 ` Eugene Syromiatnikov
2020-05-22 18:13 ` Yu-cheng Yu
2020-05-21 15:15 ` [PATCH v10 00/26] Control-flow Enforcement: Shadow Stack Josh Poimboeuf
2020-05-21 15:57 ` Yu-cheng Yu
2020-05-21 18:50 ` Josh Poimboeuf
2020-05-21 19:08 ` Yu-cheng Yu
2020-07-23 16:25 ` Sean Christopherson
2020-07-23 16:41 ` Dave Hansen
2020-07-23 16:56 ` Sean Christopherson
2020-07-23 18:41 ` Dave Hansen
2020-07-24 3:40 ` Yu-cheng Yu
2020-07-24 4:50 ` Sean Christopherson
2020-07-24 4:59 ` Sean Christopherson
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