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@amacapital.net>,
Balbir Singh <bsingharora@gmail.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.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@chromiun.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>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [RFC PATCH v3 13/24] x86/mm: Shadow stack page fault error checking
Date: Thu, 30 Aug 2018 07:38:53 -0700 [thread overview]
Message-ID: <20180830143904.3168-14-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20180830143904.3168-1-yu-cheng.yu@intel.com>
If a page fault is triggered by a shadow stack access (e.g.
call/ret) or shadow stack management instructions (e.g.
wrussq), then bit[6] of the page fault error code is set.
In access_error(), we check if a shadow stack page fault
is within a shadow stack memory area.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/include/asm/traps.h | 2 ++
arch/x86/mm/fault.c | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 5196050ff3d5..58ea2f5722e9 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -157,6 +157,7 @@ enum {
* bit 3 == 1: use of reserved bit detected
* bit 4 == 1: fault was an instruction fetch
* bit 5 == 1: protection keys block access
+ * bit 6 == 1: shadow stack access fault
*/
enum x86_pf_error_code {
X86_PF_PROT = 1 << 0,
@@ -165,5 +166,6 @@ enum x86_pf_error_code {
X86_PF_RSVD = 1 << 3,
X86_PF_INSTR = 1 << 4,
X86_PF_PK = 1 << 5,
+ X86_PF_SHSTK = 1 << 6,
};
#endif /* _ASM_X86_TRAPS_H */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index b9123c497e0a..3842353fb4a3 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1162,6 +1162,17 @@ access_error(unsigned long error_code, struct vm_area_struct *vma)
(error_code & X86_PF_INSTR), foreign))
return 1;
+ /*
+ * Verify X86_PF_SHSTK is within a shadow stack VMA.
+ * It is always an error if there is a shadow stack
+ * fault outside a shadow stack VMA.
+ */
+ if (error_code & X86_PF_SHSTK) {
+ if (!(vma->vm_flags & VM_SHSTK))
+ return 1;
+ return 0;
+ }
+
if (error_code & X86_PF_WRITE) {
/* write, present and write, not present: */
if (unlikely(!(vma->vm_flags & VM_WRITE)))
@@ -1300,6 +1311,13 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+ /*
+ * If the fault is caused by a shadow stack access,
+ * i.e. CALL/RET/SAVEPREVSSP/RSTORSSP, then set
+ * FAULT_FLAG_WRITE to effect copy-on-write.
+ */
+ if (error_code & X86_PF_SHSTK)
+ flags |= FAULT_FLAG_WRITE;
if (error_code & X86_PF_WRITE)
flags |= FAULT_FLAG_WRITE;
if (error_code & X86_PF_INSTR)
--
2.17.1
next prev parent reply other threads:[~2018-08-30 14:47 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-30 14:38 [RFC PATCH v3 00/24] Control Flow Enforcement: Shadow Stack Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 01/24] x86/cpufeatures: Add CPUIDs for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 02/24] x86/fpu/xstate: Change some names to separate XSAVES system and user states Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 03/24] x86/fpu/xstate: Enable XSAVES system states Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 04/24] x86/fpu/xstate: Add XSAVES system states for shadow stack Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 05/24] Documentation/x86: Add CET description Yu-cheng Yu
2018-08-30 20:39 ` Pavel Machek
2018-08-30 22:49 ` Yu-cheng Yu
2018-09-14 21:17 ` Yu-cheng Yu
2018-09-03 2:56 ` Randy Dunlap
2018-08-30 14:38 ` [RFC PATCH v3 06/24] x86/cet: Control protection exception handler Yu-cheng Yu
2018-08-31 15:01 ` Jann Horn
2018-08-31 16:20 ` Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 07/24] x86/cet/shstk: Add Kconfig option for user-mode shadow stack Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 08/24] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 09/24] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 10/24] x86/mm: Introduce _PAGE_DIRTY_SW Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 11/24] drm/i915/gvt: Update _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 12/24] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW Yu-cheng Yu
2018-08-30 15:49 ` Jann Horn
2018-08-30 16:02 ` Yu-cheng Yu
2018-08-30 16:08 ` Dave Hansen
2018-08-30 16:23 ` Jann Horn
2018-08-30 17:19 ` Dave Hansen
2018-08-30 17:26 ` Yu-cheng Yu
2018-08-30 17:33 ` Dave Hansen
2018-08-30 17:54 ` Yu-cheng Yu
2018-08-30 17:59 ` Jann Horn
2018-08-30 20:21 ` Yu-cheng Yu
2018-08-30 20:44 ` Jann Horn
2018-08-30 20:52 ` Yu-cheng Yu
2018-08-30 21:01 ` Jann Horn
2018-08-30 21:47 ` Jann Horn
2018-08-31 9:53 ` Peter Zijlstra
2018-08-31 14:33 ` Yu-cheng Yu
2018-08-31 14:47 ` Dave Hansen
2018-08-31 15:48 ` Yu-cheng Yu
2018-08-31 15:58 ` Dave Hansen
2018-08-31 16:29 ` Peter Zijlstra
2018-09-14 20:39 ` Yu-cheng Yu
2018-09-14 20:46 ` Dave Hansen
2018-09-14 21:08 ` Yu-cheng Yu
2018-09-14 21:33 ` Dave Hansen
2018-08-31 1:23 ` Andy Lutomirski
2018-08-30 17:34 ` Andy Lutomirski
2018-08-30 18:55 ` Dave Hansen
2018-08-31 17:46 ` Andy Lutomirski
2018-08-31 17:52 ` Dave Hansen
2018-08-30 19:59 ` Randy Dunlap
2018-08-30 20:23 ` Yu-cheng Yu
2018-08-31 16:29 ` Dave Hansen
2018-08-30 14:38 ` Yu-cheng Yu [this message]
2018-08-30 14:38 ` [RFC PATCH v3 14/24] mm: Handle shadow stack page fault Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 15/24] mm: Handle THP/HugeTLB " Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 16/24] mm: Update can_follow_write_pte/pmd for shadow stack Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 17/24] mm: Introduce do_mmap_locked() Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 18/24] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2018-08-30 16:10 ` Jann Horn
2018-08-30 16:20 ` Yu-cheng Yu
2018-08-30 14:38 ` [RFC PATCH v3 19/24] x86/cet/shstk: Introduce WRUSS instruction Yu-cheng Yu
2018-08-30 15:39 ` Jann Horn
2018-08-30 15:55 ` Andy Lutomirski
2018-08-30 16:22 ` Yu-cheng Yu
2018-08-31 21:49 ` Yu-cheng Yu
2018-08-31 22:16 ` Andy Lutomirski
2018-09-14 20:46 ` Yu-cheng Yu
2018-08-30 14:39 ` [RFC PATCH v3 20/24] x86/cet/shstk: Signal handling for shadow stack Yu-cheng Yu
2018-08-30 14:39 ` [RFC PATCH v3 21/24] x86/cet/shstk: ELF header parsing of Shadow Stack Yu-cheng Yu
2018-08-30 14:39 ` [RFC PATCH v3 22/24] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2018-08-30 14:39 ` [RFC PATCH v3 23/24] x86/cet/shstk: Add arch_prctl functions for Shadow Stack Yu-cheng Yu
2018-08-30 14:39 ` [RFC PATCH v3 24/24] x86/cet/shstk: Add Shadow Stack instructions to opcode map Yu-cheng Yu
2018-09-02 8:13 ` [RFC PATCH v3 00/24] Control Flow Enforcement: Shadow Stack Balbir Singh
2018-09-04 14:47 ` Yu-cheng Yu
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