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 14/24] mm: Handle shadow stack page fault Date: Thu, 30 Aug 2018 07:38:54 -0700 [thread overview] Message-ID: <20180830143904.3168-15-yu-cheng.yu@intel.com> (raw) In-Reply-To: <20180830143904.3168-1-yu-cheng.yu@intel.com> When a task does fork(), its shadow stack must be duplicated for the child. However, the child may not actually use all pages of of the copied shadow stack. This patch implements a flow that is similar to copy-on-write of an anonymous page, but for shadow stack memory. A shadow stack PTE needs to be RO and dirty. We use this dirty bit requirement to effect the copying of shadow stack pages. In copy_one_pte(), we clear the dirty bit from the shadow stack PTE. On the next shadow stack access to the PTE, a page fault occurs. At that time, we then copy/re-use the page and fix the PTE. Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> --- arch/x86/mm/pgtable.c | 10 ++++++++++ include/asm-generic/pgtable.h | 7 +++++++ mm/memory.c | 3 +++ 3 files changed, 20 insertions(+) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index e848a4811785..c63261128ac3 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -872,3 +872,13 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) #endif /* CONFIG_X86_64 */ #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ + +#ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER +inline pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_SHSTK) + return pte_mkdirty_shstk(pte); + else + return pte; +} +#endif /* CONFIG_X86_INTEL_SHADOW_STACK_USER */ diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index aa5271717126..558a485617cd 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -1146,6 +1146,13 @@ static inline bool pmd_dirty_hw(pmd_t pmd) { return false; } + +static inline pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma) +{ + return pte; +} +#else +pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma); #endif #endif /* _ASM_GENERIC_PGTABLE_H */ diff --git a/mm/memory.c b/mm/memory.c index c467102a5cbc..9b4e11944b5d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2462,6 +2462,7 @@ static inline void wp_page_reuse(struct vm_fault *vmf) flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = pte_mkyoung(vmf->orig_pte); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + entry = pte_set_vma_features(entry, vma); if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) update_mmu_cache(vma, vmf->address, vmf->pte); pte_unmap_unlock(vmf->pte, vmf->ptl); @@ -2535,6 +2536,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = mk_pte(new_page, vma->vm_page_prot); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + entry = pte_set_vma_features(entry, vma); /* * Clear the pte entry and flush it first, before updating the * pte with the new entry. This will avoid a race condition @@ -3187,6 +3189,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) entry = mk_pte(page, vma->vm_page_prot); if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry)); + entry = pte_set_vma_features(entry, vma); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
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 Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Subject: [RFC PATCH v3 14/24] mm: Handle shadow stack page fault Date: Thu, 30 Aug 2018 07:38:54 -0700 [thread overview] Message-ID: <20180830143904.3168-15-yu-cheng.yu@intel.com> (raw) In-Reply-To: <20180830143904.3168-1-yu-cheng.yu@intel.com> When a task does fork(), its shadow stack must be duplicated for the child. However, the child may not actually use all pages of of the copied shadow stack. This patch implements a flow that is similar to copy-on-write of an anonymous page, but for shadow stack memory. A shadow stack PTE needs to be RO and dirty. We use this dirty bit requirement to effect the copying of shadow stack pages. In copy_one_pte(), we clear the dirty bit from the shadow stack PTE. On the next shadow stack access to the PTE, a page fault occurs. At that time, we then copy/re-use the page and fix the PTE. Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> --- arch/x86/mm/pgtable.c | 10 ++++++++++ include/asm-generic/pgtable.h | 7 +++++++ mm/memory.c | 3 +++ 3 files changed, 20 insertions(+) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index e848a4811785..c63261128ac3 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -872,3 +872,13 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) #endif /* CONFIG_X86_64 */ #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ + +#ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER +inline pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_SHSTK) + return pte_mkdirty_shstk(pte); + else + return pte; +} +#endif /* CONFIG_X86_INTEL_SHADOW_STACK_USER */ diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index aa5271717126..558a485617cd 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -1146,6 +1146,13 @@ static inline bool pmd_dirty_hw(pmd_t pmd) { return false; } + +static inline pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma) +{ + return pte; +} +#else +pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma); #endif #endif /* _ASM_GENERIC_PGTABLE_H */ diff --git a/mm/memory.c b/mm/memory.c index c467102a5cbc..9b4e11944b5d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2462,6 +2462,7 @@ static inline void wp_page_reuse(struct vm_fault *vmf) flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = pte_mkyoung(vmf->orig_pte); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + entry = pte_set_vma_features(entry, vma); if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) update_mmu_cache(vma, vmf->address, vmf->pte); pte_unmap_unlock(vmf->pte, vmf->ptl); @@ -2535,6 +2536,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = mk_pte(new_page, vma->vm_page_prot); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + entry = pte_set_vma_features(entry, vma); /* * Clear the pte entry and flush it first, before updating the * pte with the new entry. This will avoid a race condition @@ -3187,6 +3189,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) entry = mk_pte(page, vma->vm_page_prot); if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry)); + entry = pte_set_vma_features(entry, vma); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); -- 2.17.1
next prev parent reply other threads:[~2018-08-30 14:44 UTC|newest] Thread overview: 167+ 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 ` 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 ` 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 ` 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 ` 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 ` Yu-cheng Yu 2018-08-30 14:38 ` [RFC PATCH v3 05/24] Documentation/x86: Add CET description Yu-cheng Yu 2018-08-30 14:38 ` Yu-cheng Yu 2018-08-30 20:39 ` Pavel Machek 2018-08-30 20:39 ` Pavel Machek 2018-08-30 22:49 ` Yu-cheng Yu 2018-08-30 22:49 ` Yu-cheng Yu 2018-08-30 22:49 ` Yu-cheng Yu 2018-09-14 21:17 ` Yu-cheng Yu 2018-09-14 21:17 ` Yu-cheng Yu 2018-09-14 21:17 ` Yu-cheng Yu 2018-09-03 2:56 ` Randy Dunlap 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 2018-08-30 14:38 ` Yu-cheng Yu 2018-08-31 15:01 ` Jann Horn 2018-08-31 15:01 ` Jann Horn 2018-08-31 16:20 ` Yu-cheng Yu 2018-08-31 16:20 ` Yu-cheng Yu 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 ` 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 ` 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 ` 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 ` 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 ` 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 14:38 ` Yu-cheng Yu 2018-08-30 15:49 ` Jann Horn 2018-08-30 15:49 ` Jann Horn 2018-08-30 16:02 ` Yu-cheng Yu 2018-08-30 16:02 ` Yu-cheng Yu 2018-08-30 16:02 ` Yu-cheng Yu 2018-08-30 16:08 ` Dave Hansen 2018-08-30 16:08 ` Dave Hansen 2018-08-30 16:23 ` Jann Horn 2018-08-30 16:23 ` Jann Horn 2018-08-30 17:19 ` Dave Hansen 2018-08-30 17:19 ` Dave Hansen 2018-08-30 17:26 ` Yu-cheng Yu 2018-08-30 17:26 ` Yu-cheng Yu 2018-08-30 17:26 ` Yu-cheng Yu 2018-08-30 17:33 ` Dave Hansen 2018-08-30 17:33 ` Dave Hansen 2018-08-30 17:54 ` Yu-cheng Yu 2018-08-30 17:54 ` Yu-cheng Yu 2018-08-30 17:54 ` Yu-cheng Yu 2018-08-30 17:59 ` Jann Horn 2018-08-30 17:59 ` Jann Horn 2018-08-30 20:21 ` Yu-cheng Yu 2018-08-30 20:21 ` Yu-cheng Yu 2018-08-30 20:21 ` Yu-cheng Yu 2018-08-30 20:44 ` Jann Horn 2018-08-30 20:44 ` Jann Horn 2018-08-30 20:52 ` Yu-cheng Yu 2018-08-30 20:52 ` Yu-cheng Yu 2018-08-30 20:52 ` Yu-cheng Yu 2018-08-30 21:01 ` Jann Horn 2018-08-30 21:01 ` Jann Horn 2018-08-30 21:47 ` Jann Horn 2018-08-30 21:47 ` Jann Horn 2018-08-31 9:53 ` Peter Zijlstra 2018-08-31 9:53 ` Peter Zijlstra 2018-08-31 14:33 ` Yu-cheng Yu 2018-08-31 14:33 ` Yu-cheng Yu 2018-08-31 14:33 ` Yu-cheng Yu 2018-08-31 14:47 ` Dave Hansen 2018-08-31 14:47 ` Dave Hansen 2018-08-31 15:48 ` Yu-cheng Yu 2018-08-31 15:48 ` Yu-cheng Yu 2018-08-31 15:48 ` Yu-cheng Yu 2018-08-31 15:58 ` Dave Hansen 2018-08-31 15:58 ` Dave Hansen 2018-08-31 16:29 ` Peter Zijlstra 2018-08-31 16:29 ` Peter Zijlstra 2018-09-14 20:39 ` Yu-cheng Yu 2018-09-14 20:39 ` Yu-cheng Yu 2018-09-14 20:39 ` Yu-cheng Yu 2018-09-14 20:46 ` Dave Hansen 2018-09-14 20:46 ` Dave Hansen 2018-09-14 20:46 ` Dave Hansen 2018-09-14 21:08 ` Yu-cheng Yu 2018-09-14 21:08 ` Yu-cheng Yu 2018-09-14 21:08 ` Yu-cheng Yu 2018-09-14 21:33 ` Dave Hansen 2018-09-14 21:33 ` Dave Hansen 2018-09-14 21:33 ` Dave Hansen 2018-08-31 1:23 ` Andy Lutomirski 2018-08-31 1:23 ` Andy Lutomirski 2018-08-30 17:34 ` Andy Lutomirski 2018-08-30 17:34 ` Andy Lutomirski 2018-08-30 18:55 ` Dave Hansen 2018-08-30 18:55 ` Dave Hansen 2018-08-31 17:46 ` Andy Lutomirski 2018-08-31 17:46 ` Andy Lutomirski 2018-08-31 17:52 ` Dave Hansen 2018-08-31 17:52 ` Dave Hansen 2018-08-31 17:52 ` Dave Hansen 2018-08-30 19:59 ` Randy Dunlap 2018-08-30 19:59 ` Randy Dunlap 2018-08-30 20:23 ` Yu-cheng Yu 2018-08-30 20:23 ` Yu-cheng Yu 2018-08-30 20:23 ` Yu-cheng Yu 2018-08-31 16:29 ` Dave Hansen 2018-08-31 16:29 ` Dave Hansen 2018-08-30 14:38 ` [RFC PATCH v3 13/24] x86/mm: Shadow stack page fault error checking Yu-cheng Yu 2018-08-30 14:38 ` Yu-cheng Yu 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 ` 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 ` 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 ` 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 14:38 ` Yu-cheng Yu 2018-08-30 16:10 ` Jann Horn 2018-08-30 16:10 ` Jann Horn 2018-08-30 16:20 ` Yu-cheng Yu 2018-08-30 16:20 ` Yu-cheng Yu 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 14:38 ` Yu-cheng Yu 2018-08-30 15:39 ` Jann Horn 2018-08-30 15:39 ` Jann Horn 2018-08-30 15:55 ` Andy Lutomirski 2018-08-30 15:55 ` Andy Lutomirski 2018-08-30 16:22 ` Yu-cheng Yu 2018-08-30 16:22 ` Yu-cheng Yu 2018-08-30 16:22 ` Yu-cheng Yu 2018-08-31 21:49 ` Yu-cheng Yu 2018-08-31 21:49 ` Yu-cheng Yu 2018-08-31 21:49 ` Yu-cheng Yu 2018-08-31 22:16 ` Andy Lutomirski 2018-08-31 22:16 ` Andy Lutomirski 2018-09-14 20:46 ` Yu-cheng Yu 2018-09-14 20:46 ` Yu-cheng Yu 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 ` 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 ` 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 ` 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 ` 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 2018-08-30 14:39 ` Yu-cheng Yu 2018-09-02 8:13 ` [RFC PATCH v3 00/24] Control Flow Enforcement: Shadow Stack Balbir Singh 2018-09-02 8:13 ` Balbir Singh 2018-09-04 14:47 ` Yu-cheng Yu 2018-09-04 14:47 ` Yu-cheng Yu 2018-09-04 14:47 ` Yu-cheng Yu
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