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>,
Pengfei Xu <pengfei.xu@intel.com>, <haitao.huang@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v20 14/25] x86/mm: Update maybe_mkwrite() for shadow stack
Date: Wed, 10 Feb 2021 09:56:52 -0800 [thread overview]
Message-ID: <20210210175703.12492-15-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20210210175703.12492-1-yu-cheng.yu@intel.com>
When serving a page fault, maybe_mkwrite() makes a PTE writable if its vma
has VM_WRITE.
A shadow stack vma has VM_SHSTK. Its PTEs have _PAGE_DIRTY, but not
_PAGE_WRITE. In fork(), _PAGE_DIRTY is cleared to effect copy-on-write,
and in page fault, _PAGE_DIRTY is restored and the shadow stack page is
writable again.
Update maybe_mkwrite() by introducing arch_maybe_mkwrite(), which sets
_PAGE_DIRTY for a shadow stack PTE.
Apply the same changes to maybe_pmd_mkwrite().
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
arch/x86/Kconfig | 4 ++++
arch/x86/mm/pgtable.c | 18 ++++++++++++++++++
include/linux/mm.h | 2 ++
include/linux/pgtable.h | 24 ++++++++++++++++++++++++
mm/huge_memory.c | 2 ++
5 files changed, 50 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1138b5fa9b4f..4f0d159a8654 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1955,6 +1955,9 @@ config X86_SGX
config ARCH_HAS_SHADOW_STACK
def_bool n
+config ARCH_MAYBE_MKWRITE
+ def_bool n
+
config X86_CET
prompt "Intel Control-flow protection for user-mode"
def_bool n
@@ -1962,6 +1965,7 @@ config X86_CET
depends on AS_WRUSS
depends on ARCH_HAS_SHADOW_STACK
select ARCH_USES_HIGH_VMA_FLAGS
+ select ARCH_MAYBE_MKWRITE
help
Control-flow protection is a set of hardware features which place
additional restrictions on indirect branches. These help
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index f6a9e2e36642..0f4fbf51a9fc 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -610,6 +610,24 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
}
#endif
+#ifdef CONFIG_ARCH_MAYBE_MKWRITE
+pte_t arch_maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
+{
+ if (likely(vma->vm_flags & VM_SHSTK))
+ pte = pte_mkwrite_shstk(pte);
+ return pte;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
+{
+ if (likely(vma->vm_flags & VM_SHSTK))
+ pmd = pmd_mkwrite_shstk(pmd);
+ return pmd;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif /* CONFIG_ARCH_MAYBE_MKWRITE */
+
/**
* reserve_top_address - reserves a hole in the top of kernel address space
* @reserve - size of hole to reserve
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7be5f8b874aa..abd756e426fc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -993,6 +993,8 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
{
if (likely(vma->vm_flags & VM_WRITE))
pte = pte_mkwrite(pte);
+ else
+ pte = arch_maybe_mkwrite(pte, vma);
return pte;
}
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8fcdfa52eb4b..d8452218d09b 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1439,6 +1439,30 @@ static inline bool arch_has_pfn_modify_check(void)
}
#endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
+#ifdef CONFIG_MMU
+#ifdef CONFIG_ARCH_MAYBE_MKWRITE
+pte_t arch_maybe_mkwrite(pte_t pte, struct vm_area_struct *vma);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#else /* !CONFIG_ARCH_MAYBE_MKWRITE */
+static inline pte_t arch_maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
+{
+ return pte;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
+{
+ return pmd;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#endif /* CONFIG_ARCH_MAYBE_MKWRITE */
+#endif /* CONFIG_MMU */
+
/*
* Architecture PAGE_KERNEL_* fallbacks
*
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 91ca9b103ee5..ac651d529dbe 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -478,6 +478,8 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
{
if (likely(vma->vm_flags & VM_WRITE))
pmd = pmd_mkwrite(pmd);
+ else
+ pmd = arch_maybe_pmd_mkwrite(pmd, vma);
return pmd;
}
--
2.21.0
next prev parent reply other threads:[~2021-02-10 17:58 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-10 17:56 [PATCH v20 00/25] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 01/25] Documentation/x86: Add CET description Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 02/25] x86/cet/shstk: Add Kconfig option for user-mode control-flow protection Yu-cheng Yu
2021-02-10 19:33 ` Kees Cook
2021-02-10 19:40 ` Yu, Yu-cheng
2021-02-10 17:56 ` [PATCH v20 03/25] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 04/25] x86/cpufeatures: Introduce X86_FEATURE_CET and setup functions Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 05/25] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 06/25] x86/cet: Add control-protection fault handler Yu-cheng Yu
2021-02-10 19:34 ` Kees Cook
2021-02-10 19:48 ` Andy Lutomirski
2021-02-10 17:56 ` [PATCH v20 07/25] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Yu-cheng Yu
2021-02-10 19:35 ` Kees Cook
2021-02-10 17:56 ` [PATCH v20 08/25] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2021-02-10 19:42 ` Kees Cook
2021-02-10 20:28 ` Yu, Yu-cheng
2021-02-15 16:49 ` Yu, Yu-cheng
2021-02-10 17:56 ` [PATCH v20 09/25] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 10/25] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 11/25] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Yu-cheng Yu
2021-02-10 19:43 ` Kees Cook
2021-02-10 17:56 ` [PATCH v20 12/25] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 13/25] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2021-02-10 17:56 ` Yu-cheng Yu [this message]
2021-02-10 17:56 ` [PATCH v20 15/25] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 16/25] mm: Add guard pages around a shadow stack Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 17/25] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 18/25] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 19/25] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 20/25] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2021-02-10 17:56 ` [PATCH v20 21/25] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2021-02-10 19:58 ` Kees Cook
2021-02-10 21:38 ` Yu, Yu-cheng
2021-02-11 2:05 ` Kees Cook
2021-02-10 17:57 ` [PATCH v20 22/25] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2021-02-10 17:57 ` [PATCH v20 23/25] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2021-02-10 17:57 ` [PATCH v20 24/25] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2021-02-10 17:57 ` [PATCH v20 25/25] mm: Introduce PROT_SHSTK " Yu-cheng Yu
2021-02-10 19:46 ` Kees Cook
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