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>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v16 14/26] x86/mm: Update maybe_mkwrite() for shadow stack
Date: Wed, 9 Dec 2020 14:23:08 -0800 [thread overview]
Message-ID: <20201209222320.1724-15-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20201209222320.1724-1-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>
---
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 78b4b5bb1272..876d26894434 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1934,6 +1934,9 @@ endchoice
config ARCH_HAS_SHADOW_STACK
def_bool n
+config ARCH_MAYBE_MKWRITE
+ def_bool n
+
config X86_CET_USER
prompt "Intel Control-flow protection for user-mode"
def_bool n
@@ -1941,6 +1944,7 @@ config X86_CET_USER
depends on AS_WRUSS
select ARCH_USES_HIGH_VMA_FLAGS
select ARCH_HAS_SHADOW_STACK
+ select ARCH_MAYBE_MKWRITE
help
Control-flow protection is a hardware security hardening feature
that detects function-return address or jump target changes by
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index dfd82f51ba66..a9666b64bc05 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 ab11e47945ee..b111f23a1be9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -977,6 +977,8 @@ 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 e237004d498d..f62b96d74689 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1384,6 +1384,30 @@ 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 ec2bb93f7431..b2160abf256d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -464,6 +464,8 @@ 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:[~2020-12-09 22:39 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 22:22 [PATCH v16 00/26] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2020-12-09 22:22 ` [PATCH v16 01/26] Documentation/x86: Add CET description Yu-cheng Yu
2020-12-09 22:22 ` [PATCH v16 02/26] x86/cet/shstk: Add Kconfig option for user-mode control-flow protection Yu-cheng Yu
2020-12-29 12:39 ` Borislav Petkov
2020-12-29 16:34 ` Yu, Yu-cheng
2020-12-29 18:54 ` Borislav Petkov
2020-12-29 19:45 ` Yu, Yu-cheng
2020-12-09 22:22 ` [PATCH v16 03/26] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2020-12-09 22:22 ` [PATCH v16 04/26] x86/cpufeatures: Introduce X86_FEATURE_CET and setup functions Yu-cheng Yu
2020-12-09 22:22 ` [PATCH v16 05/26] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 06/26] x86/cet: Add control-protection fault handler Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 07/26] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 08/26] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 09/26] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 10/26] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 11/26] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 12/26] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 13/26] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2020-12-09 22:23 ` Yu-cheng Yu [this message]
2020-12-09 22:23 ` [PATCH v16 15/26] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 16/26] mm: Add guard pages around a shadow stack Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 17/26] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 18/26] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 19/26] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 20/26] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 21/26] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 22/26] binfmt_elf: Define GNU_PROPERTY_X86_FEATURE_1_AND properties Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 23/26] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 24/26] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 25/26] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2020-12-09 22:23 ` [PATCH v16 26/26] mm: Introduce PROT_SHSTK " Yu-cheng Yu
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