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 <haitao.huang@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v22 15/28] x86/mm: Update maybe_mkwrite() for shadow stack
Date: Wed, 10 Mar 2021 14:00:33 -0800 [thread overview]
Message-ID: <20210310220046.15866-16-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20210310220046.15866-1-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 bdfecc17c2d3..102212025993 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1945,12 +1945,16 @@ 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
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 4adc8c7bef75..d739d339e1af 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -997,6 +997,8 @@ 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 cdfc4e9f253e..fb85ab22b5e5 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1442,6 +1442,30 @@ 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 395c75111d33..dfaaafa283a8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -482,6 +482,8 @@ 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:[~2021-03-10 22:02 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 22:00 [PATCH v22 00/28] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 01/28] Documentation/x86: Add CET description Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 02/28] x86/cet/shstk: Add Kconfig option for user-mode control-flow protection Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 03/28] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 04/28] x86/cpufeatures: Introduce X86_FEATURE_CET and setup functions Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 05/28] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 06/28] x86/cet: Add control-protection fault handler Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 07/28] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 08/28] x86/mm: Move pmd_write(), pud_write() up in the file Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 09/28] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 10/28] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 11/28] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 12/28] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 13/28] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 14/28] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2021-03-10 22:00 ` Yu-cheng Yu [this message]
2021-03-10 22:00 ` [PATCH v22 16/28] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 17/28] mm: Add guard pages around a shadow stack Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 18/28] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 19/28] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 20/28] mm/mprotect: Exclude shadow stack from preserve_write Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 21/28] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2021-10-14 16:15 ` Liam Howlett
2021-03-10 22:00 ` [PATCH v22 22/28] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 23/28] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 24/28] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 25/28] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 26/28] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 27/28] mm: Move arch_calc_vm_prot_bits() to arch/x86/include/asm/mman.h Yu-cheng Yu
2021-03-10 22:00 ` [PATCH v22 28/28] mm: Introduce PROT_SHSTK for shadow stack Yu-cheng Yu
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