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 19/28] mm: Update can_follow_write_pte() for shadow stack
Date: Wed, 10 Mar 2021 14:00:37 -0800 [thread overview]
Message-ID: <20210310220046.15866-20-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20210310220046.15866-1-yu-cheng.yu@intel.com>
Can_follow_write_pte() ensures a read-only page is COWed by checking the
FOLL_COW flag, and uses pte_dirty() to validate the flag is still valid.
Like a writable data page, a shadow stack page is writable, and becomes
read-only during copy-on-write, but it is always dirty. Thus, in the
can_follow_write_pte() check, it belongs to the writable page case and
should be excluded from the read-only page pte_dirty() check. Apply
the same changes to can_follow_write_pmd().
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
mm/gup.c | 8 +++++---
mm/huge_memory.c | 8 +++++---
2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index e40579624f10..4c6aa93b3c00 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -356,10 +356,12 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
* FOLL_FORCE can write to even unwritable pte's, but only
* after we've gone through a COW cycle and they are dirty.
*/
-static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
+static inline bool can_follow_write_pte(pte_t pte, unsigned int flags,
+ struct vm_area_struct *vma)
{
return pte_write(pte) ||
- ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
+ ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte) &&
+ !arch_shadow_stack_mapping(vma->vm_flags));
}
static struct page *follow_page_pte(struct vm_area_struct *vma,
@@ -402,7 +404,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
}
if ((flags & FOLL_NUMA) && pte_protnone(pte))
goto no_page;
- if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) {
+ if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags, vma)) {
pte_unmap_unlock(ptep, ptl);
return NULL;
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dfaaafa283a8..de8c8b94e840 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1342,10 +1342,12 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
* FOLL_FORCE can write to even unwritable pmd's, but only
* after we've gone through a COW cycle and they are dirty.
*/
-static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
+static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags,
+ struct vm_area_struct *vma)
{
return pmd_write(pmd) ||
- ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
+ ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd) &&
+ !arch_shadow_stack_mapping(vma->vm_flags));
}
struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
@@ -1358,7 +1360,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
assert_spin_locked(pmd_lockptr(mm, pmd));
- if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags))
+ if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags, vma))
goto out;
/* Avoid dumping huge zero page */
--
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 ` [PATCH v22 15/28] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
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 ` Yu-cheng Yu [this message]
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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