| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20220405014926.15101-1-peterx@redhat.com>
Date: Mon, 4 Apr 2022 21:49:26 -0400
From: Peter Xu <peterx@...hat.com>
To: linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc: Mike Kravetz <mike.kravetz@...cle.com>,
Nadav Amit <nadav.amit@...il.com>,
Matthew Wilcox <willy@...radead.org>,
Mike Rapoport <rppt@...ux.vnet.ibm.com>,
David Hildenbrand <david@...hat.com>,
Hugh Dickins <hughd@...gle.com>,
Jerome Glisse <jglisse@...hat.com>,
"Kirill A . Shutemov" <kirill@...temov.name>,
Andrea Arcangeli <aarcange@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Axel Rasmussen <axelrasmussen@...gle.com>,
Alistair Popple <apopple@...dia.com>, peterx@...hat.com
Subject: [PATCH v8 21/23] mm/uffd: Enable write protection for shmem & hugetlbfs
We've had all the necessary changes ready for both shmem and hugetlbfs. Turn
on all the shmem/hugetlbfs switches for userfaultfd-wp.
We can expand UFFD_API_RANGE_IOCTLS_BASIC with _UFFDIO_WRITEPROTECT too because
all existing types now support write protection mode.
Since vma_can_userfault() will be used elsewhere, move into userfaultfd_k.h.
Signed-off-by: Peter Xu <peterx@...hat.com>
---
fs/userfaultfd.c | 21 +++------------------
include/linux/userfaultfd_k.h | 20 ++++++++++++++++++++
include/uapi/linux/userfaultfd.h | 10 ++++++++--
mm/userfaultfd.c | 9 +++------
4 files changed, 34 insertions(+), 26 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 8b4a94f5a238..fb45522a2b44 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1257,24 +1257,6 @@ static __always_inline int validate_range(struct mm_struct *mm,
return 0;
}
-static inline bool vma_can_userfault(struct vm_area_struct *vma,
- unsigned long vm_flags)
-{
- /* FIXME: add WP support to hugetlbfs and shmem */
- if (vm_flags & VM_UFFD_WP) {
- if (is_vm_hugetlb_page(vma) || vma_is_shmem(vma))
- return false;
- }
-
- if (vm_flags & VM_UFFD_MINOR) {
- if (!(is_vm_hugetlb_page(vma) || vma_is_shmem(vma)))
- return false;
- }
-
- return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
- vma_is_shmem(vma);
-}
-
static int userfaultfd_register(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
@@ -1955,6 +1937,9 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
#endif
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
+#endif
+#ifndef CONFIG_PTE_MARKER_UFFD_WP
+ uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM;
#endif
uffdio_api.ioctls = UFFD_API_IOCTLS;
ret = -EFAULT;
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 827e38b7be65..ea11bed9bb7e 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -18,6 +18,7 @@
#include <linux/swap.h>
#include <linux/swapops.h>
#include <asm-generic/pgtable_uffd.h>
+#include <linux/hugetlb_inline.h>
/* The set of all possible UFFD-related VM flags. */
#define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR)
@@ -140,6 +141,25 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma)
return vma->vm_flags & __VM_UFFD_FLAGS;
}
+static inline bool vma_can_userfault(struct vm_area_struct *vma,
+ unsigned long vm_flags)
+{
+ if (vm_flags & VM_UFFD_MINOR)
+ return is_vm_hugetlb_page(vma) || vma_is_shmem(vma);
+
+#ifndef CONFIG_PTE_MARKER_UFFD_WP
+ /*
+ * If user requested uffd-wp but not enabled pte markers for
+ * uffd-wp, then shmem & hugetlbfs are not supported but only
+ * anonymous.
+ */
+ if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma))
+ return false;
+#endif
+ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
+ vma_is_shmem(vma);
+}
+
extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
extern void dup_userfaultfd_complete(struct list_head *);
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index ef739054cb1c..7d32b1e797fb 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -33,7 +33,8 @@
UFFD_FEATURE_THREAD_ID | \
UFFD_FEATURE_MINOR_HUGETLBFS | \
UFFD_FEATURE_MINOR_SHMEM | \
- UFFD_FEATURE_EXACT_ADDRESS)
+ UFFD_FEATURE_EXACT_ADDRESS | \
+ UFFD_FEATURE_WP_HUGETLBFS_SHMEM)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -47,7 +48,8 @@
#define UFFD_API_RANGE_IOCTLS_BASIC \
((__u64)1 << _UFFDIO_WAKE | \
(__u64)1 << _UFFDIO_COPY | \
- (__u64)1 << _UFFDIO_CONTINUE)
+ (__u64)1 << _UFFDIO_CONTINUE | \
+ (__u64)1 << _UFFDIO_WRITEPROTECT)
/*
* Valid ioctl command number range with this API is from 0x00 to
@@ -194,6 +196,9 @@ struct uffdio_api {
* UFFD_FEATURE_EXACT_ADDRESS indicates that the exact address of page
* faults would be provided and the offset within the page would not be
* masked.
+ *
+ * UFFD_FEATURE_WP_HUGETLBFS_SHMEM indicates that userfaultfd
+ * write-protection mode is supported on both shmem and hugetlbfs.
*/
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
#define UFFD_FEATURE_EVENT_FORK (1<<1)
@@ -207,6 +212,7 @@ struct uffdio_api {
#define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9)
#define UFFD_FEATURE_MINOR_SHMEM (1<<10)
#define UFFD_FEATURE_EXACT_ADDRESS (1<<11)
+#define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1<<12)
__u64 features;
__u64 ioctls;
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 58d67f2bf980..156e9bdf9f23 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -730,15 +730,12 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
err = -ENOENT;
dst_vma = find_dst_vma(dst_mm, start, len);
- /*
- * Make sure the vma is not shared, that the dst range is
- * both valid and fully within a single existing vma.
- */
- if (!dst_vma || (dst_vma->vm_flags & VM_SHARED))
+
+ if (!dst_vma)
goto out_unlock;
if (!userfaultfd_wp(dst_vma))
goto out_unlock;
- if (!vma_is_anonymous(dst_vma))
+ if (!vma_can_userfault(dst_vma, dst_vma->vm_flags))
goto out_unlock;
if (is_vm_hugetlb_page(dst_vma)) {
--
2.32.0
Powered by blists - more mailing lists