From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Brian Geffon <bgeffon@google.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
David Hildenbrand <david@redhat.com>,
peterx@redhat.com, Martin Cracauer <cracauer@cons.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Mel Gorman <mgorman@suse.de>,
Bobby Powers <bobbypowers@gmail.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Maya Gokhale <gokhale2@llnl.gov>,
Johannes Weiner <hannes@cmpxchg.org>,
Marty McFadden <mcfadden8@llnl.gov>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Hugh Dickins <hughd@google.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Jerome Glisse <jglisse@redhat.com>
Subject: [PATCH v6 17/19] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally
Date: Thu, 20 Feb 2020 11:31:10 -0500 [thread overview]
Message-ID: <20200220163112.11409-18-peterx@redhat.com> (raw)
In-Reply-To: <20200220163112.11409-1-peterx@redhat.com>
Only declare _UFFDIO_WRITEPROTECT if the user specified
UFFDIO_REGISTER_MODE_WP and if all the checks passed. Then when the
user registers regions with shmem/hugetlbfs we won't expose the new
ioctl to them. Even with complete anonymous memory range, we'll only
expose the new WP ioctl bit if the register mode has MODE_WP.
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/userfaultfd.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 6e878d23547c..e39fdec8a0b0 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1495,14 +1495,24 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
up_write(&mm->mmap_sem);
mmput(mm);
if (!ret) {
+ __u64 ioctls_out;
+
+ ioctls_out = basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
+ UFFD_API_RANGE_IOCTLS;
+
+ /*
+ * Declare the WP ioctl only if the WP mode is
+ * specified and all checks passed with the range
+ */
+ if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_WP))
+ ioctls_out &= ~((__u64)1 << _UFFDIO_WRITEPROTECT);
+
/*
* Now that we scanned all vmas we can already tell
* userland which ioctls methods are guaranteed to
* succeed on this range.
*/
- if (put_user(basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
- UFFD_API_RANGE_IOCTLS,
- &user_uffdio_register->ioctls))
+ if (put_user(ioctls_out, &user_uffdio_register->ioctls))
ret = -EFAULT;
}
out:
--
2.24.1
next prev parent reply other threads:[~2020-02-20 16:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 16:30 [PATCH v6 00/19] userfaultfd: write protection support Peter Xu
2020-02-20 16:30 ` [PATCH v6 01/19] userfaultfd: wp: add helper for writeprotect check Peter Xu
2020-02-20 16:30 ` [PATCH v6 02/19] userfaultfd: wp: hook userfault handler to write protection fault Peter Xu
2020-02-20 16:30 ` [PATCH v6 03/19] userfaultfd: wp: add WP pagetable tracking to x86 Peter Xu
2020-02-20 16:30 ` [PATCH v6 04/19] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers Peter Xu
2020-02-20 16:30 ` [PATCH v6 05/19] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Peter Xu
2020-02-20 16:30 ` [PATCH v6 06/19] mm: merge parameters for change_protection() Peter Xu
2020-02-20 16:31 ` [PATCH v6 07/19] userfaultfd: wp: apply _PAGE_UFFD_WP bit Peter Xu
2020-02-20 16:31 ` [PATCH v6 08/19] userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork Peter Xu
2020-02-20 16:31 ` [PATCH v6 09/19] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers Peter Xu
2020-02-20 16:31 ` [PATCH v6 10/19] userfaultfd: wp: support swap and page migration Peter Xu
2020-02-20 16:31 ` [PATCH v6 11/19] khugepaged: skip collapse if uffd-wp detected Peter Xu
2020-02-20 16:31 ` [PATCH v6 12/19] userfaultfd: wp: support write protection for userfault vma range Peter Xu
2020-02-20 16:31 ` [PATCH v6 13/19] userfaultfd: wp: add the writeprotect API to userfaultfd ioctl Peter Xu
2020-02-20 16:31 ` [PATCH v6 14/19] userfaultfd: wp: enabled write protection in userfaultfd API Peter Xu
2020-02-20 16:31 ` [PATCH v6 15/19] userfaultfd: wp: don't wake up when doing write protect Peter Xu
2020-02-20 16:31 ` [PATCH v6 16/19] userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update Peter Xu
2020-02-20 16:31 ` Peter Xu [this message]
2020-02-20 16:31 ` [PATCH v6 18/19] userfaultfd: selftests: refactor statistics Peter Xu
2020-02-20 16:31 ` [PATCH v6 19/19] userfaultfd: selftests: add write-protect test Peter Xu
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