From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>, Maya Gokhale <gokhale2@llnl.gov>,
Jerome Glisse <jglisse@redhat.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
peterx@redhat.com, Martin Cracauer <cracauer@cons.org>,
Shaohua Li <shli@fb.com>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Marty McFadden <mcfadden8@llnl.gov>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Mel Gorman <mgorman@suse.de>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH v4 25/27] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally
Date: Fri, 26 Apr 2019 12:51:49 +0800 [thread overview]
Message-ID: <20190426045151.19556-26-peterx@redhat.com> (raw)
In-Reply-To: <20190426045151.19556-1-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 f1f61a0278c2..7f87e9e4fb9b 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1456,14 +1456,24 @@ 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:
--
2.17.1
next prev parent reply other threads:[~2019-04-26 4:55 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 4:51 [PATCH v4 00/27] userfaultfd: write protection support Peter Xu
2019-04-26 4:51 ` [PATCH v4 01/27] mm: gup: rename "nonblocking" to "locked" where proper Peter Xu
2019-04-26 4:51 ` [PATCH v4 02/27] mm: userfault: return VM_FAULT_RETRY on signals Peter Xu
2019-04-26 4:51 ` [PATCH v4 03/27] userfaultfd: don't retake mmap_sem to emulate NOPAGE Peter Xu
2019-04-26 4:51 ` [PATCH v4 04/27] mm: allow VM_FAULT_RETRY for multiple times Peter Xu
2019-04-26 4:51 ` [PATCH v4 05/27] mm: gup: " Peter Xu
2019-04-26 4:51 ` [PATCH v4 06/27] userfaultfd: wp: add helper for writeprotect check Peter Xu
2019-04-26 4:51 ` [PATCH v4 07/27] userfaultfd: wp: hook userfault handler to write protection fault Peter Xu
2019-04-26 4:51 ` [PATCH v4 08/27] userfaultfd: wp: add WP pagetable tracking to x86 Peter Xu
2019-04-26 4:51 ` [PATCH v4 09/27] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers Peter Xu
2019-04-26 4:51 ` [PATCH v4 10/27] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Peter Xu
2019-04-26 4:51 ` [PATCH v4 11/27] mm: merge parameters for change_protection() Peter Xu
2019-04-26 4:51 ` [PATCH v4 12/27] userfaultfd: wp: apply _PAGE_UFFD_WP bit Peter Xu
2019-04-26 4:51 ` [PATCH v4 13/27] mm: introduce do_wp_page_cont() Peter Xu
2019-04-26 4:51 ` [PATCH v4 14/27] userfaultfd: wp: handle COW properly for uffd-wp Peter Xu
2019-04-26 4:51 ` [PATCH v4 15/27] userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork Peter Xu
2019-04-26 4:51 ` [PATCH v4 16/27] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers Peter Xu
2019-04-26 4:51 ` [PATCH v4 17/27] userfaultfd: wp: support swap and page migration Peter Xu
2019-04-26 4:51 ` [PATCH v4 18/27] khugepaged: skip collapse if uffd-wp detected Peter Xu
2019-04-26 4:51 ` [PATCH v4 19/27] userfaultfd: introduce helper vma_find_uffd Peter Xu
2019-04-26 4:51 ` [PATCH v4 20/27] userfaultfd: wp: support write protection for userfault vma range Peter Xu
2019-04-26 4:51 ` [PATCH v4 21/27] userfaultfd: wp: add the writeprotect API to userfaultfd ioctl Peter Xu
2019-04-26 4:51 ` [PATCH v4 22/27] userfaultfd: wp: enabled write protection in userfaultfd API Peter Xu
2019-04-26 4:51 ` [PATCH v4 23/27] userfaultfd: wp: don't wake up when doing write protect Peter Xu
2019-04-26 4:51 ` [PATCH v4 24/27] userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update Peter Xu
2019-04-26 4:51 ` Peter Xu [this message]
2019-04-26 4:51 ` [PATCH v4 26/27] userfaultfd: selftests: refactor statistics Peter Xu
2019-04-26 4:51 ` [PATCH v4 27/27] userfaultfd: selftests: add write-protect test Peter Xu
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