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authorPeter Xu <peterx@redhat.com>2021-06-30 18:49:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-30 20:47:27 -0700
commit00b151f21f390f1e0b294720a3660506abaf49cd (patch)
treee66aa23dd80c0e249d7646b1626dc7d5e0e46bc1 /fs/userfaultfd.c
parent8f34f1eac3820fc2722e5159acceb22545b30b0d (diff)
mm/userfaultfd: fail uffd-wp registration if not supported
We should fail uffd-wp registration immediately if the arch does not even have CONFIG_HAVE_ARCH_USERFAULTFD_WP defined. That'll block also relevant ioctls on e.g. UFFDIO_WRITEPROTECT because that'll check against VM_UFFD_WP, which can only be applied with a success registration. Remove the WP feature bit too for those archs when handling UFFDIO_API ioctl. Link: https://lkml.kernel.org/r/20210428225030.9708-5-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Oliver Upton <oupton@google.com> Cc: Shaohua Li <shli@fb.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Wang Qing <wangqing@vivo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/userfaultfd.c')
-rw-r--r--fs/userfaultfd.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 14f92285d04f..5dd78238cc15 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1304,8 +1304,12 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
vm_flags = 0;
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING)
vm_flags |= VM_UFFD_MISSING;
- if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP)
+ if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) {
+#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
+ goto out;
+#endif
vm_flags |= VM_UFFD_WP;
+ }
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) {
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
goto out;
@@ -1943,6 +1947,9 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
uffdio_api.features &= ~UFFD_FEATURE_MINOR_HUGETLBFS;
#endif
+#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
+ uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
+#endif
uffdio_api.ioctls = UFFD_API_IOCTLS;
ret = -EFAULT;
if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))