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Diffstat (limited to 'fs/userfaultfd.c')
-rw-r--r--fs/userfaultfd.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index d7f54e535294..37df7c9eedb1 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1460,7 +1460,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
- new_flags = (vma->vm_flags & ~vm_flags) | vm_flags;
+ new_flags = (vma->vm_flags &
+ ~(VM_UFFD_MISSING|VM_UFFD_WP)) | vm_flags;
prev = vma_merge(mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, vma->vm_pgoff,
vma_policy(vma),
@@ -1834,13 +1835,12 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api)))
goto out;
features = uffdio_api.features;
- if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES)) {
- memset(&uffdio_api, 0, sizeof(uffdio_api));
- if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
- goto out;
- ret = -EINVAL;
- goto out;
- }
+ ret = -EINVAL;
+ if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES))
+ goto err_out;
+ ret = -EPERM;
+ if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE))
+ goto err_out;
/* report all available features and ioctls to userland */
uffdio_api.features = UFFD_API_FEATURES;
uffdio_api.ioctls = UFFD_API_IOCTLS;
@@ -1853,6 +1853,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
ret = 0;
out:
return ret;
+err_out:
+ memset(&uffdio_api, 0, sizeof(uffdio_api));
+ if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
+ ret = -EFAULT;
+ goto out;
}
static long userfaultfd_ioctl(struct file *file, unsigned cmd,