[PATCH v2 4/6] Wire UFFD up to SELinux

[Daniel Colascione <dancol-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>]

This change gives userfaultfd file descriptors a real security
context, allowing policy to act on them.

Signed-off-by: Daniel Colascione <dancol-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
---
 fs/userfaultfd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 07b0f6e03849..11227b94a5a7 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1020,6 +1020,8 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *ctx,
 {
 	int fd;
 
+	/* Regular inode here is okay: only CAP_SYS_PTRACE callers
+	 * can monitor forks.  */
 	fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, new,
 			      O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS));
 	if (fd < 0)
@@ -1972,8 +1974,9 @@ SYSCALL_DEFINE1(userfaultfd, int, flags)
 	/* prevent the mm struct to be freed */
 	mmgrab(ctx->mm);
 
-	fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, ctx,
-			      O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS));
+	fd = anon_inode_getfd2("[userfaultfd]", &userfaultfd_fops, ctx,
+			       O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS),
+			       ANON_INODE_SECURE);
 	if (fd < 0) {
 		mmdrop(ctx->mm);
 		kmem_cache_free(userfaultfd_ctx_cachep, ctx);
-- 
2.25.0.225.g125e21ebc7-goog