userfaultfd: open userfaultfds with O_RDONLY

[sfrench/cifs-2.6.git] / fs / userfaultfd.c

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 1c44bf75f9160cd509f684f0727c8a36be085527..e6ffe7bc59e33d48c142355772ce10cac00f360a 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -991,7 +991,7 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *new,
        int fd;
 
        fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, new,
-                       O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode);
+                       O_RDONLY | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode);
        if (fd < 0)
                return fd;
 
@@ -2090,7 +2090,7 @@ SYSCALL_DEFINE1(userfaultfd, int, flags)
        mmgrab(ctx->mm);
 
        fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, ctx,
-                       O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL);
+                       O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL);
        if (fd < 0) {
                mmdrop(ctx->mm);
                kmem_cache_free(userfaultfd_ctx_cachep, ctx);