CRED: Pass credentials through dentry_open()

Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.

The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 7 insertions, 4 deletions

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 1151881ccb9a..d9393f8e4c3e 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -594,6 +594,7 @@ static int mq_attr_ok(struct mq_attr *attr)
 static struct file *do_create(struct dentry *dir, struct dentry *dentry,
                         int oflag, mode_t mode, struct mq_attr __user *u_attr)
 {
+        const struct cred *cred = current_cred();
         struct mq_attr attr;
         struct file *result;
         int ret;
@@ -618,7 +619,7 @@ static struct file *do_create(struct dentry *dir, struct dentry *dentry,
         if (ret)
                 goto out_drop_write;
 
-        result = dentry_open(dentry, mqueue_mnt, oflag);
+        result = dentry_open(dentry, mqueue_mnt, oflag, cred);
         /*
          * dentry_open() took a persistent mnt_want_write(),
          * so we can now drop this one.
@@ -637,8 +638,10 @@ out:
 /* Opens existing queue */
 static struct file *do_open(struct dentry *dentry, int oflag)
 {
-static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
-                                        MAY_READ | MAY_WRITE };
+        const struct cred *cred = current_cred();
+
+        static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
+                                                  MAY_READ | MAY_WRITE };
 
         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
                 dput(dentry);
@@ -652,7 +655,7 @@ static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
                 return ERR_PTR(-EACCES);
         }
 
-        return dentry_open(dentry, mqueue_mnt, oflag);
+        return dentry_open(dentry, mqueue_mnt, oflag, cred);
 }
 
 asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,