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>

2 files changed, 7 insertions, 4 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index b3d404aaabed..3bfec1327b8d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -315,6 +315,7 @@ struct poll_table_struct;
 struct kstatfs;
 struct vm_area_struct;
 struct vfsmount;
+struct cred;
 
 extern void __init inode_init(void);
 extern void __init inode_init_early(void);
@@ -1673,7 +1674,8 @@ extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
                         int mode);
 extern struct file *filp_open(const char *, int, int);
-extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
+extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
+                                 const struct cred *);
 extern int filp_close(struct file *, fl_owner_t id);
 extern char * getname(const char __user *);
 
diff --git a/include/linux/security.h b/include/linux/security.h
index 9239cc11eb9c..7e9fe046a0d1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1402,7 +1402,7 @@ struct security_operations {
         int (*file_send_sigiotask) (struct task_struct *tsk,
                                     struct fown_struct *fown, int sig);
         int (*file_receive) (struct file *file);
-        int (*dentry_open) (struct file *file);
+        int (*dentry_open) (struct file *file, const struct cred *cred);
 
         int (*task_create) (unsigned long clone_flags);
         int (*cred_alloc_security) (struct cred *cred);
@@ -1658,7 +1658,7 @@ int security_file_set_fowner(struct file *file);
 int security_file_send_sigiotask(struct task_struct *tsk,
                                  struct fown_struct *fown, int sig);
 int security_file_receive(struct file *file);
-int security_dentry_open(struct file *file);
+int security_dentry_open(struct file *file, const struct cred *cred);
 int security_task_create(unsigned long clone_flags);
 int security_cred_alloc(struct cred *cred);
 void security_cred_free(struct cred *cred);
@@ -2171,7 +2171,8 @@ static inline int security_file_receive(struct file *file)
         return 0;
 }
 
-static inline int security_dentry_open(struct file *file)
+static inline int security_dentry_open(struct file *file,
+                                       const struct cred *cred)
 {
         return 0;
 }