X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=include%2Flinux%2Fcred.h;h=3282ee4318e7b98791fae49bac5510114d8f1420;hb=c3d06f9ce8544fecfe13e377d1e2c2e47fe18dbc;hp=62b9e532422d2214735f57708f01446525632ce6;hpb=bb952bb98a7e479262c7eb25d5592545a3af147d;p=linux-2.6-omap-h63xx.git

diff --git a/include/linux/cred.h b/include/linux/cred.h
index 62b9e532422..3282ee4318e 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -1,4 +1,4 @@
-/* Credentials management
+/* Credentials management - see Documentation/credentials.txt
  *
  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
@@ -18,6 +18,7 @@
 
 struct user_struct;
 struct cred;
+struct inode;
 
 /*
  * COW Supplementary groups list
@@ -59,6 +60,7 @@ do {							\
 } while (0)
 
 extern struct group_info *groups_alloc(int);
+extern struct group_info init_groups;
 extern void groups_free(struct group_info *);
 extern int set_current_groups(struct group_info *);
 extern int set_groups(struct cred *, struct group_info *);
@@ -137,11 +139,36 @@ struct cred {
 	struct user_struct *user;	/* real user ID subscription */
 	struct group_info *group_info;	/* supplementary groups for euid/fsgid */
 	struct rcu_head	rcu;		/* RCU deletion hook */
-	spinlock_t	lock;		/* lock for pointer changes */
 };
 
 extern void __put_cred(struct cred *);
 extern int copy_creds(struct task_struct *, unsigned long);
+extern struct cred *prepare_creds(void);
+extern struct cred *prepare_exec_creds(void);
+extern struct cred *prepare_usermodehelper_creds(void);
+extern int commit_creds(struct cred *);
+extern void abort_creds(struct cred *);
+extern const struct cred *override_creds(const struct cred *);
+extern void revert_creds(const struct cred *);
+extern struct cred *prepare_kernel_cred(struct task_struct *);
+extern int change_create_files_as(struct cred *, struct inode *);
+extern int set_security_override(struct cred *, u32);
+extern int set_security_override_from_ctx(struct cred *, const char *);
+extern int set_create_files_as(struct cred *, struct inode *);
+extern void __init cred_init(void);
+
+/**
+ * get_new_cred - Get a reference on a new set of credentials
+ * @cred: The new credentials to reference
+ *
+ * Get a reference on the specified set of new credentials.  The caller must
+ * release the reference.
+ */
+static inline struct cred *get_new_cred(struct cred *cred)
+{
+	atomic_inc(&cred->usage);
+	return cred;
+}
 
 /**
  * get_cred - Get a reference on a set of credentials
@@ -149,11 +176,16 @@ extern int copy_creds(struct task_struct *, unsigned long);
  *
  * Get a reference on the specified set of credentials.  The caller must
  * release the reference.
+ *
+ * This is used to deal with a committed set of credentials.  Although the
+ * pointer is const, this will temporarily discard the const and increment the
+ * usage count.  The purpose of this is to attempt to catch at compile time the
+ * accidental alteration of a set of credentials that should be considered
+ * immutable.
  */
-static inline struct cred *get_cred(struct cred *cred)
+static inline const struct cred *get_cred(const struct cred *cred)
 {
-	atomic_inc(&cred->usage);
-	return cred;
+	return get_new_cred((struct cred *) cred);
 }
 
 /**
@@ -162,41 +194,47 @@ static inline struct cred *get_cred(struct cred *cred)
  *
  * Release a reference to a set of credentials, deleting them when the last ref
  * is released.
+ *
+ * This takes a const pointer to a set of credentials because the credentials
+ * on task_struct are attached by const pointers to prevent accidental
+ * alteration of otherwise immutable credential sets.
  */
 static inline void put_cred(const struct cred *_cred)
 {
 	struct cred *cred = (struct cred *) _cred;
+
+	BUG_ON(atomic_read(&(cred)->usage) <= 0);
 	if (atomic_dec_and_test(&(cred)->usage))
 		__put_cred(cred);
 }
 
 /**
- * current_cred - Access the current task's credentials
+ * current_cred - Access the current task's subjective credentials
  *
- * Access the credentials of the current task.
+ * Access the subjective credentials of the current task.
  */
 #define current_cred() \
 	(current->cred)
 
 /**
- * __task_cred - Access another task's credentials
+ * __task_cred - Access a task's objective credentials
  * @task: The task to query
  *
- * Access the credentials of another task.  The caller must hold the
- * RCU readlock.
+ * Access the objective credentials of a task.  The caller must hold the RCU
+ * readlock.
  *
  * The caller must make sure task doesn't go away, either by holding a ref on
  * task or by holding tasklist_lock to prevent it from being unlinked.
  */
 #define __task_cred(task) \
-	((const struct cred *)(rcu_dereference((task)->cred)))
+	((const struct cred *)(rcu_dereference((task)->real_cred)))
 
 /**
- * get_task_cred - Get another task's credentials
+ * get_task_cred - Get another task's objective credentials
  * @task: The task to query
  *
- * Get the credentials of a task, pinning them so that they can't go away.
- * Accessing a task's credentials directly is not permitted.
+ * Get the objective credentials of a task, pinning them so that they can't go
+ * away.  Accessing a task's credentials directly is not permitted.
  *
  * The caller must make sure task doesn't go away, either by holding a ref on
  * task or by holding tasklist_lock to prevent it from being unlinked.
@@ -212,10 +250,11 @@ static inline void put_cred(const struct cred *_cred)
 })
 
 /**
- * get_current_cred - Get the current task's credentials
+ * get_current_cred - Get the current task's subjective credentials
  *
- * Get the credentials of the current task, pinning them so that they can't go
- * away.  Accessing the current task's credentials directly is not permitted.
+ * Get the subjective credentials of the current task, pinning them so that
+ * they can't go away.  Accessing the current task's credentials directly is
+ * not permitted.
  */
 #define get_current_cred()				\
 	(get_cred(current_cred()))
@@ -250,13 +289,13 @@ static inline void put_cred(const struct cred *_cred)
 	__groups;					\
 })
 
-#define task_cred_xxx(task, xxx)		\
-({						\
-	__typeof__(task->cred->xxx) ___val;	\
-	rcu_read_lock();			\
-	___val = __task_cred((task))->xxx;	\
-	rcu_read_unlock();			\
-	___val;					\
+#define task_cred_xxx(task, xxx)			\
+({							\
+	__typeof__(((struct cred *)NULL)->xxx) ___val;	\
+	rcu_read_lock();				\
+	___val = __task_cred((task))->xxx;		\
+	rcu_read_unlock();				\
+	___val;						\
 })
 
 #define task_uid(task)		(task_cred_xxx((task), uid))
@@ -277,6 +316,7 @@ static inline void put_cred(const struct cred *_cred)
 #define current_fsgid() 	(current_cred_xxx(fsgid))
 #define current_cap()		(current_cred_xxx(cap_effective))
 #define current_user()		(current_cred_xxx(user))
+#define current_user_ns()	(current_cred_xxx(user)->user_ns)
 #define current_security()	(current_cred_xxx(security))
 
 #define current_uid_gid(_uid, _gid)		\