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linux-next/include/linux/sched/user.h
Sebastian Andrzej Siewior fc37191272 userns: use refcount_t for reference counting instead atomic_t
refcount_t type and corresponding API should be used instead of atomic_t
wh en the variable is used as a reference counter.  This avoids accidental
refcounter overflows that might lead to use-after-free situations.

Link: http://lkml.kernel.org/r/20180703200141.28415-6-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:46 -07:00

69 lines
1.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCHED_USER_H
#define _LINUX_SCHED_USER_H
#include <linux/uidgid.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/ratelimit.h>
struct key;
/*
* Some day this will be a full-fledged user tracking system..
*/
struct user_struct {
refcount_t __count; /* reference count */
atomic_t processes; /* How many processes does this user have? */
atomic_t sigpending; /* How many pending signals does this user have? */
#ifdef CONFIG_FANOTIFY
atomic_t fanotify_listeners;
#endif
#ifdef CONFIG_EPOLL
atomic_long_t epoll_watches; /* The number of file descriptors currently watched */
#endif
#ifdef CONFIG_POSIX_MQUEUE
/* protected by mq_lock */
unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */
#endif
unsigned long locked_shm; /* How many pages of mlocked shm ? */
unsigned long unix_inflight; /* How many files in flight in unix sockets */
atomic_long_t pipe_bufs; /* how many pages are allocated in pipe buffers */
#ifdef CONFIG_KEYS
struct key *uid_keyring; /* UID specific keyring */
struct key *session_keyring; /* UID's default session keyring */
#endif
/* Hash table maintenance information */
struct hlist_node uidhash_node;
kuid_t uid;
#if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \
defined(CONFIG_NET)
atomic_long_t locked_vm;
#endif
/* Miscellaneous per-user rate limit */
struct ratelimit_state ratelimit;
};
extern int uids_sysfs_init(void);
extern struct user_struct *find_user(kuid_t);
extern struct user_struct root_user;
#define INIT_USER (&root_user)
/* per-UID process charging. */
extern struct user_struct * alloc_uid(kuid_t);
static inline struct user_struct *get_uid(struct user_struct *u)
{
refcount_inc(&u->__count);
return u;
}
extern void free_uid(struct user_struct *);
#endif /* _LINUX_SCHED_USER_H */