linux-stable/include/linux/pid_namespace.h
Eric W. Biederman 69879c01a0 proc: Remove the now unnecessary internal mount of proc
There remains no more code in the kernel using pids_ns->proc_mnt,
therefore remove it from the kernel.

The big benefit of this change is that one of the most error prone and
tricky parts of the pid namespace implementation, maintaining kernel
mounts of proc is removed.

In addition removing the unnecessary complexity of the kernel mount
fixes a regression that caused the proc mount options to be ignored.
Now that the initial mount of proc comes from userspace, those mount
options are again honored.  This fixes Android's usage of the proc
hidepid option.

Reported-by: Alistair Strachan <astrachan@google.com>
Fixes: e94591d0d9 ("proc: Convert proc_mount to use mount_ns.")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-02-28 12:06:14 -06:00

103 lines
2.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PID_NS_H
#define _LINUX_PID_NS_H
#include <linux/sched.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
#include <linux/threads.h>
#include <linux/nsproxy.h>
#include <linux/kref.h>
#include <linux/ns_common.h>
#include <linux/idr.h>
/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
#define MAX_PID_NS_LEVEL 32
struct fs_pin;
enum { /* definitions for pid_namespace's hide_pid field */
HIDEPID_OFF = 0,
HIDEPID_NO_ACCESS = 1,
HIDEPID_INVISIBLE = 2,
};
struct pid_namespace {
struct kref kref;
struct idr idr;
struct rcu_head rcu;
unsigned int pid_allocated;
struct task_struct *child_reaper;
struct kmem_cache *pid_cachep;
unsigned int level;
struct pid_namespace *parent;
#ifdef CONFIG_PROC_FS
struct dentry *proc_self;
struct dentry *proc_thread_self;
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
struct fs_pin *bacct;
#endif
struct user_namespace *user_ns;
struct ucounts *ucounts;
kgid_t pid_gid;
int hide_pid;
int reboot; /* group exit code if this pidns was rebooted */
struct ns_common ns;
} __randomize_layout;
extern struct pid_namespace init_pid_ns;
#define PIDNS_ADDING (1U << 31)
#ifdef CONFIG_PID_NS
static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
{
if (ns != &init_pid_ns)
kref_get(&ns->kref);
return ns;
}
extern struct pid_namespace *copy_pid_ns(unsigned long flags,
struct user_namespace *user_ns, struct pid_namespace *ns);
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
extern void put_pid_ns(struct pid_namespace *ns);
#else /* !CONFIG_PID_NS */
#include <linux/err.h>
static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
{
return ns;
}
static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
struct user_namespace *user_ns, struct pid_namespace *ns)
{
if (flags & CLONE_NEWPID)
ns = ERR_PTR(-EINVAL);
return ns;
}
static inline void put_pid_ns(struct pid_namespace *ns)
{
}
static inline void zap_pid_ns_processes(struct pid_namespace *ns)
{
BUG();
}
static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
{
return 0;
}
#endif /* CONFIG_PID_NS */
extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
void pidhash_init(void);
void pid_idr_init(void);
#endif /* _LINUX_PID_NS_H */