include/linux/pid_namespace.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_PID_NS_H
   3 #define _LINUX_PID_NS_H
   4
   5 #include <linux/sched.h>
   6 #include <linux/bug.h>
   7 #include <linux/mm.h>
   8 #include <linux/workqueue.h>
   9 #include <linux/threads.h>
  10 #include <linux/nsproxy.h>
  11 #include <linux/ns_common.h>
  12 #include <linux/idr.h>
  13
  14 /* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
  15 #define MAX_PID_NS_LEVEL 32
  16
  17 struct fs_pin;
  18
  19 #if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
  20 /* modes for vm.memfd_noexec sysctl */
  21 #define MEMFD_NOEXEC_SCOPE_EXEC                 0 /* MFD_EXEC implied if unset */
  22 #define MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL          1 /* MFD_NOEXEC_SEAL implied if unset */
  23 #define MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED      2 /* same as 1, except MFD_EXEC rejected */
  24 #endif
  25
  26 struct pid_namespace {
  27         struct idr idr;
  28         struct rcu_head rcu;
  29         unsigned int pid_allocated;
  30         struct task_struct *child_reaper;
  31         struct kmem_cache *pid_cachep;
  32         unsigned int level;
  33         struct pid_namespace *parent;
  34 #ifdef CONFIG_BSD_PROCESS_ACCT
  35         struct fs_pin *bacct;
  36 #endif
  37         struct user_namespace *user_ns;
  38         struct ucounts *ucounts;
  39         int reboot;     /* group exit code if this pidns was rebooted */
  40         struct ns_common ns;
  41 #if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
  42         int memfd_noexec_scope;
  43 #endif
  44 } __randomize_layout;
  45
  46 extern struct pid_namespace init_pid_ns;
  47
  48 #define PIDNS_ADDING (1U << 31)
  49
  50 #ifdef CONFIG_PID_NS
  51 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  52 {
  53         if (ns != &init_pid_ns)
  54                 refcount_inc(&ns->ns.count);
  55         return ns;
  56 }
  57
  58 #if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
  59 static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns)
  60 {
  61         int scope = MEMFD_NOEXEC_SCOPE_EXEC;
  62
  63         for (; ns; ns = ns->parent)
  64                 scope = max(scope, READ_ONCE(ns->memfd_noexec_scope));
  65
  66         return scope;
  67 }
  68 #else
  69 static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns)
  70 {
  71         return 0;
  72 }
  73 #endif
  74
  75 extern struct pid_namespace *copy_pid_ns(unsigned long flags,
  76         struct user_namespace *user_ns, struct pid_namespace *ns);
  77 extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
  78 extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
  79 extern void put_pid_ns(struct pid_namespace *ns);
  80
  81 #else /* !CONFIG_PID_NS */
  82 #include <linux/err.h>
  83
  84 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  85 {
  86         return ns;
  87 }
  88
  89 static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns)
  90 {
  91         return 0;
  92 }
  93
  94 static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
  95         struct user_namespace *user_ns, struct pid_namespace *ns)
  96 {
  97         if (flags & CLONE_NEWPID)
  98                 ns = ERR_PTR(-EINVAL);
  99         return ns;
 100 }
 101
 102 static inline void put_pid_ns(struct pid_namespace *ns)
 103 {
 104 }
 105
 106 static inline void zap_pid_ns_processes(struct pid_namespace *ns)
 107 {
 108         BUG();
 109 }
 110
 111 static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
 112 {
 113         return 0;
 114 }
 115 #endif /* CONFIG_PID_NS */
 116
 117 extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
 118 void pidhash_init(void);
 119 void pid_idr_init(void);
 120
 121 static inline bool task_is_in_init_pid_ns(struct task_struct *tsk)
 122 {
 123         return task_active_pid_ns(tsk) == &init_pid_ns;
 124 }
 125
 126 #endif /* _LINUX_PID_NS_H */