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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_NSPROXY_H #define _LINUX_NSPROXY_H #include <linux/refcount.h> #include <linux/spinlock.h> #include <linux/sched.h> struct mnt_namespace; struct uts_namespace; struct ipc_namespace; struct pid_namespace; struct cgroup_namespace; struct fs_struct; /* * A structure to contain pointers to all per-process * namespaces - fs (mount), uts, network, sysvipc, etc. * * The pid namespace is an exception -- it's accessed using * task_active_pid_ns. The pid namespace here is the * namespace that children will use. * * 'count' is the number of tasks holding a reference. * The count for each namespace, then, will be the number * of nsproxies pointing to it, not the number of tasks. * * The nsproxy is shared by tasks which share all namespaces. * As soon as a single namespace is cloned or unshared, the * nsproxy is copied. */ struct nsproxy { refcount_t count; struct uts_namespace *uts_ns; struct ipc_namespace *ipc_ns; struct mnt_namespace *mnt_ns; struct pid_namespace *pid_ns_for_children; struct net *net_ns; struct time_namespace *time_ns; struct time_namespace *time_ns_for_children; struct cgroup_namespace *cgroup_ns; }; extern struct nsproxy init_nsproxy; #define to_ns_common(__ns) \ _Generic((__ns), \ struct cgroup_namespace *: &(__ns->ns), \ struct ipc_namespace *: &(__ns->ns), \ struct net *: &(__ns->ns), \ struct pid_namespace *: &(__ns->ns), \ struct mnt_namespace *: &(__ns->ns), \ struct time_namespace *: &(__ns->ns), \ struct user_namespace *: &(__ns->ns), \ struct uts_namespace *: &(__ns->ns)) /* * A structure to encompass all bits needed to install * a partial or complete new set of namespaces. * * If a new user namespace is requested cred will * point to a modifiable set of credentials. If a pointer * to a modifiable set is needed nsset_cred() must be * used and tested. */ struct nsset { unsigned flags; struct nsproxy *nsproxy; struct fs_struct *fs; const struct cred *cred; }; static inline struct cred *nsset_cred(struct nsset *set) { if (set->flags & CLONE_NEWUSER) return (struct cred *)set->cred; return NULL; } /* * the namespaces access rules are: * * 1. only current task is allowed to change tsk->nsproxy pointer or * any pointer on the nsproxy itself. Current must hold the task_lock * when changing tsk->nsproxy. * * 2. when accessing (i.e. reading) current task's namespaces - no * precautions should be taken - just dereference the pointers * * 3. the access to other task namespaces is performed like this * task_lock(task); * nsproxy = task->nsproxy; * if (nsproxy != NULL) { * / * * * work with the namespaces here * * e.g. get the reference on one of them * * / * } / * * * NULL task->nsproxy means that this task is * * almost dead (zombie) * * / * task_unlock(task); * */ int copy_namespaces(unsigned long flags, struct task_struct *tsk); void exit_task_namespaces(struct task_struct *tsk); void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new); int exec_task_namespaces(void); void free_nsproxy(struct nsproxy *ns); int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **, struct cred *, struct fs_struct *); int __init nsproxy_cache_init(void); static inline void put_nsproxy(struct nsproxy *ns) { if (refcount_dec_and_test(&ns->count)) free_nsproxy(ns); } static inline void get_nsproxy(struct nsproxy *ns) { refcount_inc(&ns->count); } DEFINE_FREE(put_nsproxy, struct nsproxy *, if (_T) put_nsproxy(_T)) #endif |