cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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nsproxy.h (3165B)

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