cregit-Linux how code gets into the kernel

Release 4.18 ipc/namespace.c

Directory: ipc
// SPDX-License-Identifier: GPL-2.0
/*
 * linux/ipc/namespace.c
 * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
 */

#include <linux/ipc.h>
#include <linux/msg.h>
#include <linux/ipc_namespace.h>
#include <linux/rcupdate.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
#include <linux/sched/task.h>

#include "util.h"


static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns) { return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann24100.00%1100.00%
Total24100.00%1100.00%


static void dec_ipc_namespaces(struct ucounts *ucounts) { dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann18100.00%1100.00%
Total18100.00%1100.00%


static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, struct ipc_namespace *old_ns) { struct ipc_namespace *ns; struct ucounts *ucounts; int err; err = -ENOSPC; ucounts = inc_ipc_namespaces(user_ns); if (!ucounts) goto fail; err = -ENOMEM; ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); if (ns == NULL) goto fail_dec; err = ns_alloc_inum(&ns->ns); if (err) goto fail_free; ns->ns.ops = &ipcns_operations; refcount_set(&ns->count, 1); ns->user_ns = get_user_ns(user_ns); ns->ucounts = ucounts; err = sem_init_ns(ns); if (err) goto fail_put; err = msg_init_ns(ns); if (err) goto fail_destroy_sem; err = shm_init_ns(ns); if (err) goto fail_destroy_msg; err = mq_init_ns(ns); if (err) goto fail_destroy_shm; return ns; fail_destroy_shm: shm_exit_ns(ns); fail_destroy_msg: msg_exit_ns(ns); fail_destroy_sem: sem_exit_ns(ns); fail_put: put_user_ns(ns->user_ns); ns_free_inum(&ns->ns); fail_free: kfree(ns); fail_dec: dec_ipc_namespaces(ucounts); fail: return ERR_PTR(err); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann10140.73%533.33%
Guillaume Knispel5220.97%16.67%
Pavel Emelyanov4618.55%16.67%
Serge E. Hallyn3514.11%320.00%
Al Viro124.84%320.00%
Elena Reshetova10.40%16.67%
Alexey Dobriyan10.40%16.67%
Total248100.00%15100.00%


struct ipc_namespace *copy_ipcs(unsigned long flags, struct user_namespace *user_ns, struct ipc_namespace *ns) { if (!(flags & CLONE_NEWIPC)) return get_ipc_ns(ns); return create_ipc_ns(user_ns, ns); }

Contributors

PersonTokensPropCommitsCommitProp
Pavel Emelyanov2659.09%116.67%
Serge E. Hallyn818.18%233.33%
Eric W. Biedermann613.64%116.67%
Alexey Dobriyan49.09%233.33%
Total44100.00%6100.00%

/* * free_ipcs - free all ipcs of one type * @ns: the namespace to remove the ipcs from * @ids: the table of ipcs to free * @free: the function called to free each individual ipc * * Called for each kind of ipc when an ipc_namespace exits. */
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) { struct kern_ipc_perm *perm; int next_id; int total, in_use; down_write(&ids->rwsem); in_use = ids->in_use; for (total = 0, next_id = 0; total < in_use; next_id++) { perm = idr_find(&ids->ipcs_idr, next_id); if (perm == NULL) continue; rcu_read_lock(); ipc_lock_object(perm); free(ns, perm); total++; } up_write(&ids->rwsem); }

Contributors

PersonTokensPropCommitsCommitProp
Pierre Peiffer11595.04%133.33%
Davidlohr Bueso A64.96%266.67%
Total121100.00%3100.00%


static void free_ipc_ns(struct ipc_namespace *ns) { sem_exit_ns(ns); msg_exit_ns(ns); shm_exit_ns(ns); dec_ipc_namespaces(ns->ucounts); put_user_ns(ns->user_ns); ns_free_inum(&ns->ns); kfree(ns); }

Contributors

PersonTokensPropCommitsCommitProp
Serge E. Hallyn1732.08%222.22%
Eric W. Biedermann1222.64%222.22%
Pavel Emelyanov1018.87%111.11%
Alexey Dobriyan611.32%111.11%
Xiaotian Feng59.43%111.11%
Al Viro35.66%222.22%
Total53100.00%9100.00%

/* * put_ipc_ns - drop a reference to an ipc namespace. * @ns: the namespace to put * * If this is the last task in the namespace exiting, and * it is dropping the refcount to 0, then it can race with * a task in another ipc namespace but in a mounts namespace * which has this ipcns's mqueuefs mounted, doing some action * with one of the mqueuefs files. That can raise the refcount. * So dropping the refcount, and raising the refcount when * accessing it through the VFS, are protected with mq_lock. * * (Clearly, a task raising the refcount on its own ipc_ns * needn't take mq_lock since it can't race with the last task * in the ipcns exiting). */
void put_ipc_ns(struct ipc_namespace *ns) { if (refcount_dec_and_lock(&ns->count, &mq_lock)) { mq_clear_sbinfo(ns); spin_unlock(&mq_lock); mq_put_mnt(ns); free_ipc_ns(ns); } }

Contributors

PersonTokensPropCommitsCommitProp
Alexey Dobriyan1839.13%120.00%
Pavel Emelyanov1634.78%120.00%
Serge E. Hallyn817.39%120.00%
Nadia Derbey36.52%120.00%
Elena Reshetova12.17%120.00%
Total46100.00%5100.00%


static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) { return container_of(ns, struct ipc_namespace, ns); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro25100.00%1100.00%
Total25100.00%1100.00%


static struct ns_common *ipcns_get(struct task_struct *task) { struct ipc_namespace *ns = NULL; struct nsproxy *nsproxy; task_lock(task); nsproxy = task->nsproxy; if (nsproxy) ns = get_ipc_ns(nsproxy->ipc_ns); task_unlock(task); return ns ? &ns->ns : NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann5585.94%250.00%
Al Viro914.06%250.00%
Total64100.00%4100.00%


static void ipcns_put(struct ns_common *ns) { return put_ipc_ns(to_ipc_ns(ns)); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann1575.00%133.33%
Al Viro525.00%266.67%
Total20100.00%3100.00%


static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new) { struct ipc_namespace *ns = to_ipc_ns(new); if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) return -EPERM; /* Ditch state from the old ipc namespace */ exit_sem(current); put_ipc_ns(nsproxy->ipc_ns); nsproxy->ipc_ns = get_ipc_ns(ns); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann7193.42%466.67%
Al Viro56.58%233.33%
Total76100.00%6100.00%


static struct user_namespace *ipcns_owner(struct ns_common *ns) { return to_ipc_ns(ns)->user_ns; }

Contributors

PersonTokensPropCommitsCommitProp
Andrey Vagin21100.00%1100.00%
Total21100.00%1100.00%

const struct proc_ns_operations ipcns_operations = { .name = "ipc", .type = CLONE_NEWIPC, .get = ipcns_get, .put = ipcns_put, .install = ipcns_install, .owner = ipcns_owner, };

Overall Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann33640.00%1029.41%
Pavel Emelyanov12014.29%12.94%
Pierre Peiffer11613.81%12.94%
Serge E. Hallyn779.17%38.82%
Al Viro597.02%514.71%
Guillaume Knispel526.19%12.94%
Alexey Dobriyan303.57%38.82%
Andrey Vagin263.10%12.94%
Davidlohr Bueso A60.71%25.88%
Ingo Molnar60.71%25.88%
Xiaotian Feng50.60%12.94%
Nadia Derbey30.36%12.94%
Elena Reshetova20.24%12.94%
David Howells10.12%12.94%
Greg Kroah-Hartman10.12%12.94%
Total840100.00%34100.00%
Directory: ipc
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