1 /* 2 * Copyright (C) 2006 IBM Corporation 3 * 4 * Author: Serge Hallyn <serue@us.ibm.com> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation, version 2 of the 9 * License. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/version.h> 14 #include <linux/nsproxy.h> 15 #include <linux/init_task.h> 16 #include <linux/namespace.h> 17 #include <linux/utsname.h> 18 19 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); 20 21 static inline void get_nsproxy(struct nsproxy *ns) 22 { 23 atomic_inc(&ns->count); 24 } 25 26 void get_task_namespaces(struct task_struct *tsk) 27 { 28 struct nsproxy *ns = tsk->nsproxy; 29 if (ns) { 30 get_nsproxy(ns); 31 } 32 } 33 34 /* 35 * creates a copy of "orig" with refcount 1. 36 * This does not grab references to the contained namespaces, 37 * so that needs to be done by dup_namespaces. 38 */ 39 static inline struct nsproxy *clone_namespaces(struct nsproxy *orig) 40 { 41 struct nsproxy *ns; 42 43 ns = kmalloc(sizeof(struct nsproxy), GFP_KERNEL); 44 if (ns) { 45 memcpy(ns, orig, sizeof(struct nsproxy)); 46 atomic_set(&ns->count, 1); 47 } 48 return ns; 49 } 50 51 /* 52 * copies the nsproxy, setting refcount to 1, and grabbing a 53 * reference to all contained namespaces. Called from 54 * sys_unshare() 55 */ 56 struct nsproxy *dup_namespaces(struct nsproxy *orig) 57 { 58 struct nsproxy *ns = clone_namespaces(orig); 59 60 if (ns) { 61 if (ns->namespace) 62 get_namespace(ns->namespace); 63 if (ns->uts_ns) 64 get_uts_ns(ns->uts_ns); 65 } 66 67 return ns; 68 } 69 70 /* 71 * called from clone. This now handles copy for nsproxy and all 72 * namespaces therein. 73 */ 74 int copy_namespaces(int flags, struct task_struct *tsk) 75 { 76 struct nsproxy *old_ns = tsk->nsproxy; 77 struct nsproxy *new_ns; 78 int err = 0; 79 80 if (!old_ns) 81 return 0; 82 83 get_nsproxy(old_ns); 84 85 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS))) 86 return 0; 87 88 new_ns = clone_namespaces(old_ns); 89 if (!new_ns) { 90 err = -ENOMEM; 91 goto out; 92 } 93 94 tsk->nsproxy = new_ns; 95 96 err = copy_namespace(flags, tsk); 97 if (err) { 98 tsk->nsproxy = old_ns; 99 put_nsproxy(new_ns); 100 goto out; 101 } 102 103 err = copy_utsname(flags, tsk); 104 if (err) { 105 if (new_ns->namespace) 106 put_namespace(new_ns->namespace); 107 tsk->nsproxy = old_ns; 108 put_nsproxy(new_ns); 109 goto out; 110 } 111 112 out: 113 put_nsproxy(old_ns); 114 return err; 115 } 116 117 void free_nsproxy(struct nsproxy *ns) 118 { 119 if (ns->namespace) 120 put_namespace(ns->namespace); 121 if (ns->uts_ns) 122 put_uts_ns(ns->uts_ns); 123 kfree(ns); 124 } 125