1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2006 IBM Corporation 4 * 5 * Author: Serge Hallyn <serue@us.ibm.com> 6 * 7 * Jun 2006 - namespaces support 8 * OpenVZ, SWsoft Inc. 9 * Pavel Emelianov <xemul@openvz.org> 10 */ 11 12 #include <linux/slab.h> 13 #include <linux/export.h> 14 #include <linux/nsproxy.h> 15 #include <linux/init_task.h> 16 #include <linux/mnt_namespace.h> 17 #include <linux/utsname.h> 18 #include <linux/pid_namespace.h> 19 #include <net/net_namespace.h> 20 #include <linux/ipc_namespace.h> 21 #include <linux/proc_ns.h> 22 #include <linux/file.h> 23 #include <linux/syscalls.h> 24 #include <linux/cgroup.h> 25 #include <linux/perf_event.h> 26 27 static struct kmem_cache *nsproxy_cachep; 28 29 struct nsproxy init_nsproxy = { 30 .count = ATOMIC_INIT(1), 31 .uts_ns = &init_uts_ns, 32 #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC) 33 .ipc_ns = &init_ipc_ns, 34 #endif 35 .mnt_ns = NULL, 36 .pid_ns_for_children = &init_pid_ns, 37 #ifdef CONFIG_NET 38 .net_ns = &init_net, 39 #endif 40 #ifdef CONFIG_CGROUPS 41 .cgroup_ns = &init_cgroup_ns, 42 #endif 43 }; 44 45 static inline struct nsproxy *create_nsproxy(void) 46 { 47 struct nsproxy *nsproxy; 48 49 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); 50 if (nsproxy) 51 atomic_set(&nsproxy->count, 1); 52 return nsproxy; 53 } 54 55 /* 56 * Create new nsproxy and all of its the associated namespaces. 57 * Return the newly created nsproxy. Do not attach this to the task, 58 * leave it to the caller to do proper locking and attach it to task. 59 */ 60 static struct nsproxy *create_new_namespaces(unsigned long flags, 61 struct task_struct *tsk, struct user_namespace *user_ns, 62 struct fs_struct *new_fs) 63 { 64 struct nsproxy *new_nsp; 65 int err; 66 67 new_nsp = create_nsproxy(); 68 if (!new_nsp) 69 return ERR_PTR(-ENOMEM); 70 71 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs); 72 if (IS_ERR(new_nsp->mnt_ns)) { 73 err = PTR_ERR(new_nsp->mnt_ns); 74 goto out_ns; 75 } 76 77 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns); 78 if (IS_ERR(new_nsp->uts_ns)) { 79 err = PTR_ERR(new_nsp->uts_ns); 80 goto out_uts; 81 } 82 83 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns); 84 if (IS_ERR(new_nsp->ipc_ns)) { 85 err = PTR_ERR(new_nsp->ipc_ns); 86 goto out_ipc; 87 } 88 89 new_nsp->pid_ns_for_children = 90 copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children); 91 if (IS_ERR(new_nsp->pid_ns_for_children)) { 92 err = PTR_ERR(new_nsp->pid_ns_for_children); 93 goto out_pid; 94 } 95 96 new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns, 97 tsk->nsproxy->cgroup_ns); 98 if (IS_ERR(new_nsp->cgroup_ns)) { 99 err = PTR_ERR(new_nsp->cgroup_ns); 100 goto out_cgroup; 101 } 102 103 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns); 104 if (IS_ERR(new_nsp->net_ns)) { 105 err = PTR_ERR(new_nsp->net_ns); 106 goto out_net; 107 } 108 109 return new_nsp; 110 111 out_net: 112 put_cgroup_ns(new_nsp->cgroup_ns); 113 out_cgroup: 114 if (new_nsp->pid_ns_for_children) 115 put_pid_ns(new_nsp->pid_ns_for_children); 116 out_pid: 117 if (new_nsp->ipc_ns) 118 put_ipc_ns(new_nsp->ipc_ns); 119 out_ipc: 120 if (new_nsp->uts_ns) 121 put_uts_ns(new_nsp->uts_ns); 122 out_uts: 123 if (new_nsp->mnt_ns) 124 put_mnt_ns(new_nsp->mnt_ns); 125 out_ns: 126 kmem_cache_free(nsproxy_cachep, new_nsp); 127 return ERR_PTR(err); 128 } 129 130 /* 131 * called from clone. This now handles copy for nsproxy and all 132 * namespaces therein. 133 */ 134 int copy_namespaces(unsigned long flags, struct task_struct *tsk) 135 { 136 struct nsproxy *old_ns = tsk->nsproxy; 137 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns); 138 struct nsproxy *new_ns; 139 140 if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 141 CLONE_NEWPID | CLONE_NEWNET | 142 CLONE_NEWCGROUP)))) { 143 get_nsproxy(old_ns); 144 return 0; 145 } 146 147 if (!ns_capable(user_ns, CAP_SYS_ADMIN)) 148 return -EPERM; 149 150 /* 151 * CLONE_NEWIPC must detach from the undolist: after switching 152 * to a new ipc namespace, the semaphore arrays from the old 153 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM 154 * means share undolist with parent, so we must forbid using 155 * it along with CLONE_NEWIPC. 156 */ 157 if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) == 158 (CLONE_NEWIPC | CLONE_SYSVSEM)) 159 return -EINVAL; 160 161 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs); 162 if (IS_ERR(new_ns)) 163 return PTR_ERR(new_ns); 164 165 tsk->nsproxy = new_ns; 166 return 0; 167 } 168 169 void free_nsproxy(struct nsproxy *ns) 170 { 171 if (ns->mnt_ns) 172 put_mnt_ns(ns->mnt_ns); 173 if (ns->uts_ns) 174 put_uts_ns(ns->uts_ns); 175 if (ns->ipc_ns) 176 put_ipc_ns(ns->ipc_ns); 177 if (ns->pid_ns_for_children) 178 put_pid_ns(ns->pid_ns_for_children); 179 put_cgroup_ns(ns->cgroup_ns); 180 put_net(ns->net_ns); 181 kmem_cache_free(nsproxy_cachep, ns); 182 } 183 184 /* 185 * Called from unshare. Unshare all the namespaces part of nsproxy. 186 * On success, returns the new nsproxy. 187 */ 188 int unshare_nsproxy_namespaces(unsigned long unshare_flags, 189 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs) 190 { 191 struct user_namespace *user_ns; 192 int err = 0; 193 194 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 195 CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP))) 196 return 0; 197 198 user_ns = new_cred ? new_cred->user_ns : current_user_ns(); 199 if (!ns_capable(user_ns, CAP_SYS_ADMIN)) 200 return -EPERM; 201 202 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns, 203 new_fs ? new_fs : current->fs); 204 if (IS_ERR(*new_nsp)) { 205 err = PTR_ERR(*new_nsp); 206 goto out; 207 } 208 209 out: 210 return err; 211 } 212 213 void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) 214 { 215 struct nsproxy *ns; 216 217 might_sleep(); 218 219 task_lock(p); 220 ns = p->nsproxy; 221 p->nsproxy = new; 222 task_unlock(p); 223 224 if (ns && atomic_dec_and_test(&ns->count)) 225 free_nsproxy(ns); 226 } 227 228 void exit_task_namespaces(struct task_struct *p) 229 { 230 switch_task_namespaces(p, NULL); 231 } 232 233 SYSCALL_DEFINE2(setns, int, fd, int, nstype) 234 { 235 struct task_struct *tsk = current; 236 struct nsproxy *new_nsproxy; 237 struct file *file; 238 struct ns_common *ns; 239 int err; 240 241 file = proc_ns_fget(fd); 242 if (IS_ERR(file)) 243 return PTR_ERR(file); 244 245 err = -EINVAL; 246 ns = get_proc_ns(file_inode(file)); 247 if (nstype && (ns->ops->type != nstype)) 248 goto out; 249 250 new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs); 251 if (IS_ERR(new_nsproxy)) { 252 err = PTR_ERR(new_nsproxy); 253 goto out; 254 } 255 256 err = ns->ops->install(new_nsproxy, ns); 257 if (err) { 258 free_nsproxy(new_nsproxy); 259 goto out; 260 } 261 switch_task_namespaces(tsk, new_nsproxy); 262 263 perf_event_namespaces(tsk); 264 out: 265 fput(file); 266 return err; 267 } 268 269 int __init nsproxy_cache_init(void) 270 { 271 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); 272 return 0; 273 } 274