Thomas Gleixner | b886d83c | 2019-06-01 10:08:55 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (C) 2004 IBM Corporation |
| 4 | * |
| 5 | * Author: Serge Hallyn <serue@us.ibm.com> |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 6 | */ |
| 7 | |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 8 | #include <linux/export.h> |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 9 | #include <linux/uts.h> |
| 10 | #include <linux/utsname.h> |
Cedric Le Goater | 467e9f4 | 2007-07-15 23:41:06 -0700 | [diff] [blame] | 11 | #include <linux/err.h> |
Robert P. J. Day | 1aeb272 | 2008-04-29 00:59:25 -0700 | [diff] [blame] | 12 | #include <linux/slab.h> |
Ingo Molnar | 5b825c3 | 2017-02-02 17:54:15 +0100 | [diff] [blame] | 13 | #include <linux/cred.h> |
Serge E. Hallyn | 59607db | 2011-03-23 16:43:16 -0700 | [diff] [blame] | 14 | #include <linux/user_namespace.h> |
David Howells | 0bb80f2 | 2013-04-12 01:50:06 +0100 | [diff] [blame] | 15 | #include <linux/proc_ns.h> |
Ingo Molnar | f719ff9b | 2017-02-06 10:57:33 +0100 | [diff] [blame] | 16 | #include <linux/sched/task.h> |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 17 | |
Alexey Dobriyan | 3ea056c | 2018-04-10 16:32:36 -0700 | [diff] [blame] | 18 | static struct kmem_cache *uts_ns_cache __ro_after_init; |
| 19 | |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 20 | static struct ucounts *inc_uts_namespaces(struct user_namespace *ns) |
| 21 | { |
| 22 | return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES); |
| 23 | } |
| 24 | |
| 25 | static void dec_uts_namespaces(struct ucounts *ucounts) |
| 26 | { |
| 27 | dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES); |
| 28 | } |
| 29 | |
Alexey Dobriyan | 4c2a7e7 | 2009-06-17 16:27:54 -0700 | [diff] [blame] | 30 | static struct uts_namespace *create_uts_ns(void) |
| 31 | { |
| 32 | struct uts_namespace *uts_ns; |
| 33 | |
Alexey Dobriyan | 3ea056c | 2018-04-10 16:32:36 -0700 | [diff] [blame] | 34 | uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL); |
Alexey Dobriyan | 4c2a7e7 | 2009-06-17 16:27:54 -0700 | [diff] [blame] | 35 | if (uts_ns) |
Kirill Tkhai | 9a56493 | 2020-08-03 13:16:21 +0300 | [diff] [blame] | 36 | refcount_set(&uts_ns->ns.count, 1); |
Alexey Dobriyan | 4c2a7e7 | 2009-06-17 16:27:54 -0700 | [diff] [blame] | 37 | return uts_ns; |
| 38 | } |
| 39 | |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 40 | /* |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 41 | * Clone a new ns copying an original utsname, setting refcount to 1 |
| 42 | * @old_ns: namespace to clone |
Alexey Dobriyan | 3ea056c | 2018-04-10 16:32:36 -0700 | [diff] [blame] | 43 | * Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 44 | */ |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 45 | static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, |
Serge E. Hallyn | bb96a6f | 2011-03-23 16:43:18 -0700 | [diff] [blame] | 46 | struct uts_namespace *old_ns) |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 47 | { |
| 48 | struct uts_namespace *ns; |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 49 | struct ucounts *ucounts; |
Eric W. Biederman | 98f842e | 2011-06-15 10:21:48 -0700 | [diff] [blame] | 50 | int err; |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 51 | |
Eric W. Biederman | df75e77 | 2016-09-22 13:08:36 -0500 | [diff] [blame] | 52 | err = -ENOSPC; |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 53 | ucounts = inc_uts_namespaces(user_ns); |
| 54 | if (!ucounts) |
| 55 | goto fail; |
| 56 | |
| 57 | err = -ENOMEM; |
Alexey Dobriyan | 4c2a7e7 | 2009-06-17 16:27:54 -0700 | [diff] [blame] | 58 | ns = create_uts_ns(); |
Cedric Le Goater | 467e9f4 | 2007-07-15 23:41:06 -0700 | [diff] [blame] | 59 | if (!ns) |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 60 | goto fail_dec; |
Cedric Le Goater | 467e9f4 | 2007-07-15 23:41:06 -0700 | [diff] [blame] | 61 | |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 62 | err = ns_alloc_inum(&ns->ns); |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 63 | if (err) |
| 64 | goto fail_free; |
Eric W. Biederman | 98f842e | 2011-06-15 10:21:48 -0700 | [diff] [blame] | 65 | |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 66 | ns->ucounts = ucounts; |
Al Viro | 33c4294 | 2014-11-01 02:32:53 -0400 | [diff] [blame] | 67 | ns->ns.ops = &utsns_operations; |
| 68 | |
Alexey Dobriyan | efc63c4 | 2007-09-18 22:46:27 -0700 | [diff] [blame] | 69 | down_read(&uts_sem); |
Cedric Le Goater | 467e9f4 | 2007-07-15 23:41:06 -0700 | [diff] [blame] | 70 | memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 71 | ns->user_ns = get_user_ns(user_ns); |
Alexey Dobriyan | efc63c4 | 2007-09-18 22:46:27 -0700 | [diff] [blame] | 72 | up_read(&uts_sem); |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 73 | return ns; |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 74 | |
| 75 | fail_free: |
Alexey Dobriyan | 3ea056c | 2018-04-10 16:32:36 -0700 | [diff] [blame] | 76 | kmem_cache_free(uts_ns_cache, ns); |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 77 | fail_dec: |
| 78 | dec_uts_namespaces(ucounts); |
| 79 | fail: |
| 80 | return ERR_PTR(err); |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 81 | } |
| 82 | |
| 83 | /* |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 84 | * Copy task tsk's utsname namespace, or clone it if flags |
| 85 | * specifies CLONE_NEWUTS. In latter case, changes to the |
| 86 | * utsname of this process won't be seen by parent, and vice |
| 87 | * versa. |
| 88 | */ |
Serge E. Hallyn | bb96a6f | 2011-03-23 16:43:18 -0700 | [diff] [blame] | 89 | struct uts_namespace *copy_utsname(unsigned long flags, |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 90 | struct user_namespace *user_ns, struct uts_namespace *old_ns) |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 91 | { |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 92 | struct uts_namespace *new_ns; |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 93 | |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 94 | BUG_ON(!old_ns); |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 95 | get_uts_ns(old_ns); |
| 96 | |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 97 | if (!(flags & CLONE_NEWUTS)) |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 98 | return old_ns; |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 99 | |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 100 | new_ns = clone_uts_ns(user_ns, old_ns); |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 101 | |
Serge E. Hallyn | 071df104 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 102 | put_uts_ns(old_ns); |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 103 | return new_ns; |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 104 | } |
| 105 | |
Kirill Tkhai | 9a56493 | 2020-08-03 13:16:21 +0300 | [diff] [blame] | 106 | void free_uts_ns(struct uts_namespace *ns) |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 107 | { |
Eric W. Biederman | f7af3d1 | 2016-08-08 14:11:25 -0500 | [diff] [blame] | 108 | dec_uts_namespaces(ns->ucounts); |
Serge E. Hallyn | 59607db | 2011-03-23 16:43:16 -0700 | [diff] [blame] | 109 | put_user_ns(ns->user_ns); |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 110 | ns_free_inum(&ns->ns); |
Alexey Dobriyan | 3ea056c | 2018-04-10 16:32:36 -0700 | [diff] [blame] | 111 | kmem_cache_free(uts_ns_cache, ns); |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 112 | } |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 113 | |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 114 | static inline struct uts_namespace *to_uts_ns(struct ns_common *ns) |
| 115 | { |
| 116 | return container_of(ns, struct uts_namespace, ns); |
| 117 | } |
| 118 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 119 | static struct ns_common *utsns_get(struct task_struct *task) |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 120 | { |
| 121 | struct uts_namespace *ns = NULL; |
| 122 | struct nsproxy *nsproxy; |
| 123 | |
Eric W. Biederman | 728dba3 | 2014-02-03 19:13:49 -0800 | [diff] [blame] | 124 | task_lock(task); |
| 125 | nsproxy = task->nsproxy; |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 126 | if (nsproxy) { |
| 127 | ns = nsproxy->uts_ns; |
| 128 | get_uts_ns(ns); |
| 129 | } |
Eric W. Biederman | 728dba3 | 2014-02-03 19:13:49 -0800 | [diff] [blame] | 130 | task_unlock(task); |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 131 | |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 132 | return ns ? &ns->ns : NULL; |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 133 | } |
| 134 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 135 | static void utsns_put(struct ns_common *ns) |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 136 | { |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 137 | put_uts_ns(to_uts_ns(ns)); |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 138 | } |
| 139 | |
Christian Brauner | f2a8d52 | 2020-05-05 16:04:30 +0200 | [diff] [blame] | 140 | static int utsns_install(struct nsset *nsset, struct ns_common *new) |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 141 | { |
Christian Brauner | f2a8d52 | 2020-05-05 16:04:30 +0200 | [diff] [blame] | 142 | struct nsproxy *nsproxy = nsset->nsproxy; |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 143 | struct uts_namespace *ns = to_uts_ns(new); |
Eric W. Biederman | 142e1d1 | 2012-07-26 01:13:20 -0700 | [diff] [blame] | 144 | |
Eric W. Biederman | 5e4a084 | 2012-12-14 07:55:36 -0800 | [diff] [blame] | 145 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
Christian Brauner | f2a8d52 | 2020-05-05 16:04:30 +0200 | [diff] [blame] | 146 | !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN)) |
Eric W. Biederman | 142e1d1 | 2012-07-26 01:13:20 -0700 | [diff] [blame] | 147 | return -EPERM; |
| 148 | |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 149 | get_uts_ns(ns); |
| 150 | put_uts_ns(nsproxy->uts_ns); |
| 151 | nsproxy->uts_ns = ns; |
| 152 | return 0; |
| 153 | } |
| 154 | |
Andrey Vagin | bcac25a | 2016-09-06 00:47:13 -0700 | [diff] [blame] | 155 | static struct user_namespace *utsns_owner(struct ns_common *ns) |
| 156 | { |
| 157 | return to_uts_ns(ns)->user_ns; |
| 158 | } |
| 159 | |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 160 | const struct proc_ns_operations utsns_operations = { |
| 161 | .name = "uts", |
| 162 | .type = CLONE_NEWUTS, |
| 163 | .get = utsns_get, |
| 164 | .put = utsns_put, |
| 165 | .install = utsns_install, |
Andrey Vagin | bcac25a | 2016-09-06 00:47:13 -0700 | [diff] [blame] | 166 | .owner = utsns_owner, |
Eric W. Biederman | 34482e8 | 2010-03-07 18:43:27 -0800 | [diff] [blame] | 167 | }; |
Alexey Dobriyan | 3ea056c | 2018-04-10 16:32:36 -0700 | [diff] [blame] | 168 | |
| 169 | void __init uts_ns_init(void) |
| 170 | { |
| 171 | uts_ns_cache = kmem_cache_create_usercopy( |
| 172 | "uts_namespace", sizeof(struct uts_namespace), 0, |
| 173 | SLAB_PANIC|SLAB_ACCOUNT, |
| 174 | offsetof(struct uts_namespace, name), |
| 175 | sizeof_field(struct uts_namespace, name), |
| 176 | NULL); |
| 177 | } |