Root/
| 1 | /* |
| 2 | * This program is free software; you can redistribute it and/or |
| 3 | * modify it under the terms of the GNU General Public License as |
| 4 | * published by the Free Software Foundation, version 2 of the |
| 5 | * License. |
| 6 | */ |
| 7 | |
| 8 | #include <linux/module.h> |
| 9 | #include <linux/nsproxy.h> |
| 10 | #include <linux/slab.h> |
| 11 | #include <linux/user_namespace.h> |
| 12 | #include <linux/highuid.h> |
| 13 | #include <linux/cred.h> |
| 14 | |
| 15 | static struct kmem_cache *user_ns_cachep __read_mostly; |
| 16 | |
| 17 | /* |
| 18 | * Create a new user namespace, deriving the creator from the user in the |
| 19 | * passed credentials, and replacing that user with the new root user for the |
| 20 | * new namespace. |
| 21 | * |
| 22 | * This is called by copy_creds(), which will finish setting the target task's |
| 23 | * credentials. |
| 24 | */ |
| 25 | int create_user_ns(struct cred *new) |
| 26 | { |
| 27 | struct user_namespace *ns; |
| 28 | struct user_struct *root_user; |
| 29 | int n; |
| 30 | |
| 31 | ns = kmem_cache_alloc(user_ns_cachep, GFP_KERNEL); |
| 32 | if (!ns) |
| 33 | return -ENOMEM; |
| 34 | |
| 35 | kref_init(&ns->kref); |
| 36 | |
| 37 | for (n = 0; n < UIDHASH_SZ; ++n) |
| 38 | INIT_HLIST_HEAD(ns->uidhash_table + n); |
| 39 | |
| 40 | /* Alloc new root user. */ |
| 41 | root_user = alloc_uid(ns, 0); |
| 42 | if (!root_user) { |
| 43 | kmem_cache_free(user_ns_cachep, ns); |
| 44 | return -ENOMEM; |
| 45 | } |
| 46 | |
| 47 | /* set the new root user in the credentials under preparation */ |
| 48 | ns->creator = new->user; |
| 49 | new->user = root_user; |
| 50 | new->uid = new->euid = new->suid = new->fsuid = 0; |
| 51 | new->gid = new->egid = new->sgid = new->fsgid = 0; |
| 52 | put_group_info(new->group_info); |
| 53 | new->group_info = get_group_info(&init_groups); |
| 54 | #ifdef CONFIG_KEYS |
| 55 | key_put(new->request_key_auth); |
| 56 | new->request_key_auth = NULL; |
| 57 | #endif |
| 58 | /* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */ |
| 59 | |
| 60 | /* root_user holds a reference to ns, our reference can be dropped */ |
| 61 | put_user_ns(ns); |
| 62 | |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * Deferred destructor for a user namespace. This is required because |
| 68 | * free_user_ns() may be called with uidhash_lock held, but we need to call |
| 69 | * back to free_uid() which will want to take the lock again. |
| 70 | */ |
| 71 | static void free_user_ns_work(struct work_struct *work) |
| 72 | { |
| 73 | struct user_namespace *ns = |
| 74 | container_of(work, struct user_namespace, destroyer); |
| 75 | free_uid(ns->creator); |
| 76 | kmem_cache_free(user_ns_cachep, ns); |
| 77 | } |
| 78 | |
| 79 | void free_user_ns(struct kref *kref) |
| 80 | { |
| 81 | struct user_namespace *ns = |
| 82 | container_of(kref, struct user_namespace, kref); |
| 83 | |
| 84 | INIT_WORK(&ns->destroyer, free_user_ns_work); |
| 85 | schedule_work(&ns->destroyer); |
| 86 | } |
| 87 | EXPORT_SYMBOL(free_user_ns); |
| 88 | |
| 89 | uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t uid) |
| 90 | { |
| 91 | struct user_namespace *tmp; |
| 92 | |
| 93 | if (likely(to == cred->user->user_ns)) |
| 94 | return uid; |
| 95 | |
| 96 | |
| 97 | /* Is cred->user the creator of the target user_ns |
| 98 | * or the creator of one of it's parents? |
| 99 | */ |
| 100 | for ( tmp = to; tmp != &init_user_ns; |
| 101 | tmp = tmp->creator->user_ns ) { |
| 102 | if (cred->user == tmp->creator) { |
| 103 | return (uid_t)0; |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | /* No useful relationship so no mapping */ |
| 108 | return overflowuid; |
| 109 | } |
| 110 | |
| 111 | gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t gid) |
| 112 | { |
| 113 | struct user_namespace *tmp; |
| 114 | |
| 115 | if (likely(to == cred->user->user_ns)) |
| 116 | return gid; |
| 117 | |
| 118 | /* Is cred->user the creator of the target user_ns |
| 119 | * or the creator of one of it's parents? |
| 120 | */ |
| 121 | for ( tmp = to; tmp != &init_user_ns; |
| 122 | tmp = tmp->creator->user_ns ) { |
| 123 | if (cred->user == tmp->creator) { |
| 124 | return (gid_t)0; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | /* No useful relationship so no mapping */ |
| 129 | return overflowgid; |
| 130 | } |
| 131 | |
| 132 | static __init int user_namespaces_init(void) |
| 133 | { |
| 134 | user_ns_cachep = KMEM_CACHE(user_namespace, SLAB_PANIC); |
| 135 | return 0; |
| 136 | } |
| 137 | module_init(user_namespaces_init); |
| 138 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9
