Uninline find_pid etc set of functions
[linux-3.10.git] / kernel / capability.c
1 /*
2  * linux/kernel/capability.c
3  *
4  * Copyright (C) 1997  Andrew Main <zefram@fysh.org>
5  *
6  * Integrated into 2.1.97+,  Andrew G. Morgan <morgan@kernel.org>
7  * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
8  */
9
10 #include <linux/capability.h>
11 #include <linux/mm.h>
12 #include <linux/module.h>
13 #include <linux/security.h>
14 #include <linux/syscalls.h>
15 #include <linux/pid_namespace.h>
16 #include <asm/uaccess.h>
17
18 /*
19  * This lock protects task->cap_* for all tasks including current.
20  * Locking rule: acquire this prior to tasklist_lock.
21  */
22 static DEFINE_SPINLOCK(task_capability_lock);
23
24 /*
25  * For sys_getproccap() and sys_setproccap(), any of the three
26  * capability set pointers may be NULL -- indicating that that set is
27  * uninteresting and/or not to be changed.
28  */
29
30 /**
31  * sys_capget - get the capabilities of a given process.
32  * @header: pointer to struct that contains capability version and
33  *      target pid data
34  * @dataptr: pointer to struct that contains the effective, permitted,
35  *      and inheritable capabilities that are returned
36  *
37  * Returns 0 on success and < 0 on error.
38  */
39 asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
40 {
41         int ret = 0;
42         pid_t pid;
43         __u32 version;
44         struct task_struct *target;
45         struct __user_cap_data_struct data;
46
47         if (get_user(version, &header->version))
48                 return -EFAULT;
49
50         if (version != _LINUX_CAPABILITY_VERSION) {
51                 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
52                         return -EFAULT;
53                 return -EINVAL;
54         }
55
56         if (get_user(pid, &header->pid))
57                 return -EFAULT;
58
59         if (pid < 0)
60                 return -EINVAL;
61
62         spin_lock(&task_capability_lock);
63         read_lock(&tasklist_lock);
64
65         if (pid && pid != task_pid_vnr(current)) {
66                 target = find_task_by_vpid(pid);
67                 if (!target) {
68                         ret = -ESRCH;
69                         goto out;
70                 }
71         } else
72                 target = current;
73
74         ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
75
76 out:
77         read_unlock(&tasklist_lock);
78         spin_unlock(&task_capability_lock);
79
80         if (!ret && copy_to_user(dataptr, &data, sizeof data))
81                 return -EFAULT;
82
83         return ret;
84 }
85
86 /*
87  * cap_set_pg - set capabilities for all processes in a given process
88  * group.  We call this holding task_capability_lock and tasklist_lock.
89  */
90 static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
91                               kernel_cap_t *inheritable,
92                               kernel_cap_t *permitted)
93 {
94         struct task_struct *g, *target;
95         int ret = -EPERM;
96         int found = 0;
97         struct pid *pgrp;
98
99         pgrp = find_vpid(pgrp_nr);
100         do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
101                 target = g;
102                 while_each_thread(g, target) {
103                         if (!security_capset_check(target, effective,
104                                                         inheritable,
105                                                         permitted)) {
106                                 security_capset_set(target, effective,
107                                                         inheritable,
108                                                         permitted);
109                                 ret = 0;
110                         }
111                         found = 1;
112                 }
113         } while_each_pid_task(pgrp, PIDTYPE_PGID, g);
114
115         if (!found)
116                 ret = 0;
117         return ret;
118 }
119
120 /*
121  * cap_set_all - set capabilities for all processes other than init
122  * and self.  We call this holding task_capability_lock and tasklist_lock.
123  */
124 static inline int cap_set_all(kernel_cap_t *effective,
125                                kernel_cap_t *inheritable,
126                                kernel_cap_t *permitted)
127 {
128      struct task_struct *g, *target;
129      int ret = -EPERM;
130      int found = 0;
131
132      do_each_thread(g, target) {
133              if (target == current || is_container_init(target->group_leader))
134                      continue;
135              found = 1;
136              if (security_capset_check(target, effective, inheritable,
137                                                 permitted))
138                      continue;
139              ret = 0;
140              security_capset_set(target, effective, inheritable, permitted);
141      } while_each_thread(g, target);
142
143      if (!found)
144              ret = 0;
145      return ret;
146 }
147
148 /**
149  * sys_capset - set capabilities for a process or a group of processes
150  * @header: pointer to struct that contains capability version and
151  *      target pid data
152  * @data: pointer to struct that contains the effective, permitted,
153  *      and inheritable capabilities
154  *
155  * Set capabilities for a given process, all processes, or all
156  * processes in a given process group.
157  *
158  * The restrictions on setting capabilities are specified as:
159  *
160  * [pid is for the 'target' task.  'current' is the calling task.]
161  *
162  * I: any raised capabilities must be a subset of the (old current) permitted
163  * P: any raised capabilities must be a subset of the (old current) permitted
164  * E: must be set to a subset of (new target) permitted
165  *
166  * Returns 0 on success and < 0 on error.
167  */
168 asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
169 {
170         kernel_cap_t inheritable, permitted, effective;
171         __u32 version;
172         struct task_struct *target;
173         int ret;
174         pid_t pid;
175
176         if (get_user(version, &header->version))
177                 return -EFAULT;
178
179         if (version != _LINUX_CAPABILITY_VERSION) {
180                 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
181                         return -EFAULT;
182                 return -EINVAL;
183         }
184
185         if (get_user(pid, &header->pid))
186                 return -EFAULT;
187
188         if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
189                 return -EPERM;
190
191         if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
192             copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
193             copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
194                 return -EFAULT;
195
196         spin_lock(&task_capability_lock);
197         read_lock(&tasklist_lock);
198
199         if (pid > 0 && pid != task_pid_vnr(current)) {
200                 target = find_task_by_vpid(pid);
201                 if (!target) {
202                         ret = -ESRCH;
203                         goto out;
204                 }
205         } else
206                 target = current;
207
208         ret = 0;
209
210         /* having verified that the proposed changes are legal,
211            we now put them into effect. */
212         if (pid < 0) {
213                 if (pid == -1)  /* all procs other than current and init */
214                         ret = cap_set_all(&effective, &inheritable, &permitted);
215
216                 else            /* all procs in process group */
217                         ret = cap_set_pg(-pid, &effective, &inheritable,
218                                          &permitted);
219         } else {
220                 ret = security_capset_check(target, &effective, &inheritable,
221                                             &permitted);
222                 if (!ret)
223                         security_capset_set(target, &effective, &inheritable,
224                                             &permitted);
225         }
226
227 out:
228         read_unlock(&tasklist_lock);
229         spin_unlock(&task_capability_lock);
230
231         return ret;
232 }
233
234 int __capable(struct task_struct *t, int cap)
235 {
236         if (security_capable(t, cap) == 0) {
237                 t->flags |= PF_SUPERPRIV;
238                 return 1;
239         }
240         return 0;
241 }
242
243 int capable(int cap)
244 {
245         return __capable(current, cap);
246 }
247 EXPORT_SYMBOL(capable);