projects/linux·blob v2.6.12-rc3 · refs

220 lines · 5.8 KiB

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