Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/capability.c | |
3 | * | |
4 | * Copyright (C) 1997 Andrew Main <zefram@fysh.org> | |
5 | * | |
72c2d582 | 6 | * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org> |
1da177e4 | 7 | * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net> |
314f70fd | 8 | */ |
1da177e4 | 9 | |
c59ede7b | 10 | #include <linux/capability.h> |
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/security.h> | |
14 | #include <linux/syscalls.h> | |
15 | #include <asm/uaccess.h> | |
16 | ||
1da177e4 LT |
17 | /* |
18 | * This lock protects task->cap_* for all tasks including current. | |
19 | * Locking rule: acquire this prior to tasklist_lock. | |
20 | */ | |
21 | static DEFINE_SPINLOCK(task_capability_lock); | |
22 | ||
23 | /* | |
24 | * For sys_getproccap() and sys_setproccap(), any of the three | |
25 | * capability set pointers may be NULL -- indicating that that set is | |
26 | * uninteresting and/or not to be changed. | |
27 | */ | |
28 | ||
207a7ba8 | 29 | /** |
1da177e4 | 30 | * sys_capget - get the capabilities of a given process. |
207a7ba8 RD |
31 | * @header: pointer to struct that contains capability version and |
32 | * target pid data | |
33 | * @dataptr: pointer to struct that contains the effective, permitted, | |
34 | * and inheritable capabilities that are returned | |
35 | * | |
36 | * Returns 0 on success and < 0 on error. | |
1da177e4 LT |
37 | */ |
38 | asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr) | |
39 | { | |
314f70fd DW |
40 | int ret = 0; |
41 | pid_t pid; | |
42 | __u32 version; | |
43 | struct task_struct *target; | |
44 | struct __user_cap_data_struct data; | |
45 | ||
46 | if (get_user(version, &header->version)) | |
47 | return -EFAULT; | |
48 | ||
49 | if (version != _LINUX_CAPABILITY_VERSION) { | |
50 | if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) | |
51 | return -EFAULT; | |
52 | return -EINVAL; | |
53 | } | |
1da177e4 | 54 | |
314f70fd DW |
55 | if (get_user(pid, &header->pid)) |
56 | return -EFAULT; | |
1da177e4 | 57 | |
314f70fd DW |
58 | if (pid < 0) |
59 | return -EINVAL; | |
1da177e4 | 60 | |
314f70fd DW |
61 | spin_lock(&task_capability_lock); |
62 | read_lock(&tasklist_lock); | |
1da177e4 | 63 | |
314f70fd DW |
64 | if (pid && pid != current->pid) { |
65 | target = find_task_by_pid(pid); | |
66 | if (!target) { | |
67 | ret = -ESRCH; | |
68 | goto out; | |
69 | } | |
70 | } else | |
71 | target = current; | |
1da177e4 | 72 | |
314f70fd | 73 | ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted); |
1da177e4 LT |
74 | |
75 | out: | |
314f70fd DW |
76 | read_unlock(&tasklist_lock); |
77 | spin_unlock(&task_capability_lock); | |
1da177e4 | 78 | |
314f70fd DW |
79 | if (!ret && copy_to_user(dataptr, &data, sizeof data)) |
80 | return -EFAULT; | |
1da177e4 | 81 | |
314f70fd | 82 | return ret; |
1da177e4 LT |
83 | } |
84 | ||
85 | /* | |
86 | * cap_set_pg - set capabilities for all processes in a given process | |
87 | * group. We call this holding task_capability_lock and tasklist_lock. | |
88 | */ | |
41487c65 | 89 | static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective, |
1da177e4 LT |
90 | kernel_cap_t *inheritable, |
91 | kernel_cap_t *permitted) | |
92 | { | |
36c8b586 | 93 | struct task_struct *g, *target; |
1da177e4 LT |
94 | int ret = -EPERM; |
95 | int found = 0; | |
41487c65 | 96 | struct pid *pgrp; |
1da177e4 | 97 | |
41487c65 EB |
98 | pgrp = find_pid(pgrp_nr); |
99 | do_each_pid_task(pgrp, PIDTYPE_PGID, g) { | |
1da177e4 LT |
100 | target = g; |
101 | while_each_thread(g, target) { | |
102 | if (!security_capset_check(target, effective, | |
103 | inheritable, | |
104 | permitted)) { | |
105 | security_capset_set(target, effective, | |
106 | inheritable, | |
107 | permitted); | |
108 | ret = 0; | |
109 | } | |
110 | found = 1; | |
111 | } | |
41487c65 | 112 | } while_each_pid_task(pgrp, PIDTYPE_PGID, g); |
1da177e4 LT |
113 | |
114 | if (!found) | |
314f70fd | 115 | ret = 0; |
1da177e4 LT |
116 | return ret; |
117 | } | |
118 | ||
119 | /* | |
120 | * cap_set_all - set capabilities for all processes other than init | |
121 | * and self. We call this holding task_capability_lock and tasklist_lock. | |
122 | */ | |
123 | static inline int cap_set_all(kernel_cap_t *effective, | |
124 | kernel_cap_t *inheritable, | |
125 | kernel_cap_t *permitted) | |
126 | { | |
36c8b586 | 127 | struct task_struct *g, *target; |
1da177e4 LT |
128 | int ret = -EPERM; |
129 | int found = 0; | |
130 | ||
131 | do_each_thread(g, target) { | |
f400e198 | 132 | if (target == current || is_init(target)) |
1da177e4 LT |
133 | continue; |
134 | found = 1; | |
135 | if (security_capset_check(target, effective, inheritable, | |
136 | permitted)) | |
137 | continue; | |
138 | ret = 0; | |
139 | security_capset_set(target, effective, inheritable, permitted); | |
140 | } while_each_thread(g, target); | |
141 | ||
142 | if (!found) | |
143 | ret = 0; | |
144 | return ret; | |
145 | } | |
146 | ||
207a7ba8 RD |
147 | /** |
148 | * sys_capset - set capabilities for a process or a group of processes | |
149 | * @header: pointer to struct that contains capability version and | |
150 | * target pid data | |
151 | * @data: pointer to struct that contains the effective, permitted, | |
152 | * and inheritable capabilities | |
153 | * | |
154 | * Set capabilities for a given process, all processes, or all | |
1da177e4 LT |
155 | * processes in a given process group. |
156 | * | |
157 | * The restrictions on setting capabilities are specified as: | |
158 | * | |
159 | * [pid is for the 'target' task. 'current' is the calling task.] | |
160 | * | |
161 | * I: any raised capabilities must be a subset of the (old current) permitted | |
162 | * P: any raised capabilities must be a subset of the (old current) permitted | |
163 | * E: must be set to a subset of (new target) permitted | |
207a7ba8 RD |
164 | * |
165 | * Returns 0 on success and < 0 on error. | |
1da177e4 LT |
166 | */ |
167 | asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) | |
168 | { | |
314f70fd DW |
169 | kernel_cap_t inheritable, permitted, effective; |
170 | __u32 version; | |
171 | struct task_struct *target; | |
172 | int ret; | |
173 | pid_t pid; | |
174 | ||
175 | if (get_user(version, &header->version)) | |
176 | return -EFAULT; | |
177 | ||
178 | if (version != _LINUX_CAPABILITY_VERSION) { | |
179 | if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) | |
180 | return -EFAULT; | |
181 | return -EINVAL; | |
182 | } | |
183 | ||
184 | if (get_user(pid, &header->pid)) | |
185 | return -EFAULT; | |
186 | ||
187 | if (pid && pid != current->pid && !capable(CAP_SETPCAP)) | |
188 | return -EPERM; | |
189 | ||
190 | if (copy_from_user(&effective, &data->effective, sizeof(effective)) || | |
191 | copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) || | |
192 | copy_from_user(&permitted, &data->permitted, sizeof(permitted))) | |
193 | return -EFAULT; | |
194 | ||
195 | spin_lock(&task_capability_lock); | |
196 | read_lock(&tasklist_lock); | |
197 | ||
198 | if (pid > 0 && pid != current->pid) { | |
199 | target = find_task_by_pid(pid); | |
200 | if (!target) { | |
201 | ret = -ESRCH; | |
202 | goto out; | |
203 | } | |
204 | } else | |
205 | target = current; | |
206 | ||
207 | ret = 0; | |
208 | ||
209 | /* having verified that the proposed changes are legal, | |
210 | we now put them into effect. */ | |
211 | if (pid < 0) { | |
212 | if (pid == -1) /* all procs other than current and init */ | |
213 | ret = cap_set_all(&effective, &inheritable, &permitted); | |
214 | ||
215 | else /* all procs in process group */ | |
216 | ret = cap_set_pg(-pid, &effective, &inheritable, | |
217 | &permitted); | |
218 | } else { | |
219 | ret = security_capset_check(target, &effective, &inheritable, | |
220 | &permitted); | |
221 | if (!ret) | |
222 | security_capset_set(target, &effective, &inheritable, | |
223 | &permitted); | |
224 | } | |
1da177e4 LT |
225 | |
226 | out: | |
314f70fd DW |
227 | read_unlock(&tasklist_lock); |
228 | spin_unlock(&task_capability_lock); | |
1da177e4 | 229 | |
314f70fd | 230 | return ret; |
1da177e4 | 231 | } |
12b5989b CW |
232 | |
233 | int __capable(struct task_struct *t, int cap) | |
234 | { | |
235 | if (security_capable(t, cap) == 0) { | |
236 | t->flags |= PF_SUPERPRIV; | |
237 | return 1; | |
238 | } | |
239 | return 0; | |
240 | } | |
12b5989b CW |
241 | |
242 | int capable(int cap) | |
243 | { | |
244 | return __capable(current, cap); | |
245 | } | |
246 | EXPORT_SYMBOL(capable); |