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1da177e4 LT |
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@transmeta.com> | |
7 | * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net> | |
8 | */ | |
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 | ||
17 | unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */ | |
18 | kernel_cap_t cap_bset = CAP_INIT_EFF_SET; | |
19 | ||
20 | EXPORT_SYMBOL(securebits); | |
21 | EXPORT_SYMBOL(cap_bset); | |
22 | ||
23 | /* | |
24 | * This lock protects task->cap_* for all tasks including current. | |
25 | * Locking rule: acquire this prior to tasklist_lock. | |
26 | */ | |
27 | static DEFINE_SPINLOCK(task_capability_lock); | |
28 | ||
29 | /* | |
30 | * For sys_getproccap() and sys_setproccap(), any of the three | |
31 | * capability set pointers may be NULL -- indicating that that set is | |
32 | * uninteresting and/or not to be changed. | |
33 | */ | |
34 | ||
207a7ba8 | 35 | /** |
1da177e4 | 36 | * sys_capget - get the capabilities of a given process. |
207a7ba8 RD |
37 | * @header: pointer to struct that contains capability version and |
38 | * target pid data | |
39 | * @dataptr: pointer to struct that contains the effective, permitted, | |
40 | * and inheritable capabilities that are returned | |
41 | * | |
42 | * Returns 0 on success and < 0 on error. | |
1da177e4 LT |
43 | */ |
44 | asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr) | |
45 | { | |
46 | int ret = 0; | |
47 | pid_t pid; | |
48 | __u32 version; | |
49 | task_t *target; | |
50 | struct __user_cap_data_struct data; | |
51 | ||
52 | if (get_user(version, &header->version)) | |
53 | return -EFAULT; | |
54 | ||
55 | if (version != _LINUX_CAPABILITY_VERSION) { | |
56 | if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) | |
57 | return -EFAULT; | |
58 | return -EINVAL; | |
59 | } | |
60 | ||
61 | if (get_user(pid, &header->pid)) | |
62 | return -EFAULT; | |
63 | ||
64 | if (pid < 0) | |
65 | return -EINVAL; | |
66 | ||
67 | spin_lock(&task_capability_lock); | |
68 | read_lock(&tasklist_lock); | |
69 | ||
70 | if (pid && pid != current->pid) { | |
71 | target = find_task_by_pid(pid); | |
72 | if (!target) { | |
73 | ret = -ESRCH; | |
74 | goto out; | |
75 | } | |
76 | } else | |
77 | target = current; | |
78 | ||
79 | ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted); | |
80 | ||
81 | out: | |
82 | read_unlock(&tasklist_lock); | |
83 | spin_unlock(&task_capability_lock); | |
84 | ||
85 | if (!ret && copy_to_user(dataptr, &data, sizeof data)) | |
86 | return -EFAULT; | |
87 | ||
88 | return ret; | |
89 | } | |
90 | ||
91 | /* | |
92 | * cap_set_pg - set capabilities for all processes in a given process | |
93 | * group. We call this holding task_capability_lock and tasklist_lock. | |
94 | */ | |
95 | static inline int cap_set_pg(int pgrp, kernel_cap_t *effective, | |
96 | kernel_cap_t *inheritable, | |
97 | kernel_cap_t *permitted) | |
98 | { | |
99 | task_t *g, *target; | |
100 | int ret = -EPERM; | |
101 | int found = 0; | |
102 | ||
103 | do_each_task_pid(pgrp, PIDTYPE_PGID, g) { | |
104 | target = g; | |
105 | while_each_thread(g, target) { | |
106 | if (!security_capset_check(target, effective, | |
107 | inheritable, | |
108 | permitted)) { | |
109 | security_capset_set(target, effective, | |
110 | inheritable, | |
111 | permitted); | |
112 | ret = 0; | |
113 | } | |
114 | found = 1; | |
115 | } | |
116 | } while_each_task_pid(pgrp, PIDTYPE_PGID, g); | |
117 | ||
118 | if (!found) | |
119 | ret = 0; | |
120 | return ret; | |
121 | } | |
122 | ||
123 | /* | |
124 | * cap_set_all - set capabilities for all processes other than init | |
125 | * and self. We call this holding task_capability_lock and tasklist_lock. | |
126 | */ | |
127 | static inline int cap_set_all(kernel_cap_t *effective, | |
128 | kernel_cap_t *inheritable, | |
129 | kernel_cap_t *permitted) | |
130 | { | |
131 | task_t *g, *target; | |
132 | int ret = -EPERM; | |
133 | int found = 0; | |
134 | ||
135 | do_each_thread(g, target) { | |
136 | if (target == current || target->pid == 1) | |
137 | continue; | |
138 | found = 1; | |
139 | if (security_capset_check(target, effective, inheritable, | |
140 | permitted)) | |
141 | continue; | |
142 | ret = 0; | |
143 | security_capset_set(target, effective, inheritable, permitted); | |
144 | } while_each_thread(g, target); | |
145 | ||
146 | if (!found) | |
147 | ret = 0; | |
148 | return ret; | |
149 | } | |
150 | ||
207a7ba8 RD |
151 | /** |
152 | * sys_capset - set capabilities for a process or a group of processes | |
153 | * @header: pointer to struct that contains capability version and | |
154 | * target pid data | |
155 | * @data: pointer to struct that contains the effective, permitted, | |
156 | * and inheritable capabilities | |
157 | * | |
158 | * Set capabilities for a given process, all processes, or all | |
1da177e4 LT |
159 | * processes in a given process group. |
160 | * | |
161 | * The restrictions on setting capabilities are specified as: | |
162 | * | |
163 | * [pid is for the 'target' task. 'current' is the calling task.] | |
164 | * | |
165 | * I: any raised capabilities must be a subset of the (old current) permitted | |
166 | * P: any raised capabilities must be a subset of the (old current) permitted | |
167 | * E: must be set to a subset of (new target) permitted | |
207a7ba8 RD |
168 | * |
169 | * Returns 0 on success and < 0 on error. | |
1da177e4 LT |
170 | */ |
171 | asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) | |
172 | { | |
173 | kernel_cap_t inheritable, permitted, effective; | |
174 | __u32 version; | |
175 | task_t *target; | |
176 | int ret; | |
177 | pid_t pid; | |
178 | ||
179 | if (get_user(version, &header->version)) | |
180 | return -EFAULT; | |
181 | ||
182 | if (version != _LINUX_CAPABILITY_VERSION) { | |
183 | if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) | |
184 | return -EFAULT; | |
185 | return -EINVAL; | |
186 | } | |
187 | ||
188 | if (get_user(pid, &header->pid)) | |
189 | return -EFAULT; | |
190 | ||
191 | if (pid && pid != current->pid && !capable(CAP_SETPCAP)) | |
192 | return -EPERM; | |
193 | ||
194 | if (copy_from_user(&effective, &data->effective, sizeof(effective)) || | |
195 | copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) || | |
196 | copy_from_user(&permitted, &data->permitted, sizeof(permitted))) | |
197 | return -EFAULT; | |
198 | ||
199 | spin_lock(&task_capability_lock); | |
200 | read_lock(&tasklist_lock); | |
201 | ||
202 | if (pid > 0 && pid != current->pid) { | |
203 | target = find_task_by_pid(pid); | |
204 | if (!target) { | |
205 | ret = -ESRCH; | |
206 | goto out; | |
207 | } | |
208 | } else | |
209 | target = current; | |
210 | ||
211 | ret = 0; | |
212 | ||
213 | /* having verified that the proposed changes are legal, | |
214 | we now put them into effect. */ | |
215 | if (pid < 0) { | |
216 | if (pid == -1) /* all procs other than current and init */ | |
217 | ret = cap_set_all(&effective, &inheritable, &permitted); | |
218 | ||
219 | else /* all procs in process group */ | |
220 | ret = cap_set_pg(-pid, &effective, &inheritable, | |
221 | &permitted); | |
222 | } else { | |
223 | ret = security_capset_check(target, &effective, &inheritable, | |
224 | &permitted); | |
225 | if (!ret) | |
226 | security_capset_set(target, &effective, &inheritable, | |
227 | &permitted); | |
228 | } | |
229 | ||
230 | out: | |
231 | read_unlock(&tasklist_lock); | |
232 | spin_unlock(&task_capability_lock); | |
233 | ||
234 | return ret; | |
235 | } | |
12b5989b CW |
236 | |
237 | int __capable(struct task_struct *t, int cap) | |
238 | { | |
239 | if (security_capable(t, cap) == 0) { | |
240 | t->flags |= PF_SUPERPRIV; | |
241 | return 1; | |
242 | } | |
243 | return 0; | |
244 | } | |
245 | EXPORT_SYMBOL(__capable); | |
246 | ||
247 | int capable(int cap) | |
248 | { | |
249 | return __capable(current, cap); | |
250 | } | |
251 | EXPORT_SYMBOL(capable); |