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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 | ||
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 | ||
16 | unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */ | |
17 | kernel_cap_t cap_bset = CAP_INIT_EFF_SET; | |
18 | ||
19 | EXPORT_SYMBOL(securebits); | |
20 | EXPORT_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 | */ | |
26 | static 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 | */ | |
37 | asmlinkage 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 | ||
74 | out: | |
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 | */ | |
88 | static 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 | */ | |
120 | static 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 | */ | |
156 | asmlinkage 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 | ||
215 | out: | |
216 | read_unlock(&tasklist_lock); | |
217 | spin_unlock(&task_capability_lock); | |
218 | ||
219 | return ret; | |
220 | } |