1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/*
* linux/kernel/capability.c
*
* Copyright (C) 1997 Andrew Main <zefram@fysh.org>
* Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com>
*/
#include <linux/mm.h>
#include <asm/uaccess.h>
kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
/* Note: never hold tasklist_lock while spinning for this one */
spinlock_t task_capability_lock = SPIN_LOCK_UNLOCKED;
/*
* For sys_getproccap() and sys_setproccap(), any of the three
* capability set pointers may be NULL -- indicating that that set is
* uninteresting and/or not to be changed.
*/
asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
{
int error, pid;
__u32 version;
struct task_struct *target;
struct __user_cap_data_struct data;
if (get_user(version, &header->version))
return -EFAULT;
error = -EINVAL;
if (version != _LINUX_CAPABILITY_VERSION) {
version = _LINUX_CAPABILITY_VERSION;
if (put_user(version, &header->version))
error = -EFAULT;
return error;
}
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid < 0)
return -EINVAL;
error = 0;
spin_lock(&task_capability_lock);
if (pid && pid != current->pid) {
read_lock(&tasklist_lock);
target = find_task_by_pid(pid); /* identify target of query */
if (!target)
error = -ESRCH;
} else {
target = current;
}
if (!error) {
data.permitted = cap_t(target->cap_permitted);
data.inheritable = cap_t(target->cap_inheritable);
data.effective = cap_t(target->cap_effective);
}
if (target != current)
read_unlock(&tasklist_lock);
spin_unlock(&task_capability_lock);
if (!error) {
if (copy_to_user(dataptr, &data, sizeof data))
return -EFAULT;
}
return error;
}
/* set capabilities for all processes in a given process group */
static void cap_set_pg(int pgrp,
kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
struct task_struct *target;
/* FIXME: do we need to have a write lock here..? */
read_lock(&tasklist_lock);
for_each_task(target) {
if (target->pgrp != pgrp)
continue;
target->cap_effective = *effective;
target->cap_inheritable = *inheritable;
target->cap_permitted = *permitted;
}
read_unlock(&tasklist_lock);
}
/* set capabilities for all processes other than 1 and self */
static void cap_set_all(kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
struct task_struct *target;
/* FIXME: do we need to have a write lock here..? */
read_lock(&tasklist_lock);
/* ALL means everyone other than self or 'init' */
for_each_task(target) {
if (target == current || target->pid == 1)
continue;
target->cap_effective = *effective;
target->cap_inheritable = *inheritable;
target->cap_permitted = *permitted;
}
read_unlock(&tasklist_lock);
}
/*
* The restrictions on setting capabilities are specified as:
*
* [pid is for the 'target' task. 'current' is the calling task.]
*
* I: any raised capabilities must be a subset of the (old current) Permitted
* P: any raised capabilities must be a subset of the (old current) permitted
* E: must be set to a subset of (new target) Permitted
*/
asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
{
kernel_cap_t inheritable, permitted, effective;
__u32 version;
struct task_struct *target;
int error, pid;
if (get_user(version, &header->version))
return -EFAULT;
if (version != _LINUX_CAPABILITY_VERSION) {
version = _LINUX_CAPABILITY_VERSION;
if (put_user(version, &header->version))
return -EFAULT;
return -EINVAL;
}
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid && !capable(CAP_SETPCAP))
return -EPERM;
if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
return -EFAULT;
error = -EPERM;
spin_lock(&task_capability_lock);
if (pid > 0 && pid != current->pid) {
read_lock(&tasklist_lock);
target = find_task_by_pid(pid); /* identify target of query */
if (!target) {
error = -ESRCH;
goto out;
}
} else {
target = current;
}
/* verify restrictions on target's new Inheritable set */
if (!cap_issubset(inheritable,
cap_combine(target->cap_inheritable,
current->cap_permitted))) {
goto out;
}
/* verify restrictions on target's new Permitted set */
if (!cap_issubset(permitted,
cap_combine(target->cap_permitted,
current->cap_permitted))) {
goto out;
}
/* verify the _new_Effective_ is a subset of the _new_Permitted_ */
if (!cap_issubset(effective, permitted)) {
goto out;
}
/* having verified that the proposed changes are legal,
we now put them into effect. */
error = 0;
if (pid < 0) {
if (pid == -1) /* all procs other than current and init */
cap_set_all(&effective, &inheritable, &permitted);
else /* all procs in process group */
cap_set_pg(-pid, &effective, &inheritable, &permitted);
goto spin_out;
} else {
/* FIXME: do we need to have a write lock here..? */
target->cap_effective = effective;
target->cap_inheritable = inheritable;
target->cap_permitted = permitted;
}
out:
if (target != current) {
read_unlock(&tasklist_lock);
}
spin_out:
spin_unlock(&task_capability_lock);
return error;
}
|
