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
|
#include <linux/stat.h>
#include <linux/sysctl.h>
#include "../fs/xfs/linux-2.6/xfs_sysctl.h"
#include <linux/sunrpc/debug.h>
#include <linux/string.h>
#include <net/ip_vs.h>
#include <linux/syscalls.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include <linux/nsproxy.h>
#include <linux/pid_namespace.h>
#include <linux/file.h>
#include <linux/ctype.h>
#include <linux/smp_lock.h>
#ifdef CONFIG_SYSCTL_SYSCALL
/* Perform the actual read/write of a sysctl table entry. */
static int do_sysctl_strategy(struct ctl_table_root *root,
struct ctl_table *table,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
int op = 0, rc;
if (oldval)
op |= MAY_READ;
if (newval)
op |= MAY_WRITE;
if (sysctl_perm(root, table, op))
return -EPERM;
if (table->strategy) {
rc = table->strategy(table, oldval, oldlenp, newval, newlen);
if (rc < 0)
return rc;
if (rc > 0)
return 0;
}
/* If there is no strategy routine, or if the strategy returns
* zero, proceed with automatic r/w */
if (table->data && table->maxlen) {
rc = sysctl_data(table, oldval, oldlenp, newval, newlen);
if (rc < 0)
return rc;
}
return 0;
}
static int parse_table(const int *name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen,
struct ctl_table_root *root,
struct ctl_table *table)
{
int n;
repeat:
if (!nlen)
return -ENOTDIR;
n = *name;
for ( ; table->ctl_name || table->procname; table++) {
if (!table->ctl_name)
continue;
if (n == table->ctl_name) {
int error;
if (table->child) {
if (sysctl_perm(root, table, MAY_EXEC))
return -EPERM;
name++;
nlen--;
table = table->child;
goto repeat;
}
error = do_sysctl_strategy(root, table,
oldval, oldlenp,
newval, newlen);
return error;
}
}
return -ENOTDIR;
}
static ssize_t binary_sysctl(const int *name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
struct ctl_table_header *head;
ssize_t error = -ENOTDIR;
for (head = sysctl_head_next(NULL); head;
head = sysctl_head_next(head)) {
error = parse_table(name, nlen, oldval, oldlenp,
newval, newlen,
head->root, head->ctl_table);
if (error != -ENOTDIR) {
sysctl_head_finish(head);
break;
}
}
return error;
}
#else /* CONFIG_SYSCTL_SYSCALL */
static ssize_t binary_sysctl(const int *ctl_name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
return -ENOSYS;
}
#endif /* CONFIG_SYSCTL_SYSCALL */
static void deprecated_sysctl_warning(const int *name, int nlen)
{
static int msg_count;
int i;
/* Ignore accesses to kernel.version */
if ((nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
return;
if (msg_count < 5) {
msg_count++;
printk(KERN_INFO
"warning: process `%s' used the deprecated sysctl "
"system call with ", current->comm);
for (i = 0; i < nlen; i++)
printk("%d.", name[i]);
printk("\n");
}
return;
}
int do_sysctl(int __user *args_name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
int name[CTL_MAXNAME];
size_t oldlen = 0;
int i;
if (nlen <= 0 || nlen >= CTL_MAXNAME)
return -ENOTDIR;
if (oldval && !oldlenp)
return -EFAULT;
if (oldlenp && get_user(oldlen, oldlenp))
return -EFAULT;
/* Read in the sysctl name for simplicity */
for (i = 0; i < nlen; i++)
if (get_user(name[i], args_name + i))
return -EFAULT;
deprecated_sysctl_warning(name, nlen);
return binary_sysctl(name, nlen, oldval, oldlenp, newval, newlen);
}
SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
{
struct __sysctl_args tmp;
int error;
if (copy_from_user(&tmp, args, sizeof(tmp)))
return -EFAULT;
lock_kernel();
error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
tmp.newval, tmp.newlen);
unlock_kernel();
return error;
}
|
