projects/linux·blob v5.5-rc2 · refs

171 lines · 3.8 KiB

1// SPDX-License-Identifier: GPL-2.0
2#include <linux/stat.h>
3#include <linux/sysctl.h>
4#include "../fs/xfs/xfs_sysctl.h"
5#include <linux/sunrpc/debug.h>
6#include <linux/string.h>
7#include <linux/syscalls.h>
8#include <linux/namei.h>
9#include <linux/mount.h>
10#include <linux/fs.h>
11#include <linux/nsproxy.h>
12#include <linux/pid_namespace.h>
13#include <linux/file.h>
14#include <linux/ctype.h>
15#include <linux/netdevice.h>
16#include <linux/kernel.h>
17#include <linux/uuid.h>
18#include <linux/slab.h>
19#include <linux/compat.h>
20
21static ssize_t binary_sysctl(const int *name, int nlen,
22 void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
23{
24 return -ENOSYS;
25}
26
27static void deprecated_sysctl_warning(const int *name, int nlen)
28{
29 int i;
30
31 /*
32 * CTL_KERN/KERN_VERSION is used by older glibc and cannot
33 * ever go away.
34 */
35 if (nlen >= 2 && name[0] == CTL_KERN && name[1] == KERN_VERSION)
36 return;
37
38 if (printk_ratelimit()) {
39 printk(KERN_INFO
40 "warning: process `%s' used the deprecated sysctl "
41 "system call with ", current->comm);
42 for (i = 0; i < nlen; i++)
43 printk(KERN_CONT "%d.", name[i]);
44 printk(KERN_CONT "\n");
45 }
46 return;
47}
48
49#define WARN_ONCE_HASH_BITS 8
50#define WARN_ONCE_HASH_SIZE (1<<WARN_ONCE_HASH_BITS)
51
52static DECLARE_BITMAP(warn_once_bitmap, WARN_ONCE_HASH_SIZE);
53
54#define FNV32_OFFSET 2166136261U
55#define FNV32_PRIME 0x01000193
56
57/*
58 * Print each legacy sysctl (approximately) only once.
59 * To avoid making the tables non-const use a external
60 * hash-table instead.
61 * Worst case hash collision: 6, but very rarely.
62 * NOTE! We don't use the SMP-safe bit tests. We simply
63 * don't care enough.
64 */
65static void warn_on_bintable(const int *name, int nlen)
66{
67 int i;
68 u32 hash = FNV32_OFFSET;
69
70 for (i = 0; i < nlen; i++)
71 hash = (hash ^ name[i]) * FNV32_PRIME;
72 hash %= WARN_ONCE_HASH_SIZE;
73 if (__test_and_set_bit(hash, warn_once_bitmap))
74 return;
75 deprecated_sysctl_warning(name, nlen);
76}
77
78static ssize_t do_sysctl(int __user *args_name, int nlen,
79 void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
80{
81 int name[CTL_MAXNAME];
82 int i;
83
84 /* Check args->nlen. */
85 if (nlen < 0 || nlen > CTL_MAXNAME)
86 return -ENOTDIR;
87 /* Read in the sysctl name for simplicity */
88 for (i = 0; i < nlen; i++)
89 if (get_user(name[i], args_name + i))
90 return -EFAULT;
91
92 warn_on_bintable(name, nlen);
93
94 return binary_sysctl(name, nlen, oldval, oldlen, newval, newlen);
95}
96
97SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
98{
99 struct __sysctl_args tmp;
100 size_t oldlen = 0;
101 ssize_t result;
102
103 if (copy_from_user(&tmp, args, sizeof(tmp)))
104 return -EFAULT;
105
106 if (tmp.oldval && !tmp.oldlenp)
107 return -EFAULT;
108
109 if (tmp.oldlenp && get_user(oldlen, tmp.oldlenp))
110 return -EFAULT;
111
112 result = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, oldlen,
113 tmp.newval, tmp.newlen);
114
115 if (result >= 0) {
116 oldlen = result;
117 result = 0;
118 }
119
120 if (tmp.oldlenp && put_user(oldlen, tmp.oldlenp))
121 return -EFAULT;
122
123 return result;
124}
125
126
127#ifdef CONFIG_COMPAT
128
129struct compat_sysctl_args {
130 compat_uptr_t name;
131 int nlen;
132 compat_uptr_t oldval;
133 compat_uptr_t oldlenp;
134 compat_uptr_t newval;
135 compat_size_t newlen;
136 compat_ulong_t __unused[4];
137};
138
139COMPAT_SYSCALL_DEFINE1(sysctl, struct compat_sysctl_args __user *, args)
140{
141 struct compat_sysctl_args tmp;
142 compat_size_t __user *compat_oldlenp;
143 size_t oldlen = 0;
144 ssize_t result;
145
146 if (copy_from_user(&tmp, args, sizeof(tmp)))
147 return -EFAULT;
148
149 if (tmp.oldval && !tmp.oldlenp)
150 return -EFAULT;
151
152 compat_oldlenp = compat_ptr(tmp.oldlenp);
153 if (compat_oldlenp && get_user(oldlen, compat_oldlenp))
154 return -EFAULT;
155
156 result = do_sysctl(compat_ptr(tmp.name), tmp.nlen,
157 compat_ptr(tmp.oldval), oldlen,
158 compat_ptr(tmp.newval), tmp.newlen);
159
160 if (result >= 0) {
161 oldlen = result;
162 result = 0;
163 }
164
165 if (compat_oldlenp && put_user(oldlen, compat_oldlenp))
166 return -EFAULT;
167
168 return result;
169}
170
171#endif /* CONFIG_COMPAT */