Linux 5.2-rc1
[linux-2.6-block.git] / fs / proc / proc_net.c
CommitLineData
3c12afe7
DM
1/*
2 * linux/fs/proc/net.c
3 *
4 * Copyright (C) 2007
5 *
6 * Author: Eric Biederman <ebiederm@xmission.com>
7 *
8 * proc net directory handling functions
9 */
10
7c0f6ba6 11#include <linux/uaccess.h>
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12
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/proc_fs.h>
16#include <linux/stat.h>
5a0e3ad6 17#include <linux/slab.h>
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18#include <linux/init.h>
19#include <linux/sched.h>
f719ff9b 20#include <linux/sched/task.h>
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21#include <linux/module.h>
22#include <linux/bitops.h>
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23#include <linux/mount.h>
24#include <linux/nsproxy.h>
c110486f 25#include <linux/uidgid.h>
3c12afe7 26#include <net/net_namespace.h>
e372c414 27#include <linux/seq_file.h>
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28
29#include "internal.h"
30
4abfd029
DH
31static inline struct net *PDE_NET(struct proc_dir_entry *pde)
32{
33 return pde->parent->data;
34}
3c12afe7 35
8086cd45
AB
36static struct net *get_proc_net(const struct inode *inode)
37{
38 return maybe_get_net(PDE_NET(PDE(inode)));
39}
40
1fde6f21
AD
41static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
42{
43 return 0;
44}
45
46static const struct dentry_operations proc_net_dentry_ops = {
47 .d_revalidate = proc_net_d_revalidate,
48 .d_delete = always_delete_dentry,
49};
50
51static void pde_force_lookup(struct proc_dir_entry *pde)
52{
53 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
54 pde->proc_dops = &proc_net_dentry_ops;
55}
56
c3506372 57static int seq_open_net(struct inode *inode, struct file *file)
e372c414 58{
c3506372 59 unsigned int state_size = PDE(inode)->state_size;
e372c414 60 struct seq_net_private *p;
c3506372 61 struct net *net;
e372c414 62
c3506372 63 WARN_ON_ONCE(state_size < sizeof(*p));
e372c414 64
564def71
DH
65 if (file->f_mode & FMODE_WRITE && !PDE(inode)->write)
66 return -EACCES;
67
c3506372
CH
68 net = get_proc_net(inode);
69 if (!net)
e372c414
DL
70 return -ENXIO;
71
c3506372
CH
72 p = __seq_open_private(file, PDE(inode)->seq_ops, state_size);
73 if (!p) {
e372c414
DL
74 put_net(net);
75 return -ENOMEM;
76 }
1218854a 77#ifdef CONFIG_NET_NS
e372c414 78 p->net = net;
1218854a 79#endif
e372c414
DL
80 return 0;
81}
c3506372
CH
82
83static int seq_release_net(struct inode *ino, struct file *f)
84{
85 struct seq_file *seq = f->private_data;
86
87 put_net(seq_file_net(seq));
88 seq_release_private(ino, f);
89 return 0;
90}
91
92static const struct file_operations proc_net_seq_fops = {
93 .open = seq_open_net,
94 .read = seq_read,
564def71 95 .write = proc_simple_write,
c3506372
CH
96 .llseek = seq_lseek,
97 .release = seq_release_net,
98};
99
100struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
101 struct proc_dir_entry *parent, const struct seq_operations *ops,
102 unsigned int state_size, void *data)
103{
104 struct proc_dir_entry *p;
105
106 p = proc_create_reg(name, mode, &parent, data);
107 if (!p)
108 return NULL;
1fde6f21 109 pde_force_lookup(p);
c3506372
CH
110 p->proc_fops = &proc_net_seq_fops;
111 p->seq_ops = ops;
112 p->state_size = state_size;
113 return proc_register(parent, p);
114}
115EXPORT_SYMBOL_GPL(proc_create_net_data);
e372c414 116
564def71
DH
117/**
118 * proc_create_net_data_write - Create a writable net_ns-specific proc file
119 * @name: The name of the file.
120 * @mode: The file's access mode.
121 * @parent: The parent directory in which to create.
122 * @ops: The seq_file ops with which to read the file.
123 * @write: The write method which which to 'modify' the file.
124 * @data: Data for retrieval by PDE_DATA().
125 *
126 * Create a network namespaced proc file in the @parent directory with the
127 * specified @name and @mode that allows reading of a file that displays a
128 * series of elements and also provides for the file accepting writes that have
129 * some arbitrary effect.
130 *
131 * The functions in the @ops table are used to iterate over items to be
132 * presented and extract the readable content using the seq_file interface.
133 *
134 * The @write function is called with the data copied into a kernel space
135 * scratch buffer and has a NUL appended for convenience. The buffer may be
136 * modified by the @write function. @write should return 0 on success.
137 *
138 * The @data value is accessible from the @show and @write functions by calling
139 * PDE_DATA() on the file inode. The network namespace must be accessed by
140 * calling seq_file_net() on the seq_file struct.
141 */
142struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode,
143 struct proc_dir_entry *parent,
144 const struct seq_operations *ops,
145 proc_write_t write,
146 unsigned int state_size, void *data)
147{
148 struct proc_dir_entry *p;
149
150 p = proc_create_reg(name, mode, &parent, data);
151 if (!p)
152 return NULL;
1fde6f21 153 pde_force_lookup(p);
564def71
DH
154 p->proc_fops = &proc_net_seq_fops;
155 p->seq_ops = ops;
156 p->state_size = state_size;
157 p->write = write;
158 return proc_register(parent, p);
159}
160EXPORT_SYMBOL_GPL(proc_create_net_data_write);
161
3617d949 162static int single_open_net(struct inode *inode, struct file *file)
de05c557 163{
3617d949 164 struct proc_dir_entry *de = PDE(inode);
de05c557 165 struct net *net;
3617d949 166 int err;
de05c557 167
de05c557 168 net = get_proc_net(inode);
3617d949
CH
169 if (!net)
170 return -ENXIO;
de05c557 171
3617d949
CH
172 err = single_open(file, de->single_show, net);
173 if (err)
174 put_net(net);
de05c557
PE
175 return err;
176}
de05c557 177
3617d949 178static int single_release_net(struct inode *ino, struct file *f)
b6fcbdb4
PE
179{
180 struct seq_file *seq = f->private_data;
181 put_net(seq->private);
182 return single_release(ino, f);
183}
3617d949
CH
184
185static const struct file_operations proc_net_single_fops = {
186 .open = single_open_net,
187 .read = seq_read,
564def71 188 .write = proc_simple_write,
3617d949
CH
189 .llseek = seq_lseek,
190 .release = single_release_net,
191};
192
193struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode,
194 struct proc_dir_entry *parent,
195 int (*show)(struct seq_file *, void *), void *data)
196{
197 struct proc_dir_entry *p;
198
199 p = proc_create_reg(name, mode, &parent, data);
200 if (!p)
201 return NULL;
1fde6f21 202 pde_force_lookup(p);
3617d949
CH
203 p->proc_fops = &proc_net_single_fops;
204 p->single_show = show;
205 return proc_register(parent, p);
206}
207EXPORT_SYMBOL_GPL(proc_create_net_single);
b6fcbdb4 208
564def71
DH
209/**
210 * proc_create_net_single_write - Create a writable net_ns-specific proc file
211 * @name: The name of the file.
212 * @mode: The file's access mode.
213 * @parent: The parent directory in which to create.
214 * @show: The seqfile show method with which to read the file.
215 * @write: The write method which which to 'modify' the file.
216 * @data: Data for retrieval by PDE_DATA().
217 *
218 * Create a network-namespaced proc file in the @parent directory with the
219 * specified @name and @mode that allows reading of a file that displays a
220 * single element rather than a series and also provides for the file accepting
221 * writes that have some arbitrary effect.
222 *
223 * The @show function is called to extract the readable content via the
224 * seq_file interface.
225 *
226 * The @write function is called with the data copied into a kernel space
227 * scratch buffer and has a NUL appended for convenience. The buffer may be
228 * modified by the @write function. @write should return 0 on success.
229 *
230 * The @data value is accessible from the @show and @write functions by calling
231 * PDE_DATA() on the file inode. The network namespace must be accessed by
232 * calling seq_file_single_net() on the seq_file struct.
233 */
234struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode,
235 struct proc_dir_entry *parent,
236 int (*show)(struct seq_file *, void *),
237 proc_write_t write,
238 void *data)
239{
240 struct proc_dir_entry *p;
241
242 p = proc_create_reg(name, mode, &parent, data);
243 if (!p)
244 return NULL;
1fde6f21 245 pde_force_lookup(p);
564def71
DH
246 p->proc_fops = &proc_net_single_fops;
247 p->single_show = show;
248 p->write = write;
249 return proc_register(parent, p);
250}
251EXPORT_SYMBOL_GPL(proc_create_net_single_write);
252
e9720acd
PE
253static struct net *get_proc_task_net(struct inode *dir)
254{
255 struct task_struct *task;
256 struct nsproxy *ns;
257 struct net *net = NULL;
258
259 rcu_read_lock();
260 task = pid_task(proc_pid(dir), PIDTYPE_PID);
261 if (task != NULL) {
728dba3a
EB
262 task_lock(task);
263 ns = task->nsproxy;
e9720acd
PE
264 if (ns != NULL)
265 net = get_net(ns->net_ns);
728dba3a 266 task_unlock(task);
e9720acd
PE
267 }
268 rcu_read_unlock();
269
270 return net;
271}
272
273static struct dentry *proc_tgid_net_lookup(struct inode *dir,
00cd8dd3 274 struct dentry *dentry, unsigned int flags)
e9720acd
PE
275{
276 struct dentry *de;
277 struct net *net;
278
279 de = ERR_PTR(-ENOENT);
280 net = get_proc_task_net(dir);
281 if (net != NULL) {
93ad5bc6 282 de = proc_lookup_de(dir, dentry, net->proc_net);
e9720acd
PE
283 put_net(net);
284 }
285 return de;
286}
287
a528d35e
DH
288static int proc_tgid_net_getattr(const struct path *path, struct kstat *stat,
289 u32 request_mask, unsigned int query_flags)
e9720acd 290{
a528d35e 291 struct inode *inode = d_inode(path->dentry);
e9720acd
PE
292 struct net *net;
293
294 net = get_proc_task_net(inode);
295
296 generic_fillattr(inode, stat);
297
298 if (net != NULL) {
299 stat->nlink = net->proc_net->nlink;
300 put_net(net);
301 }
302
303 return 0;
304}
305
306const struct inode_operations proc_net_inode_operations = {
307 .lookup = proc_tgid_net_lookup,
308 .getattr = proc_tgid_net_getattr,
309};
310
f0c3b509 311static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
e9720acd
PE
312{
313 int ret;
314 struct net *net;
315
316 ret = -EINVAL;
f0c3b509 317 net = get_proc_task_net(file_inode(file));
e9720acd 318 if (net != NULL) {
93ad5bc6 319 ret = proc_readdir_de(file, ctx, net->proc_net);
e9720acd
PE
320 put_net(net);
321 }
322 return ret;
323}
324
325const struct file_operations proc_net_operations = {
b4df2b92 326 .llseek = generic_file_llseek,
e9720acd 327 .read = generic_read_dir,
f50752ea 328 .iterate_shared = proc_tgid_net_readdir,
e9720acd
PE
329};
330
4665079c 331static __net_init int proc_net_ns_init(struct net *net)
3c12afe7 332{
e9720acd 333 struct proc_dir_entry *netd, *net_statd;
c110486f
DT
334 kuid_t uid;
335 kgid_t gid;
3c12afe7
DM
336 int err;
337
338 err = -ENOMEM;
b4884f23 339 netd = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
e9720acd 340 if (!netd)
3c12afe7
DM
341 goto out;
342
4f113437 343 netd->subdir = RB_ROOT;
e9720acd
PE
344 netd->data = net;
345 netd->nlink = 2;
e9720acd
PE
346 netd->namelen = 3;
347 netd->parent = &proc_root;
b4884f23 348 netd->name = netd->inline_name;
09570f91 349 memcpy(netd->name, "net", 4);
3c12afe7 350
c110486f
DT
351 uid = make_kuid(net->user_ns, 0);
352 if (!uid_valid(uid))
353 uid = netd->uid;
354
355 gid = make_kgid(net->user_ns, 0);
356 if (!gid_valid(gid))
357 gid = netd->gid;
358
359 proc_set_user(netd, uid, gid);
360
3c12afe7 361 err = -EEXIST;
e5d69b9f 362 net_statd = proc_net_mkdir(net, "stat", netd);
3c12afe7
DM
363 if (!net_statd)
364 goto free_net;
365
3c12afe7
DM
366 net->proc_net = netd;
367 net->proc_net_stat = net_statd;
e9720acd 368 return 0;
3c12afe7 369
e9720acd 370free_net:
b4884f23 371 pde_free(netd);
3c12afe7
DM
372out:
373 return err;
3c12afe7
DM
374}
375
4665079c 376static __net_exit void proc_net_ns_exit(struct net *net)
3c12afe7
DM
377{
378 remove_proc_entry("stat", net->proc_net);
b4884f23 379 pde_free(net->proc_net);
3c12afe7
DM
380}
381
022cbae6 382static struct pernet_operations __net_initdata proc_net_ns_ops = {
3c12afe7
DM
383 .init = proc_net_ns_init,
384 .exit = proc_net_ns_exit,
385};
386
4665079c 387int __init proc_net_init(void)
3c12afe7 388{
155134fe 389 proc_symlink("net", NULL, "self/net");
3c12afe7
DM
390
391 return register_pernet_subsys(&proc_net_ns_ops);
392}