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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
11#include <asm/uaccess.h>
12
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/proc_fs.h>
16#include <linux/stat.h>
17#include <linux/slab.h>
18#include <linux/init.h>
19#include <linux/sched.h>
20#include <linux/module.h>
21#include <linux/bitops.h>
22#include <linux/mount.h>
23#include <linux/nsproxy.h>
24#include <net/net_namespace.h>
25#include <linux/seq_file.h>
26
27#include "internal.h"
28
29
30static struct net *get_proc_net(const struct inode *inode)
31{
32 return maybe_get_net(PDE_NET(PDE(inode)));
33}
34
35int seq_open_net(struct inode *ino, struct file *f,
36 const struct seq_operations *ops, int size)
37{
38 struct net *net;
39 struct seq_net_private *p;
40
41 BUG_ON(size < sizeof(*p));
42
43 net = get_proc_net(ino);
44 if (net == NULL)
45 return -ENXIO;
46
47 p = __seq_open_private(f, ops, size);
48 if (p == NULL) {
49 put_net(net);
50 return -ENOMEM;
51 }
52#ifdef CONFIG_NET_NS
53 p->net = net;
54#endif
55 return 0;
56}
57EXPORT_SYMBOL_GPL(seq_open_net);
58
59int single_open_net(struct inode *inode, struct file *file,
60 int (*show)(struct seq_file *, void *))
61{
62 int err;
63 struct net *net;
64
65 err = -ENXIO;
66 net = get_proc_net(inode);
67 if (net == NULL)
68 goto err_net;
69
70 err = single_open(file, show, net);
71 if (err < 0)
72 goto err_open;
73
74 return 0;
75
76err_open:
77 put_net(net);
78err_net:
79 return err;
80}
81EXPORT_SYMBOL_GPL(single_open_net);
82
83int seq_release_net(struct inode *ino, struct file *f)
84{
85 struct seq_file *seq;
86
87 seq = f->private_data;
88
89 put_net(seq_file_net(seq));
90 seq_release_private(ino, f);
91 return 0;
92}
93EXPORT_SYMBOL_GPL(seq_release_net);
94
95int single_release_net(struct inode *ino, struct file *f)
96{
97 struct seq_file *seq = f->private_data;
98 put_net(seq->private);
99 return single_release(ino, f);
100}
101EXPORT_SYMBOL_GPL(single_release_net);
102
103static struct net *get_proc_task_net(struct inode *dir)
104{
105 struct task_struct *task;
106 struct nsproxy *ns;
107 struct net *net = NULL;
108
109 rcu_read_lock();
110 task = pid_task(proc_pid(dir), PIDTYPE_PID);
111 if (task != NULL) {
112 ns = task_nsproxy(task);
113 if (ns != NULL)
114 net = get_net(ns->net_ns);
115 }
116 rcu_read_unlock();
117
118 return net;
119}
120
121static struct dentry *proc_tgid_net_lookup(struct inode *dir,
122 struct dentry *dentry, struct nameidata *nd)
123{
124 struct dentry *de;
125 struct net *net;
126
127 de = ERR_PTR(-ENOENT);
128 net = get_proc_task_net(dir);
129 if (net != NULL) {
130 de = proc_lookup_de(net->proc_net, dir, dentry);
131 put_net(net);
132 }
133 return de;
134}
135
136static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
137 struct kstat *stat)
138{
139 struct inode *inode = dentry->d_inode;
140 struct net *net;
141
142 net = get_proc_task_net(inode);
143
144 generic_fillattr(inode, stat);
145
146 if (net != NULL) {
147 stat->nlink = net->proc_net->nlink;
148 put_net(net);
149 }
150
151 return 0;
152}
153
154const struct inode_operations proc_net_inode_operations = {
155 .lookup = proc_tgid_net_lookup,
156 .getattr = proc_tgid_net_getattr,
157};
158
159static int proc_tgid_net_readdir(struct file *filp, void *dirent,
160 filldir_t filldir)
161{
162 int ret;
163 struct net *net;
164
165 ret = -EINVAL;
166 net = get_proc_task_net(filp->f_path.dentry->d_inode);
167 if (net != NULL) {
168 ret = proc_readdir_de(net->proc_net, filp, dirent, filldir);
169 put_net(net);
170 }
171 return ret;
172}
173
174const struct file_operations proc_net_operations = {
175 .llseek = generic_file_llseek,
176 .read = generic_read_dir,
177 .readdir = proc_tgid_net_readdir,
178};
179
180
181struct proc_dir_entry *proc_net_fops_create(struct net *net,
182 const char *name, umode_t mode, const struct file_operations *fops)
183{
184 return proc_create(name, mode, net->proc_net, fops);
185}
186EXPORT_SYMBOL_GPL(proc_net_fops_create);
187
188void proc_net_remove(struct net *net, const char *name)
189{
190 remove_proc_entry(name, net->proc_net);
191}
192EXPORT_SYMBOL_GPL(proc_net_remove);
193
194static __net_init int proc_net_ns_init(struct net *net)
195{
196 struct proc_dir_entry *netd, *net_statd;
197 int err;
198
199 err = -ENOMEM;
200 netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
201 if (!netd)
202 goto out;
203
204 netd->data = net;
205 netd->nlink = 2;
206 netd->namelen = 3;
207 netd->parent = &proc_root;
208 memcpy(netd->name, "net", 4);
209
210 err = -EEXIST;
211 net_statd = proc_net_mkdir(net, "stat", netd);
212 if (!net_statd)
213 goto free_net;
214
215 net->proc_net = netd;
216 net->proc_net_stat = net_statd;
217 return 0;
218
219free_net:
220 kfree(netd);
221out:
222 return err;
223}
224
225static __net_exit void proc_net_ns_exit(struct net *net)
226{
227 remove_proc_entry("stat", net->proc_net);
228 kfree(net->proc_net);
229}
230
231static struct pernet_operations __net_initdata proc_net_ns_ops = {
232 .init = proc_net_ns_init,
233 .exit = proc_net_ns_exit,
234};
235
236int __init proc_net_init(void)
237{
238 proc_symlink("net", NULL, "self/net");
239
240 return register_pernet_subsys(&proc_net_ns_ops);
241}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/proc/net.c
4 *
5 * Copyright (C) 2007
6 *
7 * Author: Eric Biederman <ebiederm@xmission.com>
8 *
9 * proc net directory handling functions
10 */
11
12#include <linux/uaccess.h>
13
14#include <linux/errno.h>
15#include <linux/time.h>
16#include <linux/proc_fs.h>
17#include <linux/stat.h>
18#include <linux/slab.h>
19#include <linux/init.h>
20#include <linux/sched.h>
21#include <linux/sched/task.h>
22#include <linux/module.h>
23#include <linux/bitops.h>
24#include <linux/mount.h>
25#include <linux/nsproxy.h>
26#include <linux/uidgid.h>
27#include <net/net_namespace.h>
28#include <linux/seq_file.h>
29
30#include "internal.h"
31
32static inline struct net *PDE_NET(struct proc_dir_entry *pde)
33{
34 return pde->parent->data;
35}
36
37static struct net *get_proc_net(const struct inode *inode)
38{
39 return maybe_get_net(PDE_NET(PDE(inode)));
40}
41
42static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
43{
44 return 0;
45}
46
47static const struct dentry_operations proc_net_dentry_ops = {
48 .d_revalidate = proc_net_d_revalidate,
49 .d_delete = always_delete_dentry,
50};
51
52static void pde_force_lookup(struct proc_dir_entry *pde)
53{
54 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
55 pde->proc_dops = &proc_net_dentry_ops;
56}
57
58static int seq_open_net(struct inode *inode, struct file *file)
59{
60 unsigned int state_size = PDE(inode)->state_size;
61 struct seq_net_private *p;
62 struct net *net;
63
64 WARN_ON_ONCE(state_size < sizeof(*p));
65
66 if (file->f_mode & FMODE_WRITE && !PDE(inode)->write)
67 return -EACCES;
68
69 net = get_proc_net(inode);
70 if (!net)
71 return -ENXIO;
72
73 p = __seq_open_private(file, PDE(inode)->seq_ops, state_size);
74 if (!p) {
75 put_net(net);
76 return -ENOMEM;
77 }
78#ifdef CONFIG_NET_NS
79 p->net = net;
80#endif
81 return 0;
82}
83
84static int seq_release_net(struct inode *ino, struct file *f)
85{
86 struct seq_file *seq = f->private_data;
87
88 put_net(seq_file_net(seq));
89 seq_release_private(ino, f);
90 return 0;
91}
92
93static const struct file_operations proc_net_seq_fops = {
94 .open = seq_open_net,
95 .read = seq_read,
96 .write = proc_simple_write,
97 .llseek = seq_lseek,
98 .release = seq_release_net,
99};
100
101struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
102 struct proc_dir_entry *parent, const struct seq_operations *ops,
103 unsigned int state_size, void *data)
104{
105 struct proc_dir_entry *p;
106
107 p = proc_create_reg(name, mode, &parent, data);
108 if (!p)
109 return NULL;
110 pde_force_lookup(p);
111 p->proc_fops = &proc_net_seq_fops;
112 p->seq_ops = ops;
113 p->state_size = state_size;
114 return proc_register(parent, p);
115}
116EXPORT_SYMBOL_GPL(proc_create_net_data);
117
118/**
119 * proc_create_net_data_write - Create a writable net_ns-specific proc file
120 * @name: The name of the file.
121 * @mode: The file's access mode.
122 * @parent: The parent directory in which to create.
123 * @ops: The seq_file ops with which to read the file.
124 * @write: The write method which which to 'modify' the file.
125 * @data: Data for retrieval by PDE_DATA().
126 *
127 * Create a network namespaced proc file in the @parent directory with the
128 * specified @name and @mode that allows reading of a file that displays a
129 * series of elements and also provides for the file accepting writes that have
130 * some arbitrary effect.
131 *
132 * The functions in the @ops table are used to iterate over items to be
133 * presented and extract the readable content using the seq_file interface.
134 *
135 * The @write function is called with the data copied into a kernel space
136 * scratch buffer and has a NUL appended for convenience. The buffer may be
137 * modified by the @write function. @write should return 0 on success.
138 *
139 * The @data value is accessible from the @show and @write functions by calling
140 * PDE_DATA() on the file inode. The network namespace must be accessed by
141 * calling seq_file_net() on the seq_file struct.
142 */
143struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode,
144 struct proc_dir_entry *parent,
145 const struct seq_operations *ops,
146 proc_write_t write,
147 unsigned int state_size, void *data)
148{
149 struct proc_dir_entry *p;
150
151 p = proc_create_reg(name, mode, &parent, data);
152 if (!p)
153 return NULL;
154 pde_force_lookup(p);
155 p->proc_fops = &proc_net_seq_fops;
156 p->seq_ops = ops;
157 p->state_size = state_size;
158 p->write = write;
159 return proc_register(parent, p);
160}
161EXPORT_SYMBOL_GPL(proc_create_net_data_write);
162
163static int single_open_net(struct inode *inode, struct file *file)
164{
165 struct proc_dir_entry *de = PDE(inode);
166 struct net *net;
167 int err;
168
169 net = get_proc_net(inode);
170 if (!net)
171 return -ENXIO;
172
173 err = single_open(file, de->single_show, net);
174 if (err)
175 put_net(net);
176 return err;
177}
178
179static int single_release_net(struct inode *ino, struct file *f)
180{
181 struct seq_file *seq = f->private_data;
182 put_net(seq->private);
183 return single_release(ino, f);
184}
185
186static const struct file_operations proc_net_single_fops = {
187 .open = single_open_net,
188 .read = seq_read,
189 .write = proc_simple_write,
190 .llseek = seq_lseek,
191 .release = single_release_net,
192};
193
194struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode,
195 struct proc_dir_entry *parent,
196 int (*show)(struct seq_file *, void *), void *data)
197{
198 struct proc_dir_entry *p;
199
200 p = proc_create_reg(name, mode, &parent, data);
201 if (!p)
202 return NULL;
203 pde_force_lookup(p);
204 p->proc_fops = &proc_net_single_fops;
205 p->single_show = show;
206 return proc_register(parent, p);
207}
208EXPORT_SYMBOL_GPL(proc_create_net_single);
209
210/**
211 * proc_create_net_single_write - Create a writable net_ns-specific proc file
212 * @name: The name of the file.
213 * @mode: The file's access mode.
214 * @parent: The parent directory in which to create.
215 * @show: The seqfile show method with which to read the file.
216 * @write: The write method which which to 'modify' the file.
217 * @data: Data for retrieval by PDE_DATA().
218 *
219 * Create a network-namespaced proc file in the @parent directory with the
220 * specified @name and @mode that allows reading of a file that displays a
221 * single element rather than a series and also provides for the file accepting
222 * writes that have some arbitrary effect.
223 *
224 * The @show function is called to extract the readable content via the
225 * seq_file interface.
226 *
227 * The @write function is called with the data copied into a kernel space
228 * scratch buffer and has a NUL appended for convenience. The buffer may be
229 * modified by the @write function. @write should return 0 on success.
230 *
231 * The @data value is accessible from the @show and @write functions by calling
232 * PDE_DATA() on the file inode. The network namespace must be accessed by
233 * calling seq_file_single_net() on the seq_file struct.
234 */
235struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode,
236 struct proc_dir_entry *parent,
237 int (*show)(struct seq_file *, void *),
238 proc_write_t write,
239 void *data)
240{
241 struct proc_dir_entry *p;
242
243 p = proc_create_reg(name, mode, &parent, data);
244 if (!p)
245 return NULL;
246 pde_force_lookup(p);
247 p->proc_fops = &proc_net_single_fops;
248 p->single_show = show;
249 p->write = write;
250 return proc_register(parent, p);
251}
252EXPORT_SYMBOL_GPL(proc_create_net_single_write);
253
254static struct net *get_proc_task_net(struct inode *dir)
255{
256 struct task_struct *task;
257 struct nsproxy *ns;
258 struct net *net = NULL;
259
260 rcu_read_lock();
261 task = pid_task(proc_pid(dir), PIDTYPE_PID);
262 if (task != NULL) {
263 task_lock(task);
264 ns = task->nsproxy;
265 if (ns != NULL)
266 net = get_net(ns->net_ns);
267 task_unlock(task);
268 }
269 rcu_read_unlock();
270
271 return net;
272}
273
274static struct dentry *proc_tgid_net_lookup(struct inode *dir,
275 struct dentry *dentry, unsigned int flags)
276{
277 struct dentry *de;
278 struct net *net;
279
280 de = ERR_PTR(-ENOENT);
281 net = get_proc_task_net(dir);
282 if (net != NULL) {
283 de = proc_lookup_de(dir, dentry, net->proc_net);
284 put_net(net);
285 }
286 return de;
287}
288
289static int proc_tgid_net_getattr(const struct path *path, struct kstat *stat,
290 u32 request_mask, unsigned int query_flags)
291{
292 struct inode *inode = d_inode(path->dentry);
293 struct net *net;
294
295 net = get_proc_task_net(inode);
296
297 generic_fillattr(inode, stat);
298
299 if (net != NULL) {
300 stat->nlink = net->proc_net->nlink;
301 put_net(net);
302 }
303
304 return 0;
305}
306
307const struct inode_operations proc_net_inode_operations = {
308 .lookup = proc_tgid_net_lookup,
309 .getattr = proc_tgid_net_getattr,
310};
311
312static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
313{
314 int ret;
315 struct net *net;
316
317 ret = -EINVAL;
318 net = get_proc_task_net(file_inode(file));
319 if (net != NULL) {
320 ret = proc_readdir_de(file, ctx, net->proc_net);
321 put_net(net);
322 }
323 return ret;
324}
325
326const struct file_operations proc_net_operations = {
327 .llseek = generic_file_llseek,
328 .read = generic_read_dir,
329 .iterate_shared = proc_tgid_net_readdir,
330};
331
332static __net_init int proc_net_ns_init(struct net *net)
333{
334 struct proc_dir_entry *netd, *net_statd;
335 kuid_t uid;
336 kgid_t gid;
337 int err;
338
339 err = -ENOMEM;
340 netd = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
341 if (!netd)
342 goto out;
343
344 netd->subdir = RB_ROOT;
345 netd->data = net;
346 netd->nlink = 2;
347 netd->namelen = 3;
348 netd->parent = &proc_root;
349 netd->name = netd->inline_name;
350 memcpy(netd->name, "net", 4);
351
352 uid = make_kuid(net->user_ns, 0);
353 if (!uid_valid(uid))
354 uid = netd->uid;
355
356 gid = make_kgid(net->user_ns, 0);
357 if (!gid_valid(gid))
358 gid = netd->gid;
359
360 proc_set_user(netd, uid, gid);
361
362 err = -EEXIST;
363 net_statd = proc_net_mkdir(net, "stat", netd);
364 if (!net_statd)
365 goto free_net;
366
367 net->proc_net = netd;
368 net->proc_net_stat = net_statd;
369 return 0;
370
371free_net:
372 pde_free(netd);
373out:
374 return err;
375}
376
377static __net_exit void proc_net_ns_exit(struct net *net)
378{
379 remove_proc_entry("stat", net->proc_net);
380 pde_free(net->proc_net);
381}
382
383static struct pernet_operations __net_initdata proc_net_ns_ops = {
384 .init = proc_net_ns_init,
385 .exit = proc_net_ns_exit,
386};
387
388int __init proc_net_init(void)
389{
390 proc_symlink("net", NULL, "self/net");
391
392 return register_pernet_subsys(&proc_net_ns_ops);
393}