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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 <linux/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 <linux/uidgid.h>
25#include <net/net_namespace.h>
26#include <linux/seq_file.h>
27
28#include "internal.h"
29
30static inline struct net *PDE_NET(struct proc_dir_entry *pde)
31{
32 return pde->parent->data;
33}
34
35static struct net *get_proc_net(const struct inode *inode)
36{
37 return maybe_get_net(PDE_NET(PDE(inode)));
38}
39
40int seq_open_net(struct inode *ino, struct file *f,
41 const struct seq_operations *ops, int size)
42{
43 struct net *net;
44 struct seq_net_private *p;
45
46 BUG_ON(size < sizeof(*p));
47
48 net = get_proc_net(ino);
49 if (net == NULL)
50 return -ENXIO;
51
52 p = __seq_open_private(f, ops, size);
53 if (p == NULL) {
54 put_net(net);
55 return -ENOMEM;
56 }
57#ifdef CONFIG_NET_NS
58 p->net = net;
59#endif
60 return 0;
61}
62EXPORT_SYMBOL_GPL(seq_open_net);
63
64int single_open_net(struct inode *inode, struct file *file,
65 int (*show)(struct seq_file *, void *))
66{
67 int err;
68 struct net *net;
69
70 err = -ENXIO;
71 net = get_proc_net(inode);
72 if (net == NULL)
73 goto err_net;
74
75 err = single_open(file, show, net);
76 if (err < 0)
77 goto err_open;
78
79 return 0;
80
81err_open:
82 put_net(net);
83err_net:
84 return err;
85}
86EXPORT_SYMBOL_GPL(single_open_net);
87
88int seq_release_net(struct inode *ino, struct file *f)
89{
90 struct seq_file *seq;
91
92 seq = f->private_data;
93
94 put_net(seq_file_net(seq));
95 seq_release_private(ino, f);
96 return 0;
97}
98EXPORT_SYMBOL_GPL(seq_release_net);
99
100int single_release_net(struct inode *ino, struct file *f)
101{
102 struct seq_file *seq = f->private_data;
103 put_net(seq->private);
104 return single_release(ino, f);
105}
106EXPORT_SYMBOL_GPL(single_release_net);
107
108static struct net *get_proc_task_net(struct inode *dir)
109{
110 struct task_struct *task;
111 struct nsproxy *ns;
112 struct net *net = NULL;
113
114 rcu_read_lock();
115 task = pid_task(proc_pid(dir), PIDTYPE_PID);
116 if (task != NULL) {
117 task_lock(task);
118 ns = task->nsproxy;
119 if (ns != NULL)
120 net = get_net(ns->net_ns);
121 task_unlock(task);
122 }
123 rcu_read_unlock();
124
125 return net;
126}
127
128static struct dentry *proc_tgid_net_lookup(struct inode *dir,
129 struct dentry *dentry, unsigned int flags)
130{
131 struct dentry *de;
132 struct net *net;
133
134 de = ERR_PTR(-ENOENT);
135 net = get_proc_task_net(dir);
136 if (net != NULL) {
137 de = proc_lookup_de(net->proc_net, dir, dentry);
138 put_net(net);
139 }
140 return de;
141}
142
143static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
144 struct kstat *stat)
145{
146 struct inode *inode = d_inode(dentry);
147 struct net *net;
148
149 net = get_proc_task_net(inode);
150
151 generic_fillattr(inode, stat);
152
153 if (net != NULL) {
154 stat->nlink = net->proc_net->nlink;
155 put_net(net);
156 }
157
158 return 0;
159}
160
161const struct inode_operations proc_net_inode_operations = {
162 .lookup = proc_tgid_net_lookup,
163 .getattr = proc_tgid_net_getattr,
164};
165
166static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
167{
168 int ret;
169 struct net *net;
170
171 ret = -EINVAL;
172 net = get_proc_task_net(file_inode(file));
173 if (net != NULL) {
174 ret = proc_readdir_de(net->proc_net, file, ctx);
175 put_net(net);
176 }
177 return ret;
178}
179
180const struct file_operations proc_net_operations = {
181 .llseek = generic_file_llseek,
182 .read = generic_read_dir,
183 .iterate_shared = proc_tgid_net_readdir,
184};
185
186static __net_init int proc_net_ns_init(struct net *net)
187{
188 struct proc_dir_entry *netd, *net_statd;
189 kuid_t uid;
190 kgid_t gid;
191 int err;
192
193 err = -ENOMEM;
194 netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
195 if (!netd)
196 goto out;
197
198 netd->subdir = RB_ROOT;
199 netd->data = net;
200 netd->nlink = 2;
201 netd->namelen = 3;
202 netd->parent = &proc_root;
203 memcpy(netd->name, "net", 4);
204
205 uid = make_kuid(net->user_ns, 0);
206 if (!uid_valid(uid))
207 uid = netd->uid;
208
209 gid = make_kgid(net->user_ns, 0);
210 if (!gid_valid(gid))
211 gid = netd->gid;
212
213 proc_set_user(netd, uid, gid);
214
215 err = -EEXIST;
216 net_statd = proc_net_mkdir(net, "stat", netd);
217 if (!net_statd)
218 goto free_net;
219
220 net->proc_net = netd;
221 net->proc_net_stat = net_statd;
222 return 0;
223
224free_net:
225 kfree(netd);
226out:
227 return err;
228}
229
230static __net_exit void proc_net_ns_exit(struct net *net)
231{
232 remove_proc_entry("stat", net->proc_net);
233 kfree(net->proc_net);
234}
235
236static struct pernet_operations __net_initdata proc_net_ns_ops = {
237 .init = proc_net_ns_init,
238 .exit = proc_net_ns_exit,
239};
240
241int __init proc_net_init(void)
242{
243 proc_symlink("net", NULL, "self/net");
244
245 return register_pernet_subsys(&proc_net_ns_ops);
246}
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}