fs/proc/proc_net.c

   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/sched/task.h>
  21 #include <linux/module.h>
  22 #include <linux/bitops.h>
  23 #include <linux/mount.h>
  24 #include <linux/nsproxy.h>
  25 #include <linux/uidgid.h>
  26 #include <net/net_namespace.h>
  27 #include <linux/seq_file.h>
  28
  29 #include "internal.h"
  30
  31 static inline struct net *PDE_NET(struct proc_dir_entry *pde)
  32 {
  33         return pde->parent->data;
  34 }
  35
  36 static struct net *get_proc_net(const struct inode *inode)
  37 {
  38         return maybe_get_net(PDE_NET(PDE(inode)));
  39 }
  40
  41 int seq_open_net(struct inode *ino, struct file *f,
  42                  const struct seq_operations *ops, int size)
  43 {
  44         struct net *net;
  45         struct seq_net_private *p;
  46
  47         BUG_ON(size < sizeof(*p));
  48
  49         net = get_proc_net(ino);
  50         if (net == NULL)
  51                 return -ENXIO;
  52
  53         p = __seq_open_private(f, ops, size);
  54         if (p == NULL) {
  55                 put_net(net);
  56                 return -ENOMEM;
  57         }
  58 #ifdef CONFIG_NET_NS
  59         p->net = net;
  60 #endif
  61         return 0;
  62 }
  63 EXPORT_SYMBOL_GPL(seq_open_net);
  64
  65 int single_open_net(struct inode *inode, struct file *file,
  66                 int (*show)(struct seq_file *, void *))
  67 {
  68         int err;
  69         struct net *net;
  70
  71         err = -ENXIO;
  72         net = get_proc_net(inode);
  73         if (net == NULL)
  74                 goto err_net;
  75
  76         err = single_open(file, show, net);
  77         if (err < 0)
  78                 goto err_open;
  79
  80         return 0;
  81
  82 err_open:
  83         put_net(net);
  84 err_net:
  85         return err;
  86 }
  87 EXPORT_SYMBOL_GPL(single_open_net);
  88
  89 int seq_release_net(struct inode *ino, struct file *f)
  90 {
  91         struct seq_file *seq;
  92
  93         seq = f->private_data;
  94
  95         put_net(seq_file_net(seq));
  96         seq_release_private(ino, f);
  97         return 0;
  98 }
  99 EXPORT_SYMBOL_GPL(seq_release_net);
 100
 101 int single_release_net(struct inode *ino, struct file *f)
 102 {
 103         struct seq_file *seq = f->private_data;
 104         put_net(seq->private);
 105         return single_release(ino, f);
 106 }
 107 EXPORT_SYMBOL_GPL(single_release_net);
 108
 109 static struct net *get_proc_task_net(struct inode *dir)
 110 {
 111         struct task_struct *task;
 112         struct nsproxy *ns;
 113         struct net *net = NULL;
 114
 115         rcu_read_lock();
 116         task = pid_task(proc_pid(dir), PIDTYPE_PID);
 117         if (task != NULL) {
 118                 task_lock(task);
 119                 ns = task->nsproxy;
 120                 if (ns != NULL)
 121                         net = get_net(ns->net_ns);
 122                 task_unlock(task);
 123         }
 124         rcu_read_unlock();
 125
 126         return net;
 127 }
 128
 129 static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 130                 struct dentry *dentry, unsigned int flags)
 131 {
 132         struct dentry *de;
 133         struct net *net;
 134
 135         de = ERR_PTR(-ENOENT);
 136         net = get_proc_task_net(dir);
 137         if (net != NULL) {
 138                 de = proc_lookup_de(net->proc_net, dir, dentry);
 139                 put_net(net);
 140         }
 141         return de;
 142 }
 143
 144 static int proc_tgid_net_getattr(const struct path *path, struct kstat *stat,
 145                                  u32 request_mask, unsigned int query_flags)
 146 {
 147         struct inode *inode = d_inode(path->dentry);
 148         struct net *net;
 149
 150         net = get_proc_task_net(inode);
 151
 152         generic_fillattr(inode, stat);
 153
 154         if (net != NULL) {
 155                 stat->nlink = net->proc_net->nlink;
 156                 put_net(net);
 157         }
 158
 159         return 0;
 160 }
 161
 162 const struct inode_operations proc_net_inode_operations = {
 163         .lookup         = proc_tgid_net_lookup,
 164         .getattr        = proc_tgid_net_getattr,
 165 };
 166
 167 static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
 168 {
 169         int ret;
 170         struct net *net;
 171
 172         ret = -EINVAL;
 173         net = get_proc_task_net(file_inode(file));
 174         if (net != NULL) {
 175                 ret = proc_readdir_de(net->proc_net, file, ctx);
 176                 put_net(net);
 177         }
 178         return ret;
 179 }
 180
 181 const struct file_operations proc_net_operations = {
 182         .llseek         = generic_file_llseek,
 183         .read           = generic_read_dir,
 184         .iterate_shared = proc_tgid_net_readdir,
 185 };
 186
 187 static __net_init int proc_net_ns_init(struct net *net)
 188 {
 189         struct proc_dir_entry *netd, *net_statd;
 190         kuid_t uid;
 191         kgid_t gid;
 192         int err;
 193
 194         err = -ENOMEM;
 195         netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
 196         if (!netd)
 197                 goto out;
 198
 199         netd->subdir = RB_ROOT_CACHED;
 200         netd->data = net;
 201         netd->nlink = 2;
 202         netd->namelen = 3;
 203         netd->parent = &proc_root;
 204         memcpy(netd->name, "net", 4);
 205
 206         uid = make_kuid(net->user_ns, 0);
 207         if (!uid_valid(uid))
 208                 uid = netd->uid;
 209
 210         gid = make_kgid(net->user_ns, 0);
 211         if (!gid_valid(gid))
 212                 gid = netd->gid;
 213
 214         proc_set_user(netd, uid, gid);
 215
 216         err = -EEXIST;
 217         net_statd = proc_net_mkdir(net, "stat", netd);
 218         if (!net_statd)
 219                 goto free_net;
 220
 221         net->proc_net = netd;
 222         net->proc_net_stat = net_statd;
 223         return 0;
 224
 225 free_net:
 226         kfree(netd);
 227 out:
 228         return err;
 229 }
 230
 231 static __net_exit void proc_net_ns_exit(struct net *net)
 232 {
 233         remove_proc_entry("stat", net->proc_net);
 234         kfree(net->proc_net);
 235 }
 236
 237 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 238         .init = proc_net_ns_init,
 239         .exit = proc_net_ns_exit,
 240 };
 241
 242 int __init proc_net_init(void)
 243 {
 244         proc_symlink("net", NULL, "self/net");
 245
 246         return register_pernet_subsys(&proc_net_ns_ops);
 247 }