v4.19.13 snapshot.
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
new file mode 100644
index 0000000..d5e0fcb
--- /dev/null
+++ b/fs/proc/proc_net.c
@@ -0,0 +1,372 @@
+/*
+ * linux/fs/proc/net.c
+ *
+ * Copyright (C) 2007
+ *
+ * Author: Eric Biederman <ebiederm@xmission.com>
+ *
+ * proc net directory handling functions
+ */
+
+#include <linux/uaccess.h>
+
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/mount.h>
+#include <linux/nsproxy.h>
+#include <linux/uidgid.h>
+#include <net/net_namespace.h>
+#include <linux/seq_file.h>
+
+#include "internal.h"
+
+static inline struct net *PDE_NET(struct proc_dir_entry *pde)
+{
+ return pde->parent->data;
+}
+
+static struct net *get_proc_net(const struct inode *inode)
+{
+ return maybe_get_net(PDE_NET(PDE(inode)));
+}
+
+static int seq_open_net(struct inode *inode, struct file *file)
+{
+ unsigned int state_size = PDE(inode)->state_size;
+ struct seq_net_private *p;
+ struct net *net;
+
+ WARN_ON_ONCE(state_size < sizeof(*p));
+
+ if (file->f_mode & FMODE_WRITE && !PDE(inode)->write)
+ return -EACCES;
+
+ net = get_proc_net(inode);
+ if (!net)
+ return -ENXIO;
+
+ p = __seq_open_private(file, PDE(inode)->seq_ops, state_size);
+ if (!p) {
+ put_net(net);
+ return -ENOMEM;
+ }
+#ifdef CONFIG_NET_NS
+ p->net = net;
+#endif
+ return 0;
+}
+
+static int seq_release_net(struct inode *ino, struct file *f)
+{
+ struct seq_file *seq = f->private_data;
+
+ put_net(seq_file_net(seq));
+ seq_release_private(ino, f);
+ return 0;
+}
+
+static const struct file_operations proc_net_seq_fops = {
+ .open = seq_open_net,
+ .read = seq_read,
+ .write = proc_simple_write,
+ .llseek = seq_lseek,
+ .release = seq_release_net,
+};
+
+struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
+ struct proc_dir_entry *parent, const struct seq_operations *ops,
+ unsigned int state_size, void *data)
+{
+ struct proc_dir_entry *p;
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = &proc_net_seq_fops;
+ p->seq_ops = ops;
+ p->state_size = state_size;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_data);
+
+/**
+ * proc_create_net_data_write - Create a writable net_ns-specific proc file
+ * @name: The name of the file.
+ * @mode: The file's access mode.
+ * @parent: The parent directory in which to create.
+ * @ops: The seq_file ops with which to read the file.
+ * @write: The write method which which to 'modify' the file.
+ * @data: Data for retrieval by PDE_DATA().
+ *
+ * Create a network namespaced proc file in the @parent directory with the
+ * specified @name and @mode that allows reading of a file that displays a
+ * series of elements and also provides for the file accepting writes that have
+ * some arbitrary effect.
+ *
+ * The functions in the @ops table are used to iterate over items to be
+ * presented and extract the readable content using the seq_file interface.
+ *
+ * The @write function is called with the data copied into a kernel space
+ * scratch buffer and has a NUL appended for convenience. The buffer may be
+ * modified by the @write function. @write should return 0 on success.
+ *
+ * The @data value is accessible from the @show and @write functions by calling
+ * PDE_DATA() on the file inode. The network namespace must be accessed by
+ * calling seq_file_net() on the seq_file struct.
+ */
+struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode,
+ struct proc_dir_entry *parent,
+ const struct seq_operations *ops,
+ proc_write_t write,
+ unsigned int state_size, void *data)
+{
+ struct proc_dir_entry *p;
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = &proc_net_seq_fops;
+ p->seq_ops = ops;
+ p->state_size = state_size;
+ p->write = write;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_data_write);
+
+static int single_open_net(struct inode *inode, struct file *file)
+{
+ struct proc_dir_entry *de = PDE(inode);
+ struct net *net;
+ int err;
+
+ net = get_proc_net(inode);
+ if (!net)
+ return -ENXIO;
+
+ err = single_open(file, de->single_show, net);
+ if (err)
+ put_net(net);
+ return err;
+}
+
+static int single_release_net(struct inode *ino, struct file *f)
+{
+ struct seq_file *seq = f->private_data;
+ put_net(seq->private);
+ return single_release(ino, f);
+}
+
+static const struct file_operations proc_net_single_fops = {
+ .open = single_open_net,
+ .read = seq_read,
+ .write = proc_simple_write,
+ .llseek = seq_lseek,
+ .release = single_release_net,
+};
+
+struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode,
+ struct proc_dir_entry *parent,
+ int (*show)(struct seq_file *, void *), void *data)
+{
+ struct proc_dir_entry *p;
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = &proc_net_single_fops;
+ p->single_show = show;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_single);
+
+/**
+ * proc_create_net_single_write - Create a writable net_ns-specific proc file
+ * @name: The name of the file.
+ * @mode: The file's access mode.
+ * @parent: The parent directory in which to create.
+ * @show: The seqfile show method with which to read the file.
+ * @write: The write method which which to 'modify' the file.
+ * @data: Data for retrieval by PDE_DATA().
+ *
+ * Create a network-namespaced proc file in the @parent directory with the
+ * specified @name and @mode that allows reading of a file that displays a
+ * single element rather than a series and also provides for the file accepting
+ * writes that have some arbitrary effect.
+ *
+ * The @show function is called to extract the readable content via the
+ * seq_file interface.
+ *
+ * The @write function is called with the data copied into a kernel space
+ * scratch buffer and has a NUL appended for convenience. The buffer may be
+ * modified by the @write function. @write should return 0 on success.
+ *
+ * The @data value is accessible from the @show and @write functions by calling
+ * PDE_DATA() on the file inode. The network namespace must be accessed by
+ * calling seq_file_single_net() on the seq_file struct.
+ */
+struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode,
+ struct proc_dir_entry *parent,
+ int (*show)(struct seq_file *, void *),
+ proc_write_t write,
+ void *data)
+{
+ struct proc_dir_entry *p;
+
+ p = proc_create_reg(name, mode, &parent, data);
+ if (!p)
+ return NULL;
+ p->proc_fops = &proc_net_single_fops;
+ p->single_show = show;
+ p->write = write;
+ return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_single_write);
+
+static struct net *get_proc_task_net(struct inode *dir)
+{
+ struct task_struct *task;
+ struct nsproxy *ns;
+ struct net *net = NULL;
+
+ rcu_read_lock();
+ task = pid_task(proc_pid(dir), PIDTYPE_PID);
+ if (task != NULL) {
+ task_lock(task);
+ ns = task->nsproxy;
+ if (ns != NULL)
+ net = get_net(ns->net_ns);
+ task_unlock(task);
+ }
+ rcu_read_unlock();
+
+ return net;
+}
+
+static struct dentry *proc_tgid_net_lookup(struct inode *dir,
+ struct dentry *dentry, unsigned int flags)
+{
+ struct dentry *de;
+ struct net *net;
+
+ de = ERR_PTR(-ENOENT);
+ net = get_proc_task_net(dir);
+ if (net != NULL) {
+ de = proc_lookup_de(dir, dentry, net->proc_net);
+ put_net(net);
+ }
+ return de;
+}
+
+static int proc_tgid_net_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int query_flags)
+{
+ struct inode *inode = d_inode(path->dentry);
+ struct net *net;
+
+ net = get_proc_task_net(inode);
+
+ generic_fillattr(inode, stat);
+
+ if (net != NULL) {
+ stat->nlink = net->proc_net->nlink;
+ put_net(net);
+ }
+
+ return 0;
+}
+
+const struct inode_operations proc_net_inode_operations = {
+ .lookup = proc_tgid_net_lookup,
+ .getattr = proc_tgid_net_getattr,
+};
+
+static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
+{
+ int ret;
+ struct net *net;
+
+ ret = -EINVAL;
+ net = get_proc_task_net(file_inode(file));
+ if (net != NULL) {
+ ret = proc_readdir_de(file, ctx, net->proc_net);
+ put_net(net);
+ }
+ return ret;
+}
+
+const struct file_operations proc_net_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = proc_tgid_net_readdir,
+};
+
+static __net_init int proc_net_ns_init(struct net *net)
+{
+ struct proc_dir_entry *netd, *net_statd;
+ kuid_t uid;
+ kgid_t gid;
+ int err;
+
+ err = -ENOMEM;
+ netd = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
+ if (!netd)
+ goto out;
+
+ netd->subdir = RB_ROOT;
+ netd->data = net;
+ netd->nlink = 2;
+ netd->namelen = 3;
+ netd->parent = &proc_root;
+ netd->name = netd->inline_name;
+ memcpy(netd->name, "net", 4);
+
+ uid = make_kuid(net->user_ns, 0);
+ if (!uid_valid(uid))
+ uid = netd->uid;
+
+ gid = make_kgid(net->user_ns, 0);
+ if (!gid_valid(gid))
+ gid = netd->gid;
+
+ proc_set_user(netd, uid, gid);
+
+ err = -EEXIST;
+ net_statd = proc_net_mkdir(net, "stat", netd);
+ if (!net_statd)
+ goto free_net;
+
+ net->proc_net = netd;
+ net->proc_net_stat = net_statd;
+ return 0;
+
+free_net:
+ pde_free(netd);
+out:
+ return err;
+}
+
+static __net_exit void proc_net_ns_exit(struct net *net)
+{
+ remove_proc_entry("stat", net->proc_net);
+ pde_free(net->proc_net);
+}
+
+static struct pernet_operations __net_initdata proc_net_ns_ops = {
+ .init = proc_net_ns_init,
+ .exit = proc_net_ns_exit,
+};
+
+int __init proc_net_init(void)
+{
+ proc_symlink("net", NULL, "self/net");
+
+ return register_pernet_subsys(&proc_net_ns_ops);
+}