| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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; |
| pde_force_lookup(p); |
| 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; |
| pde_force_lookup(p); |
| 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; |
| pde_force_lookup(p); |
| 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; |
| pde_force_lookup(p); |
| 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); |
| |
| /* Seed dentry revalidation for /proc/${pid}/net */ |
| pde_force_lookup(netd); |
| |
| 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); |
| } |