diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/proc/proc_net.c | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c new file mode 100644 index 000000000..707477e27 --- /dev/null +++ b/fs/proc/proc_net.c @@ -0,0 +1,399 @@ +// 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 proc_ops proc_net_seq_ops = { + .proc_open = seq_open_net, + .proc_read = seq_read, + .proc_write = proc_simple_write, + .proc_lseek = seq_lseek, + .proc_release = seq_release_net, +}; + +int bpf_iter_init_seq_net(void *priv_data, struct bpf_iter_aux_info *aux) +{ +#ifdef CONFIG_NET_NS + struct seq_net_private *p = priv_data; + + p->net = get_net(current->nsproxy->net_ns); +#endif + return 0; +} + +void bpf_iter_fini_seq_net(void *priv_data) +{ +#ifdef CONFIG_NET_NS + struct seq_net_private *p = priv_data; + + put_net(p->net); +#endif +} + +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_ops = &proc_net_seq_ops; + 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_ops = &proc_net_seq_ops; + 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 proc_ops proc_net_single_ops = { + .proc_open = single_open_net, + .proc_read = seq_read, + .proc_write = proc_simple_write, + .proc_lseek = seq_lseek, + .proc_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_ops = &proc_net_single_ops; + 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_ops = &proc_net_single_ops; + 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); +} |