diff options
Diffstat (limited to 'fs/proc/namespaces.c')
| -rw-r--r-- | fs/proc/namespaces.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c new file mode 100644 index 000000000..8e159fc78 --- /dev/null +++ b/fs/proc/namespaces.c @@ -0,0 +1,183 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/proc_fs.h> +#include <linux/nsproxy.h> +#include <linux/ptrace.h> +#include <linux/namei.h> +#include <linux/file.h> +#include <linux/utsname.h> +#include <net/net_namespace.h> +#include <linux/ipc_namespace.h> +#include <linux/pid_namespace.h> +#include <linux/user_namespace.h> +#include "internal.h" + + +static const struct proc_ns_operations *ns_entries[] = { +#ifdef CONFIG_NET_NS + &netns_operations, +#endif +#ifdef CONFIG_UTS_NS + &utsns_operations, +#endif +#ifdef CONFIG_IPC_NS + &ipcns_operations, +#endif +#ifdef CONFIG_PID_NS + &pidns_operations, + &pidns_for_children_operations, +#endif +#ifdef CONFIG_USER_NS + &userns_operations, +#endif + &mntns_operations, +#ifdef CONFIG_CGROUPS + &cgroupns_operations, +#endif +#ifdef CONFIG_TIME_NS + &timens_operations, + &timens_for_children_operations, +#endif +}; + +static const char *proc_ns_get_link(struct dentry *dentry, + struct inode *inode, + struct delayed_call *done) +{ + const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; + struct task_struct *task; + struct path ns_path; + int error = -EACCES; + + if (!dentry) + return ERR_PTR(-ECHILD); + + task = get_proc_task(inode); + if (!task) + return ERR_PTR(-EACCES); + + if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) + goto out; + + error = ns_get_path(&ns_path, task, ns_ops); + if (error) + goto out; + + error = nd_jump_link(&ns_path); +out: + put_task_struct(task); + return ERR_PTR(error); +} + +static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) +{ + struct inode *inode = d_inode(dentry); + const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; + struct task_struct *task; + char name[50]; + int res = -EACCES; + + task = get_proc_task(inode); + if (!task) + return res; + + if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { + res = ns_get_name(name, sizeof(name), task, ns_ops); + if (res >= 0) + res = readlink_copy(buffer, buflen, name); + } + put_task_struct(task); + return res; +} + +static const struct inode_operations proc_ns_link_inode_operations = { + .readlink = proc_ns_readlink, + .get_link = proc_ns_get_link, + .setattr = proc_setattr, +}; + +static struct dentry *proc_ns_instantiate(struct dentry *dentry, + struct task_struct *task, const void *ptr) +{ + const struct proc_ns_operations *ns_ops = ptr; + struct inode *inode; + struct proc_inode *ei; + + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO); + if (!inode) + return ERR_PTR(-ENOENT); + + ei = PROC_I(inode); + inode->i_op = &proc_ns_link_inode_operations; + ei->ns_ops = ns_ops; + pid_update_inode(task, inode); + + d_set_d_op(dentry, &pid_dentry_operations); + return d_splice_alias(inode, dentry); +} + +static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) +{ + struct task_struct *task = get_proc_task(file_inode(file)); + const struct proc_ns_operations **entry, **last; + + if (!task) + return -ENOENT; + + if (!dir_emit_dots(file, ctx)) + goto out; + if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) + goto out; + entry = ns_entries + (ctx->pos - 2); + last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; + while (entry <= last) { + const struct proc_ns_operations *ops = *entry; + if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), + proc_ns_instantiate, task, ops)) + break; + ctx->pos++; + entry++; + } +out: + put_task_struct(task); + return 0; +} + +const struct file_operations proc_ns_dir_operations = { + .read = generic_read_dir, + .iterate_shared = proc_ns_dir_readdir, + .llseek = generic_file_llseek, +}; + +static struct dentry *proc_ns_dir_lookup(struct inode *dir, + struct dentry *dentry, unsigned int flags) +{ + struct task_struct *task = get_proc_task(dir); + const struct proc_ns_operations **entry, **last; + unsigned int len = dentry->d_name.len; + struct dentry *res = ERR_PTR(-ENOENT); + + if (!task) + goto out_no_task; + + last = &ns_entries[ARRAY_SIZE(ns_entries)]; + for (entry = ns_entries; entry < last; entry++) { + if (strlen((*entry)->name) != len) + continue; + if (!memcmp(dentry->d_name.name, (*entry)->name, len)) + break; + } + if (entry == last) + goto out; + + res = proc_ns_instantiate(dentry, task, *entry); +out: + put_task_struct(task); +out_no_task: + return res; +} + +const struct inode_operations proc_ns_dir_inode_operations = { + .lookup = proc_ns_dir_lookup, + .getattr = pid_getattr, + .setattr = proc_setattr, +}; |