diff options
Diffstat (limited to 'fs/proc/namespaces.c')
| -rw-r--r-- | fs/proc/namespaces.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c new file mode 100644 index 000000000000..781dec5bd682 --- /dev/null +++ b/fs/proc/namespaces.c @@ -0,0 +1,198 @@ +#include <linux/proc_fs.h> +#include <linux/nsproxy.h> +#include <linux/sched.h> +#include <linux/ptrace.h> +#include <linux/fs_struct.h> +#include <linux/mount.h> +#include <linux/path.h> +#include <linux/namei.h> +#include <linux/file.h> +#include <linux/utsname.h> +#include <net/net_namespace.h> +#include <linux/mnt_namespace.h> +#include <linux/ipc_namespace.h> +#include <linux/pid_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 +}; + +static const struct file_operations ns_file_operations = { + .llseek = no_llseek, +}; + +static struct dentry *proc_ns_instantiate(struct inode *dir, + 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; + struct dentry *error = ERR_PTR(-ENOENT); + + inode = proc_pid_make_inode(dir->i_sb, task); + if (!inode) + goto out; + + ei = PROC_I(inode); + inode->i_mode = S_IFREG|S_IRUSR; + inode->i_fop = &ns_file_operations; + ei->ns_ops = ns_ops; + ei->ns = ns_ops->get(task); + if (!ei->ns) + goto out_iput; + + dentry->d_op = &pid_dentry_operations; + d_add(dentry, inode); + /* Close the race of the process dying before we return the dentry */ + if (pid_revalidate(dentry, NULL)) + error = NULL; +out: + return error; +out_iput: + iput(inode); + goto out; +} + +static int proc_ns_fill_cache(struct file *filp, void *dirent, + filldir_t filldir, struct task_struct *task, + const struct proc_ns_operations *ops) +{ + return proc_fill_cache(filp, dirent, filldir, + ops->name, strlen(ops->name), + proc_ns_instantiate, task, ops); +} + +static int proc_ns_dir_readdir(struct file *filp, void *dirent, + filldir_t filldir) +{ + int i; + struct dentry *dentry = filp->f_path.dentry; + struct inode *inode = dentry->d_inode; + struct task_struct *task = get_proc_task(inode); + const struct proc_ns_operations **entry, **last; + ino_t ino; + int ret; + + ret = -ENOENT; + if (!task) + goto out_no_task; + + ret = -EPERM; + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + goto out; + + ret = 0; + i = filp->f_pos; + switch (i) { + case 0: + ino = inode->i_ino; + if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) + goto out; + i++; + filp->f_pos++; + /* fall through */ + case 1: + ino = parent_ino(dentry); + if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) + goto out; + i++; + filp->f_pos++; + /* fall through */ + default: + i -= 2; + if (i >= ARRAY_SIZE(ns_entries)) { + ret = 1; + goto out; + } + entry = ns_entries + i; + last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; + while (entry <= last) { + if (proc_ns_fill_cache(filp, dirent, filldir, + task, *entry) < 0) + goto out; + filp->f_pos++; + entry++; + } + } + + ret = 1; +out: + put_task_struct(task); +out_no_task: + return ret; +} + +const struct file_operations proc_ns_dir_operations = { + .read = generic_read_dir, + .readdir = proc_ns_dir_readdir, +}; + +static struct dentry *proc_ns_dir_lookup(struct inode *dir, + struct dentry *dentry, struct nameidata *nd) +{ + struct dentry *error; + struct task_struct *task = get_proc_task(dir); + const struct proc_ns_operations **entry, **last; + unsigned int len = dentry->d_name.len; + + error = ERR_PTR(-ENOENT); + + if (!task) + goto out_no_task; + + error = ERR_PTR(-EPERM); + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + goto out; + + last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; + for (entry = ns_entries; entry <= last; entry++) { + if (strlen((*entry)->name) != len) + continue; + if (!memcmp(dentry->d_name.name, (*entry)->name, len)) + break; + } + error = ERR_PTR(-ENOENT); + if (entry > last) + goto out; + + error = proc_ns_instantiate(dir, dentry, task, *entry); +out: + put_task_struct(task); +out_no_task: + return error; +} + +const struct inode_operations proc_ns_dir_inode_operations = { + .lookup = proc_ns_dir_lookup, + .getattr = pid_getattr, + .setattr = proc_setattr, +}; + +struct file *proc_ns_fget(int fd) +{ + struct file *file; + + file = fget(fd); + if (!file) + return ERR_PTR(-EBADF); + + if (file->f_op != &ns_file_operations) + goto out_invalid; + + return file; + +out_invalid: + fput(file); + return ERR_PTR(-EINVAL); +} + |