cregit-Linux how code gets into the kernel

Release 4.11 fs/nsfs.c

Directory: fs
#include <linux/mount.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/proc_ns.h>
#include <linux/magic.h>
#include <linux/ktime.h>
#include <linux/seq_file.h>
#include <linux/user_namespace.h>
#include <linux/nsfs.h>
#include <linux/uaccess.h>


static struct vfsmount *nsfs_mnt;

static long ns_ioctl(struct file *filp, unsigned int ioctl,
			unsigned long arg);

static const struct file_operations ns_file_operations = {
	.llseek		= no_llseek,
	.unlocked_ioctl = ns_ioctl,
};


static char *ns_dname(struct dentry *dentry, char *buffer, int buflen) { struct inode *inode = d_inode(dentry); const struct proc_ns_operations *ns_ops = dentry->d_fsdata; return dynamic_dname(dentry, buffer, buflen, "%s:[%lu]", ns_ops->name, inode->i_ino); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro5694.92%150.00%
David Howells35.08%150.00%
Total59100.00%2100.00%


static void ns_prune_dentry(struct dentry *dentry) { struct inode *inode = d_inode(dentry); if (inode) { struct ns_common *ns = inode->i_private; atomic_long_set(&ns->stashed, 0); } }

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PersonTokensPropCommitsCommitProp
Al Viro4393.48%150.00%
David Howells36.52%150.00%
Total46100.00%2100.00%

const struct dentry_operations ns_dentry_operations = { .d_prune = ns_prune_dentry, .d_delete = always_delete_dentry, .d_dname = ns_dname, };
static void nsfs_evict(struct inode *inode) { struct ns_common *ns = inode->i_private; clear_inode(inode); ns->ops->put(ns); }

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PersonTokensPropCommitsCommitProp
Al Viro34100.00%1100.00%
Total34100.00%1100.00%


static void *__ns_get_path(struct path *path, struct ns_common *ns) { struct vfsmount *mnt = nsfs_mnt; struct qstr qname = { .name = "", }; struct dentry *dentry; struct inode *inode; unsigned long d; rcu_read_lock(); d = atomic_long_read(&ns->stashed); if (!d) goto slow; dentry = (struct dentry *)d; if (!lockref_get_not_dead(&dentry->d_lockref)) goto slow; rcu_read_unlock(); ns->ops->put(ns); got_it: path->mnt = mntget(mnt); path->dentry = dentry; return NULL; slow: rcu_read_unlock(); inode = new_inode_pseudo(mnt->mnt_sb); if (!inode) { ns->ops->put(ns); return ERR_PTR(-ENOMEM); } inode->i_ino = ns->inum; inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); inode->i_flags |= S_IMMUTABLE; inode->i_mode = S_IFREG | S_IRUGO; inode->i_fop = &ns_file_operations; inode->i_private = ns; dentry = d_alloc_pseudo(mnt->mnt_sb, &qname); if (!dentry) { iput(inode); return ERR_PTR(-ENOMEM); } d_instantiate(dentry, inode); dentry->d_flags |= DCACHE_RCUACCESS; dentry->d_fsdata = (void *)ns->ops; d = atomic_long_cmpxchg(&ns->stashed, 0, (unsigned long)dentry); if (d) { d_delete(dentry); /* make sure ->d_prune() does nothing */ dput(dentry); cpu_relax(); return ERR_PTR(-EAGAIN); } goto got_it; }

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PersonTokensPropCommitsCommitProp
Al Viro28288.68%120.00%
Andrey Vagin237.23%120.00%
Américo Wang61.89%120.00%
Deepa Dinamani41.26%120.00%
Eric W. Biedermann30.94%120.00%
Total318100.00%5100.00%


void *ns_get_path(struct path *path, struct task_struct *task, const struct proc_ns_operations *ns_ops) { struct ns_common *ns; void *ret; again: ns = ns_ops->get(task); if (!ns) return ERR_PTR(-ENOENT); ret = __ns_get_path(path, ns); if (IS_ERR(ret) && PTR_ERR(ret) == -EAGAIN) goto again; return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Andrey Vagin8297.62%150.00%
Al Viro22.38%150.00%
Total84100.00%2100.00%

int open_related_ns(struct ns_common *ns, struct ns_common *(*get_ns)(struct ns_common *ns)) { struct path path = {}; struct file *f; void *err; int fd; fd = get_unused_fd_flags(O_CLOEXEC); if (fd < 0) return fd; while (1) { struct ns_common *relative; relative = get_ns(ns); if (IS_ERR(relative)) { put_unused_fd(fd); return PTR_ERR(relative); } err = __ns_get_path(&path, relative); if (IS_ERR(err) && PTR_ERR(err) == -EAGAIN) continue; break; } if (IS_ERR(err)) { put_unused_fd(fd); return PTR_ERR(err); } f = dentry_open(&path, O_RDONLY, current_cred()); path_put(&path); if (IS_ERR(f)) { put_unused_fd(fd); fd = PTR_ERR(f); } else fd_install(fd, f); return fd; }
static long ns_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { struct user_namespace *user_ns; struct ns_common *ns = get_proc_ns(file_inode(filp)); uid_t __user *argp; uid_t uid; switch (ioctl) { case NS_GET_USERNS: return open_related_ns(ns, ns_get_owner); case NS_GET_PARENT: if (!ns->ops->get_parent) return -EINVAL; return open_related_ns(ns, ns->ops->get_parent); case NS_GET_NSTYPE: return ns->ops->type; case NS_GET_OWNER_UID: if (ns->ops->type != CLONE_NEWUSER) return -EINVAL; user_ns = container_of(ns, struct user_namespace, ns); argp = (uid_t __user *) arg; uid = from_kuid_munged(current_user_ns(), user_ns->owner); return put_user(uid, argp); default: return -ENOTTY; } }

Contributors

PersonTokensPropCommitsCommitProp
Andrey Vagin8149.69%240.00%
Michael Kerrisk8149.69%240.00%
Al Viro10.61%120.00%
Total163100.00%5100.00%


int ns_get_name(char *buf, size_t size, struct task_struct *task, const struct proc_ns_operations *ns_ops) { struct ns_common *ns; int res = -ENOENT; ns = ns_ops->get(task); if (ns) { res = snprintf(buf, size, "%s:[%u]", ns_ops->name, ns->inum); ns_ops->put(ns); } return res; }

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Al Viro78100.00%1100.00%
Total78100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro63100.00%1100.00%
Total63100.00%1100.00%


static int nsfs_show_path(struct seq_file *seq, struct dentry *dentry) { struct inode *inode = d_inode(dentry); const struct proc_ns_operations *ns_ops = dentry->d_fsdata; seq_printf(seq, "%s:[%lu]", ns_ops->name, inode->i_ino); return 0; }

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Eric W. Biedermann5194.44%150.00%
Joe Perches35.56%150.00%
Total54100.00%2100.00%

static const struct super_operations nsfs_ops = { .statfs = simple_statfs, .evict_inode = nsfs_evict, .show_path = nsfs_show_path, };
static struct dentry *nsfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { return mount_pseudo(fs_type, "nsfs:", &nsfs_ops, &ns_dentry_operations, NSFS_MAGIC); }

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PersonTokensPropCommitsCommitProp
Al Viro41100.00%1100.00%
Total41100.00%1100.00%

static struct file_system_type nsfs = { .name = "nsfs", .mount = nsfs_mount, .kill_sb = kill_anon_super, };
void __init nsfs_init(void) { nsfs_mnt = kern_mount(&nsfs); if (IS_ERR(nsfs_mnt)) panic("can't set nsfs up\n"); nsfs_mnt->mnt_sb->s_flags &= ~MS_NOUSER; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro37100.00%1100.00%
Total37100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Al Viro73656.18%19.09%
Andrey Vagin40931.22%218.18%
Michael Kerrisk846.41%218.18%
Eric W. Biedermann624.73%218.18%
David Howells60.46%19.09%
Américo Wang60.46%19.09%
Deepa Dinamani40.31%19.09%
Joe Perches30.23%19.09%
Total1310100.00%11100.00%
Directory: fs
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