1 files changed, 52 insertions, 179 deletions

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 49a7fff2e83a..ea2b597fd92c 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
 #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>
@@ -15,7 +12,7 @@
 #include "internal.h"
 
 
-static const struct proc_ns_operations *ns_entries[] = {
+static const struct proc_ns_operations *const ns_entries[] = {
 #ifdef CONFIG_NET_NS
 	&netns_operations,
 #endif
@@ -27,195 +24,100 @@ static const struct proc_ns_operations *ns_entries[] = {
 #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 struct file_operations ns_file_operations = {
-	.llseek		= no_llseek,
-};
-
-static const struct inode_operations ns_inode_operations = {
-	.setattr	= proc_setattr,
-};
-
-static int ns_delete_dentry(const struct dentry *dentry)
-{
-	/* Don't cache namespace inodes when not in use */
-	return 1;
-}
-
-static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)
-{
-	struct inode *inode = dentry->d_inode;
-	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns.ns_ops;
-
-	return dynamic_dname(dentry, buffer, buflen, "%s:[%lu]",
-		ns_ops->name, inode->i_ino);
-}
-
-const struct dentry_operations ns_dentry_operations =
-{
-	.d_delete	= ns_delete_dentry,
-	.d_dname	= ns_dname,
-};
-
-static struct dentry *proc_ns_get_dentry(struct super_block *sb,
-	struct task_struct *task, const struct proc_ns_operations *ns_ops)
-{
-	struct dentry *dentry, *result;
-	struct inode *inode;
-	struct proc_inode *ei;
-	struct qstr qname = { .name = "", };
-	void *ns;
-
-	ns = ns_ops->get(task);
-	if (!ns)
-		return ERR_PTR(-ENOENT);
-
-	dentry = d_alloc_pseudo(sb, &qname);
-	if (!dentry) {
-		ns_ops->put(ns);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	inode = iget_locked(sb, ns_ops->inum(ns));
-	if (!inode) {
-		dput(dentry);
-		ns_ops->put(ns);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	ei = PROC_I(inode);
-	if (inode->i_state & I_NEW) {
-		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-		inode->i_op = &ns_inode_operations;
-		inode->i_mode = S_IFREG | S_IRUGO;
-		inode->i_fop = &ns_file_operations;
-		ei->ns.ns_ops = ns_ops;
-		ei->ns.ns = ns;
-		unlock_new_inode(inode);
-	} else {
-		ns_ops->put(ns);
-	}
-
-	d_set_d_op(dentry, &ns_dentry_operations);
-	result = d_instantiate_unique(dentry, inode);
-	if (result) {
-		dput(dentry);
-		dentry = result;
-	}
-
-	return dentry;
-}
-
-static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd)
+static const char *proc_ns_get_link(struct dentry *dentry,
+				    struct inode *inode,
+				    struct delayed_call *done)
 {
-	struct inode *inode = dentry->d_inode;
-	struct super_block *sb = inode->i_sb;
-	struct proc_inode *ei = PROC_I(inode);
+	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
 	struct task_struct *task;
 	struct path ns_path;
-	void *error = ERR_PTR(-EACCES);
+	int error = -EACCES;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
 
 	task = get_proc_task(inode);
 	if (!task)
-		goto out;
-
-	if (!ptrace_may_access(task, PTRACE_MODE_READ))
-		goto out_put_task;
+		return ERR_PTR(-EACCES);
 
-	ns_path.dentry = proc_ns_get_dentry(sb, task, ei->ns.ns_ops);
-	if (IS_ERR(ns_path.dentry)) {
-		error = ERR_CAST(ns_path.dentry);
-		goto out_put_task;
-	}
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
+		goto out;
 
-	ns_path.mnt = mntget(nd->path.mnt);
-	nd_jump_link(nd, &ns_path);
-	error = NULL;
+	error = ns_get_path(&ns_path, task, ns_ops);
+	if (error)
+		goto out;
 
-out_put_task:
-	put_task_struct(task);
+	error = nd_jump_link(&ns_path);
 out:
-	return error;
+	put_task_struct(task);
+	return ERR_PTR(error);
 }
 
 static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
-	struct inode *inode = dentry->d_inode;
-	struct proc_inode *ei = PROC_I(inode);
-	const struct proc_ns_operations *ns_ops = ei->ns.ns_ops;
+	struct inode *inode = d_inode(dentry);
+	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
 	struct task_struct *task;
-	void *ns;
 	char name[50];
-	int len = -EACCES;
+	int res = -EACCES;
 
 	task = get_proc_task(inode);
 	if (!task)
-		goto out;
-
-	if (!ptrace_may_access(task, PTRACE_MODE_READ))
-		goto out_put_task;
-
-	len = -ENOENT;
-	ns = ns_ops->get(task);
-	if (!ns)
-		goto out_put_task;
-
-	snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));
-	len = strlen(name);
+		return res;
 
-	if (len > buflen)
-		len = buflen;
-	if (copy_to_user(buffer, name, len))
-		len = -EFAULT;
-
-	ns_ops->put(ns);
-out_put_task:
+	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, strlen(name));
+	}
 	put_task_struct(task);
-out:
-	return len;
+	return res;
 }
 
 static const struct inode_operations proc_ns_link_inode_operations = {
 	.readlink	= proc_ns_readlink,
-	.follow_link	= proc_ns_follow_link,
+	.get_link	= proc_ns_get_link,
 	.setattr	= proc_setattr,
 };
 
-static int proc_ns_instantiate(struct inode *dir,
-	struct dentry *dentry, struct task_struct *task, const void *ptr)
+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(dir->i_sb, task);
+	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO);
 	if (!inode)
-		goto out;
+		return ERR_PTR(-ENOENT);
 
 	ei = PROC_I(inode);
-	inode->i_mode = S_IFLNK|S_IRWXUGO;
 	inode->i_op = &proc_ns_link_inode_operations;
-	ei->ns.ns_ops = ns_ops;
+	ei->ns_ops = ns_ops;
+	pid_update_inode(task, inode);
 
-	d_set_d_op(dentry, &pid_dentry_operations);
-	d_add(dentry, inode);
-	/* Close the race of the process dying before we return the dentry */
-	if (pid_revalidate(dentry, 0))
-		return 0;
-out:
-	return -ENOENT;
+	return d_splice_alias_ops(inode, dentry, &pid_dentry_operations);
 }
 
 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;
+	const struct proc_ns_operations *const *entry, *const *last;
 
 	if (!task)
 		return -ENOENT;
@@ -241,18 +143,17 @@ out:
 
 const struct file_operations proc_ns_dir_operations = {
 	.read		= generic_read_dir,
-	.iterate	= proc_ns_dir_readdir,
+	.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)
 {
-	int error;
 	struct task_struct *task = get_proc_task(dir);
-	const struct proc_ns_operations **entry, **last;
+	const struct proc_ns_operations *const *entry, *const *last;
 	unsigned int len = dentry->d_name.len;
-
-	error = -ENOENT;
+	struct dentry *res = ERR_PTR(-ENOENT);
 
 	if (!task)
 		goto out_no_task;
@@ -267,11 +168,11 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
 	if (entry == last)
 		goto out;
 
-	error = proc_ns_instantiate(dir, dentry, task, *entry);
+	res = proc_ns_instantiate(dentry, task, *entry);
 out:
 	put_task_struct(task);
 out_no_task:
-	return ERR_PTR(error);
+	return res;
 }
 
 const struct inode_operations proc_ns_dir_inode_operations = {
@@ -279,31 +180,3 @@ const struct inode_operations proc_ns_dir_inode_operations = {
 	.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);
-}
-
-struct proc_ns *get_proc_ns(struct inode *inode)
-{
-	return &PROC_I(inode)->ns;
-}
-
-bool proc_ns_inode(struct inode *inode)
-{
-	return inode->i_fop == &ns_file_operations;
-}