1 files changed, 194 insertions, 85 deletions

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 0d9e23a39e49..49a7fff2e83a 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -11,6 +11,7 @@
 #include <net/net_namespace.h>
 #include <linux/ipc_namespace.h>
 #include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
 #include "internal.h"
 
 
@@ -24,138 +25,238 @@ static const struct proc_ns_operations *ns_entries[] = {
 #ifdef CONFIG_IPC_NS
 	&ipcns_operations,
 #endif
+#ifdef CONFIG_PID_NS
+	&pidns_operations,
+#endif
+#ifdef CONFIG_USER_NS
+	&userns_operations,
+#endif
+	&mntns_operations,
 };
 
 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)
+static const struct inode_operations ns_inode_operations = {
+	.setattr	= proc_setattr,
+};
+
+static int ns_delete_dentry(const struct dentry *dentry)
 {
-	const struct proc_ns_operations *ns_ops = ptr;
+	/* 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 dentry *error = ERR_PTR(-ENOENT);
+	struct qstr qname = { .name = "", };
 	void *ns;
 
-	inode = proc_pid_make_inode(dir->i_sb, task);
-	if (!inode)
+	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)
+{
+	struct inode *inode = dentry->d_inode;
+	struct super_block *sb = inode->i_sb;
+	struct proc_inode *ei = PROC_I(inode);
+	struct task_struct *task;
+	struct path ns_path;
+	void *error = ERR_PTR(-EACCES);
+
+	task = get_proc_task(inode);
+	if (!task)
 		goto out;
 
+	if (!ptrace_may_access(task, PTRACE_MODE_READ))
+		goto out_put_task;
+
+	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;
+	}
+
+	ns_path.mnt = mntget(nd->path.mnt);
+	nd_jump_link(nd, &ns_path);
+	error = NULL;
+
+out_put_task:
+	put_task_struct(task);
+out:
+	return 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 task_struct *task;
+	void *ns;
+	char name[50];
+	int len = -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_iput;
+		goto out_put_task;
+
+	snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));
+	len = strlen(name);
+
+	if (len > buflen)
+		len = buflen;
+	if (copy_to_user(buffer, name, len))
+		len = -EFAULT;
+
+	ns_ops->put(ns);
+out_put_task:
+	put_task_struct(task);
+out:
+	return len;
+}
+
+static const struct inode_operations proc_ns_link_inode_operations = {
+	.readlink	= proc_ns_readlink,
+	.follow_link	= proc_ns_follow_link,
+	.setattr	= proc_setattr,
+};
+
+static int 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;
+
+	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;
+	inode->i_mode = S_IFLNK|S_IRWXUGO;
+	inode->i_op = &proc_ns_link_inode_operations;
+	ei->ns.ns_ops = ns_ops;
 
 	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, NULL))
-		error = NULL;
+	if (pid_revalidate(dentry, 0))
+		return 0;
 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);
+	return -ENOENT;
 }
 
-static int proc_ns_dir_readdir(struct file *filp, void *dirent,
-				filldir_t filldir)
+static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
 {
-	int i;
-	struct dentry *dentry = filp->f_path.dentry;
-	struct inode *inode = dentry->d_inode;
-	struct task_struct *task = get_proc_task(inode);
+	struct task_struct *task = get_proc_task(file_inode(file));
 	const struct proc_ns_operations **entry, **last;
-	ino_t ino;
-	int ret;
 
-	ret = -ENOENT;
 	if (!task)
-		goto out_no_task;
+		return -ENOENT;
 
-	ret = -EPERM;
-	if (!ptrace_may_access(task, PTRACE_MODE_READ))
+	if (!dir_emit_dots(file, ctx))
 		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++;
-		}
+	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++;
 	}
-
-	ret = 1;
 out:
 	put_task_struct(task);
-out_no_task:
-	return ret;
+	return 0;
 }
 
 const struct file_operations proc_ns_dir_operations = {
 	.read		= generic_read_dir,
-	.readdir	= proc_ns_dir_readdir,
+	.iterate	= proc_ns_dir_readdir,
 };
 
 static struct dentry *proc_ns_dir_lookup(struct inode *dir,
-				struct dentry *dentry, struct nameidata *nd)
+				struct dentry *dentry, unsigned int flags)
 {
-	struct dentry *error;
+	int 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);
+	error = -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)];
 	for (entry = ns_entries; entry < last; entry++) {
 		if (strlen((*entry)->name) != len)
@@ -163,7 +264,6 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
 		if (!memcmp(dentry->d_name.name, (*entry)->name, len))
 			break;
 	}
-	error = ERR_PTR(-ENOENT);
 	if (entry == last)
 		goto out;
 
@@ -171,7 +271,7 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
 out:
 	put_task_struct(task);
 out_no_task:
-	return error;
+	return ERR_PTR(error);
 }
 
 const struct inode_operations proc_ns_dir_inode_operations = {
@@ -198,3 +298,12 @@ out_invalid:
 	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;
+}