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Commit db04dc67 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

proc: Use nd_jump_link in proc_ns_follow_link 



Update proc_ns_follow_link to use nd_jump_link instead of just
manually updating nd.path.dentry.

This fixes the BUG_ON(nd->inode != parent->d_inode) reported by Dave
Jones and reproduced trivially with mkdir /proc/self/ns/uts/a.

Sigh it looks like the VFS change to require use of nd_jump_link
happend while proc_ns_follow_link was baking and since the common case
of proc_ns_follow_link continued to work without problems the need for
making this change was overlooked.

Cc: stable@vger.kernel.org
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 91417705

fs/proc/namespaces.c

+6 −6
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd) 
	struct super_block *sb = inode->i_sb;

	struct proc_inode *ei = PROC_I(inode);

	struct task_struct *task;

	struct dentry *ns_dentry;

	struct path ns_path;

	void *error = ERR_PTR(-EACCES);



	task = get_proc_task(inode);
@@ -128,14 +128,14 @@ static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd) 
	if (!ptrace_may_access(task, PTRACE_MODE_READ))

		goto out_put_task;



	ns_dentry = proc_ns_get_dentry(sb, task, ei->ns_ops);

	if (IS_ERR(ns_dentry)) {

		error = ERR_CAST(ns_dentry);

	ns_path.dentry = proc_ns_get_dentry(sb, task, ei->ns_ops);

	if (IS_ERR(ns_path.dentry)) {

		error = ERR_CAST(ns_path.dentry);

		goto out_put_task;

	}



	dput(nd->path.dentry);

	nd->path.dentry = ns_dentry;

	ns_path.mnt = mntget(nd->path.mnt);

	nd_jump_link(nd, &ns_path);

	error = NULL;



out_put_task: