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: "Eric W. Biederman" <ebiederm@xmission.com>
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@ -118,7 +118,7 @@ static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd)
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struct super_block *sb = inode->i_sb;
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struct super_block *sb = inode->i_sb;
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struct proc_inode *ei = PROC_I(inode);
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struct proc_inode *ei = PROC_I(inode);
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struct task_struct *task;
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struct task_struct *task;
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struct dentry *ns_dentry;
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struct path ns_path;
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void *error = ERR_PTR(-EACCES);
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void *error = ERR_PTR(-EACCES);
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task = get_proc_task(inode);
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task = get_proc_task(inode);
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@ -128,14 +128,14 @@ static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd)
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if (!ptrace_may_access(task, PTRACE_MODE_READ))
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if (!ptrace_may_access(task, PTRACE_MODE_READ))
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goto out_put_task;
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goto out_put_task;
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ns_dentry = proc_ns_get_dentry(sb, task, ei->ns_ops);
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ns_path.dentry = proc_ns_get_dentry(sb, task, ei->ns_ops);
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if (IS_ERR(ns_dentry)) {
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if (IS_ERR(ns_path.dentry)) {
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error = ERR_CAST(ns_dentry);
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error = ERR_CAST(ns_path.dentry);
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goto out_put_task;
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goto out_put_task;
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}
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}
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dput(nd->path.dentry);
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ns_path.mnt = mntget(nd->path.mnt);
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nd->path.dentry = ns_dentry;
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nd_jump_link(nd, &ns_path);
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error = NULL;
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error = NULL;
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out_put_task:
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out_put_task:
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