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
......@@ -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:
......
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