return 0;
}
+/**
+ * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
+ * @path: nameidate to verify
+ *
+ * Rename can sometimes move a file or directory outside of a bind
+ * mount, path_connected allows those cases to be detected.
+ */
+static bool path_connected(const struct path *path)
+{
+ struct vfsmount *mnt = path->mnt;
+
+ /* Only bind mounts can have disconnected paths */
+ if (mnt->mnt_root == mnt->mnt_sb->s_root)
+ return true;
+
+ return is_subdir(path->dentry, mnt->mnt_root);
+}
+
static inline int nd_alloc_stack(struct nameidata *nd)
{
if (likely(nd->depth != EMBEDDED_LEVELS))
return -ECHILD;
nd->path.dentry = parent;
nd->seq = seq;
+ if (unlikely(!path_connected(&nd->path)))
+ return -ENOENT;
break;
} else {
struct mount *mnt = real_mount(nd->path.mnt);
}
}
-static void follow_dotdot(struct nameidata *nd)
+static int follow_dotdot(struct nameidata *nd)
{
if (!nd->root.mnt)
set_root(nd);
/* rare case of legitimate dget_parent()... */
nd->path.dentry = dget_parent(nd->path.dentry);
dput(old);
+ if (unlikely(!path_connected(&nd->path)))
+ return -ENOENT;
break;
}
if (!follow_up(&nd->path))
}
follow_mount(&nd->path);
nd->inode = nd->path.dentry->d_inode;
+ return 0;
}
/*
negative = d_is_negative(dentry);
if (read_seqcount_retry(&dentry->d_seq, seq))
return -ECHILD;
- if (negative)
- return -ENOENT;
/*
* This sequence count validates that the parent had no
goto unlazy;
}
}
+ /*
+ * Note: do negative dentry check after revalidation in
+ * case that drops it.
+ */
+ if (negative)
+ return -ENOENT;
path->mnt = mnt;
path->dentry = dentry;
if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
if (nd->flags & LOOKUP_RCU) {
return follow_dotdot_rcu(nd);
} else
- follow_dotdot(nd);
+ return follow_dotdot(nd);
}
return 0;
}
/**
* path_mountpoint - look up a path to be umounted
- * @nameidata: lookup context
+ * @nd: lookup context
* @flags: lookup flags
* @path: pointer to container for result
*