CVE-2021-3139: Improper Limitation of a Pathname to a Restricted Directory

In Open-iSCSI tcmu-runner 1.3.x, 1.4.x, and 1.5.x through 1.5.2, xcopy_locate_udev in tcmur_cmd_handler.c lacks a check for transport-layer restrictions, allowing remote attackers to read or write files via directory traversal in an XCOPY request. For example, an attack can occur over a network if the attacker has access to one iSCSI LUN. NOTE: relative to CVE-2020-28374, this is a similar mistake in a different algorithm.