In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi: Fix stale-data leak into the SCSI sense buffer iscsi_scsi_cmd_rsp() copies the sense data of a SCSI Response from the target-supplied data segment

Overview

In the Linux kernel, the following vulnerability has been resolved:

scsi: libiscsi: Fix stale-data leak into the SCSI sense buffer

iscsi_scsi_cmd_rsp() copies the sense data of a SCSI Response from the target-supplied data segment. The segment carries a 2-byte sense length followed by the sense bytes, so it must hold 2 + senselen bytes, but the bounds check only requires datalen >= senselen:

senselen = get_unaligned_be16(data);
if (datalen < senselen)
	goto invalid_datalen;
memcpy(sc->sense_buffer, data + 2,
       min_t(uint16_t, senselen, SCSI_SENSE_BUFFERSIZE));

A target that returns a SCSI Response whose datalen equals senselen (with senselen <= SCSI_SENSE_BUFFERSIZE) makes the memcpy() from data + 2 read up to two bytes past the received data. Those bytes are stale conn->data contents and end up in the command's sense buffer, which is returned to userspace.

Account for the 2-byte sense length prefix in the check.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.