CVE-2023-52980

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

block: ublk: extending queue_size to fix overflow

When validating drafted SPDK ublk target, in a case that assigning large queue depth to multiqueue ublk device, ublk target would run into a weird incorrect state. During rounds of review and debug, An overflow bug was found in ublk driver.

In ublk_cmd.h, UBLK_MAX_QUEUE_DEPTH is 4096 which means each ublk queue depth can be set as large as 4096. But when setting qd for a ublk device, sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io) will be larger than 65535 if qd is larger than 2728. Then queue_size is overflowed, and ublk_get_queue() references a wrong pointer position. The wrong content of ublk_queue elements will lead to out-of-bounds memory access.

Extend queue_size in ublk_device as "unsigned int".

This patch fixes an integer overflow in the ublk driver where queue_size, defined as unsigned short, could overflow for large queue depths, leading to out-of-bounds memory access via invalid queue pointer offsets.