CVE-2023-53590

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

sctp: add a refcnt in sctp_stream_priorities to avoid a nested loop

With this refcnt added in sctp_stream_priorities, we don't need to traverse all streams to check if the prio is used by other streams when freeing one stream's prio in sctp_sched_prio_free_sid(). This can avoid a nested loop (up to 65535 * 65535), which may cause a stuck as Ying reported:

watchdog: BUG: soft lockup - CPU#23 stuck for 26s! [ksoftirqd/23:136]
Call Trace:
 <TASK>
 sctp_sched_prio_free_sid+0xab/0x100 [sctp]
 sctp_stream_free_ext+0x64/0xa0 [sctp]
 sctp_stream_free+0x31/0x50 [sctp]
 sctp_association_free+0xa5/0x200 [sctp]

Note that it doesn't need to use refcount_t type for this counter, as its accessing is always protected under the sock lock.

v1->v2:

• add a check in sctp_sched_prio_set to avoid the possible prio_head refcnt overflow.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.