Upstream information
Description
In the Linux kernel, the following vulnerability has been resolved: sched/fair: Prevent dead task groups from regaining cfs_rq's Kevin is reporting crashes which point to a use-after-free of a cfs_rq in update_blocked_averages(). Initial debugging revealed that we've live cfs_rq's (on_list=1) in an about to be kfree()'d task group in free_fair_sched_group(). However, it was unclear how that can happen. His kernel config happened to lead to a layout of struct sched_entity that put the 'my_q' member directly into the middle of the object which makes it incidentally overlap with SLUB's freelist pointer. That, in combination with SLAB_FREELIST_HARDENED's freelist pointer mangling, leads to a reliable access violation in form of a #GP which made the UAF fail fast. Michal seems to have run into the same issue[1]. He already correctly diagnosed that commit a7b359fc6a37 ("sched/fair: Correctly insert cfs_rq's to list on unthrottle") is causing the preconditions for the UAF to happen by re-adding cfs_rq's also to task groups that have no more running tasks, i.e. also to dead ones. His analysis, however, misses the real root cause and it cannot be seen from the crash backtrace only, as the real offender is tg_unthrottle_up() getting called via sched_cfs_period_timer() via the timer interrupt at an inconvenient time. When unregister_fair_sched_group() unlinks all cfs_rq's from the dying task group, it doesn't protect itself from getting interrupted. If the timer interrupt triggers while we iterate over all CPUs or after unregister_fair_sched_group() has finished but prior to unlinking the task group, sched_cfs_period_timer() will execute and walk the list of task groups, trying to unthrottle cfs_rq's, i.e. re-add them to the dying task group. These will later -- in free_fair_sched_group() -- be kfree()'ed while still being linked, leading to the fireworks Kevin and Michal are seeing. To fix this race, ensure the dying task group gets unlinked first. However, simply switching the order of unregistering and unlinking the task group isn't sufficient, as concurrent RCU walkers might still see it, as can be seen below: CPU1: CPU2: : timer IRQ: : do_sched_cfs_period_timer(): : : : distribute_cfs_runtime(): : rcu_read_lock(); : : : unthrottle_cfs_rq(): sched_offline_group(): : : walk_tg_tree_from(…,tg_unthrottle_up,…): list_del_rcu(&tg->list); : (1) : list_for_each_entry_rcu(child, &parent->children, siblings) : : (2) list_del_rcu(&tg->siblings); : : tg_unthrottle_up(): unregister_fair_sched_group(): struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; : : list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); : : : : if (!cfs_rq_is_decayed(cfs_rq) || cfs_rq->nr_running) (3) : list_add_leaf_cfs_rq(cfs_rq); : : : : : : : : : ---truncated---SUSE information
Overall state of this security issue: Resolved
This issue is currently rated as having moderate severity.
| SUSE | |
|---|---|
| Base Score | 5.5 |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | None |
| Integrity Impact | None |
| Availability Impact | High |
| CVSSv3 Version | 3.1 |
Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.
| Product(s) | Source package | State |
|---|---|---|
| Products under general support and receiving all security fixes. | ||
| SUSE Enterprise Storage 7.1 | kernel-default | Not affected |
| SUSE Enterprise Storage 7.1 | kernel-source | Not affected |
| SUSE Enterprise Storage 7.1 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Desktop 15 SP5 | kernel-default | Already fixed |
| SUSE Linux Enterprise Desktop 15 SP5 | kernel-source | Already fixed |
| SUSE Linux Enterprise Desktop 15 SP6 | kernel-default | Already fixed |
| SUSE Linux Enterprise Desktop 15 SP6 | kernel-source | Already fixed |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-default | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-source | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | kernel-default | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | kernel-source | Already fixed |
| SUSE Linux Enterprise Micro 5.1 | kernel-default | Not affected |
| SUSE Linux Enterprise Micro 5.1 | kernel-rt | Not affected |
| SUSE Linux Enterprise Micro 5.1 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Micro 5.2 | kernel-default | Not affected |
| SUSE Linux Enterprise Micro 5.2 | kernel-rt | Not affected |
| SUSE Linux Enterprise Micro 5.2 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Micro 5.3 | kernel-default | Already fixed |
| SUSE Linux Enterprise Micro 5.3 | kernel-rt | Already fixed |
| SUSE Linux Enterprise Micro 5.3 | kernel-source-rt | Already fixed |
| SUSE Linux Enterprise Micro 5.4 | kernel-default | Already fixed |
| SUSE Linux Enterprise Micro 5.4 | kernel-rt | Already fixed |
| SUSE Linux Enterprise Micro 5.4 | kernel-source-rt | Already fixed |
| SUSE Linux Enterprise Micro 5.5 | kernel-source-rt | Already fixed |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | kernel-default | Already fixed |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | kernel-default | Already fixed |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Development Tools 15 SP5 | kernel-default | Already fixed |
| SUSE Linux Enterprise Module for Development Tools 15 SP5 | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Development Tools 15 SP6 | kernel-default | Already fixed |
| SUSE Linux Enterprise Module for Development Tools 15 SP6 | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Public Cloud 15 SP5 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise Real Time 12 SP5 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Real Time 15 SP5 | kernel-source-rt | Already fixed |
| SUSE Linux Enterprise Server 12 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Server 12 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server 15 SP5 | kernel-default | Already fixed |
| SUSE Linux Enterprise Server 15 SP5 | kernel-source | Already fixed |
| SUSE Linux Enterprise Server 15 SP5 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise Server 15 SP6 | kernel-default | Already fixed |
| SUSE Linux Enterprise Server 15 SP6 | kernel-source | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-default | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-source | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-default | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-source | Already fixed |
| SUSE Manager Proxy 4.3 | kernel-default | Already fixed |
| SUSE Manager Proxy 4.3 | kernel-source | Already fixed |
| SUSE Manager Proxy 4.3 | kernel-source-azure | Already fixed |
| SUSE Manager Retail Branch Server 4.3 | kernel-default | Already fixed |
| SUSE Manager Retail Branch Server 4.3 | kernel-source | Already fixed |
| SUSE Manager Retail Branch Server 4.3 | kernel-source-azure | Already fixed |
| SUSE Manager Server 4.3 | kernel-default | Already fixed |
| SUSE Manager Server 4.3 | kernel-source | Already fixed |
| SUSE Manager Server 4.3 | kernel-source-azure | Already fixed |
| SUSE Real Time Module 15 SP5 | kernel-source-rt | Already fixed |
| Products under Long Term Service Pack support and receiving important and critical security fixes. | ||
| SUSE Linux Enterprise Desktop 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-default | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-source | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | kernel-default | Already fixed |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Development Tools 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise Module for Public Cloud 15 SP4 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | kernel-default | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP2 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP3 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise Server 15 SP4 | kernel-source-azure | Already fixed |
| SUSE Linux Enterprise Server 15 SP4-LTSS | kernel-default | Already fixed |
| SUSE Linux Enterprise Server 15 SP4-LTSS | kernel-source | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-default | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-source-azure | Already fixed |
| SUSE OpenStack Cloud 8 | kernel-source | Not affected |
| SUSE OpenStack Cloud 9 | kernel-default | Not affected |
| SUSE OpenStack Cloud 9 | kernel-source | Not affected |
| Products past their end of life and not receiving proactive updates anymore. | ||
| HPE Helion OpenStack 8 | kernel-source | Not affected |
| SUSE CaaS Platform 4.0 | kernel-source | Not affected |
| SUSE Enterprise Storage 6 | kernel-source | Not affected |
| SUSE Enterprise Storage 7 | kernel-source | Not affected |
| SUSE Enterprise Storage 7 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Desktop 12 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 12 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 12 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Micro 5.0 | kernel-default | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Public Cloud 15 SP2 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Module for Public Cloud 15 SP3 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Real Time 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Real Time 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Real Time 15 SP3 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Real Time 15 SP4 | kernel-source | Already fixed |
| SUSE Linux Enterprise Real Time 15 SP4 | kernel-source-rt | Already fixed |
| SUSE Linux Enterprise Server 11 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 11 SP4-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP2-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP2-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP2-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP4-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server for Raspberry Pi 12 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | kernel-source | Not affected |
| SUSE Manager Proxy 4.0 | kernel-source | Not affected |
| SUSE Manager Proxy 4.1 | kernel-source | Not affected |
| SUSE Manager Proxy 4.1 | kernel-source-azure | Not affected |
| SUSE Manager Proxy 4.2 | kernel-source | Not affected |
| SUSE Manager Proxy 4.2 | kernel-source-azure | Not affected |
| SUSE Manager Retail Branch Server 4.0 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.1 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.1 | kernel-source-azure | Not affected |
| SUSE Manager Retail Branch Server 4.2 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.2 | kernel-source-azure | Not affected |
| SUSE Manager Server 4.0 | kernel-source | Not affected |
| SUSE Manager Server 4.1 | kernel-source | Not affected |
| SUSE Manager Server 4.1 | kernel-source-azure | Not affected |
| SUSE Manager Server 4.2 | kernel-source | Not affected |
| SUSE Manager Server 4.2 | kernel-source-azure | Not affected |
| SUSE OpenStack Cloud 7 | kernel-source | Not affected |
| SUSE OpenStack Cloud Crowbar 8 | kernel-source | Not affected |
| SUSE OpenStack Cloud Crowbar 9 | kernel-default | Not affected |
| SUSE OpenStack Cloud Crowbar 9 | kernel-source | Not affected |
| SUSE Real Time Module 15 SP3 | kernel-source-rt | Not affected |
| SUSE Real Time Module 15 SP4 | kernel-source-rt | Already fixed |
SUSE Timeline for this CVE
CVE page created: Wed Apr 10 22:00:26 2024CVE page last modified: Mon Apr 29 19:03:44 2024