Bug 2468086 (CVE-2026-43314)
| Summary: | CVE-2026-43314 kernel: dm: remove fake timeout to avoid leak request | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | unspecified | CC: | rhel-process-autobot, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's device mapper (dm) driver. When an I/O timeout failure is intentionally introduced to a device mapper device, the driver does not correctly manage the timeout. This oversight causes a request to remain uncompleted, leading to system tasks hanging indefinitely. This vulnerability can result in a Denial of Service (DoS) condition, rendering the system unresponsive.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: dm: remove fake timeout to avoid leak request Since commit 15f73f5b3e59 ("blk-mq: move failure injection out of blk_mq_complete_request"), drivers are responsible for calling blk_should_fake_timeout() at appropriate code paths and opportunities. However, the dm driver does not implement its own timeout handler and relies on the timeout handling of its slave devices. If an io-timeout-fail error is injected to a dm device, the request will be leaked and never completed, causing tasks to hang indefinitely. Reproduce: 1. prepare dm which has iscsi slave device 2. inject io-timeout-fail to dm echo 1 >/sys/class/block/dm-0/io-timeout-fail echo 100 >/sys/kernel/debug/fail_io_timeout/probability echo 10 >/sys/kernel/debug/fail_io_timeout/times 3. read/write dm 4. iscsiadm -m node -u Result: hang task like below [ 862.243768] INFO: task kworker/u514:2:151 blocked for more than 122 seconds. [ 862.244133] Tainted: G E 6.19.0-rc1+ #51 [ 862.244337] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 862.244718] task:kworker/u514:2 state:D stack:0 pid:151 tgid:151 ppid:2 task_flags:0x4288060 flags:0x00080000 [ 862.245024] Workqueue: iscsi_ctrl_3:1 __iscsi_unbind_session [scsi_transport_iscsi] [ 862.245264] Call Trace: [ 862.245587] <TASK> [ 862.245814] __schedule+0x810/0x15c0 [ 862.246557] schedule+0x69/0x180 [ 862.246760] blk_mq_freeze_queue_wait+0xde/0x120 [ 862.247688] elevator_change+0x16d/0x460 [ 862.247893] elevator_set_none+0x87/0xf0 [ 862.248798] blk_unregister_queue+0x12e/0x2a0 [ 862.248995] __del_gendisk+0x231/0x7e0 [ 862.250143] del_gendisk+0x12f/0x1d0 [ 862.250339] sd_remove+0x85/0x130 [sd_mod] [ 862.250650] device_release_driver_internal+0x36d/0x530 [ 862.250849] bus_remove_device+0x1dd/0x3f0 [ 862.251042] device_del+0x38a/0x930 [ 862.252095] __scsi_remove_device+0x293/0x360 [ 862.252291] scsi_remove_target+0x486/0x760 [ 862.252654] __iscsi_unbind_session+0x18a/0x3e0 [scsi_transport_iscsi] [ 862.252886] process_one_work+0x633/0xe50 [ 862.253101] worker_thread+0x6df/0xf10 [ 862.253647] kthread+0x36d/0x720 [ 862.254533] ret_from_fork+0x2a6/0x470 [ 862.255852] ret_from_fork_asm+0x1a/0x30 [ 862.256037] </TASK> Remove the blk_should_fake_timeout() check from dm, as dm has no native timeout handling and should not attempt to fake timeouts.