Use After Free Affecting kernel-rt-core package, versions <0:4.18.0-553.16.1.rt7.357.el8_10
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL8-KERNELRTCORE-6574425
- published5 Apr 2024
- disclosed4 Apr 2024
Introduced: 4 Apr 2024
CVE-2024-26802 (opens in a new tab)How to fix?
Upgrade RHEL:8 kernel-rt-core to version 0:4.18.0-553.16.1.rt7.357.el8_10 or higher.
This issue was patched in RHSA-2024:5102.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-core package and not the kernel-rt-core package as distributed by RHEL.
See How to fix? for RHEL:8 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
stmmac: Clear variable when destroying workqueue
Currently when suspending driver and stopping workqueue it is checked whether workqueue is not NULL and if so, it is destroyed. Function destroy_workqueue() does drain queue and does clear variable, but it does not set workqueue variable to NULL. This can cause kernel/module panic if code attempts to clear workqueue that was not initialized.
This scenario is possible when resuming suspended driver in stmmac_resume(), because there is no handling for failed stmmac_hw_setup(), which can fail and return if DMA engine has failed to initialize, and workqueue is initialized after DMA engine. Should DMA engine fail to initialize, resume will proceed normally, but interface won't work and TX queue will eventually timeout, causing 'Reset adapter' error. This then does destroy workqueue during reset process. And since workqueue is initialized after DMA engine and can be skipped, it will cause kernel/module panic.
To secure against this possible crash, set workqueue variable to NULL when destroying workqueue.
Log/backtrace from crash goes as follows: [88.031977]------------[ cut here ]------------ [88.031985]NETDEV WATCHDOG: eth0 (sxgmac): transmit queue 1 timed out [88.032017]WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:477 dev_watchdog+0x390/0x398 <Skipping backtrace for watchdog timeout> [88.032251]---[ end trace e70de432e4d5c2c0 ]--- [88.032282]sxgmac 16d88000.ethernet eth0: Reset adapter. [88.036359]------------[ cut here ]------------ [88.036519]Call trace: [88.036523] flush_workqueue+0x3e4/0x430 [88.036528] drain_workqueue+0xc4/0x160 [88.036533] destroy_workqueue+0x40/0x270 [88.036537] stmmac_fpe_stop_wq+0x4c/0x70 [88.036541] stmmac_release+0x278/0x280 [88.036546] __dev_close_many+0xcc/0x158 [88.036551] dev_close_many+0xbc/0x190 [88.036555] dev_close.part.0+0x70/0xc0 [88.036560] dev_close+0x24/0x30 [88.036564] stmmac_service_task+0x110/0x140 [88.036569] process_one_work+0x1d8/0x4a0 [88.036573] worker_thread+0x54/0x408 [88.036578] kthread+0x164/0x170 [88.036583] ret_from_fork+0x10/0x20 [88.036588]---[ end trace e70de432e4d5c2c1 ]--- [88.036597]Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
References
- https://access.redhat.com/security/cve/CVE-2024-26802
- https://git.kernel.org/stable/c/17ccd9798fe0beda3db212cfa3ebe373f605cbd6
- https://git.kernel.org/stable/c/699b103e48ce32d03fc86c35b37ee8ae4288c7e3
- https://git.kernel.org/stable/c/8af411bbba1f457c33734795f024d0ef26d0963f
- https://git.kernel.org/stable/c/8e99556301172465c8fe33c7f78c39a3d4ce8462
- https://git.kernel.org/stable/c/f72cf22dccc94038cbbaa1029cb575bf52e5cbc8