Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
nfc: hci: shdlc: Stop timers and work before freeing context
llc_shdlc_deinit() purges SHDLC skb queues and frees the llc_shdlc structure while its timers and state machine work may still be active.
Timer callbacks can schedule sm_work, and sm_work accesses SHDLC state and the skb queues. If teardown happens in parallel with a queued/running work item, it can lead to UAF and other shutdown races.
Stop all SHDLC timers and cancel sm_work synchronously before purging the queues and freeing the context.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 5.14.0 (+13 more)
In the Linux kernel, the following vulnerability has been resolved:
nfc: hci: shdlc: Stop timers and work before freeing context
llc_shdlc_deinit() purges SHDLC skb queues and frees the llc_shdlc structure while its timers and state machine work may still be active.
Timer callbacks can schedule sm_work, and sm_work accesses SHDLC state and the skb queues. If teardown happens in parallel with a queued/running work item, it can lead to UAF and other shutdown races.
Stop all SHDLC timers and cancel sm_work synchronously before purging the queues and freeing the context.
Found by Linux Verification Center (linuxtesting.org) with SVACE.