Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
usb: class: cdc-wdm: fix reordering issue in read code path
Quoting the bug report:
Due to compiler optimization or CPU out-of-order execution, the desc->length update can be reordered before the memmove. If this happens, wdm_read() can see the new length and call copy_to_user() on uninitialized memory. This also violates LKMM data race rules [1].
Fix it by using WRITE_ONCE and memory barriers.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 6 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-uek @ 5.4.17 (+15 more)
In the Linux kernel, the following vulnerability has been resolved:
usb: class: cdc-wdm: fix reordering issue in read code path
Quoting the bug report:
Due to compiler optimization or CPU out-of-order execution, the desc->length update can be reordered before the memmove. If this happens, wdm_read() can see the new length and call copy_to_user() on uninitialized memory. This also violates LKMM data race rules [1].
Fix it by using WRITE_ONCE and memory barriers.