Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
dlm: prevent NPD when writing a positive value to event_done
do_uevent returns the value written to event_done. In case it is a positive value, new_lockspace would undo all the work, and lockspace would not be set. __dlm_new_lockspace, however, would treat that positive value as a success due to commit 8511a2728ab8 (“dlm: fix use count with multiple joins”).
Down the line, device_create_lockspace would pass that NULL lockspace to dlm_find_lockspace_local, leading to a NULL pointer dereference.
Treating such positive values as successes prevents the problem. Given this has been broken for so long, this is unlikely to break userspace expectations.
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 6 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 @ 2.6.32 (+16 more)
In the Linux kernel, the following vulnerability has been resolved:
dlm: prevent NPD when writing a positive value to event_done
do_uevent returns the value written to event_done. In case it is a positive value, new_lockspace would undo all the work, and lockspace would not be set. __dlm_new_lockspace, however, would treat that positive value as a success due to commit 8511a2728ab8 (“dlm: fix use count with multiple joins”).
Down the line, device_create_lockspace would pass that NULL lockspace to dlm_find_lockspace_local, leading to a NULL pointer dereference.
Treating such positive values as successes prevents the problem. Given this has been broken for so long, this is unlikely to break userspace expectations.