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.
Publication date: Wed, 16 Apr 2025 14:13:00 +0000