Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered
Russell King reports that a system with mv88e6xxx dereferences a NULL pointer when unbinding this driver: https://lore.kernel.org/netdev/[email protected]/
The crash seems to be in devlink_region_destroy(), which is not NULL tolerant but is given a NULL devlink global region pointer.
At least on some chips, some devlink regions are conditionally registered since the blamed commit, see mv88e6xxx_setup_devlink_regions_global():
if (cond && !cond(chip)) continue;
These are MV88E6XXX_REGION_STU and MV88E6XXX_REGION_PVT. If the chip does not have an STU or PVT, it should crash like this.
To fix the issue, avoid unregistering those regions which are NULL, i.e. were skipped at mv88e6xxx_setup_devlink_regions_global() time.
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered
Russell King reports that a system with mv88e6xxx dereferences a NULL pointer when unbinding this driver: https://lore.kernel.org/netdev/[email protected]/
The crash seems to be in devlink_region_destroy(), which is not NULL tolerant but is given a NULL devlink global region pointer.
At least on some chips, some devlink regions are conditionally registered since the blamed commit, see mv88e6xxx_setup_devlink_regions_global():
if (cond && !cond(chip)) continue;
These are MV88E6XXX_REGION_STU and MV88E6XXX_REGION_PVT. If the chip does not have an STU or PVT, it should crash like this.
To fix the issue, avoid unregistering those regions which are NULL, i.e. were skipped at mv88e6xxx_setup_devlink_regions_global() time.