DocumentationOverview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
net: macb: fix NULL pointer dereference on unbind with fixed-link
When the device tree describes a fixed-link and has no “mdio” child node, macb_mii_init() returns early without allocating the MDIO bus, leaving bp->mii_bus as NULL.
Two cleanup paths then dereference this NULL bus:
- On driver unbind, macb_remove() unconditionally calls mdiobus_unregister(bp->mii_bus), which oopses:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000004a8 pc : mdiobus_unregister+0x14/0xa4 lr : macb_remove+0x38/0xa4 Call trace: mdiobus_unregister+0x14/0xa4 (P) macb_remove+0x38/0xa4 platform_remove+0x20/0x30 device_release_driver_internal+0x1c8/0x224 unbind_store+0xb4/0xbc
- On the probe error path in macb_probe(), reached when macb_mii_init() has succeeded but a subsequent step fails, the err_out_unregister_mdio label runs the same unconditional cleanup.
mdiobus_unregister() and mdiobus_free() do not guard against a NULL bus, so guard the calls in both macb_remove() and the probe error path.
Details
- Affected product:
- Debian 11 ELS
- Affected packages:
- linux @ 5.10.259
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 12 | Planned | — |
| Debian 13 | Will Not Fix |
17 kernels
|