Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
firmware: dmi-sysfs: Fix null-ptr-deref in dmi_sysfs_register_handle
KASAN reported a null-ptr-deref error:
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 1373 Comm: modprobe
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:dmi_sysfs_entry_release
…
Call Trace:
It is because previous patch added kobject_put() to release the memory which will call dmi_sysfs_entry_release() and list_del().
However, list_add_tail(entry->list) is called after the error block, so the list_head is uninitialized and cannot be deleted.
Move error handling to after list_add_tail to fix this.
Details
- Affected product:
- Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
- Affected packages:
- linux-hwe @ 4.15.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
firmware: dmi-sysfs: Fix null-ptr-deref in dmi_sysfs_register_handle
KASAN reported a null-ptr-deref error:
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 1373 Comm: modprobe
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:dmi_sysfs_entry_release
…
Call Trace:
It is because previous patch added kobject_put() to release the memory which will call dmi_sysfs_entry_release() and list_del().
However, list_add_tail(entry->list) is called after the error block, so the list_head is uninitialized and cannot be deleted.
Move error handling to after list_add_tail to fix this.