CVE-2021-47102

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: marvell: prestera: fix incorrect structure access

In line:

upper = info->upper_dev;

We access upper_dev field, which is related only for particular events

(e.g. event == NETDEV_CHANGEUPPER). So, this line cause invalid memory

access for another events,

when ptr is not netdev_notifier_changeupper_info.

The KASAN logs are as follows:

[ 30.123165] BUG: KASAN: stack-out-of-bounds in prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera]

[ 30.133336] Read of size 8 at addr ffff80000cf772b0 by task udevd/778

[ 30.139866]

[ 30.141398] CPU: 0 PID: 778 Comm: udevd Not tainted 5.16.0-rc3 #6

[ 30.147588] Hardware name: DNI AmazonGo1 A7040 board (DT)

[ 30.153056] Call trace:

[ 30.155547] dump_backtrace+0x0/0x2c0

[ 30.159320] show_stack+0x18/0x30

[ 30.162729] dump_stack_lvl+0x68/0x84

[ 30.166491] print_address_description.constprop.0+0x74/0x2b8

[ 30.172346] kasan_report+0x1e8/0x250

[ 30.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References