CVE-2021-47439

When the ksz module is installed and removed using rmmod, kernel crashes with null pointer dereferrence error. During rmmod, ksz_switch_remove function tries to cancel the mib_read_workqueue using cancel_delayed_work_sync routine and unregister switch from dsa.

During dsa_unregister_switch it calls ksz_mac_link_down, which in turn reschedules the workqueue since mib_interval is non-zero. Due to which queue executed after mib_interval and it tries to access dp->slave. But the slave is unregistered in the ksz_switch_remove function. Hence kernel crashes.

To avoid this crash, before canceling the workqueue, resetted the mib_interval to 0.

v1 -> v2: -Removed the if condition in ksz_mib_read_work

References

Affected packages

Git /

Affected ranges

Database specific

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-47439.json"

unresolved_ranges

[
    {
        "events":  [
            {
                "introduced":  "5.7"
            },
            {
                "fixed":  "5.10.75"
            }
        ]
    },
    {
        "events":  [
            {
                "introduced":  "5.11"
            },
            {
                "fixed":  "5.14.14"
            }
        ]
    },
    {
        "events":  [
            {
                "introduced":  "0"
            },
            {
                "last_affected":  "5.15-rc1"
            }
        ]
    },
    {
        "events":  [
            {
                "introduced":  "0"
            },
            {
                "last_affected":  "5.15-rc2"
            }
        ]
    },
    {
        "events":  [
            {
                "introduced":  "0"
            },
            {
                "last_affected":  "5.15-rc3"
            }
        ]
    },
    {
        "events":  [
            {
                "introduced":  "0"
            },
            {
                "last_affected":  "5.15-rc4"
            }
        ]
    },
    {
        "events":  [
            {
                "introduced":  "0"
            },
            {
                "last_affected":  "5.15-rc5"
            }
        ]
    }
]