net: ethernet: mtk_wed: fix use-after-free panic in mtk_wed_setup_tc_block_cb()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: mtk_wed: fix use-after-free panic in mtk_wed_setup_tc_block_cb() When there are multiple ap interfaces on one band and with WED on, turning the interface down will cause a kernel panic on MT798X. Previously, cb_priv was freed in mtk_wed_setup_tc_block() without marking NULL,and mtk_wed_setup_tc_block_cb() didn't check the value, too. Assign NULL after free cb_priv in mtk_wed_setup_tc_block() and check NULL in mtk_wed_setup_tc_block_cb(). ---------- Unable to handle kernel paging request at virtual address 0072460bca32b4f5 Call trace: mtk_wed_setup_tc_block_cb+0x4/0x38 0xffffffc0794084bc tcf_block_playback_offloads+0x70/0x1e8 tcf_block_unbind+0x6c/0xc8 ... ---------

References

• https://git.kernel.org/stable/c/326a89321f9d5fe399fe6f9ff7c0fc766582a6a0
• https://git.kernel.org/stable/c/b453a4bbda03aa8741279c360ac82d1c3ac33548
• https://git.kernel.org/stable/c/db1b4bedb9b97c6d34b03d03815147c04fffe8b4