rtl818x: Prevent using not initialized queues

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: rtl818x: Prevent using not initialized queues Using not existing queues can panic the kernel with rtl8180/rtl8185 cards. Ignore the skb priority for those cards, they only have one tx queue. Pierre Asselin (pa@panix.com) reported the kernel crash in the Gentoo forum: https://forums.gentoo.org/viewtopic-t-1147832-postdays-0-postorder-asc-start-25.html He also confirmed that this patch fixes the issue. In summary this happened: After updating wpa_supplicant from 2.9 to 2.10 the kernel crashed with a "divide error: 0000" when connecting to an AP. Control port tx now tries to use IEEE80211_AC_VO for the priority, which wpa_supplicants starts to use in 2.10. Since only the rtl8187se part of the driver supports QoS, the priority of the skb is set to IEEE80211_AC_BE (2) by mac80211 for rtl8180/rtl8185 cards. rtl8180 is then unconditionally reading out the priority and finally crashes on drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c line 544 without this patch: idx = (ring->idx + skb_queue_len(&ring->queue)) % ring->entries "ring->entries" is zero for rtl8180/rtl8185 cards, tx_ring[2] never got initialized.

References

• https://git.kernel.org/stable/c/b5dca2cd3f0239512da808598b4e70557eb4c2a1
• https://git.kernel.org/stable/c/d7e30dfc166d33470bba31a42f9bbc346e5409d5
• https://git.kernel.org/stable/c/9d5e96cc1f1720019ce27b127a31695148d38bb0
• https://git.kernel.org/stable/c/b8ce58ab80faaea015c206382041ff3bcf5495ff
• https://git.kernel.org/stable/c/769ec2a824deae2f1268dfda14999a4d14d0d0c5
• https://git.kernel.org/stable/c/6ad81ad0cf5744738ce94c8e64051ddd80a1734c
• https://git.kernel.org/stable/c/9ad1981fc4de3afb7db3e8eb5a6a52d4c7d0d577
• https://git.kernel.org/stable/c/98e55b0b876bde3353f4e074883d66ecb55c65a3
• https://git.kernel.org/stable/c/746285cf81dc19502ab238249d75f5990bd2d231