wifi: ath9k: hif_usb: Fix use-after-free in ath9k_hif_usb_reg_in_cb()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: wifi: ath9k: hif_usb: Fix use-after-free in ath9k_hif_usb_reg_in_cb() It is possible that skb is freed in ath9k_htc_rx_msg(), then usb_submit_urb() fails and we try to free skb again. It causes use-after-free bug. Moreover, if alloc_skb() fails, urb->context becomes NULL but rx_buf is not freed and there can be a memory leak. The patch removes unnecessary nskb and makes skb processing more clear: it is supposed that ath9k_htc_rx_msg() either frees old skb or passes its managing to another callback function. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

References

• https://git.kernel.org/stable/c/5e8751a977a49a6e00cce1a8da5ca16da83f9c8c
• https://git.kernel.org/stable/c/f127c2b4c967025e5c3a4ce7e13b79135d46a33d
• https://git.kernel.org/stable/c/0c8dd2ea4b419da96ab4953e4967e9363e2f8a4f
• https://git.kernel.org/stable/c/988bd27de2484faf17afe0408db2e3d9e5ac61fc
• https://git.kernel.org/stable/c/98d9172822dc6f38138333941984bd759a89d419
• https://git.kernel.org/stable/c/355f16f756aad0c95cdaa0c14a34ab4137d32815
• https://git.kernel.org/stable/c/53b9bb1a00c4285ee7f58a11129dbea015db61bc
• https://git.kernel.org/stable/c/71fc0ad671a62c494d2aec731baeabd3bfe6c95d
• https://git.kernel.org/stable/c/dd95f2239fc846795fc926787c3ae0ca701c9840