CVE-2024-27053: NULL Pointer Dereference

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

wifi: wilc1000: fix RCU usage in connect path

With lockdep enabled, calls to the connect function from cfg802.11 layer lead to the following warning:

============================= WARNING: suspicious RCU usage 6.7.0-rc1-wt+ #333 Not tainted ----------------------------- drivers/net/wireless/microchip/wilc1000/hif.c:386 suspicious rcu_dereference_check() usage! [...] stack backtrace: CPU: 0 PID: 100 Comm: wpa_supplicant Not tainted 6.7.0-rc1-wt+ #333 Hardware name: Atmel SAMA5 unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x34/0x48 dump_stack_lvl from wilc_parse_join_bss_param+0x7dc/0x7f4 wilc_parse_join_bss_param from connect+0x2c4/0x648 connect from cfg80211_connect+0x30c/0xb74 cfg80211_connect from nl80211_connect+0x860/0xa94 nl80211_connect from genl_rcv_msg+0x3fc/0x59c genl_rcv_msg from netlink_rcv_skb+0xd0/0x1f8 netlink_rcv_skb from genl_rcv+0x2c/0x3c genl_rcv from netlink_unicast+0x3b0/0x550 netlink_unicast from netlink_sendmsg+0x368/0x688 netlink_sendmsg from ____sys_sendmsg+0x190/0x430 ____sys_sendmsg from ___sys_sendmsg+0x110/0x158 ___sys_sendmsg from sys_sendmsg+0xe8/0x150 sys_sendmsg from ret_fast_syscall+0x0/0x1c

This warning is emitted because in the connect path, when trying to parse target BSS parameters, we dereference a RCU pointer whithout being in RCU critical section. Fix RCU dereference usage by moving it to a RCU read critical section. To avoid wrapping the whole wilc_parse_join_bss_param under the critical section, just use the critical section to copy ies data