wifi: mac80211: mlme: fix null-ptr deref on failed assoc

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: mlme: fix null-ptr deref on failed assoc If association to an AP without a link 0 fails, then we crash in tracing because it assumes that either ap_mld_addr or link 0 BSS is valid, since we clear sdata->vif.valid_links and then don't add the ap_mld_addr to the struct. Since we clear also sdata->vif.cfg.ap_addr, keep a local copy of it and assign it earlier, before clearing valid_links, to fix this.

References

• https://git.kernel.org/stable/c/c695dfba8dfb82dc7ace4f22be088916cbf621ca
• https://git.kernel.org/stable/c/bb7743955a929e44b308cc3f63f8cc03873c1bee
• https://git.kernel.org/stable/c/78a6a43aaf87180ec7425a2a90468e1b4d09a1ec