In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie() The KASAN all

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

wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie()

The KASAN allocation trace shows that a malformed IE buffer is
stored via SIOCSIWGENIE (cfg80211_wext_siwgenie()) without any
validation. The crash trace shows that a subsequent SIOCSIWESSID
triggers a connection attempt which calls cfg80211_sme_get_conn_ies()
to process the stored IE buffer, causing:

• An out-of-bounds read in skip_ie() which reads ies[pos+1]
  (the length byte) past the end of the 1-byte buffer.

• An integer underflow in the memcpy size argument when offs
  returned by ieee80211_ie_split() exceeds ies_len, causing
  unsigned subtraction to wrap to SIZE_MAX and triggering a
  fortify panic.

Fix this by validating the IE buffer in cfg80211_wext_siwgenie()
before storing it.

[drop unnecessary ie_len check, update commit message]