From: Deepanshu Kartikey Date: Sat, 25 Jul 2026 14:20:28 +0000 (+0530) Subject: wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a2f5286ca4f304d3fd469f01b96b518608912a5c;p=thirdparty%2Fkernel%2Fstable.git 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. Reported-by: syzbot+cc867e537e4bd36f69bb@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=cc867e537e4bd36f69bb Signed-off-by: Deepanshu Kartikey Link: https://patch.msgid.link/20260725142028.32560-1-kartikey406@gmail.com [drop unnecessary ie_len check, update commit message] Signed-off-by: Johannes Berg --- diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c index 573b6b15a446..b5914f3658db 100644 --- a/net/wireless/wext-sme.c +++ b/net/wireless/wext-sme.c @@ -319,6 +319,15 @@ int cfg80211_wext_siwgenie(struct net_device *dev, return 0; if (ie_len) { + const struct element *elem; + + for_each_element(elem, extra, ie_len) { + /* nothing */ + } + + if (!for_each_element_completed(elem, extra, ie_len)) + return -EINVAL; + ie = kmemdup(extra, ie_len, GFP_KERNEL); if (!ie) return -ENOMEM;