From: Arend Van Spriel Date: Mon, 5 Sep 2016 09:45:47 +0000 (+0100) Subject: brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap() X-Git-Tag: firefly_0821_release~176^2~4^2~21^2~37 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b82a7f93b4e60d8689d8f4e687ef58ed2098739f;p=firefly-linux-kernel-4.4.55.git brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap() commit ded89912156b1a47d940a0c954c43afbabd0c42c upstream. User-space can choose to omit NL80211_ATTR_SSID and only provide raw IE TLV data. When doing so it can provide SSID IE with length exceeding the allowed size. The driver further processes this IE copying it into a local variable without checking the length. Hence stack can be corrupted and used as exploit. Reported-by: Daxing Guo Reviewed-by: Hante Meuleman Reviewed-by: Pieter-Paul Giesberts Reviewed-by: Franky Lin Signed-off-by: Arend van Spriel Signed-off-by: Kalle Valo Signed-off-by: Juerg Haefliger Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c index 71493d2af912..70a6985334d5 100644 --- a/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c +++ b/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c @@ -4102,7 +4102,7 @@ brcmf_cfg80211_start_ap(struct wiphy *wiphy, struct net_device *ndev, (u8 *)&settings->beacon.head[ie_offset], settings->beacon.head_len - ie_offset, WLAN_EID_SSID); - if (!ssid_ie) + if (!ssid_ie || ssid_ie->len > IEEE80211_MAX_SSID_LEN) return -EINVAL; memcpy(ssid_le.SSID, ssid_ie->data, ssid_ie->len);