From 71a5362de8d9143dd195a068bee8f3870ede2f63 Mon Sep 17 00:00:00 2001 From: Julian Squires Date: Mon, 6 Jul 2020 17:13:53 -0400 Subject: [PATCH] cfg80211: check vendor command doit pointer before use [ Upstream commit 4052d3d2e8f47a15053320bbcbe365d15610437d ] In the case where a vendor command does not implement doit, and has no flags set, doit would not be validated and a NULL pointer dereference would occur, for example when invoking the vendor command via iw. I encountered this while developing new vendor commands. Perhaps in practice it is advisable to always implement doit along with dumpit, but it seems reasonable to me to always check doit anyway, not just when NEED_WDEV. Signed-off-by: Julian Squires Link: https://lore.kernel.org/r/20200706211353.2366470-1-julian@cipht.net Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/wireless/nl80211.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 0048f90944dd..e107754e29a7 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -11317,13 +11317,13 @@ static int nl80211_vendor_cmd(struct sk_buff *skb, struct genl_info *info) if (!wdev->netdev && !wdev->p2p_started) return -ENETDOWN; } - - if (!vcmd->doit) - return -EOPNOTSUPP; } else { wdev = NULL; } + if (!vcmd->doit) + return -EOPNOTSUPP; + if (info->attrs[NL80211_ATTR_VENDOR_DATA]) { data = nla_data(info->attrs[NL80211_ATTR_VENDOR_DATA]); len = nla_len(info->attrs[NL80211_ATTR_VENDOR_DATA]);