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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+2a12f11c306afe871c1f@syzkaller.appspotmail.com,
        Johannes Berg <johannes.berg@intel.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.18 003/168] mac80211_hwsim: require at least one channel
Date:   Mon,  8 Oct 2018 20:29:43 +0200
Message-Id: <20181008175620.171849782@linuxfoundation.org>
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4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit 484004339d4514fde425f6e8a9f6a6cc979bb0c3 ]

Syzbot continues to try to create mac80211_hwsim radios, and
manages to pass parameters that are later checked with WARN_ON
in cfg80211 - catch another one in hwsim directly.

Reported-by: syzbot+2a12f11c306afe871c1f@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireless/mac80211_hwsim.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3194,6 +3194,11 @@ static int hwsim_new_radio_nl(struct sk_
 	if (info->attrs[HWSIM_ATTR_CHANNELS])
 		param.channels = nla_get_u32(info->attrs[HWSIM_ATTR_CHANNELS]);
 
+	if (param.channels < 1) {
+		GENL_SET_ERR_MSG(info, "must have at least one channel");
+		return -EINVAL;
+	}
+
 	if (param.channels > CFG80211_MAX_NUM_DIFFERENT_CHANNELS) {
 		GENL_SET_ERR_MSG(info, "too many channels specified");
 		return -EINVAL;