From: Johannes Berg <johannes.berg@intel.com>
Date: Mon, 15 Jan 2018 09:32:36 +0100
Subject: mac80211_hwsim: validate number of different channels
Patch-mainline: v4.15-rc9
Git-commit: 51a1aaa631c90223888d8beac4d649dc11d2ca55
References: bsc#1076830

When creating a new radio on the fly, hwsim allows this
to be done with an arbitrary number of channels, but
cfg80211 only supports a limited number of simultaneous
channels, leading to a warning.

Fix this by validating the number - this requires moving
the define for the maximum out to a visible header file.

Reported-by: syzbot+8dd9051ff19940290931@syzkaller.appspotmail.com
Fixes: b59ec8dd4394 ("mac80211_hwsim: fix number of channels in interface combinations")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Michal Kubecek <mkubecek@suse.cz>

---
 drivers/net/wireless/mac80211_hwsim.c | 5 +++++
 include/net/cfg80211.h                | 2 ++
 net/wireless/core.h                   | 2 --
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 69ac1b08b04e..e6f1642272e0 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3121,6 +3121,11 @@ static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info)
 	if (info->attrs[HWSIM_ATTR_CHANNELS])
 		param.channels = nla_get_u32(info->attrs[HWSIM_ATTR_CHANNELS]);
 
+	if (param.channels > CFG80211_MAX_NUM_DIFFERENT_CHANNELS) {
+		GENL_SET_ERR_MSG(info, "too many channels specified");
+		return -EINVAL;
+	}
+
 	if (info->attrs[HWSIM_ATTR_NO_VIF])
 		param.no_vif = true;
 
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index b083e6cbae8c..5258067efa94 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -813,6 +813,8 @@ struct cfg80211_csa_settings {
 	u8 count;
 };
 
+#define CFG80211_MAX_NUM_DIFFERENT_CHANNELS 10
+
 /**
  * struct iface_combination_params - input parameters for interface combinations
  *
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 6e809325af3b..d6fbb503790a 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -501,8 +501,6 @@ void cfg80211_stop_p2p_device(struct cfg80211_registered_device *rdev,
 void cfg80211_stop_nan(struct cfg80211_registered_device *rdev,
 		       struct wireless_dev *wdev);
 
-#define CFG80211_MAX_NUM_DIFFERENT_CHANNELS 10
-
 #ifdef CONFIG_CFG80211_DEVELOPER_WARNINGS
 #define CFG80211_DEV_WARN_ON(cond)	WARN_ON(cond)
 #else
-- 
2.16.1