[PATCH 4.14 007/159] mac80211_hwsim: validate number of different channels

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit 51a1aaa631c90223888d8beac4d649dc11d2ca55 upstream.

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: b59ec8dd4394 ("mac80211_hwsim: fix number of channels in interface combinations")
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3119,6 +3119,11 @@ 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 > 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;
 
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -815,6 +815,8 @@ struct cfg80211_csa_settings {
 	u8 count;
 };
 
+#define CFG80211_MAX_NUM_DIFFERENT_CHANNELS 10
+
 /**
  * struct iface_combination_params - input parameters for interface combinations
  *
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -502,8 +502,6 @@ void cfg80211_stop_p2p_device(struct cfg
 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