nl80211: fix check for valid SSID size in scan operations

In both trigger_scan and sched_scan operations, we were checking for
the SSID length before assigning the value correctly.  Since the
memory was just kzalloc'ed, the check was always failing and SSID with
over 32 characters were allowed to go through.

This was causing a buffer overflow when copying the actual SSID to the
proper place.

This bug has been there since 2.6.29-rc4.

Cc: stable@kernel.org
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
static int nl80211_authenticate(struct sk_buff *skb, struct genl_info *info)
{
	struct cfg80211_registered_device *rdev = info->user_ptr[0];
	struct net_device *dev = info->user_ptr[1];
	struct ieee80211_channel *chan;
	const u8 *bssid, *ssid, *ie = NULL;
	int err, ssid_len, ie_len = 0;
	enum nl80211_auth_type auth_type;
	struct key_parse key;
	bool local_state_change;

	if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_MAC])
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_AUTH_TYPE])
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_SSID])
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_WIPHY_FREQ])
		return -EINVAL;

	err = nl80211_parse_key(info, &key);
	if (err)
		return err;

	if (key.idx >= 0) {
		if (key.type != -1 && key.type != NL80211_KEYTYPE_GROUP)
			return -EINVAL;
		if (!key.p.key || !key.p.key_len)
			return -EINVAL;
		if ((key.p.cipher != WLAN_CIPHER_SUITE_WEP40 ||
		     key.p.key_len != WLAN_KEY_LEN_WEP40) &&
		    (key.p.cipher != WLAN_CIPHER_SUITE_WEP104 ||
		     key.p.key_len != WLAN_KEY_LEN_WEP104))
			return -EINVAL;
		if (key.idx > 4)
			return -EINVAL;
	} else {
		key.p.key_len = 0;
		key.p.key = NULL;
	}

	if (key.idx >= 0) {
		int i;
		bool ok = false;
		for (i = 0; i < rdev->wiphy.n_cipher_suites; i++) {
			if (key.p.cipher == rdev->wiphy.cipher_suites[i]) {
				ok = true;
				break;
			}
		}
		if (!ok)
			return -EINVAL;
	}

	if (!rdev->ops->auth)
		return -EOPNOTSUPP;

	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_STATION &&
	    dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_CLIENT)
		return -EOPNOTSUPP;

	bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);
	chan = ieee80211_get_channel(&rdev->wiphy,
		nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]));
	if (!chan || (chan->flags & IEEE80211_CHAN_DISABLED))
		return -EINVAL;

	ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);
	ssid_len = nla_len(info->attrs[NL80211_ATTR_SSID]);

	if (info->attrs[NL80211_ATTR_IE]) {
		ie = nla_data(info->attrs[NL80211_ATTR_IE]);
		ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
	}

	auth_type = nla_get_u32(info->attrs[NL80211_ATTR_AUTH_TYPE]);
	if (!nl80211_valid_auth_type(auth_type))
		return -EINVAL;

	local_state_change = !!info->attrs[NL80211_ATTR_LOCAL_STATE_CHANGE];

	return cfg80211_mlme_auth(rdev, dev, chan, auth_type, bssid,
				  ssid, ssid_len, ie, ie_len,
				  key.p.key, key.p.key_len, key.idx,
				  local_state_change);
}

static int nl80211_authenticate(struct sk_buff *skb, struct genl_info *info)
{
	struct cfg80211_registered_device *rdev = info->user_ptr[0];
	struct net_device *dev = info->user_ptr[1];
	struct ieee80211_channel *chan;
	const u8 *bssid, *ssid, *ie = NULL;
	int err, ssid_len, ie_len = 0;
	enum nl80211_auth_type auth_type;
	struct key_parse key;
	bool local_state_change;

	if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_MAC])
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_AUTH_TYPE])
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_SSID])
		return -EINVAL;

	if (!info->attrs[NL80211_ATTR_WIPHY_FREQ])
		return -EINVAL;

	err = nl80211_parse_key(info, &key);
	if (err)
		return err;

	if (key.idx >= 0) {
		if (key.type != -1 && key.type != NL80211_KEYTYPE_GROUP)
			return -EINVAL;
		if (!key.p.key || !key.p.key_len)
			return -EINVAL;
		if ((key.p.cipher != WLAN_CIPHER_SUITE_WEP40 ||
		     key.p.key_len != WLAN_KEY_LEN_WEP40) &&
		    (key.p.cipher != WLAN_CIPHER_SUITE_WEP104 ||
		     key.p.key_len != WLAN_KEY_LEN_WEP104))
			return -EINVAL;
		if (key.idx > 4)
			return -EINVAL;
	} else {
		key.p.key_len = 0;
		key.p.key = NULL;
	}

	if (key.idx >= 0) {
		int i;
		bool ok = false;
		for (i = 0; i < rdev->wiphy.n_cipher_suites; i++) {
			if (key.p.cipher == rdev->wiphy.cipher_suites[i]) {
				ok = true;
				break;
			}
		}
		if (!ok)
			return -EINVAL;
	}

	if (!rdev->ops->auth)
		return -EOPNOTSUPP;

	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_STATION &&
	    dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_CLIENT)
		return -EOPNOTSUPP;

	bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);
	chan = ieee80211_get_channel(&rdev->wiphy,
		nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]));
	if (!chan || (chan->flags & IEEE80211_CHAN_DISABLED))
		return -EINVAL;

	ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);
	ssid_len = nla_len(info->attrs[NL80211_ATTR_SSID]);

	if (info->attrs[NL80211_ATTR_IE]) {
		ie = nla_data(info->attrs[NL80211_ATTR_IE]);
		ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
	}

	auth_type = nla_get_u32(info->attrs[NL80211_ATTR_AUTH_TYPE]);
	if (!nl80211_valid_auth_type(auth_type))
		return -EINVAL;

	local_state_change = !!info->attrs[NL80211_ATTR_LOCAL_STATE_CHANGE];

	return cfg80211_mlme_auth(rdev, dev, chan, auth_type, bssid,
				  ssid, ssid_len, ie, ie_len,
				  key.p.key, key.p.key_len, key.idx,
				  local_state_change);
}
