wifi: iwlwifi: mvm: fix potential array out of bounds access

Account for IWL_SEC_WEP_KEY_OFFSET when needed while verifying
key_len size in iwl_mvm_sec_key_add().
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230613155501.f193b7493a93.I6948ba625b9318924b96a5e22602ac75d2bd0125@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/mld-key.c

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * Copyright (C) 2022 Intel Corporation
+ * Copyright (C) 2022 - 2023 Intel Corporation
  */
 #include <linux/kernel.h>
 #include <net/mac80211.h>
@@ -175,9 +175,14 @@ int iwl_mvm_mld_send_key(struct iwl_mvm *mvm, u32 sta_mask, u32 key_flags,
 		.u.add.key_flags = cpu_to_le32(key_flags),
 		.u.add.tx_seq = cpu_to_le64(atomic64_read(&keyconf->tx_pn)),
 	};
+	int max_key_len = sizeof(cmd.u.add.key);
 	int ret;
 
-	if (WARN_ON(keyconf->keylen > sizeof(cmd.u.add.key)))
+	if (keyconf->cipher == WLAN_CIPHER_SUITE_WEP40 ||
+	    keyconf->cipher == WLAN_CIPHER_SUITE_WEP104)
+		max_key_len -= IWL_SEC_WEP_KEY_OFFSET;
+
+	if (WARN_ON(keyconf->keylen > max_key_len))
 		return -EINVAL;
 
 	if (WARN_ON(!sta_mask))