Hi Dan,
Thanks for reporting this warning.
> The patch b877f4cf5af8: "mwifiex: add AES_CMAC support in
> key_material cmd" from Aug 3, 2012, leads to the following warning:
> drivers/net/wireless/mwifiex/sta_cmd.c:692
> mwifiex_cmd_802_11_key_material()
> error: memcpy() 'param->key' too small (16 vs 32)
I pulled latest 'smatch' code (top commit 130ba3ad) but it cannot detect this error though.
>
> 656 } else if (enc_key->key_len == WLAN_KEY_LEN_TKIP) {
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> We assume a 32 byte key_len here.
For TKIP, yes, key_len has been set to 32.
>
> 657 dev_dbg(priv->adapter->dev, "cmd: WPA_TKIP\n");
> 658 key_material->key_param_set.key_type_id =
> 659 cpu_to_le16(KEY_TYPE_ID_TKIP);
> 660 key_material->key_param_set.key_info =
> 661 cpu_to_le16(KEY_ENABLED);
>
> [snip]
>
> 686 if (le16_to_cpu(key_material->key_param_set.key_type_id) ==
> 687 KEY_TYPE_ID_AES_CMAC) {
> 688 struct mwifiex_cmac_param *param =
> 689 (void *)key_material->key_param_set.key;
> 690
> 691 memcpy(param->ipn, enc_key->pn, IGTK_PN_LEN);
> 692 memcpy(param->key, enc_key->key_material,
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 693 enc_key->key_len);
> ^^^^^^^^^^^^^^^^
> "param->key" only has space for 16 bytes.
For AES_CMAC, here key_len should have been set to 16, but compiler doesn't know that.
The following change should fix the warning. (I will send a formal patch shortly.)
diff --git a/drivers/net/wireless/mwifiex/sta_cmd.c b/drivers/net/wireless/mwifiex/
--- a/drivers/net/wireless/mwifiex/sta_cmd.c
+++ b/drivers/net/wireless/mwifiex/sta_cmd.c
@@ -690,7 +690,7 @@ mwifiex_cmd_802_11_key_material(struct mwifiex_private *priv,
memcpy(param->ipn, enc_key->pn, IGTK_PN_LEN);
memcpy(param->key, enc_key->key_material,
- enc_key->key_len);
+ WLAN_KEY_LEN_AES_CMAC);
key_param_len = sizeof(struct mwifiex_cmac_param);
key_material->key_param_set.key_len =
Thanks,
Bing
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