[X][PATCH 1/1] mwifiex: Increase AES key storage size to 256 bits

[Wen-chien Jesse Sung]

From: Maximilian Luz <luzmaximilian at gmail.com>

BugLink: https://launchpad.net/bugs/1897299

Following commit e18696786548 ("mwifiex: Prevent memory corruption
handling keys") the mwifiex driver fails to authenticate with certain
networks, specifically networks with 256 bit keys, and repeatedly asks
for the password. The kernel log repeats the following lines (id and
bssid redacted):

    mwifiex_pcie 0000:01:00.0: info: trying to associate to '<id>' bssid <bssid>
    mwifiex_pcie 0000:01:00.0: info: associated to bssid <bssid> successfully
    mwifiex_pcie 0000:01:00.0: crypto keys added
    mwifiex_pcie 0000:01:00.0: info: successfully disconnected from <bssid>: reason code 3

Tracking down this problem lead to the overflow check introduced by the
aforementioned commit into mwifiex_ret_802_11_key_material_v2(). This
check fails on networks with 256 bit keys due to the current storage
size for AES keys in struct mwifiex_aes_param being only 128 bit.

To fix this issue, increase the storage size for AES keys to 256 bit.

Fixes: e18696786548 ("mwifiex: Prevent memory corruption handling keys")
Signed-off-by: Maximilian Luz <luzmaximilian at gmail.com>
Reported-by: Kaloyan Nikolov <konik98 at gmail.com>
Tested-by: Kaloyan Nikolov <konik98 at gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter at oracle.com>
Reviewed-by: Brian Norris <briannorris at chromium.org>
Tested-by: Brian Norris <briannorris at chromium.org>
Signed-off-by: Kalle Valo <kvalo at codeaurora.org>
Link: https://lore.kernel.org/r/20200825153829.38043-1-luzmaximilian@gmail.com
(backported from commit 4afc850e2e9e781976fb2c7852ce7bac374af938)
Signed-off-by: Wen-chien Jesse Sung <jesse.sung at canonical.com>
---
 drivers/net/wireless/mwifiex/fw.h          | 2 +-
 drivers/net/wireless/mwifiex/sta_cmdresp.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mwifiex/fw.h b/drivers/net/wireless/mwifiex/fw.h
index 7ff4ee213bea..533d4a8eb75c 100644
--- a/drivers/net/wireless/mwifiex/fw.h
+++ b/drivers/net/wireless/mwifiex/fw.h
@@ -850,7 +850,7 @@ struct mwifiex_tkip_param {
 struct mwifiex_aes_param {
 	u8 pn[WPA_PN_SIZE];
 	__le16 key_len;
-	u8 key[WLAN_KEY_LEN_CCMP];
+	u8 key[WLAN_KEY_LEN_CCMP_256];
 } __packed;
 
 struct mwifiex_wapi_param {
diff --git a/drivers/net/wireless/mwifiex/sta_cmdresp.c b/drivers/net/wireless/mwifiex/sta_cmdresp.c
index 3ad48c72863b..c269f9ced970 100644
--- a/drivers/net/wireless/mwifiex/sta_cmdresp.c
+++ b/drivers/net/wireless/mwifiex/sta_cmdresp.c
@@ -631,7 +631,7 @@ static int mwifiex_ret_802_11_key_material_v2(struct mwifiex_private *priv,
 	key_v2 = &resp->params.key_material_v2;
 
 	len = le16_to_cpu(key_v2->key_param_set.key_params.aes.key_len);
-	if (len > WLAN_KEY_LEN_CCMP)
+	if (len > sizeof(key_v2->key_param_set.key_params.aes.key))
 		return -EINVAL;
 
 	if (le16_to_cpu(key_v2->action) == HostCmd_ACT_GEN_SET) {
@@ -647,7 +647,7 @@ static int mwifiex_ret_802_11_key_material_v2(struct mwifiex_private *priv,
 		return 0;
 
 	memset(priv->aes_key_v2.key_param_set.key_params.aes.key, 0,
-	       WLAN_KEY_LEN_CCMP);
+	       sizeof(key_v2->key_param_set.key_params.aes.key));
 	priv->aes_key_v2.key_param_set.key_params.aes.key_len =
 				cpu_to_le16(len);
 	memcpy(priv->aes_key_v2.key_param_set.key_params.aes.key,
-- 
2.25.1