Subject: [PATCH] wifi: iwlwifi: dvm: Add struct_group for struct iwl_keyinfo keys

From: Kees Cook <[email-masked]>
Date: Sat, 18 Feb 2023 11:11:00 -0800

Function iwlagn_send_sta_key() was trying to write across multiple
structure members in a single memcpy(). Add a struct group "keys" to
let the compiler see the intended bounds of the memcpy, which includes
the tkip keys as well. Silences false positive memcpy() run-time
warning:

  memcpy: detected field-spanning write (size 32) of single field "sta_cmd.key.key" at drivers/net/wireless/intel/iwlwifi/dvm/sta.c:1103 (size 16)

Link: https://www.alionet.org/index.php?topic=1469.0
Cc: Gregory Greenman <[email-masked]>
Cc: Kalle Valo <[email-masked]>
Cc: "David S. Miller" <[email-masked]>
Cc: Eric Dumazet <[email-masked]>
Cc: Jakub Kicinski <[email-masked]>
Cc: Paolo Abeni <[email-masked]>
Cc: Johannes Berg <[email-masked]>
Cc: Benjamin Berg <[email-masked]>
Cc: Sriram R <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Signed-off-by: Kees Cook <[email-masked]>
---
 drivers/net/wireless/intel/iwlwifi/dvm/commands.h | 10 ++++++----
 drivers/net/wireless/intel/iwlwifi/dvm/sta.c      |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
index 75a4b8e26232..0eceac4b9131 100644
--- a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
@@ -783,10 +783,12 @@ struct iwl_keyinfo {
 	__le16 tkip_rx_ttak[5];	/* 10-byte unicast TKIP TTAK */
 	u8 key_offset;
 	u8 reserved2;
-	u8 key[16];		/* 16-byte unicast decryption key */
-	__le64 tx_secur_seq_cnt;
-	__le64 hw_tkip_mic_rx_key;
-	__le64 hw_tkip_mic_tx_key;
+	struct_group(keys,
+		u8 key[16];	/* 16-byte unicast decryption key */
+		__le64 tx_secur_seq_cnt;
+		__le64 hw_tkip_mic_rx_key;
+		__le64 hw_tkip_mic_tx_key;
+	);
 } __packed;
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/sta.c b/drivers/net/wireless/intel/iwlwifi/dvm/sta.c
index cef43cf80620..a1c9e201b058 100644
--- a/drivers/net/wireless/intel/iwlwifi/dvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/sta.c
@@ -1093,14 +1093,14 @@ static int iwlagn_send_sta_key(struct iwl_priv *priv,
 	switch (keyconf->cipher) {
 	case WLAN_CIPHER_SUITE_CCMP:
 		key_flags |= STA_KEY_FLG_CCMP;
-		memcpy(sta_cmd.key.key, keyconf->key, keyconf->keylen);
+		memcpy(&sta_cmd.key.keys, keyconf->key, keyconf->keylen);
 		break;
 	case WLAN_CIPHER_SUITE_TKIP:
 		key_flags |= STA_KEY_FLG_TKIP;
 		sta_cmd.key.tkip_rx_tsc_byte2 = tkip_iv32;
 		for (i = 0; i < 5; i++)
 			sta_cmd.key.tkip_rx_ttak[i] = cpu_to_le16(tkip_p1k[i]);
-		memcpy(sta_cmd.key.key, keyconf->key, keyconf->keylen);
+		memcpy(&sta_cmd.key.keys, keyconf->key, keyconf->keylen);
 		break;
 	case WLAN_CIPHER_SUITE_WEP104:
 		key_flags |= STA_KEY_FLG_KEY_SIZE_MSK;
-- 
2.34.1