[PATCH] staging: rtl8723bs: fix heap buffer overflow in cfg80211_rtw_add_key

[Feng Ning <feng@innora.ai>]

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From: Feng Ning <feng@innora.ai>
To: gregkh@linuxfoundation.org
Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: [PATCH] staging: rtl8723bs: fix heap buffer overflow in cfg80211_rtw_add_key

The cfg80211 framework allows key sequence counters (NL80211_KEY_SEQ)
up to 16 bytes, but ieee_param.crypt.seq is a fixed 8-byte buffer.
When cfg80211_rtw_add_key() copies the sequence counter via memcpy()
without checking seq_len, a heap buffer overflow of up to 8 bytes
occurs, overwriting adjacent fields key_len and key[].

Cap the copy length at the buffer size using min_t().

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Signed-off-by: Feng Ning <feng@innora.ai>
---
 drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
index 7cb0c6f22..4fba53c2d 100644
--- a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
@@ -883,8 +883,11 @@ static int cfg80211_rtw_add_key(struct wiphy *wiphy, struct net_device *ndev,
 
 	param->u.crypt.idx = key_index;
 
-	if (params->seq_len && params->seq)
-		memcpy(param->u.crypt.seq, (u8 *)params->seq, params->seq_len);
+	if (params->seq_len && params->seq) {
+		size_t seq_copy = min_t(size_t, params->seq_len,
+				       sizeof(param->u.crypt.seq));
+		memcpy(param->u.crypt.seq, (u8 *)params->seq, seq_copy);
+	}
 
 	if (params->key_len && params->key) {
 		param->u.crypt.key_len = params->key_len;
-- 
2.43.0

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