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From:   Jhih-Ming Huang <fbihjmeric@gmail.com>
To:     gregkh@linuxfoundation.org, fabioaiuto83@gmail.com,
        ross.schm.dev@gmail.com, maqianga@uniontech.com,
        marcocesati@gmail.com, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org
Cc:     Jhih-Ming Huang <fbihjmeric@gmail.com>
Subject: [PATCH v4] rtw_security: fix cast to restricted __le32
Date:   Sat, 19 Jun 2021 15:52:55 +0800
Message-Id: <20210619075255.107807-1-fbihjmeric@gmail.com>
In-Reply-To: <YMz0DH0+v39xsCYU@zeniv-ca.linux.org.uk>
References: <YMz0DH0+v39xsCYU@zeniv-ca.linux.org.uk>
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This patch fixes the sparse warning of fix cast to restricted __le32.

There was a change for replacing private CRC-32 routines with in kernel
ones.
However, the author used le32_to_cpu to convert crc32_le(), and we
should cpu_to_le32.

Ths commit also fixes the payload checking by memcmp instead of checking element
by element.

Signed-off-by: Jhih-Ming Huang <fbihjmeric@gmail.com>
---
 drivers/staging/rtl8723bs/core/rtw_security.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_security.c b/drivers/staging/rtl8723bs/core/rtw_security.c
index a99f439328f1..3a2711e21a0f 100644
--- a/drivers/staging/rtl8723bs/core/rtw_security.c
+++ b/drivers/staging/rtl8723bs/core/rtw_security.c
@@ -92,7 +92,7 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
 void rtw_wep_decrypt(struct adapter  *padapter, u8 *precvframe)
 {
 	/*  exclude ICV */
-	u8 crc[4];
+	__le32 crc;
 	signed int	length;
 	u32 keylength;
 	u8 *pframe, *payload, *iv, wepkey[16];
@@ -121,7 +121,7 @@ void rtw_wep_decrypt(struct adapter  *padapter, u8 *precvframe)
 		arc4_crypt(ctx, payload, payload,  length);
 
 		/* calculate icv and compare the icv */
-		*((u32 *)crc) = le32_to_cpu(~crc32_le(~0, payload, length - 4));
+		crc = cpu_to_le32(~crc32_le(~0, payload, length - 4));
 
 	}
 }
@@ -537,7 +537,7 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 	u32 pnh;
 	u8   rc4key[16];
 	u8   ttkey[16];
-	u8 crc[4];
+	__le32 crc;
 	signed int			length;
 
 	u8 *pframe, *payload, *iv, *prwskey;
@@ -618,10 +618,9 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 			arc4_setkey(ctx, rc4key, 16);
 			arc4_crypt(ctx, payload, payload, length);
 
-			*((u32 *)crc) = le32_to_cpu(~crc32_le(~0, payload, length - 4));
+			crc = cpu_to_le32(~crc32_le(~0, payload, length - 4));
 
-			if (crc[3] != payload[length - 1] || crc[2] != payload[length - 2] ||
-			    crc[1] != payload[length - 3] || crc[0] != payload[length - 4])
+			if (memcmp(&crc, payload + length - 4, 4) != 0)
 				res = _FAIL;
 		} else {
 			res = _FAIL;
-- 
2.32.0.288.g62a8d224e6-goog