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From:   "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Larry Finger <Larry.Finger@lwfinger.net>,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Cc:     "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Subject: [PATCH 1/2] staging: r8188eu: Replace a custom function with crc32_le()
Date:   Fri, 30 Jul 2021 12:37:15 +0200
Message-Id: <20210730103716.27210-2-fmdefrancesco@gmail.com>
In-Reply-To: <20210730103716.27210-1-fmdefrancesco@gmail.com>
References: <20210730103716.27210-1-fmdefrancesco@gmail.com>
MIME-Version: 1.0
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Use crc32_le() in place of the custom getcrc32().

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
 drivers/staging/r8188eu/core/rtw_security.c | 74 ++++++++++-----------
 1 file changed, 35 insertions(+), 39 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_security.c b/drivers/staging/r8188eu/core/rtw_security.c
index 5df970994e23..9625beea4b3c 100644
--- a/drivers/staging/r8188eu/core/rtw_security.c
+++ b/drivers/staging/r8188eu/core/rtw_security.c
@@ -111,29 +111,15 @@ static void crc32_init(void)
 	}
 }
 
-static __le32 getcrc32(u8 *buf, int len)
-{
-	u8 *p;
-	u32  crc;
-
-	if (bcrc32initialized == 0)
-		crc32_init();
-
-	crc = 0xffffffff;       /* preload shift register, per CRC-32 spec */
-
-	for (p = buf; len > 0; ++p, --len)
-		crc = crc32_table[(crc ^ *p) & 0xff] ^ (crc >> 8);
-
-	return cpu_to_le32(~crc);    /* transmit complement, per CRC-32 spec */
-}
-
 /*
 	Need to consider the fragment  situation
 */
 void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
 {	/*  exclude ICV */
-
-	unsigned char	crc[4];
+	union {
+		__le32 f0;
+		u8 f1[4];
+	} crc;
 	struct arc4context	 mycontext;
 
 	int	curfragnum, length;
@@ -167,17 +153,17 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
 			if ((curfragnum+1) == pattrib->nr_frags) {	/* the last fragment */
 				length = pattrib->last_txcmdsz-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
 
-				*((__le32 *)crc) = getcrc32(payload, length);
+				crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 
 				arcfour_init(&mycontext, wepkey, 3+keylength);
 				arcfour_encrypt(&mycontext, payload, payload, length);
-				arcfour_encrypt(&mycontext, payload+length, crc, 4);
+				arcfour_encrypt(&mycontext, payload+length, crc.f1, 4);
 			} else {
 				length = pxmitpriv->frag_len-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
-				*((__le32 *)crc) = getcrc32(payload, length);
+				crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 				arcfour_init(&mycontext, wepkey, 3+keylength);
 				arcfour_encrypt(&mycontext, payload, payload, length);
-				arcfour_encrypt(&mycontext, payload+length, crc, 4);
+				arcfour_encrypt(&mycontext, payload+length, crc.f1, 4);
 
 				pframe += pxmitpriv->frag_len;
 				pframe = (u8 *)RND4((size_t)(pframe));
@@ -190,7 +176,10 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
 void rtw_wep_decrypt(struct adapter  *padapter, u8 *precvframe)
 {
 	/*  exclude ICV */
-	u8	crc[4];
+	union {
+		__le32 f0;
+		u8 f1[4];
+	} crc;
 	struct arc4context	 mycontext;
 	int	length;
 	u32	keylength;
@@ -217,12 +206,12 @@ void rtw_wep_decrypt(struct adapter  *padapter, u8 *precvframe)
 		arcfour_encrypt(&mycontext, payload, payload,  length);
 
 		/* calculate icv and compare the icv */
-		*((__le32 *)crc) = getcrc32(payload, length - 4);
+		crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 
-		if (crc[3] != payload[length-1] ||
-		    crc[2] != payload[length-2] ||
-		    crc[1] != payload[length-3] ||
-		    crc[0] != payload[length-4]) {
+		if (crc.f1[3] != payload[length-1] ||
+		    crc.f1[2] != payload[length-2] ||
+		    crc.f1[1] != payload[length-3] ||
+		    crc.f1[0] != payload[length-4]) {
 			RT_TRACE(_module_rtl871x_security_c_, _drv_err_,
 				 ("rtw_wep_decrypt:icv error crc (%4ph)!=payload (%4ph)\n",
 				 &crc, &payload[length-4]));
@@ -574,7 +563,10 @@ u32	rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 	u32	pnh;
 	u8	rc4key[16];
 	u8   ttkey[16];
-	u8	crc[4];
+	union {
+		__le32 f0;
+		u8 f1[4];
+	} crc;
 	u8   hw_hdr_offset = 0;
 	struct arc4context mycontext;
 	int			curfragnum, length;
@@ -624,17 +616,18 @@ u32	rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 					RT_TRACE(_module_rtl871x_security_c_, _drv_info_,
 						 ("pattrib->iv_len=%x, pattrib->icv_len=%x\n",
 						 pattrib->iv_len, pattrib->icv_len));
-					*((__le32 *)crc) = getcrc32(payload, length);/* modified by Amy*/
+					crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 
 					arcfour_init(&mycontext, rc4key, 16);
 					arcfour_encrypt(&mycontext, payload, payload, length);
-					arcfour_encrypt(&mycontext, payload+length, crc, 4);
+					arcfour_encrypt(&mycontext, payload+length, crc.f1, 4);
 				} else {
 					length = pxmitpriv->frag_len-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len ;
-					*((__le32 *)crc) = getcrc32(payload, length);/* modified by Amy*/
+					crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
+
 					arcfour_init(&mycontext, rc4key, 16);
 					arcfour_encrypt(&mycontext, payload, payload, length);
-					arcfour_encrypt(&mycontext, payload+length, crc, 4);
+					arcfour_encrypt(&mycontext, payload+length, crc.f1, 4);
 
 					pframe += pxmitpriv->frag_len;
 					pframe = (u8 *)RND4((size_t)(pframe));
@@ -656,7 +649,10 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 	u32 pnh;
 	u8   rc4key[16];
 	u8   ttkey[16];
-	u8	crc[4];
+	union {
+		__le32 f0;
+		u8 f1[4];
+	} crc;
 	struct arc4context mycontext;
 	int			length;
 
@@ -702,12 +698,12 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 			arcfour_init(&mycontext, rc4key, 16);
 			arcfour_encrypt(&mycontext, payload, payload, length);
 
-			*((__le32 *)crc) = getcrc32(payload, length-4);
+			crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 
-			if (crc[3] != payload[length-1] ||
-			    crc[2] != payload[length-2] ||
-			    crc[1] != payload[length-3] ||
-			    crc[0] != payload[length-4]) {
+			if (crc.f1[3] != payload[length-1] ||
+			    crc.f1[2] != payload[length-2] ||
+			    crc.f1[1] != payload[length-3] ||
+			    crc.f1[0] != payload[length-4]) {
 				RT_TRACE(_module_rtl871x_security_c_, _drv_err_,
 					 ("rtw_wep_decrypt:icv error crc (%4ph)!=payload (%4ph)\n",
 					 &crc, &payload[length-4]));
-- 
2.32.0