[PATCH 2/3] staging: r8188eu: use in-kernel arc4 encryption

[Michael Straube]

Replace custom arc4 implementation with in-kernel one.

Signed-off-by: Michael Straube <straube.linux@xxxxxxxxx>
---
 drivers/staging/r8188eu/core/rtw_security.c   | 102 ++++--------------
 .../staging/r8188eu/include/rtw_security.h    |   5 +
 2 files changed, 25 insertions(+), 82 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_security.c b/drivers/staging/r8188eu/core/rtw_security.c
index d0586af1abad..a7f769048a44 100644
--- a/drivers/staging/r8188eu/core/rtw_security.c
+++ b/drivers/staging/r8188eu/core/rtw_security.c
@@ -10,68 +10,6 @@
 
 /* WEP related ===== */
 
-struct arc4context {
-	u32 x;
-	u32 y;
-	u8 state[256];
-};
-
-static void arcfour_init(struct arc4context *parc4ctx, u8 *key, u32	key_len)
-{
-	u32	t, u;
-	u32	keyindex;
-	u32	stateindex;
-	u8 *state;
-	u32	counter;
-
-	state = parc4ctx->state;
-	parc4ctx->x = 0;
-	parc4ctx->y = 0;
-	for (counter = 0; counter < 256; counter++)
-		state[counter] = (u8)counter;
-	keyindex = 0;
-	stateindex = 0;
-	for (counter = 0; counter < 256; counter++) {
-		t = state[counter];
-		stateindex = (stateindex + key[keyindex] + t) & 0xff;
-		u = state[stateindex];
-		state[stateindex] = (u8)t;
-		state[counter] = (u8)u;
-		if (++keyindex >= key_len)
-			keyindex = 0;
-	}
-
-}
-
-static u32 arcfour_byte(struct arc4context *parc4ctx)
-{
-	u32 x;
-	u32 y;
-	u32 sx, sy;
-	u8 *state;
-
-	state = parc4ctx->state;
-	x = (parc4ctx->x + 1) & 0xff;
-	sx = state[x];
-	y = (sx + parc4ctx->y) & 0xff;
-	sy = state[y];
-	parc4ctx->x = x;
-	parc4ctx->y = y;
-	state[y] = (u8)sx;
-	state[x] = (u8)sy;
-
-	return state[(sx + sy) & 0xff];
-}
-
-static void arcfour_encrypt(struct arc4context *parc4ctx, u8 *dest, u8 *src, u32 len)
-{
-	u32	i;
-
-	for (i = 0; i < len; i++)
-		dest[i] = src[i] ^ (unsigned char)arcfour_byte(parc4ctx);
-
-}
-
 /*
 	Need to consider the fragment  situation
 */
@@ -81,7 +19,6 @@ void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 		__le32 f0;
 		u8 f1[4];
 	} crc;
-	struct arc4context	 mycontext;
 
 	int	curfragnum, length;
 	u32	keylength;
@@ -92,6 +29,7 @@ void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 	struct	pkt_attrib	 *pattrib = &pxmitframe->attrib;
 	struct	security_priv	*psecuritypriv = &padapter->securitypriv;
 	struct	xmit_priv		*pxmitpriv = &padapter->xmitpriv;
+	struct arc4_ctx *ctx = &psecuritypriv->xmit_arc4_ctx;
 
 	if (!pxmitframe->buf_addr)
 		return;
@@ -114,15 +52,15 @@ void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 
 				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.f1, 4);
+				arc4_setkey(ctx, wepkey, 3 + keylength);
+				arc4_crypt(ctx, payload, payload, length);
+				arc4_crypt(ctx, payload + length, crc.f1, 4);
 			} else {
 				length = pxmitpriv->frag_len - pattrib->hdrlen - pattrib->iv_len - pattrib->icv_len;
 				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.f1, 4);
+				arc4_setkey(ctx, wepkey, 3 + keylength);
+				arc4_crypt(ctx, payload, payload, length);
+				arc4_crypt(ctx, payload + length, crc.f1, 4);
 
 				pframe += pxmitpriv->frag_len;
 				pframe = (u8 *)RND4((size_t)(pframe));
@@ -135,13 +73,13 @@ void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 void rtw_wep_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 {
 	/*  exclude ICV */
-	struct arc4context	 mycontext;
 	int	length;
 	u32	keylength;
 	u8	*pframe, *payload, *iv, wepkey[16];
 	u8	 keyindex;
 	struct	rx_pkt_attrib	 *prxattrib = &precvframe->attrib;
 	struct	security_priv	*psecuritypriv = &padapter->securitypriv;
+	struct arc4_ctx *ctx = &psecuritypriv->recv_arc4_ctx;
 
 	pframe = precvframe->rx_data;
 
@@ -157,8 +95,8 @@ void rtw_wep_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 		payload = pframe + prxattrib->iv_len + prxattrib->hdrlen;
 
 		/* decrypt payload include icv */
-		arcfour_init(&mycontext, wepkey, 3 + keylength);
-		arcfour_encrypt(&mycontext, payload, payload,  length);
+		arc4_setkey(ctx, wepkey, 3 + keylength);
+		arc4_crypt(ctx, payload, payload, length);
 	}
 }
 
@@ -509,7 +447,6 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 		u8 f1[4];
 	} crc;
 	u8   hw_hdr_offset = 0;
-	struct arc4context mycontext;
 	int			curfragnum, length;
 
 	u8	*pframe, *payload, *iv, *prwskey;
@@ -518,6 +455,7 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 	struct	pkt_attrib	 *pattrib = &pxmitframe->attrib;
 	struct	security_priv	*psecuritypriv = &padapter->securitypriv;
 	struct	xmit_priv		*pxmitpriv = &padapter->xmitpriv;
+	struct arc4_ctx *ctx = &psecuritypriv->xmit_arc4_ctx;
 	u32	res = _SUCCESS;
 
 	if (!pxmitframe->buf_addr)
@@ -554,16 +492,16 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 					length = pattrib->last_txcmdsz - pattrib->hdrlen - pattrib->iv_len - pattrib->icv_len;
 					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.f1, 4);
+					arc4_setkey(ctx, rc4key, 16);
+					arc4_crypt(ctx, payload, payload, length);
+					arc4_crypt(ctx, payload + length, crc.f1, 4);
 				} else {
 					length = pxmitpriv->frag_len - pattrib->hdrlen - pattrib->iv_len - pattrib->icv_len;
 					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.f1, 4);
+					arc4_setkey(ctx, rc4key, 16);
+					arc4_crypt(ctx, payload, payload, length);
+					arc4_crypt(ctx, payload + length, crc.f1, 4);
 
 					pframe += pxmitpriv->frag_len;
 					pframe = (u8 *)RND4((size_t)(pframe));
@@ -588,7 +526,6 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 		__le32 f0;
 		u8 f1[4];
 	} crc;
-	struct arc4context mycontext;
 	int			length;
 
 	u8	*pframe, *payload, *iv, *prwskey;
@@ -596,6 +533,7 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 	struct	sta_info		*stainfo;
 	struct	rx_pkt_attrib	 *prxattrib = &precvframe->attrib;
 	struct	security_priv	*psecuritypriv = &padapter->securitypriv;
+	struct arc4_ctx *ctx = &psecuritypriv->recv_arc4_ctx;
 	u32		res = _SUCCESS;
 
 	pframe = precvframe->rx_data;
@@ -629,8 +567,8 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 
 			/* 4 decrypt payload include icv */
 
-			arcfour_init(&mycontext, rc4key, 16);
-			arcfour_encrypt(&mycontext, payload, payload, length);
+			arc4_setkey(ctx, rc4key, 16);
+			arc4_crypt(ctx, payload, payload, length);
 
 			crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 
diff --git a/drivers/staging/r8188eu/include/rtw_security.h b/drivers/staging/r8188eu/include/rtw_security.h
index 1fc1a4f30eec..8ff583cdc0a6 100644
--- a/drivers/staging/r8188eu/include/rtw_security.h
+++ b/drivers/staging/r8188eu/include/rtw_security.h
@@ -6,6 +6,7 @@
 
 #include "osdep_service.h"
 #include "drv_types.h"
+#include <crypto/arc4.h>
 
 #define _NO_PRIVACY_			0x0
 #define _WEP40_				0x1
@@ -106,6 +107,10 @@ struct security_priv {
 	union Keytype	dot118021XGrprxmickey[4];
 	union pn48	dot11Grptxpn;		/* PN48 used for Grp Key xmit.*/
 	union pn48	dot11Grprxpn;		/* PN48 used for Grp Key recv.*/
+
+	struct arc4_ctx xmit_arc4_ctx;
+	struct arc4_ctx recv_arc4_ctx;
+
 #ifdef CONFIG_88EU_AP_MODE
 	/* extend security capabilities for AP_MODE */
 	unsigned int dot8021xalg;/* 0:disable, 1:psk, 2:802.1x */
-- 
2.33.0