[PATCH v2 0/2] staging: rtl8723bs: use of generic CRC-32

[PATCH v2 0/2] staging: rtl8723bs: use of generic CRC-32

[Fabio Aiuto]

This patchset replaces all private CRC-32 routines with
generic ones.

-------------------------
Changes in v2:
	- Patch two remove comments instead of
	  moving them

Fabio Aiuto (2):
  staging: rtl8723bs: replace private CRC-32 routines with in-kernel
    ones
  staging: rtl8723bs: remove unneeded comments to silence 'line too
    long' warning

 drivers/staging/rtl8723bs/core/rtw_security.c | 67 +++----------------
 1 file changed, 8 insertions(+), 59 deletions(-)

-- 
2.20.1

[PATCH v2 1/2] staging: rtl8723bs: replace private CRC-32 routines with in-kernel ones

[Fabio Aiuto]

replace private CRC-32 routines with in-kernel ones.

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
---
 drivers/staging/rtl8723bs/core/rtw_security.c | 66 ++-----------------
 1 file changed, 7 insertions(+), 59 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_security.c b/drivers/staging/rtl8723bs/core/rtw_security.c
index 19f96025aea6..bee1b2e2504e 100644
--- a/drivers/staging/rtl8723bs/core/rtw_security.c
+++ b/drivers/staging/rtl8723bs/core/rtw_security.c
@@ -4,7 +4,7 @@
  * Copyright(c) 2007 - 2011 Realtek Corporation. All rights reserved.
  *
  ******************************************************************************/
-#include <linux/crc32poly.h>
+#include <linux/crc32.h>
 #include <drv_types.h>
 #include <rtw_debug.h>
 #include <crypto/aes.h>
@@ -31,58 +31,6 @@ const char *security_type_str(u8 value)
 
 /* WEP related ===== */
 
-static signed int bcrc32initialized;
-static u32 crc32_table[256];
-
-
-static u8 crc32_reverseBit(u8 data)
-{
-	return((u8)((data<<7)&0x80) | ((data<<5)&0x40) | ((data<<3)&0x20) | ((data<<1)&0x10) | ((data>>1)&0x08) | ((data>>3)&0x04) | ((data>>5)&0x02) | ((data>>7)&0x01));
-}
-
-static void crc32_init(void)
-{
-	if (bcrc32initialized == 1)
-		return;
-	else {
-		signed int i, j;
-		u32 c;
-		u8 *p = (u8 *)&c, *p1;
-		u8 k;
-
-		c = 0x12340000;
-
-		for (i = 0; i < 256; ++i) {
-			k = crc32_reverseBit((u8)i);
-			for (c = ((u32)k) << 24, j = 8; j > 0; --j)
-				c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY_BE : (c << 1);
-			p1 = (u8 *)&crc32_table[i];
-
-			p1[0] = crc32_reverseBit(p[3]);
-			p1[1] = crc32_reverseBit(p[2]);
-			p1[2] = crc32_reverseBit(p[1]);
-			p1[3] = crc32_reverseBit(p[0]);
-		}
-		bcrc32initialized = 1;
-	}
-}
-
-static __le32 getcrc32(u8 *buf, signed 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
 */
@@ -122,7 +70,7 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 				length = pattrib->last_txcmdsz-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
 
-				*((__le32 *)crc) = getcrc32(payload, length);
+				*((__le32 *)crc) = ~crc32_le(~0, payload, length);
 
 				arc4_setkey(&mycontext, wepkey, 3 + keylength);
 				arc4_crypt(&mycontext, payload, payload, length);
@@ -130,7 +78,7 @@ void rtw_wep_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 			} else {
 				length = pxmitpriv->frag_len-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
-				*((__le32 *)crc) = getcrc32(payload, length);
+				*((__le32 *)crc) = ~crc32_le(~0, payload, length);
 				arc4_setkey(&mycontext, wepkey, 3 + keylength);
 				arc4_crypt(&mycontext, payload, payload, length);
 				arc4_crypt(&mycontext, payload + length, crc, 4);
@@ -174,7 +122,7 @@ void rtw_wep_decrypt(struct adapter  *padapter, u8 *precvframe)
 		arc4_crypt(&mycontext, payload, payload,  length);
 
 		/* calculate icv and compare the icv */
-		*((u32 *)crc) = le32_to_cpu(getcrc32(payload, length-4));
+		*((u32 *)crc) = le32_to_cpu(~crc32_le(~0, payload, length - 4));
 
 	}
 }
@@ -559,7 +507,7 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 				if ((curfragnum+1) == pattrib->nr_frags) {	/* 4 the last fragment */
 					length = pattrib->last_txcmdsz-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
-					*((__le32 *)crc) = getcrc32(payload, length);/* modified by Amy*/
+					*((__le32 *)crc) = ~crc32_le(~0, payload, length);/* modified by Amy*/
 
 					arc4_setkey(&mycontext, rc4key, 16);
 					arc4_crypt(&mycontext, payload, payload, length);
@@ -567,7 +515,7 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 				} else {
 					length = pxmitpriv->frag_len-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
-					*((__le32 *)crc) = getcrc32(payload, length);/* modified by Amy*/
+					*((__le32 *)crc) = ~crc32_le(~0, payload, length);/* modified by Amy*/
 					arc4_setkey(&mycontext, rc4key, 16);
 					arc4_crypt(&mycontext, payload, payload, length);
 					arc4_crypt(&mycontext, payload + length, crc, 4);
@@ -670,7 +618,7 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 			arc4_setkey(&mycontext, rc4key, 16);
 			arc4_crypt(&mycontext, payload, payload, length);
 
-			*((u32 *)crc) = le32_to_cpu(getcrc32(payload, length-4));
+			*((u32 *)crc) = le32_to_cpu(~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])
-- 
2.20.1

RE: [PATCH v2 1/2] staging: rtl8723bs: replace private CRC-32 routines with in-kernel ones

[David Laight]

> replace private CRC-32 routines with in-kernel ones.

Have you verified that they compute the same CRC?

There are all sorts of subtle reasons why the outputs can differ.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH v2 1/2] staging: rtl8723bs: replace private CRC-32 routines with in-kernel ones

[Fabio Aiuto]

Hello David,

On Mon, May 10, 2021 at 01:38:49PM +0000, David Laight wrote:
> > replace private CRC-32 routines with in-kernel ones.
> 
> Have you verified that they compute the same CRC?

thank you, I forgot to write in the cover letter that
it is not tested. I don't know how could I test it without
having the hardware...
Maybe is it reliable enough writing a small standalone program
using both procedures and compare the results?

> 
> There are all sorts of subtle reasons why the outputs can differ.
> 
> 	David
> 
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
> 

thank you,

fabio

Re: [PATCH v2 1/2] staging: rtl8723bs: replace private CRC-32 routines with in-kernel ones

[Fabio Aiuto]

Hello David,

On Mon, May 10, 2021 at 01:38:49PM +0000, David Laight wrote:
> > replace private CRC-32 routines with in-kernel ones.
> 
> Have you verified that they compute the same CRC?
> 
> There are all sorts of subtle reasons why the outputs can differ.
> 
> 	David
> 
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
> 

I tried this:

#include <linux/module.h>
#include <linux/crc32poly.h>
#include <linux/crc32.h>

/* Copy pasted from rtl8723bs/core/rtw_security.c */
static signed int bcrc32initialized;
static u32 crc32_table[256];

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CRC-32 verifier");
MODULE_AUTHOR("Fabio Aiuto");

/* Copy pasted from rtl8723bs/core/rtw_security.c */
static u8 crc32_reverseBit(u8 data)
{
        return ((u8)((data<<7)&0x80) | 
                ((data<<5)&0x40) | 
                ((data<<3)&0x20) | 
                ((data<<1)&0x10) | 
                ((data>>1)&0x08) | 
                ((data>>3)&0x04) | 
                ((data>>5)&0x02) | 
                ((data>>7)&0x01));
}


/* Copy pasted from rtl8723bs/core/rtw_security.c */
static void crc32_init(void)
{
        if (bcrc32initialized == 1)
                return;
        else {
                signed int i, j;
                u32 c;
                u8 *p = (u8 *)&c, *p1;
                u8 k;

                c = 0x12340000;

                for (i = 0; i < 256; ++i) {
                        k = crc32_reverseBit((u8)i);
                        for (c = ((u32)k) << 24, j = 8; j > 0; --j)
                                c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY_BE : (c << 1);
                        p1 = (u8 *)&crc32_table[i];

                        p1[0] = crc32_reverseBit(p[3]);
                        p1[1] = crc32_reverseBit(p[2]);
                        p1[2] = crc32_reverseBit(p[1]);
                        p1[3] = crc32_reverseBit(p[0]);
                }
                bcrc32initialized = 1;
        }
}

/* Copy pasted from rtl8723bs/core/rtw_security.c */
static __le32 getcrc32(u8 *buf, signed 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 */
}

static int __init crc32_entry(void)
{
        u8 payload;
        unsigned char crc_priv[4], crc_pub[4];

        payload = (u8)1234;
        /* private crc calculation used in rtl8723bs */
        *((__le32 *)crc_priv) = getcrc32(&payload, 2);
        pr_info("private rtl8723bs crc: %x", *crc_priv);
        /* in-kernel public crc calculation */
        *((__le32 *)crc_pub) = ~crc32_le(~0, &payload, 2);
        pr_info("generic crc: %x", *crc_pub);

        return 0;

}

static void __exit crc32_exit(void)
{
}

module_init(crc32_entry);
module_exit(crc32_exit);

And run it on qemu. Don't know why to display the second pr_info()
I have to rmmod it, but both methods give the same result (62)

[   38.149979] crc32m: module is from the staging directory, the quality is unknown, you have been warned.
[   38.169208] private rtl8723bs crc: 62
[   38.169400] generic crc: 62

thank you,

fabio

[PATCH v2 2/2] staging: rtl8723bs: remove unneeded comments to silence 'line too long' warning

[Fabio Aiuto]

remove unneeded comments to fix the following post commit hook
checkpatch warnings:

WARNING: line length of 110 exceeds 100 columns
115: FILE: drivers/staging/rtl8723bs/core/rtw_security.c:510:
+					*((__le32 *)crc)
 = ~crc32_le(~0, payload, length);/* modified by Amy*/

WARNING: line length of 110 exceeds 100 columns
124: FILE: drivers/staging/rtl8723bs/core/rtw_security.c:518:
+					*((__le32 *)crc)
 = ~crc32_le(~0, payload, length);/* modified by Amy*/

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
---
 drivers/staging/rtl8723bs/core/rtw_security.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_security.c b/drivers/staging/rtl8723bs/core/rtw_security.c
index bee1b2e2504e..5ff8926c1865 100644
--- a/drivers/staging/rtl8723bs/core/rtw_security.c
+++ b/drivers/staging/rtl8723bs/core/rtw_security.c
@@ -507,7 +507,7 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 				if ((curfragnum+1) == pattrib->nr_frags) {	/* 4 the last fragment */
 					length = pattrib->last_txcmdsz-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
-					*((__le32 *)crc) = ~crc32_le(~0, payload, length);/* modified by Amy*/
+					*((__le32 *)crc) = ~crc32_le(~0, payload, length);
 
 					arc4_setkey(&mycontext, rc4key, 16);
 					arc4_crypt(&mycontext, payload, payload, length);
@@ -515,7 +515,8 @@ u32 rtw_tkip_encrypt(struct adapter *padapter, u8 *pxmitframe)
 
 				} else {
 					length = pxmitpriv->frag_len-pattrib->hdrlen-pattrib->iv_len-pattrib->icv_len;
-					*((__le32 *)crc) = ~crc32_le(~0, payload, length);/* modified by Amy*/
+					*((__le32 *)crc) = ~crc32_le(~0, payload, length);
+
 					arc4_setkey(&mycontext, rc4key, 16);
 					arc4_crypt(&mycontext, payload, payload, length);
 					arc4_crypt(&mycontext, payload + length, crc, 4);
-- 
2.20.1