2007-11-08 08:20:43

by Benny Halevy

Subject: [PATCH] libcrc32c: keep intermediate crc state in cpu order

crypto/crc32.c:chksum_final() is computing the digest as
*(__le32 *)out = ~cpu_to_le32(mctx->crc);
so the low-level crc32c_le routines should just keep
the crc in cpu order, otherwise it is getting swabbed
one too many times on big-endian machines.

Signed-off-by: Benny Halevy <[email protected]>
---
lib/libcrc32c.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
index 802f11f..b5c3287 100644
--- a/lib/libcrc32c.c
+++ b/lib/libcrc32c.c
@@ -33,7 +33,6 @@
#include <linux/crc32c.h>
#include <linux/compiler.h>
#include <linux/module.h>
-#include <asm/byteorder.h>

MODULE_AUTHOR("Clay Haapala <[email protected]>");
MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
@@ -161,15 +160,13 @@ static const u32 crc32c_table[256] = {
*/

u32 __pure
-crc32c_le(u32 seed, unsigned char const *data, size_t length)
+crc32c_le(u32 crc, unsigned char const *data, size_t length)
{
- u32 crc = __cpu_to_le32(seed);
-
while (length--)
crc =
crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);

- return __le32_to_cpu(crc);
+ return crc;
}

#endif /* CRC_LE_BITS == 8 */
--
1.5.3.3

2007-11-08 13:38:04

by Herbert Xu

Subject: Re: [PATCH] libcrc32c: keep intermediate crc state in cpu order

On Thu, Nov 08, 2007 at 10:20:34AM +0200, Benny Halevy wrote:
> crypto/crc32.c:chksum_final() is computing the digest as
> *(__le32 *)out = ~cpu_to_le32(mctx->crc);
> so the low-level crc32c_le routines should just keep
> the crc in cpu order, otherwise it is getting swabbed
> one too many times on big-endian machines.
>
> Signed-off-by: Benny Halevy <[email protected]>

Patch applied. Thanks!

I'll send this to stable too.
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

2007-11-08 18:40:16

by Dave Jiang

Subject: Re: [PATCH] libcrc32c: keep intermediate crc state in cpu order

Resolved my issue with BE open-iscsi initiator and LE IET target. Thanks!

Benny Halevy wrote:
> crypto/crc32.c:chksum_final() is computing the digest as
> *(__le32 *)out = ~cpu_to_le32(mctx->crc);
> so the low-level crc32c_le routines should just keep
> the crc in cpu order, otherwise it is getting swabbed
> one too many times on big-endian machines.
>
> Signed-off-by: Benny Halevy <[email protected]>
> ---
> lib/libcrc32c.c | 7 ++-----
> 1 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
> index 802f11f..b5c3287 100644
> --- a/lib/libcrc32c.c
> +++ b/lib/libcrc32c.c
> @@ -33,7 +33,6 @@
> #include <linux/crc32c.h>
> #include <linux/compiler.h>
> #include <linux/module.h>
> -#include <asm/byteorder.h>
>
> MODULE_AUTHOR("Clay Haapala <[email protected]>");
> MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
> @@ -161,15 +160,13 @@ static const u32 crc32c_table[256] = {
> */
>
> u32 __pure
> -crc32c_le(u32 seed, unsigned char const *data, size_t length)
> +crc32c_le(u32 crc, unsigned char const *data, size_t length)
> {
> - u32 crc = __cpu_to_le32(seed);
> -
> while (length--)
> crc =
> crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
>
> - return __le32_to_cpu(crc);
> + return crc;
> }
>
> #endif /* CRC_LE_BITS == 8 */


--

------------------------------------------------------
Dave Jiang
Software Engineer
MontaVista Software, Inc.
http://www.mvista.com
------------------------------------------------------

2007-11-08 19:37:56

by Benny Halevy

Subject: Re: [PATCH] libcrc32c: keep intermediate crc state in cpu order

On Nov. 08, 2007, 20:41 +0200, Dave Jiang <[email protected]> wrote:
> Resolved my issue with BE open-iscsi initiator and LE IET target. Thanks!

Super! Thanks for testing!

And many thanks to Tomo for identifying the byte-order problem
in the crypto code.

Benny


>
> Benny Halevy wrote:
>> crypto/crc32.c:chksum_final() is computing the digest as
>> *(__le32 *)out = ~cpu_to_le32(mctx->crc);
>> so the low-level crc32c_le routines should just keep
>> the crc in cpu order, otherwise it is getting swabbed
>> one too many times on big-endian machines.
>>
>> Signed-off-by: Benny Halevy <[email protected]>
>> ---
>> lib/libcrc32c.c | 7 ++-----
>> 1 files changed, 2 insertions(+), 5 deletions(-)
>>
>> diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
>> index 802f11f..b5c3287 100644
>> --- a/lib/libcrc32c.c
>> +++ b/lib/libcrc32c.c
>> @@ -33,7 +33,6 @@
>> #include <linux/crc32c.h>
>> #include <linux/compiler.h>
>> #include <linux/module.h>
>> -#include <asm/byteorder.h>
>>
>> MODULE_AUTHOR("Clay Haapala <[email protected]>");
>> MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
>> @@ -161,15 +160,13 @@ static const u32 crc32c_table[256] = {
>> */
>>
>> u32 __pure
>> -crc32c_le(u32 seed, unsigned char const *data, size_t length)
>> +crc32c_le(u32 crc, unsigned char const *data, size_t length)
>> {
>> - u32 crc = __cpu_to_le32(seed);
>> -
>> while (length--)
>> crc =
>> crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
>>
>> - return __le32_to_cpu(crc);
>> + return crc;
>> }
>>
>> #endif /* CRC_LE_BITS == 8 */
>
>