Skip to contentSkip to conversation

libcrc32c: keep intermediate crc state in cpu order

PATCH In review Benny Halevy 3 participants 4 messages Nov 8, 2007 6 messages not in the archive

Subsystems (2)
Library code Crypto API
lore
Share & tools
lore

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): [email protected]

Benny Halevy

author
#6 lore raw

PATCH 1/1 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(-)
lib/libcrc32c.c +2 -5
index 802f11f..b5c3287 100644
@@ -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 */
Signature · 1 line
1.5.3.3
maintainer
#7 lore raw
Quoted 7 lines · Benny Halevy

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.

Signature · 4 lines
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
#8 lore raw
In reply to Benny Halevy

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

Quoted 41 lines · Benny Halevy

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(-)
lib/libcrc32c.c +2 -5
index 802f11f..b5c3287 100644
@@ -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 */
Signature · 6 lines
------------------------------------------------------
Dave Jiang
Software Engineer
MontaVista Software, Inc.
http://www.mvista.com
------------------------------------------------------
author
#9 lore raw
Quoted 1 line · Dave Jiang

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

Quoted 45 lines
Quoted 41 lines · Benny Halevy

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(-)
lib/libcrc32c.c +2 -5
index 802f11f..b5c3287 100644
@@ -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 */