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authorHerbert Xu <herbert@gondor.apana.org.au>2008-07-08 20:54:28 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2008-07-10 20:35:18 +0800
commit5773a3e6e396d5fd9de58372abe6a86b7e258e3e (patch)
tree8c8576fdc279e95d16ed4dfd332b6380285027bf
parent20036252fc61c624a49770fb89684ea5cfdfa05e (diff)
downloadlinux-5773a3e6e396d5fd9de58372abe6a86b7e258e3e.tar.gz
crypto: crc32c - Add ahash implementation
This patch reimplements crc32c using the ahash interface. This allows one tfm to be used by an unlimited number of users provided that they all use the same key (which all current crc32c users do). Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/Kconfig2
-rw-r--r--crypto/crc32c.c128
2 files changed, 122 insertions, 8 deletions
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 43b7473ff19..ea503572fcb 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -213,7 +213,7 @@ comment "Digest"
config CRYPTO_CRC32C
tristate "CRC32c CRC algorithm"
- select CRYPTO_ALGAPI
+ select CRYPTO_HASH
select LIBCRC32C
help
Castagnoli, et al Cyclic Redundancy-Check Algorithm. Used
diff --git a/crypto/crc32c.c b/crypto/crc32c.c
index 0dcf64a74e6..a882d9e4e63 100644
--- a/crypto/crc32c.c
+++ b/crypto/crc32c.c
@@ -5,20 +5,23 @@
*
* This module file is a wrapper to invoke the lib/crc32c routines.
*
+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
+ *
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
+
+#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
-#include <linux/crypto.h>
#include <linux/crc32c.h>
#include <linux/kernel.h>
-#define CHKSUM_BLOCK_SIZE 32
+#define CHKSUM_BLOCK_SIZE 1
#define CHKSUM_DIGEST_SIZE 4
struct chksum_ctx {
@@ -71,7 +74,7 @@ static void chksum_final(struct crypto_tfm *tfm, u8 *out)
*(__le32 *)out = ~cpu_to_le32(mctx->crc);
}
-static int crc32c_cra_init(struct crypto_tfm *tfm)
+static int crc32c_cra_init_old(struct crypto_tfm *tfm)
{
struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
@@ -79,14 +82,14 @@ static int crc32c_cra_init(struct crypto_tfm *tfm)
return 0;
}
-static struct crypto_alg alg = {
+static struct crypto_alg old_alg = {
.cra_name = "crc32c",
.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
.cra_blocksize = CHKSUM_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct chksum_ctx),
.cra_module = THIS_MODULE,
- .cra_list = LIST_HEAD_INIT(alg.cra_list),
- .cra_init = crc32c_cra_init,
+ .cra_list = LIST_HEAD_INIT(old_alg.cra_list),
+ .cra_init = crc32c_cra_init_old,
.cra_u = {
.digest = {
.dia_digestsize= CHKSUM_DIGEST_SIZE,
@@ -98,14 +101,125 @@ static struct crypto_alg alg = {
}
};
+/*
+ * Setting the seed allows arbitrary accumulators and flexible XOR policy
+ * If your algorithm starts with ~0, then XOR with ~0 before you set
+ * the seed.
+ */
+static int crc32c_setkey(struct crypto_ahash *hash, const u8 *key,
+ unsigned int keylen)
+{
+ u32 *mctx = crypto_ahash_ctx(hash);
+
+ if (keylen != sizeof(u32)) {
+ crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
+ }
+ *mctx = le32_to_cpup((__le32 *)key);
+ return 0;
+}
+
+static int crc32c_init(struct ahash_request *req)
+{
+ u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ u32 *crcp = ahash_request_ctx(req);
+
+ *crcp = *mctx;
+ return 0;
+}
+
+static int crc32c_update(struct ahash_request *req)
+{
+ struct crypto_hash_walk walk;
+ u32 *crcp = ahash_request_ctx(req);
+ u32 crc = *crcp;
+ int nbytes;
+
+ for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
+ nbytes = crypto_hash_walk_done(&walk, 0))
+ crc = crc32c(crc, walk.data, nbytes);
+
+ *crcp = crc;
+ return 0;
+}
+
+static int crc32c_final(struct ahash_request *req)
+{
+ u32 *crcp = ahash_request_ctx(req);
+
+ *(__le32 *)req->result = ~cpu_to_le32p(crcp);
+ return 0;
+}
+
+static int crc32c_digest(struct ahash_request *req)
+{
+ struct crypto_hash_walk walk;
+ u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ u32 crc = *mctx;
+ int nbytes;
+
+ for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
+ nbytes = crypto_hash_walk_done(&walk, 0))
+ crc = crc32c(crc, walk.data, nbytes);
+
+ *(__le32 *)req->result = ~cpu_to_le32(crc);
+ return 0;
+}
+
+static int crc32c_cra_init(struct crypto_tfm *tfm)
+{
+ u32 *key = crypto_tfm_ctx(tfm);
+
+ *key = ~0;
+
+ tfm->crt_ahash.reqsize = sizeof(u32);
+
+ return 0;
+}
+
+static struct crypto_alg alg = {
+ .cra_name = "crc32c",
+ .cra_driver_name = "crc32c-generic",
+ .cra_priority = 100,
+ .cra_flags = CRYPTO_ALG_TYPE_AHASH,
+ .cra_blocksize = CHKSUM_BLOCK_SIZE,
+ .cra_alignmask = 3,
+ .cra_ctxsize = sizeof(u32),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_init = crc32c_cra_init,
+ .cra_type = &crypto_ahash_type,
+ .cra_u = {
+ .ahash = {
+ .digestsize = CHKSUM_DIGEST_SIZE,
+ .setkey = crc32c_setkey,
+ .init = crc32c_init,
+ .update = crc32c_update,
+ .final = crc32c_final,
+ .digest = crc32c_digest,
+ }
+ }
+};
+
static int __init crc32c_mod_init(void)
{
- return crypto_register_alg(&alg);
+ int err;
+
+ err = crypto_register_alg(&old_alg);
+ if (err)
+ return err;
+
+ err = crypto_register_alg(&alg);
+ if (err)
+ crypto_unregister_alg(&old_alg);
+
+ return err;
}
static void __exit crc32c_mod_fini(void)
{
crypto_unregister_alg(&alg);
+ crypto_unregister_alg(&old_alg);
}
module_init(crc32c_mod_init);