29195232fa
- Correctly compare the algorithm name in crc_t10dif_notify(). - Use proper NOTIFY_* status codes instead of 0. - Consistently use CRC_T10DIF_STRING instead of "crct10dif" directly. - Use a proper type for the shash_desc context. - Use crypto_shash_driver_name() instead of open-coding it. - Make crc_t10dif_transform_show() use snprintf() rather than sprintf(). This isn't actually necessary since the buffer has size PAGE_SIZE and CRYPTO_MAX_ALG_NAME < PAGE_SIZE, but it's good practice. - Give the "transform" sysfs file mode 0444 rather than 0644, since it doesn't implement a setter method. - Adjust the module description to not be the same as crct10dif-generic. Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* T10 Data Integrity Field CRC16 calculation
|
|
*
|
|
* Copyright (c) 2007 Oracle Corporation. All rights reserved.
|
|
* Written by Martin K. Petersen <martin.petersen@oracle.com>
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/module.h>
|
|
#include <linux/crc-t10dif.h>
|
|
#include <linux/err.h>
|
|
#include <linux/init.h>
|
|
#include <crypto/hash.h>
|
|
#include <crypto/algapi.h>
|
|
#include <linux/static_key.h>
|
|
#include <linux/notifier.h>
|
|
|
|
static struct crypto_shash __rcu *crct10dif_tfm;
|
|
static DEFINE_STATIC_KEY_TRUE(crct10dif_fallback);
|
|
static DEFINE_MUTEX(crc_t10dif_mutex);
|
|
static struct work_struct crct10dif_rehash_work;
|
|
|
|
static int crc_t10dif_notify(struct notifier_block *self, unsigned long val, void *data)
|
|
{
|
|
struct crypto_alg *alg = data;
|
|
|
|
if (val != CRYPTO_MSG_ALG_LOADED ||
|
|
strcmp(alg->cra_name, CRC_T10DIF_STRING))
|
|
return NOTIFY_DONE;
|
|
|
|
schedule_work(&crct10dif_rehash_work);
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static void crc_t10dif_rehash(struct work_struct *work)
|
|
{
|
|
struct crypto_shash *new, *old;
|
|
|
|
mutex_lock(&crc_t10dif_mutex);
|
|
old = rcu_dereference_protected(crct10dif_tfm,
|
|
lockdep_is_held(&crc_t10dif_mutex));
|
|
new = crypto_alloc_shash(CRC_T10DIF_STRING, 0, 0);
|
|
if (IS_ERR(new)) {
|
|
mutex_unlock(&crc_t10dif_mutex);
|
|
return;
|
|
}
|
|
rcu_assign_pointer(crct10dif_tfm, new);
|
|
mutex_unlock(&crc_t10dif_mutex);
|
|
|
|
if (old) {
|
|
synchronize_rcu();
|
|
crypto_free_shash(old);
|
|
} else {
|
|
static_branch_disable(&crct10dif_fallback);
|
|
}
|
|
}
|
|
|
|
static struct notifier_block crc_t10dif_nb = {
|
|
.notifier_call = crc_t10dif_notify,
|
|
};
|
|
|
|
__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len)
|
|
{
|
|
struct {
|
|
struct shash_desc shash;
|
|
__u16 crc;
|
|
} desc;
|
|
int err;
|
|
|
|
if (static_branch_unlikely(&crct10dif_fallback))
|
|
return crc_t10dif_generic(crc, buffer, len);
|
|
|
|
rcu_read_lock();
|
|
desc.shash.tfm = rcu_dereference(crct10dif_tfm);
|
|
desc.crc = crc;
|
|
err = crypto_shash_update(&desc.shash, buffer, len);
|
|
rcu_read_unlock();
|
|
|
|
BUG_ON(err);
|
|
|
|
return desc.crc;
|
|
}
|
|
EXPORT_SYMBOL(crc_t10dif_update);
|
|
|
|
__u16 crc_t10dif(const unsigned char *buffer, size_t len)
|
|
{
|
|
return crc_t10dif_update(0, buffer, len);
|
|
}
|
|
EXPORT_SYMBOL(crc_t10dif);
|
|
|
|
static int __init crc_t10dif_mod_init(void)
|
|
{
|
|
INIT_WORK(&crct10dif_rehash_work, crc_t10dif_rehash);
|
|
crypto_register_notifier(&crc_t10dif_nb);
|
|
crc_t10dif_rehash(&crct10dif_rehash_work);
|
|
return 0;
|
|
}
|
|
|
|
static void __exit crc_t10dif_mod_fini(void)
|
|
{
|
|
crypto_unregister_notifier(&crc_t10dif_nb);
|
|
cancel_work_sync(&crct10dif_rehash_work);
|
|
crypto_free_shash(rcu_dereference_protected(crct10dif_tfm, 1));
|
|
}
|
|
|
|
module_init(crc_t10dif_mod_init);
|
|
module_exit(crc_t10dif_mod_fini);
|
|
|
|
static int crc_t10dif_transform_show(char *buffer, const struct kernel_param *kp)
|
|
{
|
|
struct crypto_shash *tfm;
|
|
int len;
|
|
|
|
if (static_branch_unlikely(&crct10dif_fallback))
|
|
return sprintf(buffer, "fallback\n");
|
|
|
|
rcu_read_lock();
|
|
tfm = rcu_dereference(crct10dif_tfm);
|
|
len = snprintf(buffer, PAGE_SIZE, "%s\n",
|
|
crypto_shash_driver_name(tfm));
|
|
rcu_read_unlock();
|
|
|
|
return len;
|
|
}
|
|
|
|
module_param_call(transform, NULL, crc_t10dif_transform_show, NULL, 0444);
|
|
|
|
MODULE_DESCRIPTION("T10 DIF CRC calculation (library API)");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_SOFTDEP("pre: crct10dif");
|