bcachefs-tools/linux/crypto/shash.c

/*
 * Synchronous Cryptographic Hash operations.
 *
 * 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/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>

#include "internal.h"

static int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
			   unsigned int keylen)
{
	return -ENOSYS;
}

static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
				  unsigned int keylen)
{
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);
	unsigned long absize;
	u8 *buffer, *alignbuffer;
	int err;

	absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
	buffer = kmalloc(absize, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
	memcpy(alignbuffer, key, keylen);
	err = shash->setkey(tfm, alignbuffer, keylen);
	kzfree(buffer);
	return err;
}

int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
			unsigned int keylen)
{
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);

	if ((unsigned long)key & alignmask)
		return shash_setkey_unaligned(tfm, key, keylen);

	return shash->setkey(tfm, key, keylen);
}

static inline unsigned int shash_align_buffer_size(unsigned len,
						   unsigned long mask)
{
	typedef u8 __attribute__ ((aligned)) u8_aligned;
	return len + (mask & ~(__alignof__(u8_aligned) - 1));
}

static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
				  unsigned int len)
{
	struct crypto_shash *tfm = desc->tfm;
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);
	unsigned int unaligned_len = alignmask + 1 -
				     ((unsigned long)data & alignmask);
	u8 ubuf[shash_align_buffer_size(unaligned_len, alignmask)]
		__attribute__ ((aligned));
	u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
	int err;

	if (unaligned_len > len)
		unaligned_len = len;

	memcpy(buf, data, unaligned_len);
	err = shash->update(desc, buf, unaligned_len);
	memset(buf, 0, unaligned_len);

	return err ?:
	       shash->update(desc, data + unaligned_len, len - unaligned_len);
}

int crypto_shash_update(struct shash_desc *desc, const u8 *data,
			unsigned int len)
{
	struct crypto_shash *tfm = desc->tfm;
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);

	if ((unsigned long)data & alignmask)
		return shash_update_unaligned(desc, data, len);

	return shash->update(desc, data, len);
}

static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
{
	struct crypto_shash *tfm = desc->tfm;
	unsigned long alignmask = crypto_shash_alignmask(tfm);
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned int ds = crypto_shash_digestsize(tfm);
	u8 ubuf[shash_align_buffer_size(ds, alignmask)]
		__attribute__ ((aligned));
	u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
	int err;

	err = shash->final(desc, buf);
	if (err)
		goto out;

	memcpy(out, buf, ds);

out:
	memset(buf, 0, ds);
	return err;
}

int crypto_shash_final(struct shash_desc *desc, u8 *out)
{
	struct crypto_shash *tfm = desc->tfm;
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);

	if ((unsigned long)out & alignmask)
		return shash_final_unaligned(desc, out);

	return shash->final(desc, out);
}

static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
				 unsigned int len, u8 *out)
{
	return crypto_shash_update(desc, data, len) ?:
	       crypto_shash_final(desc, out);
}

int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
		       unsigned int len, u8 *out)
{
	struct crypto_shash *tfm = desc->tfm;
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);

	if (((unsigned long)data | (unsigned long)out) & alignmask)
		return shash_finup_unaligned(desc, data, len, out);

	return shash->finup(desc, data, len, out);
}

static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
				  unsigned int len, u8 *out)
{
	return crypto_shash_init(desc) ?:
	       crypto_shash_finup(desc, data, len, out);
}

int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
			unsigned int len, u8 *out)
{
	struct crypto_shash *tfm = desc->tfm;
	struct shash_alg *shash = crypto_shash_alg(tfm);
	unsigned long alignmask = crypto_shash_alignmask(tfm);

	if (((unsigned long)data | (unsigned long)out) & alignmask)
		return shash_digest_unaligned(desc, data, len, out);

	return shash->digest(desc, data, len, out);
}

static int shash_default_export(struct shash_desc *desc, void *out)
{
	memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
	return 0;
}

static int shash_default_import(struct shash_desc *desc, const void *in)
{
	memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
	return 0;
}

static int crypto_shash_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_shash *hash = __crypto_shash_cast(tfm);

	hash->descsize = crypto_shash_alg(hash)->descsize;
	return 0;
}

static const struct crypto_type crypto_shash_type = {
	.extsize = crypto_alg_extsize,
	.init_tfm = crypto_shash_init_tfm,
	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	.maskset = CRYPTO_ALG_TYPE_MASK,
	.type = CRYPTO_ALG_TYPE_SHASH,
	.tfmsize = offsetof(struct crypto_shash, base),
};

struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
					u32 mask)
{
	return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
}

static int shash_prepare_alg(struct shash_alg *alg)
{
	struct crypto_alg *base = &alg->base;

	if (alg->digestsize > PAGE_SIZE / 8 ||
	    alg->descsize > PAGE_SIZE / 8 ||
	    alg->statesize > PAGE_SIZE / 8)
		return -EINVAL;

	base->cra_type = &crypto_shash_type;
	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;

	if (!alg->finup)
		alg->finup = shash_finup_unaligned;
	if (!alg->digest)
		alg->digest = shash_digest_unaligned;
	if (!alg->export) {
		alg->export = shash_default_export;
		alg->import = shash_default_import;
		alg->statesize = alg->descsize;
	}
	if (!alg->setkey)
		alg->setkey = shash_no_setkey;

	return 0;
}

int crypto_register_shash(struct shash_alg *alg)
{
	struct crypto_alg *base = &alg->base;
	int err;

	err = shash_prepare_alg(alg);
	if (err)
		return err;

	return crypto_register_alg(base);
}

int crypto_unregister_shash(struct shash_alg *alg)
{
	return crypto_unregister_alg(&alg->base);
}

int crypto_register_shashes(struct shash_alg *algs, int count)
{
	int i, ret;

	for (i = 0; i < count; i++) {
		ret = crypto_register_shash(&algs[i]);
		if (ret)
			goto err;
	}

	return 0;

err:
	for (--i; i >= 0; --i)
		crypto_unregister_shash(&algs[i]);

	return ret;
}

int crypto_unregister_shashes(struct shash_alg *algs, int count)
{
	int i, ret;

	for (i = count - 1; i >= 0; --i) {
		ret = crypto_unregister_shash(&algs[i]);
		if (ret)
			pr_err("Failed to unregister %s %s: %d\n",
			       algs[i].base.cra_driver_name,
			       algs[i].base.cra_name, ret);
	}

	return 0;
}

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Synchronous cryptographic hash type");