crypto/hmac.c - linux - Git at Google

 /*
  * Cryptographic API.
  *
  * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * The HMAC implementation is derived from USAGI.
  * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
  *
  * 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/algapi.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/string.h>

 struct hmac_ctx {
 	struct crypto_hash *child;
 };

 static inline void *align_ptr(void *p, unsigned int align)
 {
 	return (void *)ALIGN((unsigned long)p, align);
 }

 static inline struct hmac_ctx *hmac_ctx(struct crypto_hash *tfm)
 {
 	return align_ptr(crypto_hash_ctx_aligned(tfm) +
 			 crypto_hash_blocksize(tfm) * 2 +
 			 crypto_hash_digestsize(tfm), sizeof(void *));
 }

 static int hmac_setkey(struct crypto_hash *parent,
 		       const u8 *inkey, unsigned int keylen)
 {
 	int bs = crypto_hash_blocksize(parent);
 	int ds = crypto_hash_digestsize(parent);
 	char *ipad = crypto_hash_ctx_aligned(parent);
 	char *opad = ipad + bs;
 	char *digest = opad + bs;
 	struct hmac_ctx *ctx = align_ptr(digest + ds, sizeof(void *));
 	struct crypto_hash *tfm = ctx->child;
 	unsigned int i;

 	if (keylen > bs) {
 		struct hash_desc desc;
 		struct scatterlist tmp;
 		int err;

 		desc.tfm = tfm;
 		desc.flags = crypto_hash_get_flags(parent);
 		desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;
 		sg_set_buf(&tmp, inkey, keylen);

 		err = crypto_hash_digest(&desc, &tmp, keylen, digest);
 		if (err)
 			return err;

 		inkey = digest;
 		keylen = ds;
 	}

 	memcpy(ipad, inkey, keylen);
 	memset(ipad + keylen, 0, bs - keylen);
 	memcpy(opad, ipad, bs);

 	for (i = 0; i < bs; i++) {
 		ipad[i] ^= 0x36;
 		opad[i] ^= 0x5c;
 	}

 	return 0;
 }

 static int hmac_init(struct hash_desc *pdesc)
 {
 	struct crypto_hash *parent = pdesc->tfm;
 	int bs = crypto_hash_blocksize(parent);
 	int ds = crypto_hash_digestsize(parent);
 	char *ipad = crypto_hash_ctx_aligned(parent);
 	struct hmac_ctx *ctx = align_ptr(ipad + bs * 2 + ds, sizeof(void *));
 	struct hash_desc desc;
 	struct scatterlist tmp;
 	int err;

 	desc.tfm = ctx->child;
 	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
 	sg_set_buf(&tmp, ipad, bs);

 	err = crypto_hash_init(&desc);
 	if (unlikely(err))
 		return err;

 	return crypto_hash_update(&desc, &tmp, bs);
 }

 static int hmac_update(struct hash_desc *pdesc,
 		       struct scatterlist *sg, unsigned int nbytes)
 {
 	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
 	struct hash_desc desc;

 	desc.tfm = ctx->child;
 	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

 	return crypto_hash_update(&desc, sg, nbytes);
 }

 static int hmac_final(struct hash_desc *pdesc, u8 *out)
 {
 	struct crypto_hash *parent = pdesc->tfm;
 	int bs = crypto_hash_blocksize(parent);
 	int ds = crypto_hash_digestsize(parent);
 	char *opad = crypto_hash_ctx_aligned(parent) + bs;
 	char *digest = opad + bs;
 	struct hmac_ctx *ctx = align_ptr(digest + ds, sizeof(void *));
 	struct hash_desc desc;
 	struct scatterlist tmp;
 	int err;

 	desc.tfm = ctx->child;
 	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
 	sg_set_buf(&tmp, opad, bs + ds);

 	err = crypto_hash_final(&desc, digest);
 	if (unlikely(err))
 		return err;

 	return crypto_hash_digest(&desc, &tmp, bs + ds, out);
 }

 static int hmac_digest(struct hash_desc *pdesc, struct scatterlist *sg,
 		       unsigned int nbytes, u8 *out)
 {
 	struct crypto_hash *parent = pdesc->tfm;
 	int bs = crypto_hash_blocksize(parent);
 	int ds = crypto_hash_digestsize(parent);
 	char *ipad = crypto_hash_ctx_aligned(parent);
 	char *opad = ipad + bs;
 	char *digest = opad + bs;
 	struct hmac_ctx *ctx = align_ptr(digest + ds, sizeof(void *));
 	struct hash_desc desc;
 	struct scatterlist sg1[2];
 	struct scatterlist sg2[1];
 	int err;

 	desc.tfm = ctx->child;
 	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

 	sg_set_buf(sg1, ipad, bs);

 	sg_set_page(&sg[1], (void *) sg, 0, 0);
 	sg_set_buf(sg2, opad, bs + ds);

 	err = crypto_hash_digest(&desc, sg1, nbytes + bs, digest);
 	if (unlikely(err))
 		return err;

 	return crypto_hash_digest(&desc, sg2, bs + ds, out);
 }

 static int hmac_init_tfm(struct crypto_tfm *tfm)
 {
 	struct crypto_hash *hash;
 	struct crypto_instance *inst = (void *)tfm->__crt_alg;
 	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));

 	hash = crypto_spawn_hash(spawn);
 	if (IS_ERR(hash))
 		return PTR_ERR(hash);

 	ctx->child = hash;
 	return 0;
 }

 static void hmac_exit_tfm(struct crypto_tfm *tfm)
 {
 	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
 	crypto_free_hash(ctx->child);
 }

 static void hmac_free(struct crypto_instance *inst)
 {
 	crypto_drop_spawn(crypto_instance_ctx(inst));
 	kfree(inst);
 }

 static struct crypto_instance *hmac_alloc(struct rtattr **tb)
 {
 	struct crypto_instance *inst;
 	struct crypto_alg *alg;
 	int err;

 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
 	if (err)
 		return ERR_PTR(err);

 	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_HASH,
 				  CRYPTO_ALG_TYPE_HASH_MASK);
 	if (IS_ERR(alg))
 		return ERR_PTR(PTR_ERR(alg));

 	inst = crypto_alloc_instance("hmac", alg);
 	if (IS_ERR(inst))
 		goto out_put_alg;

 	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
 	inst->alg.cra_priority = alg->cra_priority;
 	inst->alg.cra_blocksize = alg->cra_blocksize;
 	inst->alg.cra_alignmask = alg->cra_alignmask;
 	inst->alg.cra_type = &crypto_hash_type;

 	inst->alg.cra_hash.digestsize =
 		(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 		CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
 				       alg->cra_digest.dia_digestsize;

 	inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
 				ALIGN(inst->alg.cra_blocksize * 2 +
 				      inst->alg.cra_hash.digestsize,
 				      sizeof(void *));

 	inst->alg.cra_init = hmac_init_tfm;
 	inst->alg.cra_exit = hmac_exit_tfm;

 	inst->alg.cra_hash.init = hmac_init;
 	inst->alg.cra_hash.update = hmac_update;
 	inst->alg.cra_hash.final = hmac_final;
 	inst->alg.cra_hash.digest = hmac_digest;
 	inst->alg.cra_hash.setkey = hmac_setkey;

 out_put_alg:
 	crypto_mod_put(alg);
 	return inst;
 }

 static struct crypto_template hmac_tmpl = {
 	.name = "hmac",
 	.alloc = hmac_alloc,
 	.free = hmac_free,
 	.module = THIS_MODULE,
 };

 static int __init hmac_module_init(void)
 {
 	return crypto_register_template(&hmac_tmpl);
 }

 static void __exit hmac_module_exit(void)
 {
 	crypto_unregister_template(&hmac_tmpl);
 }

 module_init(hmac_module_init);
 module_exit(hmac_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("HMAC hash algorithm");
	/*
	* Cryptographic API.
	*
	* HMAC: Keyed-Hashing for Message Authentication (RFC2104).
	*
	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
	* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
	*
	* The HMAC implementation is derived from USAGI.
	* Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
	*
	* 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/algapi.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/scatterlist.h>
	#include <linux/slab.h>
	#include <linux/string.h>

	struct hmac_ctx {
	struct crypto_hash *child;
	};

	static inline void align_ptr(void p, unsigned int align)
	{
	return (void *)ALIGN((unsigned long)p, align);
	}

	static inline struct hmac_ctx hmac_ctx(struct crypto_hash tfm)
	{
	return align_ptr(crypto_hash_ctx_aligned(tfm) +
	crypto_hash_blocksize(tfm) * 2 +
	crypto_hash_digestsize(tfm), sizeof(void *));
	}

	static int hmac_setkey(struct crypto_hash *parent,
	const u8 *inkey, unsigned int keylen)
	{
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *ipad = crypto_hash_ctx_aligned(parent);
	char *opad = ipad + bs;
	char *digest = opad + bs;
	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	struct crypto_hash *tfm = ctx->child;
	unsigned int i;

	if (keylen > bs) {
	struct hash_desc desc;
	struct scatterlist tmp;
	int err;

	desc.tfm = tfm;
	desc.flags = crypto_hash_get_flags(parent);
	desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;
	sg_set_buf(&tmp, inkey, keylen);

	err = crypto_hash_digest(&desc, &tmp, keylen, digest);
	if (err)
	return err;

	inkey = digest;
	keylen = ds;
	}

	memcpy(ipad, inkey, keylen);
	memset(ipad + keylen, 0, bs - keylen);
	memcpy(opad, ipad, bs);

	for (i = 0; i < bs; i++) {
	ipad[i] ^= 0x36;
	opad[i] ^= 0x5c;
	}

	return 0;
	}

	static int hmac_init(struct hash_desc *pdesc)
	{
	struct crypto_hash *parent = pdesc->tfm;
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *ipad = crypto_hash_ctx_aligned(parent);
	struct hmac_ctx ctx = align_ptr(ipad + bs 2 + ds, sizeof(void *));
	struct hash_desc desc;
	struct scatterlist tmp;
	int err;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	sg_set_buf(&tmp, ipad, bs);

	err = crypto_hash_init(&desc);
	if (unlikely(err))
	return err;

	return crypto_hash_update(&desc, &tmp, bs);
	}

	static int hmac_update(struct hash_desc *pdesc,
	struct scatterlist *sg, unsigned int nbytes)
	{
	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
	struct hash_desc desc;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	return crypto_hash_update(&desc, sg, nbytes);
	}

	static int hmac_final(struct hash_desc pdesc, u8 out)
	{
	struct crypto_hash *parent = pdesc->tfm;
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *opad = crypto_hash_ctx_aligned(parent) + bs;
	char *digest = opad + bs;
	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	struct hash_desc desc;
	struct scatterlist tmp;
	int err;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	sg_set_buf(&tmp, opad, bs + ds);

	err = crypto_hash_final(&desc, digest);
	if (unlikely(err))
	return err;

	return crypto_hash_digest(&desc, &tmp, bs + ds, out);
	}

	static int hmac_digest(struct hash_desc pdesc, struct scatterlist sg,
	unsigned int nbytes, u8 *out)
	{
	struct crypto_hash *parent = pdesc->tfm;
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *ipad = crypto_hash_ctx_aligned(parent);
	char *opad = ipad + bs;
	char *digest = opad + bs;
	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	struct hash_desc desc;
	struct scatterlist sg1[2];
	struct scatterlist sg2[1];
	int err;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	sg_set_buf(sg1, ipad, bs);

	sg_set_page(&sg[1], (void *) sg, 0, 0);
	sg_set_buf(sg2, opad, bs + ds);

	err = crypto_hash_digest(&desc, sg1, nbytes + bs, digest);
	if (unlikely(err))
	return err;

	return crypto_hash_digest(&desc, sg2, bs + ds, out);
	}

	static int hmac_init_tfm(struct crypto_tfm *tfm)
	{
	struct crypto_hash *hash;
	struct crypto_instance inst = (void )tfm->__crt_alg;
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));

	hash = crypto_spawn_hash(spawn);
	if (IS_ERR(hash))
	return PTR_ERR(hash);

	ctx->child = hash;
	return 0;
	}

	static void hmac_exit_tfm(struct crypto_tfm *tfm)
	{
	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
	crypto_free_hash(ctx->child);
	}

	static void hmac_free(struct crypto_instance *inst)
	{
	crypto_drop_spawn(crypto_instance_ctx(inst));
	kfree(inst);
	}

	static struct crypto_instance hmac_alloc(struct rtattr *tb)
	{
	struct crypto_instance *inst;
	struct crypto_alg *alg;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
	if (err)
	return ERR_PTR(err);

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_HASH,
	CRYPTO_ALG_TYPE_HASH_MASK);
	if (IS_ERR(alg))
	return ERR_PTR(PTR_ERR(alg));

	inst = crypto_alloc_instance("hmac", alg);
	if (IS_ERR(inst))
	goto out_put_alg;

	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
	inst->alg.cra_priority = alg->cra_priority;
	inst->alg.cra_blocksize = alg->cra_blocksize;
	inst->alg.cra_alignmask = alg->cra_alignmask;
	inst->alg.cra_type = &crypto_hash_type;

	inst->alg.cra_hash.digestsize =
	(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
	CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
	alg->cra_digest.dia_digestsize;

	inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
	ALIGN(inst->alg.cra_blocksize * 2 +
	inst->alg.cra_hash.digestsize,
	sizeof(void *));

	inst->alg.cra_init = hmac_init_tfm;
	inst->alg.cra_exit = hmac_exit_tfm;

	inst->alg.cra_hash.init = hmac_init;
	inst->alg.cra_hash.update = hmac_update;
	inst->alg.cra_hash.final = hmac_final;
	inst->alg.cra_hash.digest = hmac_digest;
	inst->alg.cra_hash.setkey = hmac_setkey;

	out_put_alg:
	crypto_mod_put(alg);
	return inst;
	}

	static struct crypto_template hmac_tmpl = {
	.name = "hmac",
	.alloc = hmac_alloc,
	.free = hmac_free,
	.module = THIS_MODULE,
	};

	static int __init hmac_module_init(void)
	{
	return crypto_register_template(&hmac_tmpl);
	}

	static void __exit hmac_module_exit(void)
	{
	crypto_unregister_template(&hmac_tmpl);
	}

	module_init(hmac_module_init);
	module_exit(hmac_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("HMAC hash algorithm");