/* * 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);	sg1[1].page = (void *)sg;	sg1[1].length = 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(void *param, unsigned int len){	struct crypto_instance *inst;	struct crypto_alg *alg; 	alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_HASH,				  CRYPTO_ALG_TYPE_HASH_MASK | CRYPTO_ALG_ASYNC);	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");