// SPDX-License-Identifier: GPL-2.0-or-later/* * 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 */ #include <crypto/hmac.h>#include <crypto/internal/hash.h>#include <crypto/scatterwalk.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/scatterlist.h>#include <linux/string.h> struct hmac_ctx {	struct crypto_shash *hash;}; 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_shash *tfm){	return align_ptr(crypto_shash_ctx_aligned(tfm) +			 crypto_shash_statesize(tfm) * 2,			 crypto_tfm_ctx_alignment());} static int hmac_setkey(struct crypto_shash *parent,		       const u8 *inkey, unsigned int keylen){	int bs = crypto_shash_blocksize(parent);	int ds = crypto_shash_digestsize(parent);	int ss = crypto_shash_statesize(parent);	char *ipad = crypto_shash_ctx_aligned(parent);	char *opad = ipad + ss;	struct hmac_ctx *ctx = align_ptr(opad + ss,					 crypto_tfm_ctx_alignment());	struct crypto_shash *hash = ctx->hash;	SHASH_DESC_ON_STACK(shash, hash);	unsigned int i; 	shash->tfm = hash; 	if (keylen > bs) {		int err; 		err = crypto_shash_digest(shash, inkey, keylen, ipad);		if (err)			return err; 		keylen = ds;	} else		memcpy(ipad, inkey, keylen); 	memset(ipad + keylen, 0, bs - keylen);	memcpy(opad, ipad, bs); 	for (i = 0; i < bs; i++) {		ipad[i] ^= HMAC_IPAD_VALUE;		opad[i] ^= HMAC_OPAD_VALUE;	} 	return crypto_shash_init(shash) ?:	       crypto_shash_update(shash, ipad, bs) ?:	       crypto_shash_export(shash, ipad) ?:	       crypto_shash_init(shash) ?:	       crypto_shash_update(shash, opad, bs) ?:	       crypto_shash_export(shash, opad);} static int hmac_export(struct shash_desc *pdesc, void *out){	struct shash_desc *desc = shash_desc_ctx(pdesc); 	return crypto_shash_export(desc, out);} static int hmac_import(struct shash_desc *pdesc, const void *in){	struct shash_desc *desc = shash_desc_ctx(pdesc);	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm); 	desc->tfm = ctx->hash; 	return crypto_shash_import(desc, in);} static int hmac_init(struct shash_desc *pdesc){	return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));} static int hmac_update(struct shash_desc *pdesc,		       const u8 *data, unsigned int nbytes){	struct shash_desc *desc = shash_desc_ctx(pdesc); 	return crypto_shash_update(desc, data, nbytes);} static int hmac_final(struct shash_desc *pdesc, u8 *out){	struct crypto_shash *parent = pdesc->tfm;	int ds = crypto_shash_digestsize(parent);	int ss = crypto_shash_statesize(parent);	char *opad = crypto_shash_ctx_aligned(parent) + ss;	struct shash_desc *desc = shash_desc_ctx(pdesc); 	return crypto_shash_final(desc, out) ?:	       crypto_shash_import(desc, opad) ?:	       crypto_shash_finup(desc, out, ds, out);} static int hmac_finup(struct shash_desc *pdesc, const u8 *data,		      unsigned int nbytes, u8 *out){ 	struct crypto_shash *parent = pdesc->tfm;	int ds = crypto_shash_digestsize(parent);	int ss = crypto_shash_statesize(parent);	char *opad = crypto_shash_ctx_aligned(parent) + ss;	struct shash_desc *desc = shash_desc_ctx(pdesc); 	return crypto_shash_finup(desc, data, nbytes, out) ?:	       crypto_shash_import(desc, opad) ?:	       crypto_shash_finup(desc, out, ds, out);} static int hmac_init_tfm(struct crypto_shash *parent){	struct crypto_shash *hash;	struct shash_instance *inst = shash_alg_instance(parent);	struct crypto_shash_spawn *spawn = shash_instance_ctx(inst);	struct hmac_ctx *ctx = hmac_ctx(parent); 	hash = crypto_spawn_shash(spawn);	if (IS_ERR(hash))		return PTR_ERR(hash); 	parent->descsize = sizeof(struct shash_desc) +			   crypto_shash_descsize(hash); 	ctx->hash = hash;	return 0;} static void hmac_exit_tfm(struct crypto_shash *parent){	struct hmac_ctx *ctx = hmac_ctx(parent);	crypto_free_shash(ctx->hash);} static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb){	struct shash_instance *inst;	struct crypto_shash_spawn *spawn;	struct crypto_alg *alg;	struct shash_alg *salg;	u32 mask;	int err;	int ds;	int ss; 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);	if (err)		return err; 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);	if (!inst)		return -ENOMEM;	spawn = shash_instance_ctx(inst); 	err = crypto_grab_shash(spawn, shash_crypto_instance(inst),				crypto_attr_alg_name(tb[1]), 0, mask);	if (err)		goto err_free_inst;	salg = crypto_spawn_shash_alg(spawn);	alg = &salg->base; 	/* The underlying hash algorithm must not require a key */	err = -EINVAL;	if (crypto_shash_alg_needs_key(salg))		goto err_free_inst; 	ds = salg->digestsize;	ss = salg->statesize;	if (ds > alg->cra_blocksize ||	    ss < alg->cra_blocksize)		goto err_free_inst; 	err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);	if (err)		goto err_free_inst; 	inst->alg.base.cra_priority = alg->cra_priority;	inst->alg.base.cra_blocksize = alg->cra_blocksize;	inst->alg.base.cra_alignmask = alg->cra_alignmask; 	ss = ALIGN(ss, alg->cra_alignmask + 1);	inst->alg.digestsize = ds;	inst->alg.statesize = ss; 	inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +				     ALIGN(ss * 2, crypto_tfm_ctx_alignment()); 	inst->alg.init = hmac_init;	inst->alg.update = hmac_update;	inst->alg.final = hmac_final;	inst->alg.finup = hmac_finup;	inst->alg.export = hmac_export;	inst->alg.import = hmac_import;	inst->alg.setkey = hmac_setkey;	inst->alg.init_tfm = hmac_init_tfm;	inst->alg.exit_tfm = hmac_exit_tfm; 	inst->free = shash_free_singlespawn_instance; 	err = shash_register_instance(tmpl, inst);	if (err) {err_free_inst:		shash_free_singlespawn_instance(inst);	}	return err;} static struct crypto_template hmac_tmpl = {	.name = "hmac",	.create = hmac_create,	.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);} subsys_initcall(hmac_module_init);module_exit(hmac_module_exit); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("HMAC hash algorithm");MODULE_ALIAS_CRYPTO("hmac");