/* * 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/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; shash->flags = crypto_shash_get_flags(parent) & CRYPTO_TFM_REQ_MAY_SLEEP; 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); desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP; 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; desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP; 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); desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP; 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); desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP; 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); desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP; 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_tfm *tfm) { struct crypto_shash *parent = __crypto_shash_cast(tfm); struct crypto_shash *hash; struct crypto_instance *inst = (void *)tfm->__crt_alg; struct crypto_shash_spawn *spawn = crypto_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_tfm *tfm) { struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm)); crypto_free_shash(ctx->hash); } static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb) { struct shash_instance *inst; struct crypto_alg *alg; struct shash_alg *salg; int err; int ds; int ss; err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH); if (err) return err; salg = shash_attr_alg(tb[1], 0, 0); if (IS_ERR(salg)) return PTR_ERR(salg); alg = &salg->base; /* The underlying hash algorithm must be unkeyed */ err = -EINVAL; if (crypto_shash_alg_has_setkey(salg)) goto out_put_alg; ds = salg->digestsize; ss = salg->statesize; if (ds > alg->cra_blocksize || ss < alg->cra_blocksize) goto out_put_alg; inst = shash_alloc_instance("hmac", alg); err = PTR_ERR(inst); if (IS_ERR(inst)) goto out_put_alg; err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg, shash_crypto_instance(inst)); if (err) goto out_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.base.cra_init = hmac_init_tfm; inst->alg.base.cra_exit = hmac_exit_tfm; 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; err = shash_register_instance(tmpl, inst); if (err) { out_free_inst: shash_free_instance(shash_crypto_instance(inst)); } out_put_alg: crypto_mod_put(alg); return err; } static struct crypto_template hmac_tmpl = { .name = "hmac", .create = hmac_create, .free = shash_free_instance, .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"); MODULE_ALIAS_CRYPTO("hmac");