diff options
Diffstat (limited to 'crypto/hmac.c')
-rw-r--r-- | crypto/hmac.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/crypto/hmac.c b/crypto/hmac.c new file mode 100644 index 00000000..8d9544cf --- /dev/null +++ b/crypto/hmac.c @@ -0,0 +1,273 @@ +/* + * 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/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; + struct { + struct shash_desc shash; + char ctx[crypto_shash_descsize(hash)]; + } desc; + unsigned int i; + + desc.shash.tfm = hash; + desc.shash.flags = crypto_shash_get_flags(parent) & + CRYPTO_TFM_REQ_MAY_SLEEP; + + if (keylen > bs) { + int err; + + err = crypto_shash_digest(&desc.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] ^= 0x36; + opad[i] ^= 0x5c; + } + + return crypto_shash_init(&desc.shash) ?: + crypto_shash_update(&desc.shash, ipad, bs) ?: + crypto_shash_export(&desc.shash, ipad) ?: + crypto_shash_init(&desc.shash) ?: + crypto_shash_update(&desc.shash, opad, bs) ?: + crypto_shash_export(&desc.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); + + err = -EINVAL; + ds = salg->digestsize; + ss = salg->statesize; + alg = &salg->base; + 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"); |