| // 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"); |