diff options
Diffstat (limited to 'crypto/authenc.c')
| -rw-r--r-- | crypto/authenc.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/crypto/authenc.c b/crypto/authenc.c new file mode 100644 index 0000000..86b3ac8 --- /dev/null +++ b/crypto/authenc.c @@ -0,0 +1,400 @@ +/* + * Authenc: Simple AEAD wrapper for IPsec + * + * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> + * + * 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/slab.h> +#include <linux/spinlock.h> + +#include "scatterwalk.h" + +struct authenc_instance_ctx { + struct crypto_spawn auth; + struct crypto_spawn enc; + + unsigned int authsize; + unsigned int enckeylen; +}; + +struct crypto_authenc_ctx { + spinlock_t auth_lock; + struct crypto_hash *auth; + struct crypto_ablkcipher *enc; +}; + +static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, + unsigned int keylen) +{ + struct authenc_instance_ctx *ictx = + crypto_instance_ctx(crypto_aead_alg_instance(authenc)); + unsigned int enckeylen = ictx->enckeylen; + unsigned int authkeylen; + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct crypto_hash *auth = ctx->auth; + struct crypto_ablkcipher *enc = ctx->enc; + int err = -EINVAL; + + if (keylen < enckeylen) { + crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); + goto out; + } + authkeylen = keylen - enckeylen; + + crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); + crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) & + CRYPTO_TFM_REQ_MASK); + err = crypto_hash_setkey(auth, key, authkeylen); + crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) & + CRYPTO_TFM_RES_MASK); + + if (err) + goto out; + + crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); + crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) & + CRYPTO_TFM_REQ_MASK); + err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen); + crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) & + CRYPTO_TFM_RES_MASK); + +out: + return err; +} + +static int crypto_authenc_hash(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct authenc_instance_ctx *ictx = + crypto_instance_ctx(crypto_aead_alg_instance(authenc)); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct crypto_hash *auth = ctx->auth; + struct hash_desc desc = { + .tfm = auth, + }; + u8 *hash = aead_request_ctx(req); + struct scatterlist *dst; + unsigned int cryptlen; + int err; + + hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth), + crypto_hash_alignmask(auth) + 1); + + spin_lock_bh(&ctx->auth_lock); + err = crypto_hash_init(&desc); + if (err) + goto auth_unlock; + + err = crypto_hash_update(&desc, req->assoc, req->assoclen); + if (err) + goto auth_unlock; + + cryptlen = req->cryptlen; + dst = req->dst; + err = crypto_hash_update(&desc, dst, cryptlen); + if (err) + goto auth_unlock; + + err = crypto_hash_final(&desc, hash); +auth_unlock: + spin_unlock_bh(&ctx->auth_lock); + + if (err) + return err; + + scatterwalk_map_and_copy(hash, dst, cryptlen, ictx->authsize, 1); + return 0; +} + +static void crypto_authenc_encrypt_done(struct crypto_async_request *req, + int err) +{ + if (!err) + err = crypto_authenc_hash(req->data); + + aead_request_complete(req->data, err); +} + +static int crypto_authenc_encrypt(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct ablkcipher_request *abreq = aead_request_ctx(req); + int err; + + ablkcipher_request_set_tfm(abreq, ctx->enc); + ablkcipher_request_set_callback(abreq, aead_request_flags(req), + crypto_authenc_encrypt_done, req); + ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, + req->iv); + + err = crypto_ablkcipher_encrypt(abreq); + if (err) + return err; + + return crypto_authenc_hash(req); +} + +static int crypto_authenc_verify(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct authenc_instance_ctx *ictx = + crypto_instance_ctx(crypto_aead_alg_instance(authenc)); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct crypto_hash *auth = ctx->auth; + struct hash_desc desc = { + .tfm = auth, + .flags = aead_request_flags(req), + }; + u8 *ohash = aead_request_ctx(req); + u8 *ihash; + struct scatterlist *src; + unsigned int cryptlen; + unsigned int authsize; + int err; + + ohash = (u8 *)ALIGN((unsigned long)ohash + crypto_hash_alignmask(auth), + crypto_hash_alignmask(auth) + 1); + ihash = ohash + crypto_hash_digestsize(auth); + + spin_lock_bh(&ctx->auth_lock); + err = crypto_hash_init(&desc); + if (err) + goto auth_unlock; + + err = crypto_hash_update(&desc, req->assoc, req->assoclen); + if (err) + goto auth_unlock; + + cryptlen = req->cryptlen; + src = req->src; + err = crypto_hash_update(&desc, src, cryptlen); + if (err) + goto auth_unlock; + + err = crypto_hash_final(&desc, ohash); +auth_unlock: + spin_unlock_bh(&ctx->auth_lock); + + if (err) + return err; + + authsize = ictx->authsize; + scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0); + return memcmp(ihash, ohash, authsize) ? -EINVAL : 0; +} + +static void crypto_authenc_decrypt_done(struct crypto_async_request *req, + int err) +{ + aead_request_complete(req->data, err); +} + +static int crypto_authenc_decrypt(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct ablkcipher_request *abreq = aead_request_ctx(req); + int err; + + err = crypto_authenc_verify(req); + if (err) + return err; + + ablkcipher_request_set_tfm(abreq, ctx->enc); + ablkcipher_request_set_callback(abreq, aead_request_flags(req), + crypto_authenc_decrypt_done, req); + ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, + req->iv); + + return crypto_ablkcipher_decrypt(abreq); +} + +static int crypto_authenc_init_tfm(struct crypto_tfm *tfm) +{ + struct crypto_instance *inst = (void *)tfm->__crt_alg; + struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst); + struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); + struct crypto_hash *auth; + struct crypto_ablkcipher *enc; + unsigned int digestsize; + int err; + + auth = crypto_spawn_hash(&ictx->auth); + if (IS_ERR(auth)) + return PTR_ERR(auth); + + err = -EINVAL; + digestsize = crypto_hash_digestsize(auth); + if (ictx->authsize > digestsize) + goto err_free_hash; + + enc = crypto_spawn_ablkcipher(&ictx->enc); + err = PTR_ERR(enc); + if (IS_ERR(enc)) + goto err_free_hash; + + ctx->auth = auth; + ctx->enc = enc; + tfm->crt_aead.reqsize = max_t(unsigned int, + (crypto_hash_alignmask(auth) & + ~(crypto_tfm_ctx_alignment() - 1)) + + digestsize * 2, + sizeof(struct ablkcipher_request) + + crypto_ablkcipher_reqsize(enc)); + + spin_lock_init(&ctx->auth_lock); + + return 0; + +err_free_hash: + crypto_free_hash(auth); + return err; +} + +static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm) +{ + struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); + + crypto_free_hash(ctx->auth); + crypto_free_ablkcipher(ctx->enc); +} + +static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb) +{ + struct crypto_instance *inst; + struct crypto_alg *auth; + struct crypto_alg *enc; + struct authenc_instance_ctx *ctx; + unsigned int authsize; + unsigned int enckeylen; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD); + if (err) + return ERR_PTR(err); + + auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, + CRYPTO_ALG_TYPE_HASH_MASK); + if (IS_ERR(auth)) + return ERR_PTR(PTR_ERR(auth)); + + err = crypto_attr_u32(tb[2], &authsize); + inst = ERR_PTR(err); + if (err) + goto out_put_auth; + + enc = crypto_attr_alg(tb[3], CRYPTO_ALG_TYPE_BLKCIPHER, + CRYPTO_ALG_TYPE_MASK); + inst = ERR_PTR(PTR_ERR(enc)); + if (IS_ERR(enc)) + goto out_put_auth; + + err = crypto_attr_u32(tb[4], &enckeylen); + if (err) + goto out_put_enc; + + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); + err = -ENOMEM; + if (!inst) + goto out_put_enc; + + err = -ENAMETOOLONG; + if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, + "authenc(%s, %u, %s, %u)", auth->cra_name, authsize, + enc->cra_name, enckeylen) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, + "authenc(%s, %u, %s, %u)", auth->cra_driver_name, + authsize, enc->cra_driver_name, enckeylen) >= + CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + ctx = crypto_instance_ctx(inst); + ctx->authsize = authsize; + ctx->enckeylen = enckeylen; + + err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK); + if (err) + goto err_free_inst; + + err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK); + if (err) + goto err_drop_auth; + + inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC; + inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority; + inst->alg.cra_blocksize = enc->cra_blocksize; + inst->alg.cra_alignmask = max(auth->cra_alignmask, enc->cra_alignmask); + inst->alg.cra_type = &crypto_aead_type; + + inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize; + inst->alg.cra_aead.authsize = authsize; + + inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx); + + inst->alg.cra_init = crypto_authenc_init_tfm; + inst->alg.cra_exit = crypto_authenc_exit_tfm; + + inst->alg.cra_aead.setkey = crypto_authenc_setkey; + inst->alg.cra_aead.encrypt = crypto_authenc_encrypt; + inst->alg.cra_aead.decrypt = crypto_authenc_decrypt; + +out: + crypto_mod_put(enc); +out_put_auth: + crypto_mod_put(auth); + return inst; + +err_drop_auth: + crypto_drop_spawn(&ctx->auth); +err_free_inst: + kfree(inst); +out_put_enc: + inst = ERR_PTR(err); + goto out; +} + +static void crypto_authenc_free(struct crypto_instance *inst) +{ + struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst); + + crypto_drop_spawn(&ctx->enc); + crypto_drop_spawn(&ctx->auth); + kfree(inst); +} + +static struct crypto_template crypto_authenc_tmpl = { + .name = "authenc", + .alloc = crypto_authenc_alloc, + .free = crypto_authenc_free, + .module = THIS_MODULE, +}; + +static int __init crypto_authenc_module_init(void) +{ + return crypto_register_template(&crypto_authenc_tmpl); +} + +static void __exit crypto_authenc_module_exit(void) +{ + crypto_unregister_template(&crypto_authenc_tmpl); +} + +module_init(crypto_authenc_module_init); +module_exit(crypto_authenc_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); |
