diff options
Diffstat (limited to '')
| -rw-r--r-- | crypto/authenc.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/crypto/authenc.c b/crypto/authenc.c new file mode 100644 index 000000000..02d4d8517 --- /dev/null +++ b/crypto/authenc.c @@ -0,0 +1,516 @@ +/* + * Authenc: Simple AEAD wrapper for IPsec + * + * Copyright (c) 2007-2015 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/internal/aead.h> +#include <crypto/internal/hash.h> +#include <crypto/internal/skcipher.h> +#include <crypto/authenc.h> +#include <crypto/null.h> +#include <crypto/scatterwalk.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/rtnetlink.h> +#include <linux/slab.h> +#include <linux/spinlock.h> + +struct authenc_instance_ctx { + struct crypto_ahash_spawn auth; + struct crypto_skcipher_spawn enc; + unsigned int reqoff; +}; + +struct crypto_authenc_ctx { + struct crypto_ahash *auth; + struct crypto_skcipher *enc; + struct crypto_skcipher *null; +}; + +struct authenc_request_ctx { + struct scatterlist src[2]; + struct scatterlist dst[2]; + char tail[]; +}; + +static void authenc_request_complete(struct aead_request *req, int err) +{ + if (err != -EINPROGRESS) + aead_request_complete(req, err); +} + +int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key, + unsigned int keylen) +{ + struct rtattr *rta = (struct rtattr *)key; + struct crypto_authenc_key_param *param; + + if (!RTA_OK(rta, keylen)) + return -EINVAL; + if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) + return -EINVAL; + + /* + * RTA_OK() didn't align the rtattr's payload when validating that it + * fits in the buffer. Yet, the keys should start on the next 4-byte + * aligned boundary. To avoid confusion, require that the rtattr + * payload be exactly the param struct, which has a 4-byte aligned size. + */ + if (RTA_PAYLOAD(rta) != sizeof(*param)) + return -EINVAL; + BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO); + + param = RTA_DATA(rta); + keys->enckeylen = be32_to_cpu(param->enckeylen); + + key += rta->rta_len; + keylen -= rta->rta_len; + + if (keylen < keys->enckeylen) + return -EINVAL; + + keys->authkeylen = keylen - keys->enckeylen; + keys->authkey = key; + keys->enckey = key + keys->authkeylen; + + return 0; +} +EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); + +static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, + unsigned int keylen) +{ + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct crypto_ahash *auth = ctx->auth; + struct crypto_skcipher *enc = ctx->enc; + struct crypto_authenc_keys keys; + int err = -EINVAL; + + if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) + goto badkey; + + crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); + crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) & + CRYPTO_TFM_REQ_MASK); + err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); + crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) & + CRYPTO_TFM_RES_MASK); + + if (err) + goto out; + + crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); + crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & + CRYPTO_TFM_REQ_MASK); + err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); + crypto_aead_set_flags(authenc, crypto_skcipher_get_flags(enc) & + CRYPTO_TFM_RES_MASK); + +out: + memzero_explicit(&keys, sizeof(keys)); + return err; + +badkey: + crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); + goto out; +} + +static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) +{ + struct aead_request *req = areq->data; + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(authenc); + struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); + struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); + struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); + + if (err) + goto out; + + scatterwalk_map_and_copy(ahreq->result, req->dst, + req->assoclen + req->cryptlen, + crypto_aead_authsize(authenc), 1); + +out: + aead_request_complete(req, err); +} + +static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(authenc); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); + struct crypto_ahash *auth = ctx->auth; + struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); + struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); + u8 *hash = areq_ctx->tail; + int err; + + hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), + crypto_ahash_alignmask(auth) + 1); + + ahash_request_set_tfm(ahreq, auth); + ahash_request_set_crypt(ahreq, req->dst, hash, + req->assoclen + req->cryptlen); + ahash_request_set_callback(ahreq, flags, + authenc_geniv_ahash_done, req); + + err = crypto_ahash_digest(ahreq); + if (err) + return err; + + scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, + crypto_aead_authsize(authenc), 1); + + return 0; +} + +static void crypto_authenc_encrypt_done(struct crypto_async_request *req, + int err) +{ + struct aead_request *areq = req->data; + + if (err) + goto out; + + err = crypto_authenc_genicv(areq, 0); + +out: + authenc_request_complete(areq, err); +} + +static int crypto_authenc_copy_assoc(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); + + skcipher_request_set_tfm(skreq, ctx->null); + skcipher_request_set_callback(skreq, aead_request_flags(req), + NULL, NULL); + skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, + NULL); + + return crypto_skcipher_encrypt(skreq); +} + +static int crypto_authenc_encrypt(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(authenc); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); + struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); + struct crypto_skcipher *enc = ctx->enc; + unsigned int cryptlen = req->cryptlen; + struct skcipher_request *skreq = (void *)(areq_ctx->tail + + ictx->reqoff); + struct scatterlist *src, *dst; + int err; + + src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); + dst = src; + + if (req->src != req->dst) { + err = crypto_authenc_copy_assoc(req); + if (err) + return err; + + dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); + } + + skcipher_request_set_tfm(skreq, enc); + skcipher_request_set_callback(skreq, aead_request_flags(req), + crypto_authenc_encrypt_done, req); + skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); + + err = crypto_skcipher_encrypt(skreq); + if (err) + return err; + + return crypto_authenc_genicv(req, aead_request_flags(req)); +} + +static int crypto_authenc_decrypt_tail(struct aead_request *req, + unsigned int flags) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + struct aead_instance *inst = aead_alg_instance(authenc); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); + struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); + struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); + struct skcipher_request *skreq = (void *)(areq_ctx->tail + + ictx->reqoff); + unsigned int authsize = crypto_aead_authsize(authenc); + u8 *ihash = ahreq->result + authsize; + struct scatterlist *src, *dst; + + scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); + + if (crypto_memneq(ihash, ahreq->result, authsize)) + return -EBADMSG; + + src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); + dst = src; + + if (req->src != req->dst) + dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); + + skcipher_request_set_tfm(skreq, ctx->enc); + skcipher_request_set_callback(skreq, flags, + req->base.complete, req->base.data); + skcipher_request_set_crypt(skreq, src, dst, + req->cryptlen - authsize, req->iv); + + return crypto_skcipher_decrypt(skreq); +} + +static void authenc_verify_ahash_done(struct crypto_async_request *areq, + int err) +{ + struct aead_request *req = areq->data; + + if (err) + goto out; + + err = crypto_authenc_decrypt_tail(req, 0); + +out: + authenc_request_complete(req, err); +} + +static int crypto_authenc_decrypt(struct aead_request *req) +{ + struct crypto_aead *authenc = crypto_aead_reqtfm(req); + unsigned int authsize = crypto_aead_authsize(authenc); + struct aead_instance *inst = aead_alg_instance(authenc); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); + struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); + struct crypto_ahash *auth = ctx->auth; + struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); + struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); + u8 *hash = areq_ctx->tail; + int err; + + hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), + crypto_ahash_alignmask(auth) + 1); + + ahash_request_set_tfm(ahreq, auth); + ahash_request_set_crypt(ahreq, req->src, hash, + req->assoclen + req->cryptlen - authsize); + ahash_request_set_callback(ahreq, aead_request_flags(req), + authenc_verify_ahash_done, req); + + err = crypto_ahash_digest(ahreq); + if (err) + return err; + + return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); +} + +static int crypto_authenc_init_tfm(struct crypto_aead *tfm) +{ + struct aead_instance *inst = aead_alg_instance(tfm); + struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); + struct crypto_ahash *auth; + struct crypto_skcipher *enc; + struct crypto_skcipher *null; + int err; + + auth = crypto_spawn_ahash(&ictx->auth); + if (IS_ERR(auth)) + return PTR_ERR(auth); + + enc = crypto_spawn_skcipher(&ictx->enc); + err = PTR_ERR(enc); + if (IS_ERR(enc)) + goto err_free_ahash; + + null = crypto_get_default_null_skcipher(); + err = PTR_ERR(null); + if (IS_ERR(null)) + goto err_free_skcipher; + + ctx->auth = auth; + ctx->enc = enc; + ctx->null = null; + + crypto_aead_set_reqsize( + tfm, + sizeof(struct authenc_request_ctx) + + ictx->reqoff + + max_t(unsigned int, + crypto_ahash_reqsize(auth) + + sizeof(struct ahash_request), + sizeof(struct skcipher_request) + + crypto_skcipher_reqsize(enc))); + + return 0; + +err_free_skcipher: + crypto_free_skcipher(enc); +err_free_ahash: + crypto_free_ahash(auth); + return err; +} + +static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) +{ + struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); + + crypto_free_ahash(ctx->auth); + crypto_free_skcipher(ctx->enc); + crypto_put_default_null_skcipher(); +} + +static void crypto_authenc_free(struct aead_instance *inst) +{ + struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); + + crypto_drop_skcipher(&ctx->enc); + crypto_drop_ahash(&ctx->auth); + kfree(inst); +} + +static int crypto_authenc_create(struct crypto_template *tmpl, + struct rtattr **tb) +{ + struct crypto_attr_type *algt; + struct aead_instance *inst; + struct hash_alg_common *auth; + struct crypto_alg *auth_base; + struct skcipher_alg *enc; + struct authenc_instance_ctx *ctx; + const char *enc_name; + int err; + + algt = crypto_get_attr_type(tb); + if (IS_ERR(algt)) + return PTR_ERR(algt); + + if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) + return -EINVAL; + + auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, + CRYPTO_ALG_TYPE_AHASH_MASK | + crypto_requires_sync(algt->type, algt->mask)); + if (IS_ERR(auth)) + return PTR_ERR(auth); + + auth_base = &auth->base; + + enc_name = crypto_attr_alg_name(tb[2]); + err = PTR_ERR(enc_name); + if (IS_ERR(enc_name)) + goto out_put_auth; + + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); + err = -ENOMEM; + if (!inst) + goto out_put_auth; + + ctx = aead_instance_ctx(inst); + + err = crypto_init_ahash_spawn(&ctx->auth, auth, + aead_crypto_instance(inst)); + if (err) + goto err_free_inst; + + crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); + err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, + crypto_requires_sync(algt->type, + algt->mask)); + if (err) + goto err_drop_auth; + + enc = crypto_spawn_skcipher_alg(&ctx->enc); + + ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, + auth_base->cra_alignmask + 1); + + err = -ENAMETOOLONG; + if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, + "authenc(%s,%s)", auth_base->cra_name, + enc->base.cra_name) >= + CRYPTO_MAX_ALG_NAME) + goto err_drop_enc; + + if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, + "authenc(%s,%s)", auth_base->cra_driver_name, + enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) + goto err_drop_enc; + + inst->alg.base.cra_flags = (auth_base->cra_flags | + enc->base.cra_flags) & CRYPTO_ALG_ASYNC; + inst->alg.base.cra_priority = enc->base.cra_priority * 10 + + auth_base->cra_priority; + inst->alg.base.cra_blocksize = enc->base.cra_blocksize; + inst->alg.base.cra_alignmask = auth_base->cra_alignmask | + enc->base.cra_alignmask; + inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); + + inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); + inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); + inst->alg.maxauthsize = auth->digestsize; + + inst->alg.init = crypto_authenc_init_tfm; + inst->alg.exit = crypto_authenc_exit_tfm; + + inst->alg.setkey = crypto_authenc_setkey; + inst->alg.encrypt = crypto_authenc_encrypt; + inst->alg.decrypt = crypto_authenc_decrypt; + + inst->free = crypto_authenc_free; + + err = aead_register_instance(tmpl, inst); + if (err) + goto err_drop_enc; + +out: + crypto_mod_put(auth_base); + return err; + +err_drop_enc: + crypto_drop_skcipher(&ctx->enc); +err_drop_auth: + crypto_drop_ahash(&ctx->auth); +err_free_inst: + kfree(inst); +out_put_auth: + goto out; +} + +static struct crypto_template crypto_authenc_tmpl = { + .name = "authenc", + .create = crypto_authenc_create, + .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"); +MODULE_ALIAS_CRYPTO("authenc"); |