/* * 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/aead.h> #include <crypto/internal/skcipher.h> #include <crypto/authenc.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_spawn auth; struct crypto_skcipher_spawn enc; }; 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) { unsigned int authkeylen; unsigned int enckeylen; struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct crypto_hash *auth = ctx->auth; struct crypto_ablkcipher *enc = ctx->enc; struct rtattr *rta = (void *)key; struct crypto_authenc_key_param *param; int err = -EINVAL; if (!RTA_OK(rta, keylen)) goto badkey; if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) goto badkey; if (RTA_PAYLOAD(rta) < sizeof(*param)) goto badkey; param = RTA_DATA(rta); enckeylen = be32_to_cpu(param->enckeylen); key += RTA_ALIGN(rta->rta_len); keylen -= RTA_ALIGN(rta->rta_len); if (keylen < enckeylen) goto badkey; 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; badkey: crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); goto out; } static void authenc_chain(struct scatterlist *head, struct scatterlist *sg, int chain) { if (chain) { head->length += sg->length; sg = scatterwalk_sg_next(sg); } if (sg) scatterwalk_sg_chain(head, 2, sg); else sg_mark_end(head); } static u8 *crypto_authenc_hash(struct aead_request *req, unsigned int flags, struct scatterlist *cipher, unsigned int cryptlen) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); 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) & flags, }; u8 *hash = aead_request_ctx(req); 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; err = crypto_hash_update(&desc, cipher, cryptlen); if (err) goto auth_unlock; err = crypto_hash_final(&desc, hash); auth_unlock: spin_unlock_bh(&ctx->auth_lock); if (err) return ERR_PTR(err); return hash; } static int crypto_authenc_genicv(struct aead_request *req, u8 *iv, unsigned int flags) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct scatterlist *dst = req->dst; struct scatterlist cipher[2]; struct page *dstp; unsigned int ivsize = crypto_aead_ivsize(authenc); unsigned int cryptlen; u8 *vdst; u8 *hash; dstp = sg_page(dst); vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset; sg_init_table(cipher, 2); sg_set_buf(cipher, iv, ivsize); authenc_chain(cipher, dst, vdst == iv + ivsize); cryptlen = req->cryptlen + ivsize; hash = crypto_authenc_hash(req, flags, cipher, cryptlen); if (IS_ERR(hash)) return PTR_ERR(hash); scatterwalk_map_and_copy(hash, cipher, 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) { struct crypto_aead *authenc = crypto_aead_reqtfm(areq); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct ablkcipher_request *abreq = aead_request_ctx(areq); u8 *iv = (u8 *)(abreq + 1) + crypto_ablkcipher_reqsize(ctx->enc); err = crypto_authenc_genicv(areq, iv, 0); } aead_request_complete(areq, 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); struct crypto_ablkcipher *enc = ctx->enc; struct scatterlist *dst = req->dst; unsigned int cryptlen = req->cryptlen; u8 *iv = (u8 *)(abreq + 1) + crypto_ablkcipher_reqsize(enc); int err; ablkcipher_request_set_tfm(abreq, enc); ablkcipher_request_set_callback(abreq, aead_request_flags(req), crypto_authenc_encrypt_done, req); ablkcipher_request_set_crypt(abreq, req->src, dst, cryptlen, req->iv); memcpy(iv, req->iv, crypto_aead_ivsize(authenc)); err = crypto_ablkcipher_encrypt(abreq); if (err) return err; return crypto_authenc_genicv(req, iv, CRYPTO_TFM_REQ_MAY_SLEEP); } static void crypto_authenc_givencrypt_done(struct crypto_async_request *req, int err) { struct aead_request *areq = req->data; if (!err) { struct skcipher_givcrypt_request *greq = aead_request_ctx(areq); err = crypto_authenc_genicv(areq, greq->giv, 0); } aead_request_complete(areq, err); } static int crypto_authenc_givencrypt(struct aead_givcrypt_request *req) { struct crypto_aead *authenc = aead_givcrypt_reqtfm(req); struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); struct aead_request *areq = &req->areq; struct skcipher_givcrypt_request *greq = aead_request_ctx(areq); u8 *iv = req->giv; int err; skcipher_givcrypt_set_tfm(greq, ctx->enc); skcipher_givcrypt_set_callback(greq, aead_request_flags(areq), crypto_authenc_givencrypt_done, areq); skcipher_givcrypt_set_crypt(greq, areq->src, areq->dst, areq->cryptlen, areq->iv); skcipher_givcrypt_set_giv(greq, iv, req->seq); err = crypto_skcipher_givencrypt(greq); if (err) return err; return crypto_authenc_genicv(areq, iv, CRYPTO_TFM_REQ_MAY_SLEEP); } static int crypto_authenc_verify(struct aead_request *req, struct scatterlist *cipher, unsigned int cryptlen) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); u8 *ohash; u8 *ihash; unsigned int authsize; ohash = crypto_authenc_hash(req, CRYPTO_TFM_REQ_MAY_SLEEP, cipher, cryptlen); if (IS_ERR(ohash)) return PTR_ERR(ohash); authsize = crypto_aead_authsize(authenc); ihash = ohash + authsize; scatterwalk_map_and_copy(ihash, cipher, cryptlen, authsize, 0); return memcmp(ihash, ohash, authsize) ? -EBADMSG: 0; } static int crypto_authenc_iverify(struct aead_request *req, u8 *iv, unsigned int cryptlen) { struct crypto_aead *authenc = crypto_aead_reqtfm(req); struct scatterlist *src = req->src; struct scatterlist cipher[2]; struct page *srcp; unsigned int ivsize = crypto_aead_ivsize(authenc); u8 *vsrc; srcp = sg_page(src); vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + src->offset; sg_init_table(cipher, 2); sg_set_buf(cipher, iv, ivsize); authenc_chain(cipher, src, vsrc == iv + ivsize); return crypto_authenc_verify(req, cipher, cryptlen + ivsize); } 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); unsigned int cryptlen = req->cryptlen; unsigned int authsize = crypto_aead_authsize(authenc); u8 *iv = req->iv; int err; if (cryptlen < authsize) return -EINVAL; cryptlen -= authsize; err = crypto_authenc_iverify(req, iv, cryptlen); if (err) return err; ablkcipher_request_set_tfm(abreq, ctx->enc); ablkcipher_request_set_callback(abreq, aead_request_flags(req), req->base.complete, req->base.data); ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen, 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; int err; auth = crypto_spawn_hash(&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_hash; ctx->auth = auth; ctx->enc = enc; tfm->crt_aead.reqsize = max_t(unsigned int, (crypto_hash_alignmask(auth) & ~(crypto_tfm_ctx_alignment() - 1)) + crypto_hash_digestsize(auth) * 2, sizeof(struct skcipher_givcrypt_request) + crypto_ablkcipher_reqsize(enc) + crypto_ablkcipher_ivsize(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_attr_type *algt; struct crypto_instance *inst; struct crypto_alg *auth; struct crypto_alg *enc; struct authenc_instance_ctx *ctx; const char *enc_name; int err; algt = crypto_get_attr_type(tb); err = PTR_ERR(algt); if (IS_ERR(algt)) return ERR_PTR(err); if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) return ERR_PTR(-EINVAL); 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)); 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 = crypto_instance_ctx(inst); err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK); if (err) goto err_free_inst; crypto_set_skcipher_spawn(&ctx->enc, 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_skcipher_spawn_alg(&ctx->enc); err = -ENAMETOOLONG; if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)", auth->cra_name, enc->cra_name) >= CRYPTO_MAX_ALG_NAME) goto err_drop_enc; if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)", auth->cra_driver_name, enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) goto err_drop_enc; inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; inst->alg.cra_flags |= enc->cra_flags & 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 = auth->cra_alignmask | enc->cra_alignmask; inst->alg.cra_type = &crypto_aead_type; inst->alg.cra_aead.ivsize = enc->cra_ablkcipher.ivsize; inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ? auth->cra_hash.digestsize : auth->cra_digest.dia_digestsize; 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; inst->alg.cra_aead.givencrypt = crypto_authenc_givencrypt; out: crypto_mod_put(auth); return inst; err_drop_enc: crypto_drop_skcipher(&ctx->enc); err_drop_auth: crypto_drop_spawn(&ctx->auth); err_free_inst: kfree(inst); out_put_auth: 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_skcipher(&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");