diff options
Diffstat (limited to 'crypto/seqiv.c')
| -rw-r--r-- | crypto/seqiv.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/crypto/seqiv.c b/crypto/seqiv.c new file mode 100644 index 000000000..39dbf2f7e --- /dev/null +++ b/crypto/seqiv.c @@ -0,0 +1,220 @@ +/* + * seqiv: Sequence Number IV Generator + * + * This generator generates an IV based on a sequence number by xoring it + * with a salt. This algorithm is mainly useful for CTR and similar modes. + * + * 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/internal/geniv.h> +#include <crypto/scatterwalk.h> +#include <crypto/skcipher.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/string.h> + +static void seqiv_free(struct crypto_instance *inst); + +static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err) +{ + struct aead_request *subreq = aead_request_ctx(req); + struct crypto_aead *geniv; + + if (err == -EINPROGRESS) + return; + + if (err) + goto out; + + geniv = crypto_aead_reqtfm(req); + memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv)); + +out: + kzfree(subreq->iv); +} + +static void seqiv_aead_encrypt_complete(struct crypto_async_request *base, + int err) +{ + struct aead_request *req = base->data; + + seqiv_aead_encrypt_complete2(req, err); + aead_request_complete(req, err); +} + +static int seqiv_aead_encrypt(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv); + struct aead_request *subreq = aead_request_ctx(req); + crypto_completion_t compl; + void *data; + u8 *info; + unsigned int ivsize = 8; + int err; + + if (req->cryptlen < ivsize) + return -EINVAL; + + aead_request_set_tfm(subreq, ctx->child); + + compl = req->base.complete; + data = req->base.data; + info = req->iv; + + if (req->src != req->dst) { + SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull); + + skcipher_request_set_tfm(nreq, ctx->sknull); + skcipher_request_set_callback(nreq, req->base.flags, + NULL, NULL); + skcipher_request_set_crypt(nreq, req->src, req->dst, + req->assoclen + req->cryptlen, + NULL); + + err = crypto_skcipher_encrypt(nreq); + if (err) + return err; + } + + if (unlikely(!IS_ALIGNED((unsigned long)info, + crypto_aead_alignmask(geniv) + 1))) { + info = kmalloc(ivsize, req->base.flags & + CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: + GFP_ATOMIC); + if (!info) + return -ENOMEM; + + memcpy(info, req->iv, ivsize); + compl = seqiv_aead_encrypt_complete; + data = req; + } + + aead_request_set_callback(subreq, req->base.flags, compl, data); + aead_request_set_crypt(subreq, req->dst, req->dst, + req->cryptlen - ivsize, info); + aead_request_set_ad(subreq, req->assoclen + ivsize); + + crypto_xor(info, ctx->salt, ivsize); + scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1); + + err = crypto_aead_encrypt(subreq); + if (unlikely(info != req->iv)) + seqiv_aead_encrypt_complete2(req, err); + return err; +} + +static int seqiv_aead_decrypt(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv); + struct aead_request *subreq = aead_request_ctx(req); + crypto_completion_t compl; + void *data; + unsigned int ivsize = 8; + + if (req->cryptlen < ivsize + crypto_aead_authsize(geniv)) + return -EINVAL; + + aead_request_set_tfm(subreq, ctx->child); + + compl = req->base.complete; + data = req->base.data; + + aead_request_set_callback(subreq, req->base.flags, compl, data); + aead_request_set_crypt(subreq, req->src, req->dst, + req->cryptlen - ivsize, req->iv); + aead_request_set_ad(subreq, req->assoclen + ivsize); + + scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0); + + return crypto_aead_decrypt(subreq); +} + +static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + struct aead_instance *inst; + int err; + + inst = aead_geniv_alloc(tmpl, tb, 0, 0); + + if (IS_ERR(inst)) + return PTR_ERR(inst); + + err = -EINVAL; + if (inst->alg.ivsize != sizeof(u64)) + goto free_inst; + + inst->alg.encrypt = seqiv_aead_encrypt; + inst->alg.decrypt = seqiv_aead_decrypt; + + inst->alg.init = aead_init_geniv; + inst->alg.exit = aead_exit_geniv; + + inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx); + inst->alg.base.cra_ctxsize += inst->alg.ivsize; + + err = aead_register_instance(tmpl, inst); + if (err) + goto free_inst; + +out: + return err; + +free_inst: + aead_geniv_free(inst); + goto out; +} + +static int seqiv_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + struct crypto_attr_type *algt; + + algt = crypto_get_attr_type(tb); + if (IS_ERR(algt)) + return PTR_ERR(algt); + + if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK) + return -EINVAL; + + return seqiv_aead_create(tmpl, tb); +} + +static void seqiv_free(struct crypto_instance *inst) +{ + aead_geniv_free(aead_instance(inst)); +} + +static struct crypto_template seqiv_tmpl = { + .name = "seqiv", + .create = seqiv_create, + .free = seqiv_free, + .module = THIS_MODULE, +}; + +static int __init seqiv_module_init(void) +{ + return crypto_register_template(&seqiv_tmpl); +} + +static void __exit seqiv_module_exit(void) +{ + crypto_unregister_template(&seqiv_tmpl); +} + +module_init(seqiv_module_init); +module_exit(seqiv_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Sequence Number IV Generator"); +MODULE_ALIAS_CRYPTO("seqiv"); |