/* * 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/aead.h> #include <crypto/internal/skcipher.h> #include <linux/err.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/random.h> #include <linux/spinlock.h> #include <linux/string.h> struct seqiv_ctx { spinlock_t lock; u8 salt[] __attribute__ ((aligned(__alignof__(u32)))); }; static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err) { struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req); struct crypto_ablkcipher *geniv; if (err == -EINPROGRESS) return; if (err) goto out; geniv = skcipher_givcrypt_reqtfm(req); memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv)); out: kfree(subreq->info); } static void seqiv_complete(struct crypto_async_request *base, int err) { struct skcipher_givcrypt_request *req = base->data; seqiv_complete2(req, err); skcipher_givcrypt_complete(req, err); } static void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err) { struct aead_request *subreq = aead_givcrypt_reqctx(req); struct crypto_aead *geniv; if (err == -EINPROGRESS) return; if (err) goto out; geniv = aead_givcrypt_reqtfm(req); memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv)); out: kfree(subreq->iv); } static void seqiv_aead_complete(struct crypto_async_request *base, int err) { struct aead_givcrypt_request *req = base->data; seqiv_aead_complete2(req, err); aead_givcrypt_complete(req, err); } static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq, unsigned int ivsize) { unsigned int len = ivsize; if (ivsize > sizeof(u64)) { memset(info, 0, ivsize - sizeof(u64)); len = sizeof(u64); } seq = cpu_to_be64(seq); memcpy(info + ivsize - len, &seq, len); crypto_xor(info, ctx->salt, ivsize); } static int seqiv_givencrypt(struct skcipher_givcrypt_request *req) { struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req); struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req); crypto_completion_t complete; void *data; u8 *info; unsigned int ivsize; int err; ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv)); complete = req->creq.base.complete; data = req->creq.base.data; info = req->creq.info; ivsize = crypto_ablkcipher_ivsize(geniv); if (unlikely(!IS_ALIGNED((unsigned long)info, crypto_ablkcipher_alignmask(geniv) + 1))) { info = kmalloc(ivsize, req->creq.base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: GFP_ATOMIC); if (!info) return -ENOMEM; complete = seqiv_complete; data = req; } ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete, data); ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst, req->creq.nbytes, info); seqiv_geniv(ctx, info, req->seq, ivsize); memcpy(req->giv, info, ivsize); err = crypto_ablkcipher_encrypt(subreq); if (unlikely(info != req->creq.info)) seqiv_complete2(req, err); return err; } static int seqiv_aead_givencrypt(struct aead_givcrypt_request *req) { struct crypto_aead *geniv = aead_givcrypt_reqtfm(req); struct seqiv_ctx *ctx = crypto_aead_ctx(geniv); struct aead_request *areq = &req->areq; struct aead_request *subreq = aead_givcrypt_reqctx(req); crypto_completion_t complete; void *data; u8 *info; unsigned int ivsize; int err; aead_request_set_tfm(subreq, aead_geniv_base(geniv)); complete = areq->base.complete; data = areq->base.data; info = areq->iv; ivsize = crypto_aead_ivsize(geniv); if (unlikely(!IS_ALIGNED((unsigned long)info, crypto_aead_alignmask(geniv) + 1))) { info = kmalloc(ivsize, areq->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: GFP_ATOMIC); if (!info) return -ENOMEM; complete = seqiv_aead_complete; data = req; } aead_request_set_callback(subreq, areq->base.flags, complete, data); aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen, info); aead_request_set_assoc(subreq, areq->assoc, areq->assoclen); seqiv_geniv(ctx, info, req->seq, ivsize); memcpy(req->giv, info, ivsize); err = crypto_aead_encrypt(subreq); if (unlikely(info != areq->iv)) seqiv_aead_complete2(req, err); return err; } static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req) { struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req); struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); spin_lock_bh(&ctx->lock); if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first) goto unlock; crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt; get_random_bytes(ctx->salt, crypto_ablkcipher_ivsize(geniv)); unlock: spin_unlock_bh(&ctx->lock); return seqiv_givencrypt(req); } static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req) { struct crypto_aead *geniv = aead_givcrypt_reqtfm(req); struct seqiv_ctx *ctx = crypto_aead_ctx(geniv); spin_lock_bh(&ctx->lock); if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first) goto unlock; crypto_aead_crt(geniv)->givencrypt = seqiv_aead_givencrypt; get_random_bytes(ctx->salt, crypto_aead_ivsize(geniv)); unlock: spin_unlock_bh(&ctx->lock); return seqiv_aead_givencrypt(req); } static int seqiv_init(struct crypto_tfm *tfm) { struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm); struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); spin_lock_init(&ctx->lock); tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request); return skcipher_geniv_init(tfm); } static int seqiv_aead_init(struct crypto_tfm *tfm) { struct crypto_aead *geniv = __crypto_aead_cast(tfm); struct seqiv_ctx *ctx = crypto_aead_ctx(geniv); spin_lock_init(&ctx->lock); tfm->crt_aead.reqsize = sizeof(struct aead_request); return aead_geniv_init(tfm); } static struct crypto_template seqiv_tmpl; static struct crypto_instance *seqiv_ablkcipher_alloc(struct rtattr **tb) { struct crypto_instance *inst; inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0); if (IS_ERR(inst)) goto out; inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first; inst->alg.cra_init = seqiv_init; inst->alg.cra_exit = skcipher_geniv_exit; inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize; out: return inst; } static struct crypto_instance *seqiv_aead_alloc(struct rtattr **tb) { struct crypto_instance *inst; inst = aead_geniv_alloc(&seqiv_tmpl, tb, 0, 0); if (IS_ERR(inst)) goto out; inst->alg.cra_aead.givencrypt = seqiv_aead_givencrypt_first; inst->alg.cra_init = seqiv_aead_init; inst->alg.cra_exit = aead_geniv_exit; inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize; out: return inst; } static struct crypto_instance *seqiv_alloc(struct rtattr **tb) { struct crypto_attr_type *algt; struct crypto_instance *inst; 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) & CRYPTO_ALG_TYPE_MASK) inst = seqiv_ablkcipher_alloc(tb); else inst = seqiv_aead_alloc(tb); if (IS_ERR(inst)) goto out; inst->alg.cra_alignmask |= __alignof__(u32) - 1; inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx); out: return inst; } static void seqiv_free(struct crypto_instance *inst) { if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK) skcipher_geniv_free(inst); else aead_geniv_free(inst); } static struct crypto_template seqiv_tmpl = { .name = "seqiv", .alloc = seqiv_alloc, .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");