| /* |
| * CTR: Counter mode |
| * |
| * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com> |
| * |
| * 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 <crypto/ctr.h> |
| #include <linux/err.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/random.h> |
| #include <linux/scatterlist.h> |
| #include <linux/slab.h> |
| |
| struct crypto_ctr_ctx { |
| struct crypto_cipher *child; |
| }; |
| |
| struct crypto_rfc3686_ctx { |
| struct crypto_blkcipher *child; |
| u8 nonce[CTR_RFC3686_NONCE_SIZE]; |
| }; |
| |
| static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key, |
| unsigned int keylen) |
| { |
| struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent); |
| struct crypto_cipher *child = ctx->child; |
| int err; |
| |
| crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); |
| crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) & |
| CRYPTO_TFM_REQ_MASK); |
| err = crypto_cipher_setkey(child, key, keylen); |
| crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) & |
| CRYPTO_TFM_RES_MASK); |
| |
| return err; |
| } |
| |
| static void crypto_ctr_crypt_final(struct blkcipher_walk *walk, |
| struct crypto_cipher *tfm) |
| { |
| unsigned int bsize = crypto_cipher_blocksize(tfm); |
| unsigned long alignmask = crypto_cipher_alignmask(tfm); |
| u8 *ctrblk = walk->iv; |
| u8 tmp[bsize + alignmask]; |
| u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1); |
| u8 *src = walk->src.virt.addr; |
| u8 *dst = walk->dst.virt.addr; |
| unsigned int nbytes = walk->nbytes; |
| |
| crypto_cipher_encrypt_one(tfm, keystream, ctrblk); |
| crypto_xor(keystream, src, nbytes); |
| memcpy(dst, keystream, nbytes); |
| |
| crypto_inc(ctrblk, bsize); |
| } |
| |
| static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk, |
| struct crypto_cipher *tfm) |
| { |
| void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = |
| crypto_cipher_alg(tfm)->cia_encrypt; |
| unsigned int bsize = crypto_cipher_blocksize(tfm); |
| u8 *ctrblk = walk->iv; |
| u8 *src = walk->src.virt.addr; |
| u8 *dst = walk->dst.virt.addr; |
| unsigned int nbytes = walk->nbytes; |
| |
| do { |
| /* create keystream */ |
| fn(crypto_cipher_tfm(tfm), dst, ctrblk); |
| crypto_xor(dst, src, bsize); |
| |
| /* increment counter in counterblock */ |
| crypto_inc(ctrblk, bsize); |
| |
| src += bsize; |
| dst += bsize; |
| } while ((nbytes -= bsize) >= bsize); |
| |
| return nbytes; |
| } |
| |
| static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk, |
| struct crypto_cipher *tfm) |
| { |
| void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = |
| crypto_cipher_alg(tfm)->cia_encrypt; |
| unsigned int bsize = crypto_cipher_blocksize(tfm); |
| unsigned long alignmask = crypto_cipher_alignmask(tfm); |
| unsigned int nbytes = walk->nbytes; |
| u8 *ctrblk = walk->iv; |
| u8 *src = walk->src.virt.addr; |
| u8 tmp[bsize + alignmask]; |
| u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1); |
| |
| do { |
| /* create keystream */ |
| fn(crypto_cipher_tfm(tfm), keystream, ctrblk); |
| crypto_xor(src, keystream, bsize); |
| |
| /* increment counter in counterblock */ |
| crypto_inc(ctrblk, bsize); |
| |
| src += bsize; |
| } while ((nbytes -= bsize) >= bsize); |
| |
| return nbytes; |
| } |
| |
| static int crypto_ctr_crypt(struct blkcipher_desc *desc, |
| struct scatterlist *dst, struct scatterlist *src, |
| unsigned int nbytes) |
| { |
| struct blkcipher_walk walk; |
| struct crypto_blkcipher *tfm = desc->tfm; |
| struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm); |
| struct crypto_cipher *child = ctx->child; |
| unsigned int bsize = crypto_cipher_blocksize(child); |
| int err; |
| |
| blkcipher_walk_init(&walk, dst, src, nbytes); |
| err = blkcipher_walk_virt_block(desc, &walk, bsize); |
| |
| while (walk.nbytes >= bsize) { |
| if (walk.src.virt.addr == walk.dst.virt.addr) |
| nbytes = crypto_ctr_crypt_inplace(&walk, child); |
| else |
| nbytes = crypto_ctr_crypt_segment(&walk, child); |
| |
| err = blkcipher_walk_done(desc, &walk, nbytes); |
| } |
| |
| if (walk.nbytes) { |
| crypto_ctr_crypt_final(&walk, child); |
| err = blkcipher_walk_done(desc, &walk, 0); |
| } |
| |
| return err; |
| } |
| |
| static int crypto_ctr_init_tfm(struct crypto_tfm *tfm) |
| { |
| struct crypto_instance *inst = (void *)tfm->__crt_alg; |
| struct crypto_spawn *spawn = crypto_instance_ctx(inst); |
| struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm); |
| struct crypto_cipher *cipher; |
| |
| cipher = crypto_spawn_cipher(spawn); |
| if (IS_ERR(cipher)) |
| return PTR_ERR(cipher); |
| |
| ctx->child = cipher; |
| |
| return 0; |
| } |
| |
| static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm) |
| { |
| struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm); |
| |
| crypto_free_cipher(ctx->child); |
| } |
| |
| static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb) |
| { |
| struct crypto_instance *inst; |
| struct crypto_alg *alg; |
| int err; |
| |
| err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER); |
| if (err) |
| return ERR_PTR(err); |
| |
| alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, |
| CRYPTO_ALG_TYPE_MASK); |
| if (IS_ERR(alg)) |
| return ERR_CAST(alg); |
| |
| /* Block size must be >= 4 bytes. */ |
| err = -EINVAL; |
| if (alg->cra_blocksize < 4) |
| goto out_put_alg; |
| |
| /* If this is false we'd fail the alignment of crypto_inc. */ |
| if (alg->cra_blocksize % 4) |
| goto out_put_alg; |
| |
| inst = crypto_alloc_instance("ctr", alg); |
| if (IS_ERR(inst)) |
| goto out; |
| |
| inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; |
| inst->alg.cra_priority = alg->cra_priority; |
| inst->alg.cra_blocksize = 1; |
| inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1); |
| inst->alg.cra_type = &crypto_blkcipher_type; |
| |
| inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize; |
| inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize; |
| inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize; |
| |
| inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx); |
| |
| inst->alg.cra_init = crypto_ctr_init_tfm; |
| inst->alg.cra_exit = crypto_ctr_exit_tfm; |
| |
| inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey; |
| inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt; |
| inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt; |
| |
| inst->alg.cra_blkcipher.geniv = "chainiv"; |
| |
| out: |
| crypto_mod_put(alg); |
| return inst; |
| |
| out_put_alg: |
| inst = ERR_PTR(err); |
| goto out; |
| } |
| |
| static void crypto_ctr_free(struct crypto_instance *inst) |
| { |
| crypto_drop_spawn(crypto_instance_ctx(inst)); |
| kfree(inst); |
| } |
| |
| static struct crypto_template crypto_ctr_tmpl = { |
| .name = "ctr", |
| .alloc = crypto_ctr_alloc, |
| .free = crypto_ctr_free, |
| .module = THIS_MODULE, |
| }; |
| |
| static int crypto_rfc3686_setkey(struct crypto_tfm *parent, const u8 *key, |
| unsigned int keylen) |
| { |
| struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(parent); |
| struct crypto_blkcipher *child = ctx->child; |
| int err; |
| |
| /* the nonce is stored in bytes at end of key */ |
| if (keylen < CTR_RFC3686_NONCE_SIZE) |
| return -EINVAL; |
| |
| memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE), |
| CTR_RFC3686_NONCE_SIZE); |
| |
| keylen -= CTR_RFC3686_NONCE_SIZE; |
| |
| crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); |
| crypto_blkcipher_set_flags(child, crypto_tfm_get_flags(parent) & |
| CRYPTO_TFM_REQ_MASK); |
| err = crypto_blkcipher_setkey(child, key, keylen); |
| crypto_tfm_set_flags(parent, crypto_blkcipher_get_flags(child) & |
| CRYPTO_TFM_RES_MASK); |
| |
| return err; |
| } |
| |
| static int crypto_rfc3686_crypt(struct blkcipher_desc *desc, |
| struct scatterlist *dst, |
| struct scatterlist *src, unsigned int nbytes) |
| { |
| struct crypto_blkcipher *tfm = desc->tfm; |
| struct crypto_rfc3686_ctx *ctx = crypto_blkcipher_ctx(tfm); |
| struct crypto_blkcipher *child = ctx->child; |
| unsigned long alignmask = crypto_blkcipher_alignmask(tfm); |
| u8 ivblk[CTR_RFC3686_BLOCK_SIZE + alignmask]; |
| u8 *iv = PTR_ALIGN(ivblk + 0, alignmask + 1); |
| u8 *info = desc->info; |
| int err; |
| |
| /* set up counter block */ |
| memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE); |
| memcpy(iv + CTR_RFC3686_NONCE_SIZE, info, CTR_RFC3686_IV_SIZE); |
| |
| /* initialize counter portion of counter block */ |
| *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) = |
| cpu_to_be32(1); |
| |
| desc->tfm = child; |
| desc->info = iv; |
| err = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes); |
| desc->tfm = tfm; |
| desc->info = info; |
| |
| return err; |
| } |
| |
| static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm) |
| { |
| struct crypto_instance *inst = (void *)tfm->__crt_alg; |
| struct crypto_spawn *spawn = crypto_instance_ctx(inst); |
| struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm); |
| struct crypto_blkcipher *cipher; |
| |
| cipher = crypto_spawn_blkcipher(spawn); |
| if (IS_ERR(cipher)) |
| return PTR_ERR(cipher); |
| |
| ctx->child = cipher; |
| |
| return 0; |
| } |
| |
| static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm) |
| { |
| struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm); |
| |
| crypto_free_blkcipher(ctx->child); |
| } |
| |
| static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb) |
| { |
| struct crypto_instance *inst; |
| struct crypto_alg *alg; |
| int err; |
| |
| err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER); |
| if (err) |
| return ERR_PTR(err); |
| |
| alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_BLKCIPHER, |
| CRYPTO_ALG_TYPE_MASK); |
| err = PTR_ERR(alg); |
| if (IS_ERR(alg)) |
| return ERR_PTR(err); |
| |
| /* We only support 16-byte blocks. */ |
| err = -EINVAL; |
| if (alg->cra_blkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE) |
| goto out_put_alg; |
| |
| /* Not a stream cipher? */ |
| if (alg->cra_blocksize != 1) |
| goto out_put_alg; |
| |
| inst = crypto_alloc_instance("rfc3686", alg); |
| if (IS_ERR(inst)) |
| goto out; |
| |
| inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; |
| inst->alg.cra_priority = alg->cra_priority; |
| inst->alg.cra_blocksize = 1; |
| inst->alg.cra_alignmask = alg->cra_alignmask; |
| inst->alg.cra_type = &crypto_blkcipher_type; |
| |
| inst->alg.cra_blkcipher.ivsize = CTR_RFC3686_IV_SIZE; |
| inst->alg.cra_blkcipher.min_keysize = alg->cra_blkcipher.min_keysize |
| + CTR_RFC3686_NONCE_SIZE; |
| inst->alg.cra_blkcipher.max_keysize = alg->cra_blkcipher.max_keysize |
| + CTR_RFC3686_NONCE_SIZE; |
| |
| inst->alg.cra_blkcipher.geniv = "seqiv"; |
| |
| inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx); |
| |
| inst->alg.cra_init = crypto_rfc3686_init_tfm; |
| inst->alg.cra_exit = crypto_rfc3686_exit_tfm; |
| |
| inst->alg.cra_blkcipher.setkey = crypto_rfc3686_setkey; |
| inst->alg.cra_blkcipher.encrypt = crypto_rfc3686_crypt; |
| inst->alg.cra_blkcipher.decrypt = crypto_rfc3686_crypt; |
| |
| out: |
| crypto_mod_put(alg); |
| return inst; |
| |
| out_put_alg: |
| inst = ERR_PTR(err); |
| goto out; |
| } |
| |
| static struct crypto_template crypto_rfc3686_tmpl = { |
| .name = "rfc3686", |
| .alloc = crypto_rfc3686_alloc, |
| .free = crypto_ctr_free, |
| .module = THIS_MODULE, |
| }; |
| |
| static int __init crypto_ctr_module_init(void) |
| { |
| int err; |
| |
| err = crypto_register_template(&crypto_ctr_tmpl); |
| if (err) |
| goto out; |
| |
| err = crypto_register_template(&crypto_rfc3686_tmpl); |
| if (err) |
| goto out_drop_ctr; |
| |
| out: |
| return err; |
| |
| out_drop_ctr: |
| crypto_unregister_template(&crypto_ctr_tmpl); |
| goto out; |
| } |
| |
| static void __exit crypto_ctr_module_exit(void) |
| { |
| crypto_unregister_template(&crypto_rfc3686_tmpl); |
| crypto_unregister_template(&crypto_ctr_tmpl); |
| } |
| |
| module_init(crypto_ctr_module_init); |
| module_exit(crypto_ctr_module_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_DESCRIPTION("CTR Counter block mode"); |
| MODULE_ALIAS_CRYPTO("rfc3686"); |
| MODULE_ALIAS_CRYPTO("ctr"); |