diff options
Diffstat (limited to 'kernel/crypto/skcipher.c')
| -rw-r--r-- | kernel/crypto/skcipher.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/kernel/crypto/skcipher.c b/kernel/crypto/skcipher.c new file mode 100644 index 000000000..d199c0b17 --- /dev/null +++ b/kernel/crypto/skcipher.c @@ -0,0 +1,247 @@ +/* + * Symmetric key cipher operations. + * + * Generic encrypt/decrypt wrapper for ciphers, handles operations across + * multiple page boundaries by using temporary blocks. In user context, + * the kernel is given a chance to schedule us once per page. + * + * Copyright (c) 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/skcipher.h> +#include <linux/bug.h> +#include <linux/module.h> + +#include "internal.h" + +static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg) +{ + if (alg->cra_type == &crypto_blkcipher_type) + return sizeof(struct crypto_blkcipher *); + + BUG_ON(alg->cra_type != &crypto_ablkcipher_type && + alg->cra_type != &crypto_givcipher_type); + + return sizeof(struct crypto_ablkcipher *); +} + +static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm, + const u8 *key, unsigned int keylen) +{ + struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm); + struct crypto_blkcipher *blkcipher = *ctx; + int err; + + crypto_blkcipher_clear_flags(blkcipher, ~0); + crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_MASK); + err = crypto_blkcipher_setkey(blkcipher, key, keylen); + crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) & + CRYPTO_TFM_RES_MASK); + + return err; +} + +static int skcipher_crypt_blkcipher(struct skcipher_request *req, + int (*crypt)(struct blkcipher_desc *, + struct scatterlist *, + struct scatterlist *, + unsigned int)) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm); + struct blkcipher_desc desc = { + .tfm = *ctx, + .info = req->iv, + .flags = req->base.flags, + }; + + + return crypt(&desc, req->dst, req->src, req->cryptlen); +} + +static int skcipher_encrypt_blkcipher(struct skcipher_request *req) +{ + struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); + struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); + struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; + + return skcipher_crypt_blkcipher(req, alg->encrypt); +} + +static int skcipher_decrypt_blkcipher(struct skcipher_request *req) +{ + struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); + struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); + struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; + + return skcipher_crypt_blkcipher(req, alg->decrypt); +} + +static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm) +{ + struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm); + + crypto_free_blkcipher(*ctx); +} + +static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm) +{ + struct crypto_alg *calg = tfm->__crt_alg; + struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm); + struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm); + struct crypto_blkcipher *blkcipher; + struct crypto_tfm *btfm; + + if (!crypto_mod_get(calg)) + return -EAGAIN; + + btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER, + CRYPTO_ALG_TYPE_MASK); + if (IS_ERR(btfm)) { + crypto_mod_put(calg); + return PTR_ERR(btfm); + } + + blkcipher = __crypto_blkcipher_cast(btfm); + *ctx = blkcipher; + tfm->exit = crypto_exit_skcipher_ops_blkcipher; + + skcipher->setkey = skcipher_setkey_blkcipher; + skcipher->encrypt = skcipher_encrypt_blkcipher; + skcipher->decrypt = skcipher_decrypt_blkcipher; + + skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher); + skcipher->has_setkey = calg->cra_blkcipher.max_keysize; + + return 0; +} + +static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm, + const u8 *key, unsigned int keylen) +{ + struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm); + struct crypto_ablkcipher *ablkcipher = *ctx; + int err; + + crypto_ablkcipher_clear_flags(ablkcipher, ~0); + crypto_ablkcipher_set_flags(ablkcipher, + crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_MASK); + err = crypto_ablkcipher_setkey(ablkcipher, key, keylen); + crypto_skcipher_set_flags(tfm, + crypto_ablkcipher_get_flags(ablkcipher) & + CRYPTO_TFM_RES_MASK); + + return err; +} + +static int skcipher_crypt_ablkcipher(struct skcipher_request *req, + int (*crypt)(struct ablkcipher_request *)) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm); + struct ablkcipher_request *subreq = skcipher_request_ctx(req); + + ablkcipher_request_set_tfm(subreq, *ctx); + ablkcipher_request_set_callback(subreq, skcipher_request_flags(req), + req->base.complete, req->base.data); + ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, + req->iv); + + return crypt(subreq); +} + +static int skcipher_encrypt_ablkcipher(struct skcipher_request *req) +{ + struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); + struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); + struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher; + + return skcipher_crypt_ablkcipher(req, alg->encrypt); +} + +static int skcipher_decrypt_ablkcipher(struct skcipher_request *req) +{ + struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); + struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); + struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher; + + return skcipher_crypt_ablkcipher(req, alg->decrypt); +} + +static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm) +{ + struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm); + + crypto_free_ablkcipher(*ctx); +} + +static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm) +{ + struct crypto_alg *calg = tfm->__crt_alg; + struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm); + struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm); + struct crypto_ablkcipher *ablkcipher; + struct crypto_tfm *abtfm; + + if (!crypto_mod_get(calg)) + return -EAGAIN; + + abtfm = __crypto_alloc_tfm(calg, 0, 0); + if (IS_ERR(abtfm)) { + crypto_mod_put(calg); + return PTR_ERR(abtfm); + } + + ablkcipher = __crypto_ablkcipher_cast(abtfm); + *ctx = ablkcipher; + tfm->exit = crypto_exit_skcipher_ops_ablkcipher; + + skcipher->setkey = skcipher_setkey_ablkcipher; + skcipher->encrypt = skcipher_encrypt_ablkcipher; + skcipher->decrypt = skcipher_decrypt_ablkcipher; + + skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher); + skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) + + sizeof(struct ablkcipher_request); + skcipher->has_setkey = calg->cra_ablkcipher.max_keysize; + + return 0; +} + +static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm) +{ + if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type) + return crypto_init_skcipher_ops_blkcipher(tfm); + + BUG_ON(tfm->__crt_alg->cra_type != &crypto_ablkcipher_type && + tfm->__crt_alg->cra_type != &crypto_givcipher_type); + + return crypto_init_skcipher_ops_ablkcipher(tfm); +} + +static const struct crypto_type crypto_skcipher_type2 = { + .extsize = crypto_skcipher_extsize, + .init_tfm = crypto_skcipher_init_tfm, + .maskclear = ~CRYPTO_ALG_TYPE_MASK, + .maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK, + .type = CRYPTO_ALG_TYPE_BLKCIPHER, + .tfmsize = offsetof(struct crypto_skcipher, base), +}; + +struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name, + u32 type, u32 mask) +{ + return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask); +} +EXPORT_SYMBOL_GPL(crypto_alloc_skcipher); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Symmetric key cipher type"); |