crypto: add key wrapping block chaining mode

Message ID	6218629.uO4632Hmli@myon.chronox.de (mailing list archive)
State	Changes Requested
Delegated to:	Herbert Xu
Headers	show Return-Path: <linux-crypto-owner@kernel.org> From: Stephan Mueller <smueller@chronox.de> To: herbert@gondor.apana.org.au Cc: linux-crypto@vger.kernel.org Subject: [PATCH] crypto: add key wrapping block chaining mode Date: Wed, 22 Apr 2015 06:36:59 +0200 Message-ID: <6218629.uO4632Hmli@myon.chronox.de> User-Agent: KMail/4.14.6 (Linux/3.19.3-200.fc21.x86_64; KDE/4.14.6; x86_64; ; ) MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk

diff --git a/crypto/Kconfig b/crypto/Kconfig index 8aaf298..c3e1779 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -217,6 +217,12 @@ config CRYPTO_GCM Support for Galois/Counter Mode (GCM) and Galois Message Authentication Code (GMAC). Required for IPSec. +config CRYPTO_KEYWRAP + tristate "Key wrapping support" + select CRYPTO_AEAD + help + Support for key wrapping (NIST SP800-38F / RFC3394). + config CRYPTO_SEQIV tristate "Sequence Number IV Generator" select CRYPTO_AEAD diff --git a/crypto/Makefile b/crypto/Makefile index 97b7d3a..2e8e053 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -58,6 +58,7 @@ obj-$(CONFIG_CRYPTO_XTS) += xts.o obj-$(CONFIG_CRYPTO_CTR) += ctr.o obj-$(CONFIG_CRYPTO_GCM) += gcm.o obj-$(CONFIG_CRYPTO_CCM) += ccm.o +obj-$(CONFIG_CRYPTO_KEYWRAP) += keywrap.o obj-$(CONFIG_CRYPTO_PCRYPT) += pcrypt.o obj-$(CONFIG_CRYPTO_CRYPTD) += cryptd.o obj-$(CONFIG_CRYPTO_MCRYPTD) += mcryptd.o diff --git a/crypto/keywrap.c b/crypto/keywrap.c new file mode 100644 index 0000000..68cf552 --- /dev/null +++ b/crypto/keywrap.c @@ -0,0 +1,518 @@ +/* + * Key Wrapping: RFC3394 / NIST SP800-38F + * + * Implemented modes as defined in NIST SP800-38F: KW + * + * Copyright (C) 2015, Stephan Mueller <smueller@chronox.de> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, and the entire permission notice in its entirety, + * including the disclaimer of warranties. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * ALTERNATIVELY, this product may be distributed under the terms of + * the GNU General Public License, in which case the provisions of the GPL2 + * are required INSTEAD OF the above restrictions. (This clause is + * necessary due to a potential bad interaction between the GPL and + * the restrictions contained in a BSD-style copyright.) + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF + * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR + * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE + * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + */ + +/* + * Note for using key wrapping as an AEAD cipher: + * + * * For encryption, the ciphertext is larger by one half block size. The + * caller must ensure that the destination buffer is sufficiently large. + * That half blocksize is considered as the "authentication tag" (even + * though the key wrapping does not have an authentication tag). + * + * * AAD can be set with the key wrapping cipher, but it is not processed + * as such data is not needed. + * + * * If the caller does not set an IV, the default IV from SP800-38F is + * used for encryption and decryption. If an IV is set, it must be + * exactly be as large as half a block of the cipher. + */ + +#include <linux/module.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> +#include <crypto/scatterwalk.h> +#include <crypto/internal/aead.h> + +struct crypto_kw_ctx { + struct crypto_cipher *child; +}; + +struct crypto_kw_block { +#define SEMIBSIZE 8 + u8 A[SEMIBSIZE]; + u8 R[SEMIBSIZE]; +}; + +/* convert 64 bit integer into its string representation */ +static inline void crypto_kw_cpu_to_be64(u64 val, u8 *buf) +{ + struct s { + __be64 conv; + }; + struct s *conversion = (struct s *) buf; + + conversion->conv = cpu_to_be64(val); +} + +static inline void crypto_kw_copy_scatterlist(struct scatterlist *src, + struct scatterlist *dst) +{ + memcpy(dst, src, sizeof(struct scatterlist)); +} + +/* find the next memory block in scatter_walk of given size */ +static inline bool crypto_kw_scatterwalk_find(struct scatter_walk *walk, + unsigned int size) +{ + int n = scatterwalk_clamp(walk, size); + + if (!n) { + scatterwalk_start(walk, sg_next(walk->sg)); + n = scatterwalk_clamp(walk, size); + } + if (n != size) + return false; + return true; +} + +/* + * Copy out the memory block from or to scatter_walk of requested size + * before the walk->offset pointer. The scatter_walk is processed in reverse. + */ +static bool crypto_kw_scatterwalk_memcpy_rev(struct scatter_walk *walk, + unsigned int *walklen, + u8 *buf, unsigned int bufsize, + bool out) +{ + u8 *ptr = NULL; + + walk->offset -= bufsize; + if (!crypto_kw_scatterwalk_find(walk, bufsize)) + return false; + + ptr = scatterwalk_map(walk); + if (out) + memcpy(ptr, buf, bufsize); + else + memcpy(buf, ptr, bufsize); + *walklen -= bufsize; + scatterwalk_unmap(ptr); + scatterwalk_done(walk, 0, *walklen); + + return true; +} + +/* + * Copy the memory block from or to scatter_walk of requested size + * at the walk->offset pointer. The scatter_walk is processed forward. + */ +static bool crypto_kw_scatterwalk_memcpy(struct scatter_walk *walk, + unsigned int *walklen, + u8 *buf, unsigned int bufsize, + bool out) +{ + u8 *ptr = NULL; + + if (!crypto_kw_scatterwalk_find(walk, bufsize)) + return false; + + ptr = scatterwalk_map(walk); + if (out) + memcpy(ptr, buf, bufsize); + else + memcpy(buf, ptr, bufsize); + *walklen -= bufsize; + scatterwalk_unmap(ptr); + scatterwalk_advance(walk, bufsize); + scatterwalk_done(walk, 0, *walklen); + + return true; +} + +static int crypto_kw_decrypt(struct aead_request *req) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct crypto_kw_ctx *ctx = crypto_aead_ctx(aead); + struct crypto_cipher *tfm = ctx->child; + unsigned long alignmask = crypto_cipher_alignmask(tfm); + unsigned int src_nbytes, dst_nbytes, i; + struct scatter_walk src_walk, dst_walk; + struct crypto_kw_block block; + u8 tmpblock[SEMIBSIZE]; + u64 t = 6 * ((req->cryptlen - SEMIBSIZE) >> 3); + int ret = -EAGAIN; + struct scatterlist src, dst; + /* IV of KW defined by section 6.2 */ + u8 *default_iv = "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6"; + unsigned int outcryptlen = req->cryptlen - SEMIBSIZE; + + /* + * Require at least 3 semiblocks as defined in SP800-38F and ensure + * that the given data is aligned to semiblock. + */ + if (req->cryptlen < (3 * SEMIBSIZE) || req->cryptlen % 8) + return -EINVAL; + + /* + * src scatterlist is read only. dst scatterlist is r/w. During the + * first loop, src points to req->src and dst to req->dst. For any + * subsequent round, the code operates on req->dst only. + */ + crypto_kw_copy_scatterlist(req->src, &src); + crypto_kw_copy_scatterlist(req->dst, &dst); + + for (i = 0; i < 6; i++) { + u8 tbe_buffer[SEMIBSIZE + alignmask]; + /* alignment for the crypto_xor operation */ + u8 *tbe = PTR_ALIGN(tbe_buffer + 0, alignmask + 1); + bool first_loop = true; + + scatterwalk_start(&src_walk, &src); + scatterwalk_start(&dst_walk, &dst); + + src_nbytes = dst_nbytes = outcryptlen; + if (!i) { + src_nbytes = req->cryptlen; + if (!crypto_kw_scatterwalk_memcpy(&src_walk, + &src_nbytes, block.A, SEMIBSIZE, false)) + goto out; + } + + /* + * Point to the end of the source scatterlist to walk them + * backwards. + */ + src_walk.offset += src_nbytes; + dst_walk.offset += dst_nbytes; + + while (src_nbytes) { + if (!crypto_kw_scatterwalk_memcpy_rev(&src_walk, + &src_nbytes, block.R, SEMIBSIZE, false)) + goto out; + crypto_kw_cpu_to_be64(t, tbe); + crypto_xor(block.A, tbe, SEMIBSIZE); + t--; + crypto_cipher_decrypt_one(tfm, (u8*)&block, + (u8*)&block); + if (!first_loop) { + /* + * Copy block.R from last round into + * place. + */ + if (!crypto_kw_scatterwalk_memcpy_rev(&dst_walk, + &dst_nbytes, tmpblock, SEMIBSIZE, true)) + goto out; + } else { + first_loop = false; + } + + /* + * Store current block.R in temp buffer to + * copy it in place in the next round. + */ + memcpy(&tmpblock, block.R, SEMIBSIZE); + } + + /* process the final block.R */ + if (!crypto_kw_scatterwalk_memcpy_rev(&dst_walk, &dst_nbytes, + tmpblock, SEMIBSIZE, true)) + goto out; + + /* we now start to operate on the dst buffers only */ + crypto_kw_copy_scatterlist(req->dst, &src); + crypto_kw_copy_scatterlist(req->dst, &dst); + } + + if (req->iv) + ret = crypto_memneq(block.A, req->iv, SEMIBSIZE); + else + ret = crypto_memneq(block.A, default_iv, SEMIBSIZE); + + if (ret) + ret = -EBADMSG; + else + ret = 0; +out: + memzero_explicit(&block, sizeof(struct crypto_kw_block)); + memzero_explicit(tmpblock, sizeof(tmpblock)); + + return ret; +} + +static int crypto_kw_encrypt(struct aead_request *req) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct crypto_kw_ctx *ctx = crypto_aead_ctx(aead); + struct crypto_cipher *tfm = ctx->child; + unsigned long alignmask = crypto_cipher_alignmask(tfm); + unsigned int src_nbytes, dst_nbytes, i; + struct scatter_walk src_walk, dst_walk; + struct crypto_kw_block block; + u8 tmpblock[SEMIBSIZE]; + u64 t = 1; + struct scatterlist src, dst; + /* IV of KW defined by section 6.2 */ + u8 *default_iv = "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6"; + int ret = -EAGAIN; + + /* + * Require at least 2 semiblocks (note, the 3rd semiblock that is + * required by SP800-38F is the IV that occupies the first semiblock. + * This means that the dst memory must be one semiblock larger than src. + * Also ensure that the given data is aligned to semiblock. + */ + if (req->cryptlen < (2 * SEMIBSIZE) || req->cryptlen % 8) + return -EINVAL; + + if (req->iv) + memcpy(&block.A, req->iv, SEMIBSIZE); + else + memcpy(&block.A, default_iv, SEMIBSIZE); + + /* + * src scatterlist is read only. dst scatterlist is r/w. During the + * first loop, src points to req->src and dst to req->dst. For any + * subsequent round, the code operates on req->dst only. + */ + crypto_kw_copy_scatterlist(req->src, &src); + crypto_kw_copy_scatterlist(req->dst, &dst); + + for (i = 0; i < 6; i++) { + u8 tbe_buffer[SEMIBSIZE + alignmask]; + u8 *tbe = PTR_ALIGN(tbe_buffer + 0, alignmask + 1); + bool first_loop = true; + + scatterwalk_start(&src_walk, &src); + scatterwalk_start(&dst_walk, &dst); + + /* + * In the first round, we do not need to advance the buffer + * as our first buffer is the IV copied in place above already + * and we start picking up the first block from the plaintext. + * + * In subsequent rounds, the first semiblock is empty and + * reserved for the last block.A. + */ + if (i) { + if (!crypto_kw_scatterwalk_find(&src_walk, SEMIBSIZE)) + goto out; + scatterwalk_advance(&src_walk, SEMIBSIZE); + } + src_nbytes = req->cryptlen; + + /* Advance the buffer to leave the first semiblock untouched. */ + if (!crypto_kw_scatterwalk_find(&dst_walk, SEMIBSIZE)) + goto out; + scatterwalk_advance(&dst_walk, SEMIBSIZE); + dst_nbytes = req->cryptlen; + + while (src_nbytes) { + if (!crypto_kw_scatterwalk_memcpy(&src_walk, + &src_nbytes, block.R, SEMIBSIZE, false)) + goto out; + crypto_cipher_encrypt_one(tfm, (u8*)&block, + (u8*)&block); + crypto_kw_cpu_to_be64(t, tbe); + crypto_xor(block.A, tbe, SEMIBSIZE); + t++; + if (!first_loop) { + /* + * Copy block.R from last round into + * place. + */ + if (!crypto_kw_scatterwalk_memcpy(&dst_walk, + &dst_nbytes, tmpblock, SEMIBSIZE, true)) + goto out; + } else { + first_loop = false; + } + + /* + * Store current block.R in temp buffer to + * copy it in place in the next round. + */ + memcpy(&tmpblock, block.R, SEMIBSIZE); + } + + /* process the final block.R */ + if (!crypto_kw_scatterwalk_memcpy(&dst_walk, &dst_nbytes, + tmpblock, SEMIBSIZE, true)) + goto out; + + /* we now start to operate on the dst buffers only */ + crypto_kw_copy_scatterlist(req->dst, &src); + crypto_kw_copy_scatterlist(req->dst, &dst); + } + + scatterwalk_start(&dst_walk, &dst); + dst_nbytes = req->cryptlen + SEMIBSIZE; + /* establish the first semiblock of ciphertext */ + crypto_kw_scatterwalk_memcpy(&dst_walk, &dst_nbytes, block.A, + SEMIBSIZE, true); + + ret = 0; +out: + memzero_explicit(&block, sizeof(struct crypto_kw_block)); + memzero_explicit(tmpblock, sizeof(tmpblock)); + return ret; +} + +static int crypto_kw_setkey(struct crypto_aead *aead, const u8 *key, + unsigned int keylen) +{ + struct crypto_kw_ctx *ctx = crypto_aead_ctx(aead); + struct crypto_cipher *child = ctx->child; + int err; + + crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); + crypto_cipher_set_flags(child, crypto_aead_get_flags(aead) & + CRYPTO_TFM_REQ_MASK); + err = crypto_cipher_setkey(child, key, keylen); + crypto_aead_set_flags(aead, crypto_cipher_get_flags(child) & + CRYPTO_TFM_RES_MASK); + return err; +} + +static int crypto_kw_setauthsize(struct crypto_aead *tfm, + unsigned int authsize) +{ + if (authsize == SEMIBSIZE) + return 0; + return -EINVAL; +} + + +static int crypto_kw_init_tfm(struct crypto_tfm *tfm) +{ + struct crypto_instance *inst = crypto_tfm_alg_instance(tfm); + struct crypto_spawn *spawn = crypto_instance_ctx(inst); + struct crypto_kw_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; + + tfm->crt_aead.reqsize = 0; + + return 0; +} + +static void crypto_kw_exit_tfm(struct crypto_tfm *tfm) +{ + struct crypto_kw_ctx *ctx = crypto_tfm_ctx(tfm); + + crypto_free_cipher(ctx->child); +} + +static struct crypto_instance *crypto_kw_alloc(struct rtattr **tb) +{ + struct crypto_instance *inst = NULL; + struct crypto_alg *alg = NULL; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD); + if (err) + return ERR_PTR(err); + + alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, + CRYPTO_ALG_TYPE_MASK); + if (IS_ERR(alg)) + return ERR_CAST(alg); + + inst = ERR_PTR(-EINVAL); + /* Section 5.1 requirement for KW and KWP */ + if (alg->cra_blocksize != 2 * SEMIBSIZE) + goto err; + + inst = crypto_alloc_instance("kw", alg); + if (IS_ERR(inst)) + goto err; + + inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; + inst->alg.cra_priority = alg->cra_priority; + inst->alg.cra_blocksize = SEMIBSIZE; + + /* We access the data in semiblocks. */ + BUILD_BUG_ON(sizeof(u64) != SEMIBSIZE); + inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u64) - 1); + + inst->alg.cra_type = &crypto_aead_type; + + inst->alg.cra_aead.ivsize = SEMIBSIZE; + inst->alg.cra_aead.maxauthsize = SEMIBSIZE; + + inst->alg.cra_ctxsize = sizeof(struct crypto_kw_ctx); + + inst->alg.cra_init = crypto_kw_init_tfm; + inst->alg.cra_exit = crypto_kw_exit_tfm; + + inst->alg.cra_aead.setkey = crypto_kw_setkey; + inst->alg.cra_aead.setauthsize = crypto_kw_setauthsize; + inst->alg.cra_aead.encrypt = crypto_kw_encrypt; + inst->alg.cra_aead.decrypt = crypto_kw_decrypt; + +err: + crypto_mod_put(alg); + return inst; +} + +static void crypto_kw_free(struct crypto_instance *inst) +{ + crypto_drop_spawn(crypto_instance_ctx(inst)); + kfree(inst); +} + +static struct crypto_template crypto_kw_tmpl = { + .name = "kw", + .alloc = crypto_kw_alloc, + .free = crypto_kw_free, + .module = THIS_MODULE, +}; + +static int __init crypto_kw_init(void) +{ + return crypto_register_template(&crypto_kw_tmpl); +} + +static void __exit crypto_kw_exit(void) +{ + crypto_unregister_template(&crypto_kw_tmpl); +} + +module_init(crypto_kw_init); +module_exit(crypto_kw_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); +MODULE_DESCRIPTION("Key Wrapping (RFC3394 / NIST SP800-38F)"); +MODULE_ALIAS_CRYPTO("kw"); diff --git a/crypto/testmgr.c b/crypto/testmgr.c index f9bce3d..eaaebc9 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -3095,6 +3095,22 @@ static const struct alg_test_desc alg_test_descs[] = { } } }, { + .alg = "kw(aes)", + .test = alg_test_aead, + .fips_allowed = 1, + .suite = { + .aead = { + .enc = { + .vecs = aes_kw_enc_tv_template, + .count = ARRAY_SIZE(aes_kw_enc_tv_template) + }, + .dec = { + .vecs = aes_kw_dec_tv_template, + .count = ARRAY_SIZE(aes_kw_dec_tv_template) + } + } + } + }, { .alg = "lrw(aes)", .test = alg_test_skcipher, .suite = { diff --git a/crypto/testmgr.h b/crypto/testmgr.h index 62e2485..d952e19 100644 --- a/crypto/testmgr.h +++ b/crypto/testmgr.h @@ -20704,6 +20704,44 @@ static struct aead_testvec aes_ccm_rfc4309_dec_tv_template[] = { }; /* + * All key wrapping test vectors taken from + * http://csrc.nist.gov/groups/STM/cavp/documents/mac/kwtestvectors.zip + */ +static struct aead_testvec aes_kw_enc_tv_template[] = { + { + .key = "\x75\x75\xda\x3a\x93\x60\x7c\xc2" + "\xbf\xd8\xce\xc7\xaa\xdf\xd9\xa6", + .klen = 16, + .input = "\x42\x13\x6d\x3c\x38\x4a\x3e\xea" + "\xc9\x5a\x06\x6f\xd2\x8f\xed\x3f", + .ilen = 16, + .result = "\x03\x1f\x6b\xd7\xe6\x1e\x64\x3d\xf6\x85\x94\x81" + "\x6f\x64\xca\xa3\xf5\x6f\xab\xea\x25\x48\xf5\xfb", + .rlen = 24, + /* default IV as the testmgr uses a NULL IV otherwise */ + .iv = "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", + }, +}; + +static struct aead_testvec aes_kw_dec_tv_template[] = { + { + .key = "\x80\xaa\x99\x73\x27\xa4\x80\x6b" + "\x6a\x7a\x41\xa5\x2b\x86\xc3\x71" + "\x03\x86\xf9\x32\x78\x6e\xf7\x96" + "\x76\xfa\xfb\x90\xb8\x26\x3c\x5f", + .klen = 32, + .input = "\x42\x3c\x96\x0d\x8a\x2a\xc4\xc1\xd3\x3d\x3d\x97" + "\x7b\xf0\xa9\x15\x59\xf9\x9c\x8a\xcd\x29\x3d\x43", + .ilen = 24, + .result = "\x0a\x25\x6b\xa7\x5c\xfa\x03\xaa" + "\xa0\x2b\xa9\x42\x03\xf1\x5b\xaa", + .rlen = 16, + /* default IV as the testmgr uses a NULL IV otherwise */ + .iv = "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", + }, +}; + +/* * ANSI X9.31 Continuous Pseudo-Random Number Generator (AES mode) * test vectors, taken from Appendix B.2.9 and B.2.10: * http://csrc.nist.gov/groups/STM/cavp/documents/rng/RNGVS.pdf

crypto: add key wrapping block chaining mode

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