[v2] crypto: add key wrapping block chaining mode

Message ID	3407264.GJDOVGtEDe@myon.chronox.de (mailing list archive)
State	RFC
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 v2] crypto: add key wrapping block chaining mode Date: Sun, 26 Apr 2015 00:08:20 +0200 Message-ID: <3407264.GJDOVGtEDe@myon.chronox.de> User-Agent: KMail/4.14.6 (Linux/3.19.4-200.fc21.x86_64; KDE/4.14.6; x86_64; ; ) In-Reply-To: <1515730.LIeS5qas5m@myon.chronox.de> References: <1515730.LIeS5qas5m@myon.chronox.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk

On Sun, Apr 26, 2015 at 12:08:20AM +0200, Stephan Mueller wrote: > This patch implements the AES key wrapping as specified in > NIST SP800-38F and RFC3394. This is my attempt at turning kw into a givcipher. The encrypt part is complete but untested as I gave up after finding the reverse SG problem with your decrypt code. /* * 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: * * * The result of the encryption operation is the ciphertext starting * with the 2nd semiblock. The first semiblock is provided as the IV. * The IV uses to start the encryption operation is the default IV. * * * The input for the decryption is the first semiblock handed in as an * IV. The ciphertext is the data starting with the 2nd semiblock. The * return code of the decryption operation will be EBADMSG in case an * integrity error occurs. * * To obtain the full result of an encryption as expected by SP800-38F, the * caller must allocate a buffer of plaintext + 8 bytes: * * unsigned int datalen = ptlen + crypto_ablkcipher_ivsize(tfm); * u8 data[datalen]; * u8 *iv = data; * u8 *pt = data + crypto_ablkcipher_ivsize(tfm); * <ensure that pt contains the plaintext of size ptlen> * sg_init_one(&sg, ptdata, ptlen); * ablkcipher_request_set_crypt(req, &sg, &sg, ptlen, iv); * * ==> After encryption, data now contains full KW result as per SP800-38F. * * In case of decryption, ciphertext now already has the expected length * and must be segmented appropriately: * * unsigned int datalen = CTLEN; * u8 data[datalen]; * <ensure that data contains full ciphertext> * u8 *iv = data; * u8 *ct = data + crypto_ablkcipher_ivsize(tfm); * unsigned int ctlen = datalen - crypto_ablkcipher_ivsize(tfm); * sg_init_one(&sg, ctdata, ctlen); * ablkcipher_request_set_crypt(req, &sg, &sg, ptlen, iv); * * ==> After decryption (which hopefully does not return EBADMSG), the ct * pointer now points to the plaintext of size ctlen. */ #include <crypto/internal/skcipher.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> struct crypto_kw_ctx { struct crypto_cipher *child; }; struct crypto_rfc3394_ctx { struct crypto_ablkcipher *child; }; struct crypto_kw_block { #define SEMIBSIZE sizeof(be64) union { struct { be64 A; be64 R; }; u8 V[]; }; }; /* 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 ablkcipher_request *req) { struct scatterlist *src = req->src; struct scatterlist *dst = req->dst; unsigned int nbytes = req->nbytes; struct crypto_ablkcipher *tfm = crypto_ablkcipher_tfm(req); struct crypto_kw_ctx *ctx = crypto_ablkcipher_ctx(tfm); struct crypto_cipher *child = ctx->child; unsigned long alignmask = crypto_cipher_alignmask(child) | 7; unsigned int i; struct blkcipher_walk walk; u8 blockbuf[sizeof(struct crypto_kw_block) + alignmask]; struct crypto_kw_block *block = (struct crypto_kw_block *) PTR_ALIGN(blockbuf + 0, alignmask + 1); u64 t = 6 * ((nbytes) >> 3); int ret; /* * Require at least 2 semiblocks (note, the 3rd semiblock that is * required by SP800-38F is the IV. */ if (nbytes < (2 * SEMIBSIZE) || nbytes % SEMIBSIZE) 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. */ for (i = 0; i < 6; i++) { be64 tbe; blkcipher_walk_init(&walk, dst, src, nbytes); ret = blkcipher_walk_virt_ablkcipher(req, &walk); if (ret) goto out; /* * Point to the end of the scatterlists 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(child, (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(dst, &lsrc); crypto_kw_copy_scatterlist(dst, &ldst); } if (crypto_memneq("\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", block->A, SEMIBSIZE)) ret = -EBADMSG; out: memzero_explicit(&block, sizeof(struct crypto_kw_block)); memzero_explicit(tmpblock, sizeof(tmpblock)); return ret; } static int crypto_kw_encrypt(struct ablkcipher_request *req) { struct scatterlist *src = req->src; struct scatterlist *dst = req->dst; unsigned int nbytes = req->nbytes; struct crypto_ablkcipher *tfm = crypto_ablkcipher_tfm(req); struct crypto_kw_ctx *ctx = crypto_ablkcipher_ctx(tfm); struct crypto_cipher *child = ctx->child; unsigned long alignmask = crypto_cipher_alignmask(child) | 7; unsigned int i; struct blkcipher_walk walk; u8 blockbuf[sizeof(struct crypto_kw_block) + alignmask]; struct crypto_kw_block *block = (struct crypto_kw_block *) PTR_ALIGN(blockbuf + 0, alignmask + 1); u64 t = 1; int ret; /* * 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 (nbytes < (2 * SEMIBSIZE) || nbytes % SEMIBSIZE) 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. */ for (i = 0; i < 6; i++) { be64 tbe; blkcipher_walk_init(&walk, dst, src, nbytes); ret = blkcipher_walk_virt_ablkcipher(req, &walk); if (ret) goto out; while (walk.nbytes) { unsigned int leftover = walk.nbytes; be64 *vsrc = (be64 *)walk->src.virt.addr; block->A = *(be64 *)walk->iv; do { block->R = *vsrc++; crypto_cipher_encrypt_one(child, block->V, block->V); *vdst++ = block->R; tbe = cpu_to_be64(t++); crypto_xor(block->A, tbe, SEMIBSIZE); } while ((leftover -= SEMIBSIZE) >= bsize); *(be64 *)walk->iv = block->A; ret = blkcipher_walk_done(desc, &walk, nbytes); if (ret) goto out; } /* we now start to operate on the dst buffers only */ dst = src; } ret = 0; out: memzero_explicit(&block, sizeof(struct crypto_kw_block)); return ret; } static int crypto_kw_givencrypt(struct skcipher_givcrypt_request *req) { memcpy(req->giv, "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", SEMIBSIZE); memcpy(req->creq.info, req->giv, SEMIBSIZE); return crypto_kw_encrypt(&req->creq); } static int crypto_kw_givdecrypt(struct skcipher_givcrypt_request *req) { int err = crypto_kw_decrypt(&req->creq); if (err) return err; return memcmp(req->creq.info, "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", SEMIBSIZE) ? -EBADMSG : 0; } static int crypto_kw_setkey(struct crypto_tfm *parent, const u8 *key, unsigned int keylen) { struct crypto_kw_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 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; 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_GIVCIPHER | CRYPTO_ALG_GENIV); 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_GIVCIPHER | CRYPTO_ALG_GENIV; inst->alg.cra_priority = alg->cra_priority; inst->alg.cra_blocksize = SEMIBSIZE; inst->alg.cra_alignmask = 7; inst->alg.cra_type = &crypto_givcipher_type; inst->alg.cra_ablkcipher.ivsize = SEMIBSIZE; inst->alg.cra_ablkcipher.min_keysize = alg->cra_cipher.cia_min_keysize; inst->alg.cra_ablkcipher.max_keysize = alg->cra_cipher.cia_max_keysize; 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_ablkcipher.setkey = crypto_kw_setkey; inst->alg.cra_ablkcipher.encrypt = crypto_kw_encrypt; inst->alg.cra_ablkcipher.decrypt = crypto_kw_decrypt; inst->alg.cra_ablkcipher.givencrypt = crypto_kw_givencrypt; inst->alg.cra_ablkcipher.givdecrypt = crypto_kw_givdecrypt; 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("Dual BSD/GPL"); MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); MODULE_DESCRIPTION("Key Wrapping (RFC3394 / NIST SP800-38F)"); MODULE_ALIAS_CRYPTO("kw"); Cheers,

diff --git a/crypto/Kconfig b/crypto/Kconfig index 8aaf298..3d62d8a 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -295,6 +295,13 @@ config CRYPTO_XTS key size 256, 384 or 512 bits. This implementation currently can't handle a sectorsize which is not a multiple of 16 bytes. +config CRYPTO_KEYWRAP + tristate "Key wrapping support" + select CRYPTO_BLKCIPHER + help + Support for key wrapping (NIST SP800-38F / RFC3394) without + padding. + comment "Hash modes" config CRYPTO_CMAC diff --git a/crypto/Makefile b/crypto/Makefile index 97b7d3a..d2f4b69 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -56,6 +56,7 @@ obj-$(CONFIG_CRYPTO_CTS) += cts.o obj-$(CONFIG_CRYPTO_LRW) += lrw.o obj-$(CONFIG_CRYPTO_XTS) += xts.o obj-$(CONFIG_CRYPTO_CTR) += ctr.o +obj-$(CONFIG_CRYPTO_KEYWRAP) += keywrap.o obj-$(CONFIG_CRYPTO_GCM) += gcm.o obj-$(CONFIG_CRYPTO_CCM) += ccm.o obj-$(CONFIG_CRYPTO_PCRYPT) += pcrypt.o diff --git a/crypto/keywrap.c b/crypto/keywrap.c new file mode 100644 index 0000000..d70b0b3 --- /dev/null +++ b/crypto/keywrap.c @@ -0,0 +1,502 @@ +/* + * 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: + * + * * The result of the encryption operation is the ciphertext starting + * with the 2nd semiblock. The first semiblock is provided as the IV. + * The IV uses to start the encryption operation is the default IV. + * + * * The input for the decryption is the first semiblock handed in as an + * IV. The ciphertext is the data starting with the 2nd semiblock. The + * return code of the decryption operation will be EBADMSG in case an + * integrity error occurs. + * + * To obtain the full result of an encryption as expected by SP800-38F, the + * caller must allocate a buffer of plaintext + 8 bytes: + * + * unsigned int datalen = ptlen + crypto_ablkcipher_ivsize(tfm); + * u8 data[datalen]; + * u8 *iv = data; + * u8 *pt = data + crypto_ablkcipher_ivsize(tfm); + * <ensure that pt contains the plaintext of size ptlen> + * sg_init_one(&sg, ptdata, ptlen); + * ablkcipher_request_set_crypt(req, &sg, &sg, ptlen, iv); + * + * ==> After encryption, data now contains full KW result as per SP800-38F. + * + * In case of decryption, ciphertext now already has the expected length + * and must be segmented appropriately: + * + * unsigned int datalen = CTLEN; + * u8 data[datalen]; + * <ensure that data contains full ciphertext> + * u8 *iv = data; + * u8 *ct = data + crypto_ablkcipher_ivsize(tfm); + * unsigned int ctlen = datalen - crypto_ablkcipher_ivsize(tfm); + * sg_init_one(&sg, ctdata, ctlen); + * ablkcipher_request_set_crypt(req, &sg, &sg, ptlen, iv); + * + * ==> After decryption (which hopefully does not return EBADMSG), the ct + * pointer now points to the plaintext of size ctlen. + */ + +#include <linux/module.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> +#include <crypto/scatterwalk.h> +#include <crypto/internal/skcipher.h> + +struct crypto_kw_ctx { + struct crypto_cipher *child; +}; + +struct crypto_rfc3394_ctx { + struct crypto_ablkcipher *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 blkcipher_desc *desc, + struct scatterlist *dst, struct scatterlist *src, + unsigned int nbytes) +{ + struct crypto_blkcipher *tfm = desc->tfm; + struct crypto_kw_ctx *ctx = crypto_blkcipher_ctx(tfm); + struct crypto_cipher *child = ctx->child; + + unsigned long alignmask = max_t(unsigned long, 4, + crypto_cipher_alignmask(child)); + unsigned int src_nbytes, dst_nbytes, i; + struct scatter_walk src_walk, dst_walk; + + u8 blockbuf[sizeof(struct crypto_kw_block) + alignmask]; + struct crypto_kw_block *block = (struct crypto_kw_block *) + PTR_ALIGN(blockbuf + 0, alignmask + 1); + + u8 tmpblock[SEMIBSIZE]; + u64 t = 6 * ((nbytes) >> 3); + int ret = 0; + struct scatterlist lsrc, ldst; + + /* + * Require at least 2 semiblocks (note, the 3rd semiblock that is + * required by SP800-38F is the IV. + */ + if (nbytes < (2 * SEMIBSIZE) || nbytes % 8) + return -EINVAL; + memcpy(block->A, desc->info, 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(src, &lsrc); + crypto_kw_copy_scatterlist(dst, &ldst); + + 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, &lsrc); + scatterwalk_start(&dst_walk, &ldst); + src_nbytes = dst_nbytes = nbytes; + + /* + * Point to the end of the scatterlists 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(child, (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(dst, &lsrc); + crypto_kw_copy_scatterlist(dst, &ldst); + } + + if (crypto_memneq("\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", block->A, + SEMIBSIZE)) + ret = -EBADMSG; + +out: + memzero_explicit(&block, sizeof(struct crypto_kw_block)); + memzero_explicit(tmpblock, sizeof(tmpblock)); + + return ret; +} + +static int crypto_kw_encrypt(struct blkcipher_desc *desc, + struct scatterlist *dst, struct scatterlist *src, + unsigned int nbytes) +{ + struct crypto_blkcipher *tfm = desc->tfm; + struct crypto_kw_ctx *ctx = crypto_blkcipher_ctx(tfm); + struct crypto_cipher *child = ctx->child; + + unsigned long alignmask = max_t(unsigned long, 4, + crypto_cipher_alignmask(child)); + unsigned int src_nbytes, dst_nbytes, i; + struct scatter_walk src_walk, dst_walk; + + u8 blockbuf[sizeof(struct crypto_kw_block) + alignmask]; + struct crypto_kw_block *block = (struct crypto_kw_block *) + PTR_ALIGN(blockbuf + 0, alignmask + 1); + + u8 tmpblock[SEMIBSIZE]; + u64 t = 1; + struct scatterlist lsrc, ldst; + 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 (nbytes < (2 * SEMIBSIZE) || nbytes % 8) + return -EINVAL; + + memcpy(block->A, "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6", 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(src, &lsrc); + crypto_kw_copy_scatterlist(dst, &ldst); + + 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, &lsrc); + scatterwalk_start(&dst_walk, &ldst); + src_nbytes = dst_nbytes = nbytes; + + while (src_nbytes) { + if (!crypto_kw_scatterwalk_memcpy(&src_walk, + &src_nbytes, block->R, SEMIBSIZE, false)) + goto out; + crypto_cipher_encrypt_one(child, (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(dst, &lsrc); + crypto_kw_copy_scatterlist(dst, &ldst); + } + + /* establish the final IV */ + memcpy(desc->info, block->A, SEMIBSIZE); + + 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_tfm *parent, const u8 *key, + unsigned int keylen) +{ + struct crypto_kw_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 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; + 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_BLKCIPHER); + 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_BLKCIPHER; + inst->alg.cra_priority = alg->cra_priority; + inst->alg.cra_blocksize = SEMIBSIZE; + inst->alg.cra_alignmask = 0; + inst->alg.cra_type = &crypto_blkcipher_type; + inst->alg.cra_blkcipher.ivsize = SEMIBSIZE; + 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_kw_ctx); + + inst->alg.cra_init = crypto_kw_init_tfm; + inst->alg.cra_exit = crypto_kw_exit_tfm; + + inst->alg.cra_blkcipher.setkey = crypto_kw_setkey; + inst->alg.cra_blkcipher.encrypt = crypto_kw_encrypt; + inst->alg.cra_blkcipher.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("Dual BSD/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 d463978..4744437 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -1021,6 +1021,15 @@ static int __test_skcipher(struct crypto_ablkcipher *tfm, int enc, ret = -EINVAL; goto out; } + if (template[i].ivout && + memcmp(req->info, template[i].ivout, + crypto_ablkcipher_ivsize(tfm))) { + pr_err("alg: skcipher%s: IV-test %d failed on %s for %s\n", + d, j, e, algo); + hexdump(req->info, crypto_ablkcipher_ivsize(tfm)); + ret = -EINVAL; + goto out; + } } j = 0; @@ -3097,6 +3106,22 @@ static const struct alg_test_desc alg_test_descs[] = { } } }, { + .alg = "kw(aes)", + .test = alg_test_skcipher, + .fips_allowed = 1, + .suite = { + .cipher = { + .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..a9845fc 100644 --- a/crypto/testmgr.h +++ b/crypto/testmgr.h @@ -49,6 +49,7 @@ struct hash_testvec { struct cipher_testvec { char *key; char *iv; + char *ivout; char *input; char *result; unsigned short tap[MAX_TAP]; @@ -20704,6 +20705,46 @@ 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 + * + * Note: as documented in keywrap.c, the ivout for encryption is the first + * semiblock of the ciphertext from the test vector. For decryption, iv is + * the first semiblock of the ciphertext. + */ +static struct cipher_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 = "\xf6\x85\x94\x81\x6f\x64\xca\xa3" + "\xf5\x6f\xab\xea\x25\x48\xf5\xfb", + .rlen = 16, + .ivout = "\x03\x1f\x6b\xd7\xe6\x1e\x64\x3d", + }, +}; + +static struct cipher_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 = "\xd3\x3d\x3d\x97\x7b\xf0\xa9\x15" + "\x59\xf9\x9c\x8a\xcd\x29\x3d\x43", + .ilen = 16, + .result = "\x0a\x25\x6b\xa7\x5c\xfa\x03\xaa" + "\xa0\x2b\xa9\x42\x03\xf1\x5b\xaa", + .rlen = 16, + .iv = "\x42\x3c\x96\x0d\x8a\x2a\xc4\xc1", + }, +}; + +/* * 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

[v2] crypto: add key wrapping block chaining mode

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