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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
367 lines
8.9 KiB
C
367 lines
8.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* XTS: as defined in IEEE1619/D16
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* http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
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* (sector sizes which are not a multiple of 16 bytes are,
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* however currently unsupported)
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*
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* Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
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*
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* Based on ecb.c
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* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <crypto/internal/skcipher.h>
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#include <crypto/scatterwalk.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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#include <crypto/xts.h>
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#include <crypto/b128ops.h>
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#include <crypto/gf128mul.h>
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struct priv {
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struct crypto_skcipher *child;
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struct crypto_cipher *tweak;
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};
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struct xts_instance_ctx {
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struct crypto_skcipher_spawn spawn;
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char name[CRYPTO_MAX_ALG_NAME];
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};
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struct rctx {
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le128 t;
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struct skcipher_request subreq;
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};
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static int setkey(struct crypto_skcipher *parent, const u8 *key,
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unsigned int keylen)
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{
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struct priv *ctx = crypto_skcipher_ctx(parent);
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struct crypto_skcipher *child;
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struct crypto_cipher *tweak;
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int err;
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err = xts_verify_key(parent, key, keylen);
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if (err)
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return err;
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keylen /= 2;
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/* we need two cipher instances: one to compute the initial 'tweak'
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* by encrypting the IV (usually the 'plain' iv) and the other
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* one to encrypt and decrypt the data */
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/* tweak cipher, uses Key2 i.e. the second half of *key */
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tweak = ctx->tweak;
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crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
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crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_cipher_setkey(tweak, key + keylen, keylen);
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crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) &
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CRYPTO_TFM_RES_MASK);
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if (err)
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return err;
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/* data cipher, uses Key1 i.e. the first half of *key */
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child = ctx->child;
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crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
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crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_skcipher_setkey(child, key, keylen);
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crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
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CRYPTO_TFM_RES_MASK);
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return err;
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}
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/*
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* We compute the tweak masks twice (both before and after the ECB encryption or
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* decryption) to avoid having to allocate a temporary buffer and/or make
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* mutliple calls to the 'ecb(..)' instance, which usually would be slower than
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* just doing the gf128mul_x_ble() calls again.
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*/
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static int xor_tweak(struct skcipher_request *req, bool second_pass)
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{
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struct rctx *rctx = skcipher_request_ctx(req);
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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const int bs = XTS_BLOCK_SIZE;
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struct skcipher_walk w;
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le128 t = rctx->t;
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int err;
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if (second_pass) {
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req = &rctx->subreq;
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/* set to our TFM to enforce correct alignment: */
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skcipher_request_set_tfm(req, tfm);
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}
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err = skcipher_walk_virt(&w, req, false);
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while (w.nbytes) {
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unsigned int avail = w.nbytes;
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le128 *wsrc;
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le128 *wdst;
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wsrc = w.src.virt.addr;
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wdst = w.dst.virt.addr;
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do {
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le128_xor(wdst++, &t, wsrc++);
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gf128mul_x_ble(&t, &t);
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} while ((avail -= bs) >= bs);
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err = skcipher_walk_done(&w, avail);
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}
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return err;
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}
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static int xor_tweak_pre(struct skcipher_request *req)
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{
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return xor_tweak(req, false);
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}
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static int xor_tweak_post(struct skcipher_request *req)
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{
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return xor_tweak(req, true);
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}
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static void crypt_done(struct crypto_async_request *areq, int err)
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{
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struct skcipher_request *req = areq->data;
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if (!err) {
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struct rctx *rctx = skcipher_request_ctx(req);
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rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
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err = xor_tweak_post(req);
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}
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skcipher_request_complete(req, err);
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}
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static void init_crypt(struct skcipher_request *req)
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{
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struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
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struct rctx *rctx = skcipher_request_ctx(req);
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struct skcipher_request *subreq = &rctx->subreq;
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skcipher_request_set_tfm(subreq, ctx->child);
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skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
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skcipher_request_set_crypt(subreq, req->dst, req->dst,
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req->cryptlen, NULL);
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/* calculate first value of T */
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crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
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}
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static int encrypt(struct skcipher_request *req)
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{
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struct rctx *rctx = skcipher_request_ctx(req);
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struct skcipher_request *subreq = &rctx->subreq;
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init_crypt(req);
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return xor_tweak_pre(req) ?:
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crypto_skcipher_encrypt(subreq) ?:
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xor_tweak_post(req);
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}
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static int decrypt(struct skcipher_request *req)
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{
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struct rctx *rctx = skcipher_request_ctx(req);
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struct skcipher_request *subreq = &rctx->subreq;
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init_crypt(req);
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return xor_tweak_pre(req) ?:
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crypto_skcipher_decrypt(subreq) ?:
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xor_tweak_post(req);
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}
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static int init_tfm(struct crypto_skcipher *tfm)
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{
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struct skcipher_instance *inst = skcipher_alg_instance(tfm);
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struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
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struct priv *ctx = crypto_skcipher_ctx(tfm);
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struct crypto_skcipher *child;
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struct crypto_cipher *tweak;
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child = crypto_spawn_skcipher(&ictx->spawn);
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if (IS_ERR(child))
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return PTR_ERR(child);
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ctx->child = child;
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tweak = crypto_alloc_cipher(ictx->name, 0, 0);
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if (IS_ERR(tweak)) {
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crypto_free_skcipher(ctx->child);
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return PTR_ERR(tweak);
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}
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ctx->tweak = tweak;
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crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
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sizeof(struct rctx));
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return 0;
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}
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static void exit_tfm(struct crypto_skcipher *tfm)
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{
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struct priv *ctx = crypto_skcipher_ctx(tfm);
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crypto_free_skcipher(ctx->child);
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crypto_free_cipher(ctx->tweak);
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}
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static void free(struct skcipher_instance *inst)
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{
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crypto_drop_skcipher(skcipher_instance_ctx(inst));
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kfree(inst);
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}
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static int create(struct crypto_template *tmpl, struct rtattr **tb)
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{
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struct skcipher_instance *inst;
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struct crypto_attr_type *algt;
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struct xts_instance_ctx *ctx;
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struct skcipher_alg *alg;
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const char *cipher_name;
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u32 mask;
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int err;
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algt = crypto_get_attr_type(tb);
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if (IS_ERR(algt))
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return PTR_ERR(algt);
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if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
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return -EINVAL;
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cipher_name = crypto_attr_alg_name(tb[1]);
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if (IS_ERR(cipher_name))
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return PTR_ERR(cipher_name);
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inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
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if (!inst)
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return -ENOMEM;
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ctx = skcipher_instance_ctx(inst);
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crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));
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mask = crypto_requires_off(algt->type, algt->mask,
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CRYPTO_ALG_NEED_FALLBACK |
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CRYPTO_ALG_ASYNC);
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err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
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if (err == -ENOENT) {
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err = -ENAMETOOLONG;
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if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
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cipher_name) >= CRYPTO_MAX_ALG_NAME)
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goto err_free_inst;
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err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
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}
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if (err)
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goto err_free_inst;
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alg = crypto_skcipher_spawn_alg(&ctx->spawn);
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err = -EINVAL;
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if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
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goto err_drop_spawn;
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if (crypto_skcipher_alg_ivsize(alg))
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goto err_drop_spawn;
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err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
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&alg->base);
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if (err)
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goto err_drop_spawn;
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err = -EINVAL;
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cipher_name = alg->base.cra_name;
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/* Alas we screwed up the naming so we have to mangle the
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* cipher name.
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*/
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if (!strncmp(cipher_name, "ecb(", 4)) {
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unsigned len;
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len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
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if (len < 2 || len >= sizeof(ctx->name))
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goto err_drop_spawn;
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if (ctx->name[len - 1] != ')')
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goto err_drop_spawn;
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ctx->name[len - 1] = 0;
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if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
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"xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
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err = -ENAMETOOLONG;
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goto err_drop_spawn;
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}
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} else
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goto err_drop_spawn;
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inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
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inst->alg.base.cra_priority = alg->base.cra_priority;
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inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
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inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
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(__alignof__(u64) - 1);
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inst->alg.ivsize = XTS_BLOCK_SIZE;
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inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
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inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
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inst->alg.base.cra_ctxsize = sizeof(struct priv);
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inst->alg.init = init_tfm;
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inst->alg.exit = exit_tfm;
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inst->alg.setkey = setkey;
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inst->alg.encrypt = encrypt;
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inst->alg.decrypt = decrypt;
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inst->free = free;
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err = skcipher_register_instance(tmpl, inst);
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if (err)
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goto err_drop_spawn;
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out:
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return err;
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err_drop_spawn:
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crypto_drop_skcipher(&ctx->spawn);
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err_free_inst:
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kfree(inst);
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goto out;
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}
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static struct crypto_template crypto_tmpl = {
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.name = "xts",
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.create = create,
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.module = THIS_MODULE,
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};
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static int __init crypto_module_init(void)
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{
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return crypto_register_template(&crypto_tmpl);
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}
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static void __exit crypto_module_exit(void)
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{
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crypto_unregister_template(&crypto_tmpl);
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}
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subsys_initcall(crypto_module_init);
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module_exit(crypto_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("XTS block cipher mode");
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MODULE_ALIAS_CRYPTO("xts");
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