linux/arch/x86/crypto/glue_helper.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Shared glue code for 128bit block ciphers
   4 *
   5 * Copyright © 2012-2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
   6 *
   7 * CBC & ECB parts based on code (crypto/cbc.c,ecb.c) by:
   8 *   Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   9 * CTR part based on code (crypto/ctr.c) by:
  10 *   (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
  11 */
  12
  13#include <linux/module.h>
  14#include <crypto/b128ops.h>
  15#include <crypto/gf128mul.h>
  16#include <crypto/internal/skcipher.h>
  17#include <crypto/scatterwalk.h>
  18#include <crypto/xts.h>
  19#include <asm/crypto/glue_helper.h>
  20
  21int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
  22                        struct skcipher_request *req)
  23{
  24        void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
  25        const unsigned int bsize = 128 / 8;
  26        struct skcipher_walk walk;
  27        bool fpu_enabled = false;
  28        unsigned int nbytes;
  29        int err;
  30
  31        err = skcipher_walk_virt(&walk, req, false);
  32
  33        while ((nbytes = walk.nbytes)) {
  34                const u8 *src = walk.src.virt.addr;
  35                u8 *dst = walk.dst.virt.addr;
  36                unsigned int func_bytes;
  37                unsigned int i;
  38
  39                fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
  40                                             &walk, fpu_enabled, nbytes);
  41                for (i = 0; i < gctx->num_funcs; i++) {
  42                        func_bytes = bsize * gctx->funcs[i].num_blocks;
  43
  44                        if (nbytes < func_bytes)
  45                                continue;
  46
  47                        /* Process multi-block batch */
  48                        do {
  49                                gctx->funcs[i].fn_u.ecb(ctx, dst, src);
  50                                src += func_bytes;
  51                                dst += func_bytes;
  52                                nbytes -= func_bytes;
  53                        } while (nbytes >= func_bytes);
  54
  55                        if (nbytes < bsize)
  56                                break;
  57                }
  58                err = skcipher_walk_done(&walk, nbytes);
  59        }
  60
  61        glue_fpu_end(fpu_enabled);
  62        return err;
  63}
  64EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);
  65
  66int glue_cbc_encrypt_req_128bit(const common_glue_func_t fn,
  67                                struct skcipher_request *req)
  68{
  69        void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
  70        const unsigned int bsize = 128 / 8;
  71        struct skcipher_walk walk;
  72        unsigned int nbytes;
  73        int err;
  74
  75        err = skcipher_walk_virt(&walk, req, false);
  76
  77        while ((nbytes = walk.nbytes)) {
  78                const u128 *src = (u128 *)walk.src.virt.addr;
  79                u128 *dst = (u128 *)walk.dst.virt.addr;
  80                u128 *iv = (u128 *)walk.iv;
  81
  82                do {
  83                        u128_xor(dst, src, iv);
  84                        fn(ctx, (u8 *)dst, (u8 *)dst);
  85                        iv = dst;
  86                        src++;
  87                        dst++;
  88                        nbytes -= bsize;
  89                } while (nbytes >= bsize);
  90
  91                *(u128 *)walk.iv = *iv;
  92                err = skcipher_walk_done(&walk, nbytes);
  93        }
  94        return err;
  95}
  96EXPORT_SYMBOL_GPL(glue_cbc_encrypt_req_128bit);
  97
  98int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
  99                                struct skcipher_request *req)
 100{
 101        void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 102        const unsigned int bsize = 128 / 8;
 103        struct skcipher_walk walk;
 104        bool fpu_enabled = false;
 105        unsigned int nbytes;
 106        int err;
 107
 108        err = skcipher_walk_virt(&walk, req, false);
 109
 110        while ((nbytes = walk.nbytes)) {
 111                const u128 *src = walk.src.virt.addr;
 112                u128 *dst = walk.dst.virt.addr;
 113                unsigned int func_bytes, num_blocks;
 114                unsigned int i;
 115                u128 last_iv;
 116
 117                fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
 118                                             &walk, fpu_enabled, nbytes);
 119                /* Start of the last block. */
 120                src += nbytes / bsize - 1;
 121                dst += nbytes / bsize - 1;
 122
 123                last_iv = *src;
 124
 125                for (i = 0; i < gctx->num_funcs; i++) {
 126                        num_blocks = gctx->funcs[i].num_blocks;
 127                        func_bytes = bsize * num_blocks;
 128
 129                        if (nbytes < func_bytes)
 130                                continue;
 131
 132                        /* Process multi-block batch */
 133                        do {
 134                                src -= num_blocks - 1;
 135                                dst -= num_blocks - 1;
 136
 137                                gctx->funcs[i].fn_u.cbc(ctx, dst, src);
 138
 139                                nbytes -= func_bytes;
 140                                if (nbytes < bsize)
 141                                        goto done;
 142
 143                                u128_xor(dst, dst, --src);
 144                                dst--;
 145                        } while (nbytes >= func_bytes);
 146                }
 147done:
 148                u128_xor(dst, dst, (u128 *)walk.iv);
 149                *(u128 *)walk.iv = last_iv;
 150                err = skcipher_walk_done(&walk, nbytes);
 151        }
 152
 153        glue_fpu_end(fpu_enabled);
 154        return err;
 155}
 156EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
 157
 158int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 159                        struct skcipher_request *req)
 160{
 161        void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 162        const unsigned int bsize = 128 / 8;
 163        struct skcipher_walk walk;
 164        bool fpu_enabled = false;
 165        unsigned int nbytes;
 166        int err;
 167
 168        err = skcipher_walk_virt(&walk, req, false);
 169
 170        while ((nbytes = walk.nbytes) >= bsize) {
 171                const u128 *src = walk.src.virt.addr;
 172                u128 *dst = walk.dst.virt.addr;
 173                unsigned int func_bytes, num_blocks;
 174                unsigned int i;
 175                le128 ctrblk;
 176
 177                fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
 178                                             &walk, fpu_enabled, nbytes);
 179
 180                be128_to_le128(&ctrblk, (be128 *)walk.iv);
 181
 182                for (i = 0; i < gctx->num_funcs; i++) {
 183                        num_blocks = gctx->funcs[i].num_blocks;
 184                        func_bytes = bsize * num_blocks;
 185
 186                        if (nbytes < func_bytes)
 187                                continue;
 188
 189                        /* Process multi-block batch */
 190                        do {
 191                                gctx->funcs[i].fn_u.ctr(ctx, dst, src, &ctrblk);
 192                                src += num_blocks;
 193                                dst += num_blocks;
 194                                nbytes -= func_bytes;
 195                        } while (nbytes >= func_bytes);
 196
 197                        if (nbytes < bsize)
 198                                break;
 199                }
 200
 201                le128_to_be128((be128 *)walk.iv, &ctrblk);
 202                err = skcipher_walk_done(&walk, nbytes);
 203        }
 204
 205        glue_fpu_end(fpu_enabled);
 206
 207        if (nbytes) {
 208                le128 ctrblk;
 209                u128 tmp;
 210
 211                be128_to_le128(&ctrblk, (be128 *)walk.iv);
 212                memcpy(&tmp, walk.src.virt.addr, nbytes);
 213                gctx->funcs[gctx->num_funcs - 1].fn_u.ctr(ctx, &tmp, &tmp,
 214                                                          &ctrblk);
 215                memcpy(walk.dst.virt.addr, &tmp, nbytes);
 216                le128_to_be128((be128 *)walk.iv, &ctrblk);
 217
 218                err = skcipher_walk_done(&walk, 0);
 219        }
 220
 221        return err;
 222}
 223EXPORT_SYMBOL_GPL(glue_ctr_req_128bit);
 224
 225static unsigned int __glue_xts_req_128bit(const struct common_glue_ctx *gctx,
 226                                          void *ctx,
 227                                          struct skcipher_walk *walk)
 228{
 229        const unsigned int bsize = 128 / 8;
 230        unsigned int nbytes = walk->nbytes;
 231        u128 *src = walk->src.virt.addr;
 232        u128 *dst = walk->dst.virt.addr;
 233        unsigned int num_blocks, func_bytes;
 234        unsigned int i;
 235
 236        /* Process multi-block batch */
 237        for (i = 0; i < gctx->num_funcs; i++) {
 238                num_blocks = gctx->funcs[i].num_blocks;
 239                func_bytes = bsize * num_blocks;
 240
 241                if (nbytes >= func_bytes) {
 242                        do {
 243                                gctx->funcs[i].fn_u.xts(ctx, dst, src,
 244                                                        walk->iv);
 245
 246                                src += num_blocks;
 247                                dst += num_blocks;
 248                                nbytes -= func_bytes;
 249                        } while (nbytes >= func_bytes);
 250
 251                        if (nbytes < bsize)
 252                                goto done;
 253                }
 254        }
 255
 256done:
 257        return nbytes;
 258}
 259
 260int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
 261                        struct skcipher_request *req,
 262                        common_glue_func_t tweak_fn, void *tweak_ctx,
 263                        void *crypt_ctx, bool decrypt)
 264{
 265        const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
 266        const unsigned int bsize = 128 / 8;
 267        struct skcipher_request subreq;
 268        struct skcipher_walk walk;
 269        bool fpu_enabled = false;
 270        unsigned int nbytes, tail;
 271        int err;
 272
 273        if (req->cryptlen < XTS_BLOCK_SIZE)
 274                return -EINVAL;
 275
 276        if (unlikely(cts)) {
 277                struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 278
 279                tail = req->cryptlen % XTS_BLOCK_SIZE + XTS_BLOCK_SIZE;
 280
 281                skcipher_request_set_tfm(&subreq, tfm);
 282                skcipher_request_set_callback(&subreq,
 283                                              crypto_skcipher_get_flags(tfm),
 284                                              NULL, NULL);
 285                skcipher_request_set_crypt(&subreq, req->src, req->dst,
 286                                           req->cryptlen - tail, req->iv);
 287                req = &subreq;
 288        }
 289
 290        err = skcipher_walk_virt(&walk, req, false);
 291        nbytes = walk.nbytes;
 292        if (err)
 293                return err;
 294
 295        /* set minimum length to bsize, for tweak_fn */
 296        fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
 297                                     &walk, fpu_enabled,
 298                                     nbytes < bsize ? bsize : nbytes);
 299
 300        /* calculate first value of T */
 301        tweak_fn(tweak_ctx, walk.iv, walk.iv);
 302
 303        while (nbytes) {
 304                nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
 305
 306                err = skcipher_walk_done(&walk, nbytes);
 307                nbytes = walk.nbytes;
 308        }
 309
 310        if (unlikely(cts)) {
 311                u8 *next_tweak, *final_tweak = req->iv;
 312                struct scatterlist *src, *dst;
 313                struct scatterlist s[2], d[2];
 314                le128 b[2];
 315
 316                dst = src = scatterwalk_ffwd(s, req->src, req->cryptlen);
 317                if (req->dst != req->src)
 318                        dst = scatterwalk_ffwd(d, req->dst, req->cryptlen);
 319
 320                if (decrypt) {
 321                        next_tweak = memcpy(b, req->iv, XTS_BLOCK_SIZE);
 322                        gf128mul_x_ble(b, b);
 323                } else {
 324                        next_tweak = req->iv;
 325                }
 326
 327                skcipher_request_set_crypt(&subreq, src, dst, XTS_BLOCK_SIZE,
 328                                           next_tweak);
 329
 330                err = skcipher_walk_virt(&walk, req, false) ?:
 331                      skcipher_walk_done(&walk,
 332                                __glue_xts_req_128bit(gctx, crypt_ctx, &walk));
 333                if (err)
 334                        goto out;
 335
 336                scatterwalk_map_and_copy(b, dst, 0, XTS_BLOCK_SIZE, 0);
 337                memcpy(b + 1, b, tail - XTS_BLOCK_SIZE);
 338                scatterwalk_map_and_copy(b, src, XTS_BLOCK_SIZE,
 339                                         tail - XTS_BLOCK_SIZE, 0);
 340                scatterwalk_map_and_copy(b, dst, 0, tail, 1);
 341
 342                skcipher_request_set_crypt(&subreq, dst, dst, XTS_BLOCK_SIZE,
 343                                           final_tweak);
 344
 345                err = skcipher_walk_virt(&walk, req, false) ?:
 346                      skcipher_walk_done(&walk,
 347                                __glue_xts_req_128bit(gctx, crypt_ctx, &walk));
 348        }
 349
 350out:
 351        glue_fpu_end(fpu_enabled);
 352
 353        return err;
 354}
 355EXPORT_SYMBOL_GPL(glue_xts_req_128bit);
 356
 357void glue_xts_crypt_128bit_one(void *ctx, u128 *dst, const u128 *src, le128 *iv,
 358                               common_glue_func_t fn)
 359{
 360        le128 ivblk = *iv;
 361
 362        /* generate next IV */
 363        gf128mul_x_ble(iv, &ivblk);
 364
 365        /* CC <- T xor C */
 366        u128_xor(dst, src, (u128 *)&ivblk);
 367
 368        /* PP <- D(Key2,CC) */
 369        fn(ctx, (u8 *)dst, (u8 *)dst);
 370
 371        /* P <- T xor PP */
 372        u128_xor(dst, dst, (u128 *)&ivblk);
 373}
 374EXPORT_SYMBOL_GPL(glue_xts_crypt_128bit_one);
 375
 376MODULE_LICENSE("GPL");
 377