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, (u8 *)dst,
 138                                                        (const u8 *)src);
 139
 140                                nbytes -= func_bytes;
 141                                if (nbytes < bsize)
 142                                        goto done;
 143
 144                                u128_xor(dst, dst, --src);
 145                                dst--;
 146                        } while (nbytes >= func_bytes);
 147                }
 148done:
 149                u128_xor(dst, dst, (u128 *)walk.iv);
 150                *(u128 *)walk.iv = last_iv;
 151                err = skcipher_walk_done(&walk, nbytes);
 152        }
 153
 154        glue_fpu_end(fpu_enabled);
 155        return err;
 156}
 157EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
 158
 159int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 160                        struct skcipher_request *req)
 161{
 162        void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 163        const unsigned int bsize = 128 / 8;
 164        struct skcipher_walk walk;
 165        bool fpu_enabled = false;
 166        unsigned int nbytes;
 167        int err;
 168
 169        err = skcipher_walk_virt(&walk, req, false);
 170
 171        while ((nbytes = walk.nbytes) >= bsize) {
 172                const u128 *src = walk.src.virt.addr;
 173                u128 *dst = walk.dst.virt.addr;
 174                unsigned int func_bytes, num_blocks;
 175                unsigned int i;
 176                le128 ctrblk;
 177
 178                fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
 179                                             &walk, fpu_enabled, nbytes);
 180
 181                be128_to_le128(&ctrblk, (be128 *)walk.iv);
 182
 183                for (i = 0; i < gctx->num_funcs; i++) {
 184                        num_blocks = gctx->funcs[i].num_blocks;
 185                        func_bytes = bsize * num_blocks;
 186
 187                        if (nbytes < func_bytes)
 188                                continue;
 189
 190                        /* Process multi-block batch */
 191                        do {
 192                                gctx->funcs[i].fn_u.ctr(ctx, (u8 *)dst,
 193                                                        (const u8 *)src,
 194                                                        &ctrblk);
 195                                src += num_blocks;
 196                                dst += num_blocks;
 197                                nbytes -= func_bytes;
 198                        } while (nbytes >= func_bytes);
 199
 200                        if (nbytes < bsize)
 201                                break;
 202                }
 203
 204                le128_to_be128((be128 *)walk.iv, &ctrblk);
 205                err = skcipher_walk_done(&walk, nbytes);
 206        }
 207
 208        glue_fpu_end(fpu_enabled);
 209
 210        if (nbytes) {
 211                le128 ctrblk;
 212                u128 tmp;
 213
 214                be128_to_le128(&ctrblk, (be128 *)walk.iv);
 215                memcpy(&tmp, walk.src.virt.addr, nbytes);
 216                gctx->funcs[gctx->num_funcs - 1].fn_u.ctr(ctx, (u8 *)&tmp,
 217                                                          (const u8 *)&tmp,
 218                                                          &ctrblk);
 219                memcpy(walk.dst.virt.addr, &tmp, nbytes);
 220                le128_to_be128((be128 *)walk.iv, &ctrblk);
 221
 222                err = skcipher_walk_done(&walk, 0);
 223        }
 224
 225        return err;
 226}
 227EXPORT_SYMBOL_GPL(glue_ctr_req_128bit);
 228
 229static unsigned int __glue_xts_req_128bit(const struct common_glue_ctx *gctx,
 230                                          void *ctx,
 231                                          struct skcipher_walk *walk)
 232{
 233        const unsigned int bsize = 128 / 8;
 234        unsigned int nbytes = walk->nbytes;
 235        u128 *src = walk->src.virt.addr;
 236        u128 *dst = walk->dst.virt.addr;
 237        unsigned int num_blocks, func_bytes;
 238        unsigned int i;
 239
 240        /* Process multi-block batch */
 241        for (i = 0; i < gctx->num_funcs; i++) {
 242                num_blocks = gctx->funcs[i].num_blocks;
 243                func_bytes = bsize * num_blocks;
 244
 245                if (nbytes >= func_bytes) {
 246                        do {
 247                                gctx->funcs[i].fn_u.xts(ctx, (u8 *)dst,
 248                                                        (const u8 *)src,
 249                                                        walk->iv);
 250
 251                                src += num_blocks;
 252                                dst += num_blocks;
 253                                nbytes -= func_bytes;
 254                        } while (nbytes >= func_bytes);
 255
 256                        if (nbytes < bsize)
 257                                goto done;
 258                }
 259        }
 260
 261done:
 262        return nbytes;
 263}
 264
 265int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
 266                        struct skcipher_request *req,
 267                        common_glue_func_t tweak_fn, void *tweak_ctx,
 268                        void *crypt_ctx, bool decrypt)
 269{
 270        const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
 271        const unsigned int bsize = 128 / 8;
 272        struct skcipher_request subreq;
 273        struct skcipher_walk walk;
 274        bool fpu_enabled = false;
 275        unsigned int nbytes, tail;
 276        int err;
 277
 278        if (req->cryptlen < XTS_BLOCK_SIZE)
 279                return -EINVAL;
 280
 281        if (unlikely(cts)) {
 282                struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 283
 284                tail = req->cryptlen % XTS_BLOCK_SIZE + XTS_BLOCK_SIZE;
 285
 286                skcipher_request_set_tfm(&subreq, tfm);
 287                skcipher_request_set_callback(&subreq,
 288                                              crypto_skcipher_get_flags(tfm),
 289                                              NULL, NULL);
 290                skcipher_request_set_crypt(&subreq, req->src, req->dst,
 291                                           req->cryptlen - tail, req->iv);
 292                req = &subreq;
 293        }
 294
 295        err = skcipher_walk_virt(&walk, req, false);
 296        nbytes = walk.nbytes;
 297        if (err)
 298                return err;
 299
 300        /* set minimum length to bsize, for tweak_fn */
 301        fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
 302                                     &walk, fpu_enabled,
 303                                     nbytes < bsize ? bsize : nbytes);
 304
 305        /* calculate first value of T */
 306        tweak_fn(tweak_ctx, walk.iv, walk.iv);
 307
 308        while (nbytes) {
 309                nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
 310
 311                err = skcipher_walk_done(&walk, nbytes);
 312                nbytes = walk.nbytes;
 313        }
 314
 315        if (unlikely(cts)) {
 316                u8 *next_tweak, *final_tweak = req->iv;
 317                struct scatterlist *src, *dst;
 318                struct scatterlist s[2], d[2];
 319                le128 b[2];
 320
 321                dst = src = scatterwalk_ffwd(s, req->src, req->cryptlen);
 322                if (req->dst != req->src)
 323                        dst = scatterwalk_ffwd(d, req->dst, req->cryptlen);
 324
 325                if (decrypt) {
 326                        next_tweak = memcpy(b, req->iv, XTS_BLOCK_SIZE);
 327                        gf128mul_x_ble(b, b);
 328                } else {
 329                        next_tweak = req->iv;
 330                }
 331
 332                skcipher_request_set_crypt(&subreq, src, dst, XTS_BLOCK_SIZE,
 333                                           next_tweak);
 334
 335                err = skcipher_walk_virt(&walk, req, false) ?:
 336                      skcipher_walk_done(&walk,
 337                                __glue_xts_req_128bit(gctx, crypt_ctx, &walk));
 338                if (err)
 339                        goto out;
 340
 341                scatterwalk_map_and_copy(b, dst, 0, XTS_BLOCK_SIZE, 0);
 342                memcpy(b + 1, b, tail - XTS_BLOCK_SIZE);
 343                scatterwalk_map_and_copy(b, src, XTS_BLOCK_SIZE,
 344                                         tail - XTS_BLOCK_SIZE, 0);
 345                scatterwalk_map_and_copy(b, dst, 0, tail, 1);
 346
 347                skcipher_request_set_crypt(&subreq, dst, dst, XTS_BLOCK_SIZE,
 348                                           final_tweak);
 349
 350                err = skcipher_walk_virt(&walk, req, false) ?:
 351                      skcipher_walk_done(&walk,
 352                                __glue_xts_req_128bit(gctx, crypt_ctx, &walk));
 353        }
 354
 355out:
 356        glue_fpu_end(fpu_enabled);
 357
 358        return err;
 359}
 360EXPORT_SYMBOL_GPL(glue_xts_req_128bit);
 361
 362void glue_xts_crypt_128bit_one(const void *ctx, u8 *dst, const u8 *src,
 363                               le128 *iv, common_glue_func_t fn)
 364{
 365        le128 ivblk = *iv;
 366
 367        /* generate next IV */
 368        gf128mul_x_ble(iv, &ivblk);
 369
 370        /* CC <- T xor C */
 371        u128_xor((u128 *)dst, (const u128 *)src, (u128 *)&ivblk);
 372
 373        /* PP <- D(Key2,CC) */
 374        fn(ctx, dst, dst);
 375
 376        /* P <- T xor PP */
 377        u128_xor((u128 *)dst, (u128 *)dst, (u128 *)&ivblk);
 378}
 379EXPORT_SYMBOL_GPL(glue_xts_crypt_128bit_one);
 380
 381MODULE_LICENSE("GPL");
 382