linux/crypto/deflate.c
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   1/*
   2 * Cryptographic API.
   3 *
   4 * Deflate algorithm (RFC 1951), implemented here primarily for use
   5 * by IPCOMP (RFC 3173 & RFC 2394).
   6 *
   7 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
   8 *
   9 * This program is free software; you can redistribute it and/or modify it
  10 * under the terms of the GNU General Public License as published by the Free
  11 * Software Foundation; either version 2 of the License, or (at your option)
  12 * any later version.
  13 *
  14 * FIXME: deflate transforms will require up to a total of about 436k of kernel
  15 * memory on i386 (390k for compression, the rest for decompression), as the
  16 * current zlib kernel code uses a worst case pre-allocation system by default.
  17 * This needs to be fixed so that the amount of memory required is properly
  18 * related to the  winbits and memlevel parameters.
  19 *
  20 * The default winbits of 11 should suit most packets, and it may be something
  21 * to configure on a per-tfm basis in the future.
  22 *
  23 * Currently, compression history is not maintained between tfm calls, as
  24 * it is not needed for IPCOMP and keeps the code simpler.  It can be
  25 * implemented if someone wants it.
  26 */
  27#include <linux/init.h>
  28#include <linux/module.h>
  29#include <linux/crypto.h>
  30#include <linux/zlib.h>
  31#include <linux/vmalloc.h>
  32#include <linux/interrupt.h>
  33#include <linux/mm.h>
  34#include <linux/net.h>
  35#include <crypto/internal/scompress.h>
  36
  37#define DEFLATE_DEF_LEVEL               Z_DEFAULT_COMPRESSION
  38#define DEFLATE_DEF_WINBITS             11
  39#define DEFLATE_DEF_MEMLEVEL            MAX_MEM_LEVEL
  40
  41struct deflate_ctx {
  42        struct z_stream_s comp_stream;
  43        struct z_stream_s decomp_stream;
  44};
  45
  46static int deflate_comp_init(struct deflate_ctx *ctx, int format)
  47{
  48        int ret = 0;
  49        struct z_stream_s *stream = &ctx->comp_stream;
  50
  51        stream->workspace = vzalloc(zlib_deflate_workspacesize(
  52                                    MAX_WBITS, MAX_MEM_LEVEL));
  53        if (!stream->workspace) {
  54                ret = -ENOMEM;
  55                goto out;
  56        }
  57        if (format)
  58                ret = zlib_deflateInit(stream, 3);
  59        else
  60                ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
  61                                        -DEFLATE_DEF_WINBITS,
  62                                        DEFLATE_DEF_MEMLEVEL,
  63                                        Z_DEFAULT_STRATEGY);
  64        if (ret != Z_OK) {
  65                ret = -EINVAL;
  66                goto out_free;
  67        }
  68out:
  69        return ret;
  70out_free:
  71        vfree(stream->workspace);
  72        goto out;
  73}
  74
  75static int deflate_decomp_init(struct deflate_ctx *ctx, int format)
  76{
  77        int ret = 0;
  78        struct z_stream_s *stream = &ctx->decomp_stream;
  79
  80        stream->workspace = vzalloc(zlib_inflate_workspacesize());
  81        if (!stream->workspace) {
  82                ret = -ENOMEM;
  83                goto out;
  84        }
  85        if (format)
  86                ret = zlib_inflateInit(stream);
  87        else
  88                ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
  89        if (ret != Z_OK) {
  90                ret = -EINVAL;
  91                goto out_free;
  92        }
  93out:
  94        return ret;
  95out_free:
  96        vfree(stream->workspace);
  97        goto out;
  98}
  99
 100static void deflate_comp_exit(struct deflate_ctx *ctx)
 101{
 102        zlib_deflateEnd(&ctx->comp_stream);
 103        vfree(ctx->comp_stream.workspace);
 104}
 105
 106static void deflate_decomp_exit(struct deflate_ctx *ctx)
 107{
 108        zlib_inflateEnd(&ctx->decomp_stream);
 109        vfree(ctx->decomp_stream.workspace);
 110}
 111
 112static int __deflate_init(void *ctx, int format)
 113{
 114        int ret;
 115
 116        ret = deflate_comp_init(ctx, format);
 117        if (ret)
 118                goto out;
 119        ret = deflate_decomp_init(ctx, format);
 120        if (ret)
 121                deflate_comp_exit(ctx);
 122out:
 123        return ret;
 124}
 125
 126static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
 127{
 128        struct deflate_ctx *ctx;
 129        int ret;
 130
 131        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 132        if (!ctx)
 133                return ERR_PTR(-ENOMEM);
 134
 135        ret = __deflate_init(ctx, format);
 136        if (ret) {
 137                kfree(ctx);
 138                return ERR_PTR(ret);
 139        }
 140
 141        return ctx;
 142}
 143
 144static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
 145{
 146        return gen_deflate_alloc_ctx(tfm, 0);
 147}
 148
 149static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
 150{
 151        return gen_deflate_alloc_ctx(tfm, 1);
 152}
 153
 154static int deflate_init(struct crypto_tfm *tfm)
 155{
 156        struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
 157
 158        return __deflate_init(ctx, 0);
 159}
 160
 161static void __deflate_exit(void *ctx)
 162{
 163        deflate_comp_exit(ctx);
 164        deflate_decomp_exit(ctx);
 165}
 166
 167static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
 168{
 169        __deflate_exit(ctx);
 170        kzfree(ctx);
 171}
 172
 173static void deflate_exit(struct crypto_tfm *tfm)
 174{
 175        struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
 176
 177        __deflate_exit(ctx);
 178}
 179
 180static int __deflate_compress(const u8 *src, unsigned int slen,
 181                              u8 *dst, unsigned int *dlen, void *ctx)
 182{
 183        int ret = 0;
 184        struct deflate_ctx *dctx = ctx;
 185        struct z_stream_s *stream = &dctx->comp_stream;
 186
 187        ret = zlib_deflateReset(stream);
 188        if (ret != Z_OK) {
 189                ret = -EINVAL;
 190                goto out;
 191        }
 192
 193        stream->next_in = (u8 *)src;
 194        stream->avail_in = slen;
 195        stream->next_out = (u8 *)dst;
 196        stream->avail_out = *dlen;
 197
 198        ret = zlib_deflate(stream, Z_FINISH);
 199        if (ret != Z_STREAM_END) {
 200                ret = -EINVAL;
 201                goto out;
 202        }
 203        ret = 0;
 204        *dlen = stream->total_out;
 205out:
 206        return ret;
 207}
 208
 209static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
 210                            unsigned int slen, u8 *dst, unsigned int *dlen)
 211{
 212        struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
 213
 214        return __deflate_compress(src, slen, dst, dlen, dctx);
 215}
 216
 217static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
 218                             unsigned int slen, u8 *dst, unsigned int *dlen,
 219                             void *ctx)
 220{
 221        return __deflate_compress(src, slen, dst, dlen, ctx);
 222}
 223
 224static int __deflate_decompress(const u8 *src, unsigned int slen,
 225                                u8 *dst, unsigned int *dlen, void *ctx)
 226{
 227
 228        int ret = 0;
 229        struct deflate_ctx *dctx = ctx;
 230        struct z_stream_s *stream = &dctx->decomp_stream;
 231
 232        ret = zlib_inflateReset(stream);
 233        if (ret != Z_OK) {
 234                ret = -EINVAL;
 235                goto out;
 236        }
 237
 238        stream->next_in = (u8 *)src;
 239        stream->avail_in = slen;
 240        stream->next_out = (u8 *)dst;
 241        stream->avail_out = *dlen;
 242
 243        ret = zlib_inflate(stream, Z_SYNC_FLUSH);
 244        /*
 245         * Work around a bug in zlib, which sometimes wants to taste an extra
 246         * byte when being used in the (undocumented) raw deflate mode.
 247         * (From USAGI).
 248         */
 249        if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
 250                u8 zerostuff = 0;
 251                stream->next_in = &zerostuff;
 252                stream->avail_in = 1;
 253                ret = zlib_inflate(stream, Z_FINISH);
 254        }
 255        if (ret != Z_STREAM_END) {
 256                ret = -EINVAL;
 257                goto out;
 258        }
 259        ret = 0;
 260        *dlen = stream->total_out;
 261out:
 262        return ret;
 263}
 264
 265static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
 266                              unsigned int slen, u8 *dst, unsigned int *dlen)
 267{
 268        struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
 269
 270        return __deflate_decompress(src, slen, dst, dlen, dctx);
 271}
 272
 273static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 274                               unsigned int slen, u8 *dst, unsigned int *dlen,
 275                               void *ctx)
 276{
 277        return __deflate_decompress(src, slen, dst, dlen, ctx);
 278}
 279
 280static struct crypto_alg alg = {
 281        .cra_name               = "deflate",
 282        .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 283        .cra_ctxsize            = sizeof(struct deflate_ctx),
 284        .cra_module             = THIS_MODULE,
 285        .cra_init               = deflate_init,
 286        .cra_exit               = deflate_exit,
 287        .cra_u                  = { .compress = {
 288        .coa_compress           = deflate_compress,
 289        .coa_decompress         = deflate_decompress } }
 290};
 291
 292static struct scomp_alg scomp[] = { {
 293        .alloc_ctx              = deflate_alloc_ctx,
 294        .free_ctx               = deflate_free_ctx,
 295        .compress               = deflate_scompress,
 296        .decompress             = deflate_sdecompress,
 297        .base                   = {
 298                .cra_name       = "deflate",
 299                .cra_driver_name = "deflate-scomp",
 300                .cra_module      = THIS_MODULE,
 301        }
 302}, {
 303        .alloc_ctx              = zlib_deflate_alloc_ctx,
 304        .free_ctx               = deflate_free_ctx,
 305        .compress               = deflate_scompress,
 306        .decompress             = deflate_sdecompress,
 307        .base                   = {
 308                .cra_name       = "zlib-deflate",
 309                .cra_driver_name = "zlib-deflate-scomp",
 310                .cra_module      = THIS_MODULE,
 311        }
 312} };
 313
 314static int __init deflate_mod_init(void)
 315{
 316        int ret;
 317
 318        ret = crypto_register_alg(&alg);
 319        if (ret)
 320                return ret;
 321
 322        ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
 323        if (ret) {
 324                crypto_unregister_alg(&alg);
 325                return ret;
 326        }
 327
 328        return ret;
 329}
 330
 331static void __exit deflate_mod_fini(void)
 332{
 333        crypto_unregister_alg(&alg);
 334        crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
 335}
 336
 337module_init(deflate_mod_init);
 338module_exit(deflate_mod_fini);
 339
 340MODULE_LICENSE("GPL");
 341MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
 342MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 343MODULE_ALIAS_CRYPTO("deflate");
 344