crypto/deflate.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Cryptographic API.
   4  *
   5  * Deflate algorithm (RFC 1951), implemented here primarily for use
   6  * by IPCOMP (RFC 3173 & RFC 2394).
   7  *
   8  * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
   9  *
  10  * FIXME: deflate transforms will require up to a total of about 436k of kernel
  11  * memory on i386 (390k for compression, the rest for decompression), as the
  12  * current zlib kernel code uses a worst case pre-allocation system by default.
  13  * This needs to be fixed so that the amount of memory required is properly
  14  * related to the  winbits and memlevel parameters.
  15  *
  16  * The default winbits of 11 should suit most packets, and it may be something
  17  * to configure on a per-tfm basis in the future.
  18  *
  19  * Currently, compression history is not maintained between tfm calls, as
  20  * it is not needed for IPCOMP and keeps the code simpler.  It can be
  21  * implemented if someone wants it.
  22  */
  23 #include <linux/init.h>
  24 #include <linux/module.h>
  25 #include <linux/crypto.h>
  26 #include <linux/zlib.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/mm.h>
  30 #include <linux/net.h>
  31 #include <crypto/internal/scompress.h>
  32
  33 #define DEFLATE_DEF_LEVEL               Z_DEFAULT_COMPRESSION
  34 #define DEFLATE_DEF_WINBITS             11
  35 #define DEFLATE_DEF_MEMLEVEL            MAX_MEM_LEVEL
  36
  37 struct deflate_ctx {
  38         struct z_stream_s comp_stream;
  39         struct z_stream_s decomp_stream;
  40 };
  41
  42 static int deflate_comp_init(struct deflate_ctx *ctx, int format)
  43 {
  44         int ret = 0;
  45         struct z_stream_s *stream = &ctx->comp_stream;
  46
  47         stream->workspace = vzalloc(zlib_deflate_workspacesize(
  48                                     MAX_WBITS, MAX_MEM_LEVEL));
  49         if (!stream->workspace) {
  50                 ret = -ENOMEM;
  51                 goto out;
  52         }
  53         if (format)
  54                 ret = zlib_deflateInit(stream, 3);
  55         else
  56                 ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
  57                                         -DEFLATE_DEF_WINBITS,
  58                                         DEFLATE_DEF_MEMLEVEL,
  59                                         Z_DEFAULT_STRATEGY);
  60         if (ret != Z_OK) {
  61                 ret = -EINVAL;
  62                 goto out_free;
  63         }
  64 out:
  65         return ret;
  66 out_free:
  67         vfree(stream->workspace);
  68         goto out;
  69 }
  70
  71 static int deflate_decomp_init(struct deflate_ctx *ctx, int format)
  72 {
  73         int ret = 0;
  74         struct z_stream_s *stream = &ctx->decomp_stream;
  75
  76         stream->workspace = vzalloc(zlib_inflate_workspacesize());
  77         if (!stream->workspace) {
  78                 ret = -ENOMEM;
  79                 goto out;
  80         }
  81         if (format)
  82                 ret = zlib_inflateInit(stream);
  83         else
  84                 ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
  85         if (ret != Z_OK) {
  86                 ret = -EINVAL;
  87                 goto out_free;
  88         }
  89 out:
  90         return ret;
  91 out_free:
  92         vfree(stream->workspace);
  93         goto out;
  94 }
  95
  96 static void deflate_comp_exit(struct deflate_ctx *ctx)
  97 {
  98         zlib_deflateEnd(&ctx->comp_stream);
  99         vfree(ctx->comp_stream.workspace);
 100 }
 101
 102 static void deflate_decomp_exit(struct deflate_ctx *ctx)
 103 {
 104         zlib_inflateEnd(&ctx->decomp_stream);
 105         vfree(ctx->decomp_stream.workspace);
 106 }
 107
 108 static int __deflate_init(void *ctx, int format)
 109 {
 110         int ret;
 111
 112         ret = deflate_comp_init(ctx, format);
 113         if (ret)
 114                 goto out;
 115         ret = deflate_decomp_init(ctx, format);
 116         if (ret)
 117                 deflate_comp_exit(ctx);
 118 out:
 119         return ret;
 120 }
 121
 122 static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
 123 {
 124         struct deflate_ctx *ctx;
 125         int ret;
 126
 127         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 128         if (!ctx)
 129                 return ERR_PTR(-ENOMEM);
 130
 131         ret = __deflate_init(ctx, format);
 132         if (ret) {
 133                 kfree(ctx);
 134                 return ERR_PTR(ret);
 135         }
 136
 137         return ctx;
 138 }
 139
 140 static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
 141 {
 142         return gen_deflate_alloc_ctx(tfm, 0);
 143 }
 144
 145 static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
 146 {
 147         return gen_deflate_alloc_ctx(tfm, 1);
 148 }
 149
 150 static int deflate_init(struct crypto_tfm *tfm)
 151 {
 152         struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
 153
 154         return __deflate_init(ctx, 0);
 155 }
 156
 157 static void __deflate_exit(void *ctx)
 158 {
 159         deflate_comp_exit(ctx);
 160         deflate_decomp_exit(ctx);
 161 }
 162
 163 static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
 164 {
 165         __deflate_exit(ctx);
 166         kfree_sensitive(ctx);
 167 }
 168
 169 static void deflate_exit(struct crypto_tfm *tfm)
 170 {
 171         struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
 172
 173         __deflate_exit(ctx);
 174 }
 175
 176 static int __deflate_compress(const u8 *src, unsigned int slen,
 177                               u8 *dst, unsigned int *dlen, void *ctx)
 178 {
 179         int ret = 0;
 180         struct deflate_ctx *dctx = ctx;
 181         struct z_stream_s *stream = &dctx->comp_stream;
 182
 183         ret = zlib_deflateReset(stream);
 184         if (ret != Z_OK) {
 185                 ret = -EINVAL;
 186                 goto out;
 187         }
 188
 189         stream->next_in = (u8 *)src;
 190         stream->avail_in = slen;
 191         stream->next_out = (u8 *)dst;
 192         stream->avail_out = *dlen;
 193
 194         ret = zlib_deflate(stream, Z_FINISH);
 195         if (ret != Z_STREAM_END) {
 196                 ret = -EINVAL;
 197                 goto out;
 198         }
 199         ret = 0;
 200         *dlen = stream->total_out;
 201 out:
 202         return ret;
 203 }
 204
 205 static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
 206                             unsigned int slen, u8 *dst, unsigned int *dlen)
 207 {
 208         struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
 209
 210         return __deflate_compress(src, slen, dst, dlen, dctx);
 211 }
 212
 213 static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
 214                              unsigned int slen, u8 *dst, unsigned int *dlen,
 215                              void *ctx)
 216 {
 217         return __deflate_compress(src, slen, dst, dlen, ctx);
 218 }
 219
 220 static int __deflate_decompress(const u8 *src, unsigned int slen,
 221                                 u8 *dst, unsigned int *dlen, void *ctx)
 222 {
 223
 224         int ret = 0;
 225         struct deflate_ctx *dctx = ctx;
 226         struct z_stream_s *stream = &dctx->decomp_stream;
 227
 228         ret = zlib_inflateReset(stream);
 229         if (ret != Z_OK) {
 230                 ret = -EINVAL;
 231                 goto out;
 232         }
 233
 234         stream->next_in = (u8 *)src;
 235         stream->avail_in = slen;
 236         stream->next_out = (u8 *)dst;
 237         stream->avail_out = *dlen;
 238
 239         ret = zlib_inflate(stream, Z_SYNC_FLUSH);
 240         /*
 241          * Work around a bug in zlib, which sometimes wants to taste an extra
 242          * byte when being used in the (undocumented) raw deflate mode.
 243          * (From USAGI).
 244          */
 245         if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
 246                 u8 zerostuff = 0;
 247                 stream->next_in = &zerostuff;
 248                 stream->avail_in = 1;
 249                 ret = zlib_inflate(stream, Z_FINISH);
 250         }
 251         if (ret != Z_STREAM_END) {
 252                 ret = -EINVAL;
 253                 goto out;
 254         }
 255         ret = 0;
 256         *dlen = stream->total_out;
 257 out:
 258         return ret;
 259 }
 260
 261 static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
 262                               unsigned int slen, u8 *dst, unsigned int *dlen)
 263 {
 264         struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
 265
 266         return __deflate_decompress(src, slen, dst, dlen, dctx);
 267 }
 268
 269 static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 270                                unsigned int slen, u8 *dst, unsigned int *dlen,
 271                                void *ctx)
 272 {
 273         return __deflate_decompress(src, slen, dst, dlen, ctx);
 274 }
 275
 276 static struct crypto_alg alg = {
 277         .cra_name               = "deflate",
 278         .cra_driver_name        = "deflate-generic",
 279         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 280         .cra_ctxsize            = sizeof(struct deflate_ctx),
 281         .cra_module             = THIS_MODULE,
 282         .cra_init               = deflate_init,
 283         .cra_exit               = deflate_exit,
 284         .cra_u                  = { .compress = {
 285         .coa_compress           = deflate_compress,
 286         .coa_decompress         = deflate_decompress } }
 287 };
 288
 289 static struct scomp_alg scomp[] = { {
 290         .alloc_ctx              = deflate_alloc_ctx,
 291         .free_ctx               = deflate_free_ctx,
 292         .compress               = deflate_scompress,
 293         .decompress             = deflate_sdecompress,
 294         .base                   = {
 295                 .cra_name       = "deflate",
 296                 .cra_driver_name = "deflate-scomp",
 297                 .cra_module      = THIS_MODULE,
 298         }
 299 }, {
 300         .alloc_ctx              = zlib_deflate_alloc_ctx,
 301         .free_ctx               = deflate_free_ctx,
 302         .compress               = deflate_scompress,
 303         .decompress             = deflate_sdecompress,
 304         .base                   = {
 305                 .cra_name       = "zlib-deflate",
 306                 .cra_driver_name = "zlib-deflate-scomp",
 307                 .cra_module      = THIS_MODULE,
 308         }
 309 } };
 310
 311 static int __init deflate_mod_init(void)
 312 {
 313         int ret;
 314
 315         ret = crypto_register_alg(&alg);
 316         if (ret)
 317                 return ret;
 318
 319         ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
 320         if (ret) {
 321                 crypto_unregister_alg(&alg);
 322                 return ret;
 323         }
 324
 325         return ret;
 326 }
 327
 328 static void __exit deflate_mod_fini(void)
 329 {
 330         crypto_unregister_alg(&alg);
 331         crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
 332 }
 333
 334 subsys_initcall(deflate_mod_init);
 335 module_exit(deflate_mod_fini);
 336
 337 MODULE_LICENSE("GPL");
 338 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
 339 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 340 MODULE_ALIAS_CRYPTO("deflate");