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)
  43 {
  44         int ret = 0;
  45         struct z_stream_s *stream = &ctx->comp_stream;
  46
  47         stream->workspace = vzalloc(zlib_deflate_workspacesize(
  48                                     -DEFLATE_DEF_WINBITS, MAX_MEM_LEVEL));
  49         if (!stream->workspace) {
  50                 ret = -ENOMEM;
  51                 goto out;
  52         }
  53         ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
  54                                 -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
  55                                 Z_DEFAULT_STRATEGY);
  56         if (ret != Z_OK) {
  57                 ret = -EINVAL;
  58                 goto out_free;
  59         }
  60 out:
  61         return ret;
  62 out_free:
  63         vfree(stream->workspace);
  64         goto out;
  65 }
  66
  67 static int deflate_decomp_init(struct deflate_ctx *ctx)
  68 {
  69         int ret = 0;
  70         struct z_stream_s *stream = &ctx->decomp_stream;
  71
  72         stream->workspace = vzalloc(zlib_inflate_workspacesize());
  73         if (!stream->workspace) {
  74                 ret = -ENOMEM;
  75                 goto out;
  76         }
  77         ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
  78         if (ret != Z_OK) {
  79                 ret = -EINVAL;
  80                 goto out_free;
  81         }
  82 out:
  83         return ret;
  84 out_free:
  85         vfree(stream->workspace);
  86         goto out;
  87 }
  88
  89 static void deflate_comp_exit(struct deflate_ctx *ctx)
  90 {
  91         zlib_deflateEnd(&ctx->comp_stream);
  92         vfree(ctx->comp_stream.workspace);
  93 }
  94
  95 static void deflate_decomp_exit(struct deflate_ctx *ctx)
  96 {
  97         zlib_inflateEnd(&ctx->decomp_stream);
  98         vfree(ctx->decomp_stream.workspace);
  99 }
 100
 101 static int __deflate_init(void *ctx)
 102 {
 103         int ret;
 104
 105         ret = deflate_comp_init(ctx);
 106         if (ret)
 107                 goto out;
 108         ret = deflate_decomp_init(ctx);
 109         if (ret)
 110                 deflate_comp_exit(ctx);
 111 out:
 112         return ret;
 113 }
 114
 115 static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
 116 {
 117         struct deflate_ctx *ctx;
 118         int ret;
 119
 120         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 121         if (!ctx)
 122                 return ERR_PTR(-ENOMEM);
 123
 124         ret = __deflate_init(ctx);
 125         if (ret) {
 126                 kfree(ctx);
 127                 return ERR_PTR(ret);
 128         }
 129
 130         return ctx;
 131 }
 132
 133 static int deflate_init(struct crypto_tfm *tfm)
 134 {
 135         struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
 136
 137         return __deflate_init(ctx);
 138 }
 139
 140 static void __deflate_exit(void *ctx)
 141 {
 142         deflate_comp_exit(ctx);
 143         deflate_decomp_exit(ctx);
 144 }
 145
 146 static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
 147 {
 148         __deflate_exit(ctx);
 149         kfree_sensitive(ctx);
 150 }
 151
 152 static void deflate_exit(struct crypto_tfm *tfm)
 153 {
 154         struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
 155
 156         __deflate_exit(ctx);
 157 }
 158
 159 static int __deflate_compress(const u8 *src, unsigned int slen,
 160                               u8 *dst, unsigned int *dlen, void *ctx)
 161 {
 162         int ret = 0;
 163         struct deflate_ctx *dctx = ctx;
 164         struct z_stream_s *stream = &dctx->comp_stream;
 165
 166         ret = zlib_deflateReset(stream);
 167         if (ret != Z_OK) {
 168                 ret = -EINVAL;
 169                 goto out;
 170         }
 171
 172         stream->next_in = (u8 *)src;
 173         stream->avail_in = slen;
 174         stream->next_out = (u8 *)dst;
 175         stream->avail_out = *dlen;
 176
 177         ret = zlib_deflate(stream, Z_FINISH);
 178         if (ret != Z_STREAM_END) {
 179                 ret = -EINVAL;
 180                 goto out;
 181         }
 182         ret = 0;
 183         *dlen = stream->total_out;
 184 out:
 185         return ret;
 186 }
 187
 188 static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
 189                             unsigned int slen, u8 *dst, unsigned int *dlen)
 190 {
 191         struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
 192
 193         return __deflate_compress(src, slen, dst, dlen, dctx);
 194 }
 195
 196 static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
 197                              unsigned int slen, u8 *dst, unsigned int *dlen,
 198                              void *ctx)
 199 {
 200         return __deflate_compress(src, slen, dst, dlen, ctx);
 201 }
 202
 203 static int __deflate_decompress(const u8 *src, unsigned int slen,
 204                                 u8 *dst, unsigned int *dlen, void *ctx)
 205 {
 206
 207         int ret = 0;
 208         struct deflate_ctx *dctx = ctx;
 209         struct z_stream_s *stream = &dctx->decomp_stream;
 210
 211         ret = zlib_inflateReset(stream);
 212         if (ret != Z_OK) {
 213                 ret = -EINVAL;
 214                 goto out;
 215         }
 216
 217         stream->next_in = (u8 *)src;
 218         stream->avail_in = slen;
 219         stream->next_out = (u8 *)dst;
 220         stream->avail_out = *dlen;
 221
 222         ret = zlib_inflate(stream, Z_SYNC_FLUSH);
 223         /*
 224          * Work around a bug in zlib, which sometimes wants to taste an extra
 225          * byte when being used in the (undocumented) raw deflate mode.
 226          * (From USAGI).
 227          */
 228         if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
 229                 u8 zerostuff = 0;
 230                 stream->next_in = &zerostuff;
 231                 stream->avail_in = 1;
 232                 ret = zlib_inflate(stream, Z_FINISH);
 233         }
 234         if (ret != Z_STREAM_END) {
 235                 ret = -EINVAL;
 236                 goto out;
 237         }
 238         ret = 0;
 239         *dlen = stream->total_out;
 240 out:
 241         return ret;
 242 }
 243
 244 static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
 245                               unsigned int slen, u8 *dst, unsigned int *dlen)
 246 {
 247         struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
 248
 249         return __deflate_decompress(src, slen, dst, dlen, dctx);
 250 }
 251
 252 static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 253                                unsigned int slen, u8 *dst, unsigned int *dlen,
 254                                void *ctx)
 255 {
 256         return __deflate_decompress(src, slen, dst, dlen, ctx);
 257 }
 258
 259 static struct crypto_alg alg = {
 260         .cra_name               = "deflate",
 261         .cra_driver_name        = "deflate-generic",
 262         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 263         .cra_ctxsize            = sizeof(struct deflate_ctx),
 264         .cra_module             = THIS_MODULE,
 265         .cra_init               = deflate_init,
 266         .cra_exit               = deflate_exit,
 267         .cra_u                  = { .compress = {
 268         .coa_compress           = deflate_compress,
 269         .coa_decompress         = deflate_decompress } }
 270 };
 271
 272 static struct scomp_alg scomp = {
 273         .alloc_ctx              = deflate_alloc_ctx,
 274         .free_ctx               = deflate_free_ctx,
 275         .compress               = deflate_scompress,
 276         .decompress             = deflate_sdecompress,
 277         .base                   = {
 278                 .cra_name       = "deflate",
 279                 .cra_driver_name = "deflate-scomp",
 280                 .cra_module      = THIS_MODULE,
 281         }
 282 };
 283
 284 static int __init deflate_mod_init(void)
 285 {
 286         int ret;
 287
 288         ret = crypto_register_alg(&alg);
 289         if (ret)
 290                 return ret;
 291
 292         ret = crypto_register_scomp(&scomp);
 293         if (ret) {
 294                 crypto_unregister_alg(&alg);
 295                 return ret;
 296         }
 297
 298         return ret;
 299 }
 300
 301 static void __exit deflate_mod_fini(void)
 302 {
 303         crypto_unregister_alg(&alg);
 304         crypto_unregister_scomp(&scomp);
 305 }
 306
 307 subsys_initcall(deflate_mod_init);
 308 module_exit(deflate_mod_fini);
 309
 310 MODULE_LICENSE("GPL");
 311 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
 312 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 313 MODULE_ALIAS_CRYPTO("deflate");