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 41 struct deflate_ctx { 42 struct z_stream_s comp_stream; 43 struct z_stream_s decomp_stream; 44 }; 45 46 static 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 } 68 out: 69 return ret; 70 out_free: 71 vfree(stream->workspace); 72 goto out; 73 } 74 75 static 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 } 93 out: 94 return ret; 95 out_free: 96 vfree(stream->workspace); 97 goto out; 98 } 99 100 static void deflate_comp_exit(struct deflate_ctx *ctx) 101 { 102 zlib_deflateEnd(&ctx->comp_stream); 103 vfree(ctx->comp_stream.workspace); 104 } 105 106 static void deflate_decomp_exit(struct deflate_ctx *ctx) 107 { 108 zlib_inflateEnd(&ctx->decomp_stream); 109 vfree(ctx->decomp_stream.workspace); 110 } 111 112 static 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); 122 out: 123 return ret; 124 } 125 126 static 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 } 143 144 static void *deflate_alloc_ctx(struct crypto_scomp *tfm) 145 { 146 return gen_deflate_alloc_ctx(tfm, 0); 147 } 148 149 static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm) 150 { 151 return gen_deflate_alloc_ctx(tfm, 1); 152 } 153 154 static 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 } 160 161 static void __deflate_exit(void *ctx) 162 { 163 deflate_comp_exit(ctx); 164 deflate_decomp_exit(ctx); 165 } 166 167 static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx) 168 { 169 __deflate_exit(ctx); 170 kzfree(ctx); 171 } 172 173 static void deflate_exit(struct crypto_tfm *tfm) 174 { 175 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm); 176 177 __deflate_exit(ctx); 178 } 179 180 static 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; 205 out: 206 return ret; 207 } 208 209 static 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 } 216 217 static 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 } 223 224 static 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; 261 out: 262 return ret; 263 } 264 265 static 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 } 272 273 static 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 } 279 280 static 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 }; 291 292 static 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 } }; 313 314 static 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 } 330 331 static void __exit deflate_mod_fini(void) 332 { 333 crypto_unregister_alg(&alg); 334 crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp)); 335 } 336 337 subsys_initcall(deflate_mod_init); 338 module_exit(deflate_mod_fini); 339 340 MODULE_LICENSE("GPL"); 341 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); 342 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); 343 MODULE_ALIAS_CRYPTO("deflate"); 344