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"); 341