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"); 314