| 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 | kzfree(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"); |