Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 | |
| 36 | #define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION |
| 37 | #define DEFLATE_DEF_WINBITS 11 |
| 38 | #define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL |
| 39 | |
| 40 | struct deflate_ctx { |
| 41 | struct z_stream_s comp_stream; |
| 42 | struct z_stream_s decomp_stream; |
| 43 | }; |
| 44 | |
| 45 | static int deflate_comp_init(struct deflate_ctx *ctx) |
| 46 | { |
| 47 | int ret = 0; |
| 48 | struct z_stream_s *stream = &ctx->comp_stream; |
| 49 | |
| 50 | stream->workspace = vzalloc(zlib_deflate_workspacesize( |
| 51 | -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL)); |
| 52 | if (!stream->workspace) { |
| 53 | ret = -ENOMEM; |
| 54 | goto out; |
| 55 | } |
| 56 | ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, |
| 57 | -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL, |
| 58 | Z_DEFAULT_STRATEGY); |
| 59 | if (ret != Z_OK) { |
| 60 | ret = -EINVAL; |
| 61 | goto out_free; |
| 62 | } |
| 63 | out: |
| 64 | return ret; |
| 65 | out_free: |
| 66 | vfree(stream->workspace); |
| 67 | goto out; |
| 68 | } |
| 69 | |
| 70 | static int deflate_decomp_init(struct deflate_ctx *ctx) |
| 71 | { |
| 72 | int ret = 0; |
| 73 | struct z_stream_s *stream = &ctx->decomp_stream; |
| 74 | |
| 75 | stream->workspace = vzalloc(zlib_inflate_workspacesize()); |
| 76 | if (!stream->workspace) { |
| 77 | ret = -ENOMEM; |
| 78 | goto out; |
| 79 | } |
| 80 | ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS); |
| 81 | if (ret != Z_OK) { |
| 82 | ret = -EINVAL; |
| 83 | goto out_free; |
| 84 | } |
| 85 | out: |
| 86 | return ret; |
| 87 | out_free: |
| 88 | vfree(stream->workspace); |
| 89 | goto out; |
| 90 | } |
| 91 | |
| 92 | static void deflate_comp_exit(struct deflate_ctx *ctx) |
| 93 | { |
| 94 | zlib_deflateEnd(&ctx->comp_stream); |
| 95 | vfree(ctx->comp_stream.workspace); |
| 96 | } |
| 97 | |
| 98 | static void deflate_decomp_exit(struct deflate_ctx *ctx) |
| 99 | { |
| 100 | zlib_inflateEnd(&ctx->decomp_stream); |
| 101 | vfree(ctx->decomp_stream.workspace); |
| 102 | } |
| 103 | |
| 104 | static int deflate_init(struct crypto_tfm *tfm) |
| 105 | { |
| 106 | struct deflate_ctx *ctx = crypto_tfm_ctx(tfm); |
| 107 | int ret; |
| 108 | |
| 109 | ret = deflate_comp_init(ctx); |
| 110 | if (ret) |
| 111 | goto out; |
| 112 | ret = deflate_decomp_init(ctx); |
| 113 | if (ret) |
| 114 | deflate_comp_exit(ctx); |
| 115 | out: |
| 116 | return ret; |
| 117 | } |
| 118 | |
| 119 | static void deflate_exit(struct crypto_tfm *tfm) |
| 120 | { |
| 121 | struct deflate_ctx *ctx = crypto_tfm_ctx(tfm); |
| 122 | |
| 123 | deflate_comp_exit(ctx); |
| 124 | deflate_decomp_exit(ctx); |
| 125 | } |
| 126 | |
| 127 | static int deflate_compress(struct crypto_tfm *tfm, const u8 *src, |
| 128 | unsigned int slen, u8 *dst, unsigned int *dlen) |
| 129 | { |
| 130 | int ret = 0; |
| 131 | struct deflate_ctx *dctx = crypto_tfm_ctx(tfm); |
| 132 | struct z_stream_s *stream = &dctx->comp_stream; |
| 133 | |
| 134 | ret = zlib_deflateReset(stream); |
| 135 | if (ret != Z_OK) { |
| 136 | ret = -EINVAL; |
| 137 | goto out; |
| 138 | } |
| 139 | |
| 140 | stream->next_in = (u8 *)src; |
| 141 | stream->avail_in = slen; |
| 142 | stream->next_out = (u8 *)dst; |
| 143 | stream->avail_out = *dlen; |
| 144 | |
| 145 | ret = zlib_deflate(stream, Z_FINISH); |
| 146 | if (ret != Z_STREAM_END) { |
| 147 | ret = -EINVAL; |
| 148 | goto out; |
| 149 | } |
| 150 | ret = 0; |
| 151 | *dlen = stream->total_out; |
| 152 | out: |
| 153 | return ret; |
| 154 | } |
| 155 | |
| 156 | static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src, |
| 157 | unsigned int slen, u8 *dst, unsigned int *dlen) |
| 158 | { |
| 159 | |
| 160 | int ret = 0; |
| 161 | struct deflate_ctx *dctx = crypto_tfm_ctx(tfm); |
| 162 | struct z_stream_s *stream = &dctx->decomp_stream; |
| 163 | |
| 164 | ret = zlib_inflateReset(stream); |
| 165 | if (ret != Z_OK) { |
| 166 | ret = -EINVAL; |
| 167 | goto out; |
| 168 | } |
| 169 | |
| 170 | stream->next_in = (u8 *)src; |
| 171 | stream->avail_in = slen; |
| 172 | stream->next_out = (u8 *)dst; |
| 173 | stream->avail_out = *dlen; |
| 174 | |
| 175 | ret = zlib_inflate(stream, Z_SYNC_FLUSH); |
| 176 | /* |
| 177 | * Work around a bug in zlib, which sometimes wants to taste an extra |
| 178 | * byte when being used in the (undocumented) raw deflate mode. |
| 179 | * (From USAGI). |
| 180 | */ |
| 181 | if (ret == Z_OK && !stream->avail_in && stream->avail_out) { |
| 182 | u8 zerostuff = 0; |
| 183 | stream->next_in = &zerostuff; |
| 184 | stream->avail_in = 1; |
| 185 | ret = zlib_inflate(stream, Z_FINISH); |
| 186 | } |
| 187 | if (ret != Z_STREAM_END) { |
| 188 | ret = -EINVAL; |
| 189 | goto out; |
| 190 | } |
| 191 | ret = 0; |
| 192 | *dlen = stream->total_out; |
| 193 | out: |
| 194 | return ret; |
| 195 | } |
| 196 | |
| 197 | static struct crypto_alg alg = { |
| 198 | .cra_name = "deflate", |
| 199 | .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, |
| 200 | .cra_ctxsize = sizeof(struct deflate_ctx), |
| 201 | .cra_module = THIS_MODULE, |
| 202 | .cra_init = deflate_init, |
| 203 | .cra_exit = deflate_exit, |
| 204 | .cra_u = { .compress = { |
| 205 | .coa_compress = deflate_compress, |
| 206 | .coa_decompress = deflate_decompress } } |
| 207 | }; |
| 208 | |
| 209 | static int __init deflate_mod_init(void) |
| 210 | { |
| 211 | return crypto_register_alg(&alg); |
| 212 | } |
| 213 | |
| 214 | static void __exit deflate_mod_fini(void) |
| 215 | { |
| 216 | crypto_unregister_alg(&alg); |
| 217 | } |
| 218 | |
| 219 | module_init(deflate_mod_init); |
| 220 | module_exit(deflate_mod_fini); |
| 221 | |
| 222 | MODULE_LICENSE("GPL"); |
| 223 | MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); |
| 224 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); |
| 225 | MODULE_ALIAS_CRYPTO("deflate"); |