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(void) 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 void __deflate_exit(void *ctx) 134 { 135 deflate_comp_exit(ctx); 136 deflate_decomp_exit(ctx); 137 } 138 139 static void deflate_free_ctx(void *ctx) 140 { 141 __deflate_exit(ctx); 142 kfree_sensitive(ctx); 143 } 144 145 static int __deflate_compress(const u8 *src, unsigned int slen, 146 u8 *dst, unsigned int *dlen, void *ctx) 147 { 148 int ret = 0; 149 struct deflate_ctx *dctx = ctx; 150 struct z_stream_s *stream = &dctx->comp_stream; 151 152 ret = zlib_deflateReset(stream); 153 if (ret != Z_OK) { 154 ret = -EINVAL; 155 goto out; 156 } 157 158 stream->next_in = (u8 *)src; 159 stream->avail_in = slen; 160 stream->next_out = (u8 *)dst; 161 stream->avail_out = *dlen; 162 163 ret = zlib_deflate(stream, Z_FINISH); 164 if (ret != Z_STREAM_END) { 165 ret = -EINVAL; 166 goto out; 167 } 168 ret = 0; 169 *dlen = stream->total_out; 170 out: 171 return ret; 172 } 173 174 static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src, 175 unsigned int slen, u8 *dst, unsigned int *dlen, 176 void *ctx) 177 { 178 return __deflate_compress(src, slen, dst, dlen, ctx); 179 } 180 181 static int __deflate_decompress(const u8 *src, unsigned int slen, 182 u8 *dst, unsigned int *dlen, void *ctx) 183 { 184 185 int ret = 0; 186 struct deflate_ctx *dctx = ctx; 187 struct z_stream_s *stream = &dctx->decomp_stream; 188 189 ret = zlib_inflateReset(stream); 190 if (ret != Z_OK) { 191 ret = -EINVAL; 192 goto out; 193 } 194 195 stream->next_in = (u8 *)src; 196 stream->avail_in = slen; 197 stream->next_out = (u8 *)dst; 198 stream->avail_out = *dlen; 199 200 ret = zlib_inflate(stream, Z_SYNC_FLUSH); 201 /* 202 * Work around a bug in zlib, which sometimes wants to taste an extra 203 * byte when being used in the (undocumented) raw deflate mode. 204 * (From USAGI). 205 */ 206 if (ret == Z_OK && !stream->avail_in && stream->avail_out) { 207 u8 zerostuff = 0; 208 stream->next_in = &zerostuff; 209 stream->avail_in = 1; 210 ret = zlib_inflate(stream, Z_FINISH); 211 } 212 if (ret != Z_STREAM_END) { 213 ret = -EINVAL; 214 goto out; 215 } 216 ret = 0; 217 *dlen = stream->total_out; 218 out: 219 return ret; 220 } 221 222 static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src, 223 unsigned int slen, u8 *dst, unsigned int *dlen, 224 void *ctx) 225 { 226 return __deflate_decompress(src, slen, dst, dlen, ctx); 227 } 228 229 static struct scomp_alg scomp = { 230 .alloc_ctx = deflate_alloc_ctx, 231 .free_ctx = deflate_free_ctx, 232 .compress = deflate_scompress, 233 .decompress = deflate_sdecompress, 234 .base = { 235 .cra_name = "deflate", 236 .cra_driver_name = "deflate-scomp", 237 .cra_module = THIS_MODULE, 238 } 239 }; 240 241 static int __init deflate_mod_init(void) 242 { 243 return crypto_register_scomp(&scomp); 244 } 245 246 static void __exit deflate_mod_fini(void) 247 { 248 crypto_unregister_scomp(&scomp); 249 } 250 251 subsys_initcall(deflate_mod_init); 252 module_exit(deflate_mod_fini); 253 254 MODULE_LICENSE("GPL"); 255 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); 256 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); 257 MODULE_ALIAS_CRYPTO("deflate"); 258 MODULE_ALIAS_CRYPTO("deflate-generic"); 259