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#include <crypto/internal/scompress.h>
36
37#define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION
38#define DEFLATE_DEF_WINBITS 11
39#define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
40
41struct deflate_ctx {
42 struct z_stream_s comp_stream;
43 struct z_stream_s decomp_stream;
44};
45
46static int deflate_comp_init(struct deflate_ctx *ctx, int format)
47{
48 int ret = 0;
49 struct z_stream_s *stream = &ctx->comp_stream;
50
51 stream->workspace = vzalloc(zlib_deflate_workspacesize(
52 MAX_WBITS, MAX_MEM_LEVEL));
53 if (!stream->workspace) {
54 ret = -ENOMEM;
55 goto out;
56 }
57 if (format)
58 ret = zlib_deflateInit(stream, 3);
59 else
60 ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
61 -DEFLATE_DEF_WINBITS,
62 DEFLATE_DEF_MEMLEVEL,
63 Z_DEFAULT_STRATEGY);
64 if (ret != Z_OK) {
65 ret = -EINVAL;
66 goto out_free;
67 }
68out:
69 return ret;
70out_free:
71 vfree(stream->workspace);
72 goto out;
73}
74
75static int deflate_decomp_init(struct deflate_ctx *ctx, int format)
76{
77 int ret = 0;
78 struct z_stream_s *stream = &ctx->decomp_stream;
79
80 stream->workspace = vzalloc(zlib_inflate_workspacesize());
81 if (!stream->workspace) {
82 ret = -ENOMEM;
83 goto out;
84 }
85 if (format)
86 ret = zlib_inflateInit(stream);
87 else
88 ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
89 if (ret != Z_OK) {
90 ret = -EINVAL;
91 goto out_free;
92 }
93out:
94 return ret;
95out_free:
96 vfree(stream->workspace);
97 goto out;
98}
99
100static void deflate_comp_exit(struct deflate_ctx *ctx)
101{
102 zlib_deflateEnd(&ctx->comp_stream);
103 vfree(ctx->comp_stream.workspace);
104}
105
106static void deflate_decomp_exit(struct deflate_ctx *ctx)
107{
108 zlib_inflateEnd(&ctx->decomp_stream);
109 vfree(ctx->decomp_stream.workspace);
110}
111
112static int __deflate_init(void *ctx, int format)
113{
114 int ret;
115
116 ret = deflate_comp_init(ctx, format);
117 if (ret)
118 goto out;
119 ret = deflate_decomp_init(ctx, format);
120 if (ret)
121 deflate_comp_exit(ctx);
122out:
123 return ret;
124}
125
126static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
127{
128 struct deflate_ctx *ctx;
129 int ret;
130
131 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
132 if (!ctx)
133 return ERR_PTR(-ENOMEM);
134
135 ret = __deflate_init(ctx, format);
136 if (ret) {
137 kfree(ctx);
138 return ERR_PTR(ret);
139 }
140
141 return ctx;
142}
143
144static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
145{
146 return gen_deflate_alloc_ctx(tfm, 0);
147}
148
149static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
150{
151 return gen_deflate_alloc_ctx(tfm, 1);
152}
153
154static int deflate_init(struct crypto_tfm *tfm)
155{
156 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
157
158 return __deflate_init(ctx, 0);
159}
160
161static void __deflate_exit(void *ctx)
162{
163 deflate_comp_exit(ctx);
164 deflate_decomp_exit(ctx);
165}
166
167static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
168{
169 __deflate_exit(ctx);
170 kzfree(ctx);
171}
172
173static void deflate_exit(struct crypto_tfm *tfm)
174{
175 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
176
177 __deflate_exit(ctx);
178}
179
180static int __deflate_compress(const u8 *src, unsigned int slen,
181 u8 *dst, unsigned int *dlen, void *ctx)
182{
183 int ret = 0;
184 struct deflate_ctx *dctx = ctx;
185 struct z_stream_s *stream = &dctx->comp_stream;
186
187 ret = zlib_deflateReset(stream);
188 if (ret != Z_OK) {
189 ret = -EINVAL;
190 goto out;
191 }
192
193 stream->next_in = (u8 *)src;
194 stream->avail_in = slen;
195 stream->next_out = (u8 *)dst;
196 stream->avail_out = *dlen;
197
198 ret = zlib_deflate(stream, Z_FINISH);
199 if (ret != Z_STREAM_END) {
200 ret = -EINVAL;
201 goto out;
202 }
203 ret = 0;
204 *dlen = stream->total_out;
205out:
206 return ret;
207}
208
209static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
210 unsigned int slen, u8 *dst, unsigned int *dlen)
211{
212 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
213
214 return __deflate_compress(src, slen, dst, dlen, dctx);
215}
216
217static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
218 unsigned int slen, u8 *dst, unsigned int *dlen,
219 void *ctx)
220{
221 return __deflate_compress(src, slen, dst, dlen, ctx);
222}
223
224static int __deflate_decompress(const u8 *src, unsigned int slen,
225 u8 *dst, unsigned int *dlen, void *ctx)
226{
227
228 int ret = 0;
229 struct deflate_ctx *dctx = ctx;
230 struct z_stream_s *stream = &dctx->decomp_stream;
231
232 ret = zlib_inflateReset(stream);
233 if (ret != Z_OK) {
234 ret = -EINVAL;
235 goto out;
236 }
237
238 stream->next_in = (u8 *)src;
239 stream->avail_in = slen;
240 stream->next_out = (u8 *)dst;
241 stream->avail_out = *dlen;
242
243 ret = zlib_inflate(stream, Z_SYNC_FLUSH);
244 /*
245 * Work around a bug in zlib, which sometimes wants to taste an extra
246 * byte when being used in the (undocumented) raw deflate mode.
247 * (From USAGI).
248 */
249 if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
250 u8 zerostuff = 0;
251 stream->next_in = &zerostuff;
252 stream->avail_in = 1;
253 ret = zlib_inflate(stream, Z_FINISH);
254 }
255 if (ret != Z_STREAM_END) {
256 ret = -EINVAL;
257 goto out;
258 }
259 ret = 0;
260 *dlen = stream->total_out;
261out:
262 return ret;
263}
264
265static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
266 unsigned int slen, u8 *dst, unsigned int *dlen)
267{
268 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
269
270 return __deflate_decompress(src, slen, dst, dlen, dctx);
271}
272
273static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
274 unsigned int slen, u8 *dst, unsigned int *dlen,
275 void *ctx)
276{
277 return __deflate_decompress(src, slen, dst, dlen, ctx);
278}
279
280static struct crypto_alg alg = {
281 .cra_name = "deflate",
282 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
283 .cra_ctxsize = sizeof(struct deflate_ctx),
284 .cra_module = THIS_MODULE,
285 .cra_init = deflate_init,
286 .cra_exit = deflate_exit,
287 .cra_u = { .compress = {
288 .coa_compress = deflate_compress,
289 .coa_decompress = deflate_decompress } }
290};
291
292static struct scomp_alg scomp[] = { {
293 .alloc_ctx = deflate_alloc_ctx,
294 .free_ctx = deflate_free_ctx,
295 .compress = deflate_scompress,
296 .decompress = deflate_sdecompress,
297 .base = {
298 .cra_name = "deflate",
299 .cra_driver_name = "deflate-scomp",
300 .cra_module = THIS_MODULE,
301 }
302}, {
303 .alloc_ctx = zlib_deflate_alloc_ctx,
304 .free_ctx = deflate_free_ctx,
305 .compress = deflate_scompress,
306 .decompress = deflate_sdecompress,
307 .base = {
308 .cra_name = "zlib-deflate",
309 .cra_driver_name = "zlib-deflate-scomp",
310 .cra_module = THIS_MODULE,
311 }
312} };
313
314static int __init deflate_mod_init(void)
315{
316 int ret;
317
318 ret = crypto_register_alg(&alg);
319 if (ret)
320 return ret;
321
322 ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
323 if (ret) {
324 crypto_unregister_alg(&alg);
325 return ret;
326 }
327
328 return ret;
329}
330
331static void __exit deflate_mod_fini(void)
332{
333 crypto_unregister_alg(&alg);
334 crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
335}
336
337module_init(deflate_mod_init);
338module_exit(deflate_mod_fini);
339
340MODULE_LICENSE("GPL");
341MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
342MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
343MODULE_ALIAS_CRYPTO("deflate");
344