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
deflate_comp_init(struct deflate_ctx * ctx,int format)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
deflate_decomp_init(struct deflate_ctx * ctx,int format)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
deflate_comp_exit(struct deflate_ctx * ctx)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
deflate_decomp_exit(struct deflate_ctx * ctx)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
__deflate_init(void * ctx,int format)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
gen_deflate_alloc_ctx(struct crypto_scomp * tfm,int format)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
deflate_alloc_ctx(struct crypto_scomp * tfm)140 static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
141 {
142 return gen_deflate_alloc_ctx(tfm, 0);
143 }
144
zlib_deflate_alloc_ctx(struct crypto_scomp * tfm)145 static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
146 {
147 return gen_deflate_alloc_ctx(tfm, 1);
148 }
149
deflate_init(struct crypto_tfm * tfm)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
__deflate_exit(void * ctx)157 static void __deflate_exit(void *ctx)
158 {
159 deflate_comp_exit(ctx);
160 deflate_decomp_exit(ctx);
161 }
162
deflate_free_ctx(struct crypto_scomp * tfm,void * ctx)163 static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
164 {
165 __deflate_exit(ctx);
166 kzfree(ctx);
167 }
168
deflate_exit(struct crypto_tfm * tfm)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
__deflate_compress(const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen,void * ctx)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
deflate_compress(struct crypto_tfm * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen)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
deflate_scompress(struct crypto_scomp * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen,void * ctx)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
__deflate_decompress(const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen,void * ctx)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
deflate_decompress(struct crypto_tfm * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen)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
deflate_sdecompress(struct crypto_scomp * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen,void * ctx)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
deflate_mod_init(void)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
deflate_mod_fini(void)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");
341
