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(struct crypto_scomp *tfm)
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 int deflate_init(struct crypto_tfm *tfm)
134 {
135 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
136
137 return __deflate_init(ctx);
138 }
139
140 static void __deflate_exit(void *ctx)
141 {
142 deflate_comp_exit(ctx);
143 deflate_decomp_exit(ctx);
144 }
145
146 static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
147 {
148 __deflate_exit(ctx);
149 kfree_sensitive(ctx);
150 }
151
152 static void deflate_exit(struct crypto_tfm *tfm)
153 {
154 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
155
156 __deflate_exit(ctx);
157 }
158
159 static int __deflate_compress(const u8 *src, unsigned int slen,
160 u8 *dst, unsigned int *dlen, void *ctx)
161 {
162 int ret = 0;
163 struct deflate_ctx *dctx = ctx;
164 struct z_stream_s *stream = &dctx->comp_stream;
165
166 ret = zlib_deflateReset(stream);
167 if (ret != Z_OK) {
168 ret = -EINVAL;
169 goto out;
170 }
171
172 stream->next_in = (u8 *)src;
173 stream->avail_in = slen;
174 stream->next_out = (u8 *)dst;
175 stream->avail_out = *dlen;
176
177 ret = zlib_deflate(stream, Z_FINISH);
178 if (ret != Z_STREAM_END) {
179 ret = -EINVAL;
180 goto out;
181 }
182 ret = 0;
183 *dlen = stream->total_out;
184 out:
185 return ret;
186 }
187
188 static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
189 unsigned int slen, u8 *dst, unsigned int *dlen)
190 {
191 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
192
193 return __deflate_compress(src, slen, dst, dlen, dctx);
194 }
195
196 static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
197 unsigned int slen, u8 *dst, unsigned int *dlen,
198 void *ctx)
199 {
200 return __deflate_compress(src, slen, dst, dlen, ctx);
201 }
202
203 static int __deflate_decompress(const u8 *src, unsigned int slen,
204 u8 *dst, unsigned int *dlen, void *ctx)
205 {
206
207 int ret = 0;
208 struct deflate_ctx *dctx = ctx;
209 struct z_stream_s *stream = &dctx->decomp_stream;
210
211 ret = zlib_inflateReset(stream);
212 if (ret != Z_OK) {
213 ret = -EINVAL;
214 goto out;
215 }
216
217 stream->next_in = (u8 *)src;
218 stream->avail_in = slen;
219 stream->next_out = (u8 *)dst;
220 stream->avail_out = *dlen;
221
222 ret = zlib_inflate(stream, Z_SYNC_FLUSH);
223 /*
224 * Work around a bug in zlib, which sometimes wants to taste an extra
225 * byte when being used in the (undocumented) raw deflate mode.
226 * (From USAGI).
227 */
228 if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
229 u8 zerostuff = 0;
230 stream->next_in = &zerostuff;
231 stream->avail_in = 1;
232 ret = zlib_inflate(stream, Z_FINISH);
233 }
234 if (ret != Z_STREAM_END) {
235 ret = -EINVAL;
236 goto out;
237 }
238 ret = 0;
239 *dlen = stream->total_out;
240 out:
241 return ret;
242 }
243
244 static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
245 unsigned int slen, u8 *dst, unsigned int *dlen)
246 {
247 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
248
249 return __deflate_decompress(src, slen, dst, dlen, dctx);
250 }
251
252 static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
253 unsigned int slen, u8 *dst, unsigned int *dlen,
254 void *ctx)
255 {
256 return __deflate_decompress(src, slen, dst, dlen, ctx);
257 }
258
259 static struct crypto_alg alg = {
260 .cra_name = "deflate",
261 .cra_driver_name = "deflate-generic",
262 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
263 .cra_ctxsize = sizeof(struct deflate_ctx),
264 .cra_module = THIS_MODULE,
265 .cra_init = deflate_init,
266 .cra_exit = deflate_exit,
267 .cra_u = { .compress = {
268 .coa_compress = deflate_compress,
269 .coa_decompress = deflate_decompress } }
270 };
271
272 static struct scomp_alg scomp = {
273 .alloc_ctx = deflate_alloc_ctx,
274 .free_ctx = deflate_free_ctx,
275 .compress = deflate_scompress,
276 .decompress = deflate_sdecompress,
277 .base = {
278 .cra_name = "deflate",
279 .cra_driver_name = "deflate-scomp",
280 .cra_module = THIS_MODULE,
281 }
282 };
283
284 static int __init deflate_mod_init(void)
285 {
286 int ret;
287
288 ret = crypto_register_alg(&alg);
289 if (ret)
290 return ret;
291
292 ret = crypto_register_scomp(&scomp);
293 if (ret) {
294 crypto_unregister_alg(&alg);
295 return ret;
296 }
297
298 return ret;
299 }
300
301 static void __exit deflate_mod_fini(void)
302 {
303 crypto_unregister_alg(&alg);
304 crypto_unregister_scomp(&scomp);
305 }
306
307 subsys_initcall(deflate_mod_init);
308 module_exit(deflate_mod_fini);
309
310 MODULE_LICENSE("GPL");
311 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
312 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
313 MODULE_ALIAS_CRYPTO("deflate");
314 MODULE_ALIAS_CRYPTO("deflate-generic");
315
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