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
37struct deflate_ctx {
38	struct z_stream_s comp_stream;
39	struct z_stream_s decomp_stream;
40};
41
42static 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	}
60out:
61	return ret;
62out_free:
63	vfree(stream->workspace);
64	goto out;
65}
66
67static 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	}
82out:
83	return ret;
84out_free:
85	vfree(stream->workspace);
86	goto out;
87}
88
89static void deflate_comp_exit(struct deflate_ctx *ctx)
90{
91	zlib_deflateEnd(&ctx->comp_stream);
92	vfree(ctx->comp_stream.workspace);
93}
94
95static void deflate_decomp_exit(struct deflate_ctx *ctx)
96{
97	zlib_inflateEnd(&ctx->decomp_stream);
98	vfree(ctx->decomp_stream.workspace);
99}
100
101static 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);
111out:
112	return ret;
113}
114
115static 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
133static 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
140static void __deflate_exit(void *ctx)
141{
142	deflate_comp_exit(ctx);
143	deflate_decomp_exit(ctx);
144}
145
146static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
147{
148	__deflate_exit(ctx);
149	kfree_sensitive(ctx);
150}
151
152static void deflate_exit(struct crypto_tfm *tfm)
153{
154	struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
155
156	__deflate_exit(ctx);
157}
158
159static 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;
184out:
185	return ret;
186}
187
188static 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
196static 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
203static 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;
240out:
241	return ret;
242}
243
244static 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
252static 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
259static 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
272static 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
284static 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
301static void __exit deflate_mod_fini(void)
302{
303	crypto_unregister_alg(&alg);
304	crypto_unregister_scomp(&scomp);
305}
306
307subsys_initcall(deflate_mod_init);
308module_exit(deflate_mod_fini);
309
310MODULE_LICENSE("GPL");
311MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
312MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
313MODULE_ALIAS_CRYPTO("deflate");
314