1 // SPDX-License-Identifier: GPL-2.0-or-later
5 * Deflate algorithm (RFC 1951), implemented here primarily for use
6 * by IPCOMP (RFC 3173 & RFC 2394).
8 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
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.
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.
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.
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>
30 #include <linux/net.h>
31 #include <crypto/internal/scompress.h>
33 #define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION
34 #define DEFLATE_DEF_WINBITS 11
35 #define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
38 struct z_stream_s comp_stream;
39 struct z_stream_s decomp_stream;
42 static int deflate_comp_init(struct deflate_ctx *ctx, int format)
45 struct z_stream_s *stream = &ctx->comp_stream;
47 stream->workspace = vzalloc(zlib_deflate_workspacesize(
48 MAX_WBITS, MAX_MEM_LEVEL));
49 if (!stream->workspace) {
54 ret = zlib_deflateInit(stream, 3);
56 ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
67 vfree(stream->workspace);
71 static int deflate_decomp_init(struct deflate_ctx *ctx, int format)
74 struct z_stream_s *stream = &ctx->decomp_stream;
76 stream->workspace = vzalloc(zlib_inflate_workspacesize());
77 if (!stream->workspace) {
82 ret = zlib_inflateInit(stream);
84 ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
92 vfree(stream->workspace);
96 static void deflate_comp_exit(struct deflate_ctx *ctx)
98 zlib_deflateEnd(&ctx->comp_stream);
99 vfree(ctx->comp_stream.workspace);
102 static void deflate_decomp_exit(struct deflate_ctx *ctx)
104 zlib_inflateEnd(&ctx->decomp_stream);
105 vfree(ctx->decomp_stream.workspace);
108 static int __deflate_init(void *ctx, int format)
112 ret = deflate_comp_init(ctx, format);
115 ret = deflate_decomp_init(ctx, format);
117 deflate_comp_exit(ctx);
122 static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
124 struct deflate_ctx *ctx;
127 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
129 return ERR_PTR(-ENOMEM);
131 ret = __deflate_init(ctx, format);
140 static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
142 return gen_deflate_alloc_ctx(tfm, 0);
145 static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
147 return gen_deflate_alloc_ctx(tfm, 1);
150 static int deflate_init(struct crypto_tfm *tfm)
152 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
154 return __deflate_init(ctx, 0);
157 static void __deflate_exit(void *ctx)
159 deflate_comp_exit(ctx);
160 deflate_decomp_exit(ctx);
163 static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
166 kfree_sensitive(ctx);
169 static void deflate_exit(struct crypto_tfm *tfm)
171 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
176 static int __deflate_compress(const u8 *src, unsigned int slen,
177 u8 *dst, unsigned int *dlen, void *ctx)
180 struct deflate_ctx *dctx = ctx;
181 struct z_stream_s *stream = &dctx->comp_stream;
183 ret = zlib_deflateReset(stream);
189 stream->next_in = (u8 *)src;
190 stream->avail_in = slen;
191 stream->next_out = (u8 *)dst;
192 stream->avail_out = *dlen;
194 ret = zlib_deflate(stream, Z_FINISH);
195 if (ret != Z_STREAM_END) {
200 *dlen = stream->total_out;
205 static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
206 unsigned int slen, u8 *dst, unsigned int *dlen)
208 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
210 return __deflate_compress(src, slen, dst, dlen, dctx);
213 static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
214 unsigned int slen, u8 *dst, unsigned int *dlen,
217 return __deflate_compress(src, slen, dst, dlen, ctx);
220 static int __deflate_decompress(const u8 *src, unsigned int slen,
221 u8 *dst, unsigned int *dlen, void *ctx)
225 struct deflate_ctx *dctx = ctx;
226 struct z_stream_s *stream = &dctx->decomp_stream;
228 ret = zlib_inflateReset(stream);
234 stream->next_in = (u8 *)src;
235 stream->avail_in = slen;
236 stream->next_out = (u8 *)dst;
237 stream->avail_out = *dlen;
239 ret = zlib_inflate(stream, Z_SYNC_FLUSH);
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.
245 if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
247 stream->next_in = &zerostuff;
248 stream->avail_in = 1;
249 ret = zlib_inflate(stream, Z_FINISH);
251 if (ret != Z_STREAM_END) {
256 *dlen = stream->total_out;
261 static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
262 unsigned int slen, u8 *dst, unsigned int *dlen)
264 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
266 return __deflate_decompress(src, slen, dst, dlen, dctx);
269 static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
270 unsigned int slen, u8 *dst, unsigned int *dlen,
273 return __deflate_decompress(src, slen, dst, dlen, ctx);
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 } }
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,
295 .cra_name = "deflate",
296 .cra_driver_name = "deflate-scomp",
297 .cra_module = THIS_MODULE,
300 .alloc_ctx = zlib_deflate_alloc_ctx,
301 .free_ctx = deflate_free_ctx,
302 .compress = deflate_scompress,
303 .decompress = deflate_sdecompress,
305 .cra_name = "zlib-deflate",
306 .cra_driver_name = "zlib-deflate-scomp",
307 .cra_module = THIS_MODULE,
311 static int __init deflate_mod_init(void)
315 ret = crypto_register_alg(&alg);
319 ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
321 crypto_unregister_alg(&alg);
328 static void __exit deflate_mod_fini(void)
330 crypto_unregister_alg(&alg);
331 crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
334 subsys_initcall(deflate_mod_init);
335 module_exit(deflate_mod_fini);
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");