1 /*
2 * LZO decompressor for the Linux kernel. Code borrowed from the lzo
3 * implementation by Markus Franz Xaver Johannes Oberhumer.
4 *
5 * Linux kernel adaptation:
6 * Copyright (C) 2009
7 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
8 *
9 * Original code:
10 * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
11 * All Rights Reserved.
12 *
13 * lzop and the LZO library are free software; you can redistribute them
14 * and/or modify them under the terms of the GNU General Public License as
15 * published by the Free Software Foundation; either version 2 of
16 * the License, or (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; see the file COPYING.
25 * If not, write to the Free Software Foundation, Inc.,
26 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 *
28 * Markus F.X.J. Oberhumer
29 * <markus@oberhumer.com>
30 * http://www.oberhumer.com/opensource/lzop/
31 */
32
33 #ifdef STATIC
34 #include "lzo/lzo1x_decompress_safe.c"
35 #else
36 #include <linux/decompress/unlzo.h>
37 #endif
38
39 #include <linux/types.h>
40 #include <linux/lzo.h>
41 #include <linux/decompress/mm.h>
42
43 #include <linux/compiler.h>
44 #include <asm/unaligned.h>
45
46 static const unsigned char lzop_magic[] = {
47 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
48
49 #define LZO_BLOCK_SIZE (256*1024l)
50 #define HEADER_HAS_FILTER 0x00000800L
51 #define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4)
52 #define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)
53
parse_header(u8 * input,int * skip,int in_len)54 STATIC inline int INIT parse_header(u8 *input, int *skip, int in_len)
55 {
56 int l;
57 u8 *parse = input;
58 u8 *end = input + in_len;
59 u8 level = 0;
60 u16 version;
61
62 /*
63 * Check that there's enough input to possibly have a valid header.
64 * Then it is possible to parse several fields until the minimum
65 * size may have been used.
66 */
67 if (in_len < HEADER_SIZE_MIN)
68 return 0;
69
70 /* read magic: 9 first bits */
71 for (l = 0; l < 9; l++) {
72 if (*parse++ != lzop_magic[l])
73 return 0;
74 }
75 /* get version (2bytes), skip library version (2),
76 * 'need to be extracted' version (2) and
77 * method (1) */
78 version = get_unaligned_be16(parse);
79 parse += 7;
80 if (version >= 0x0940)
81 level = *parse++;
82 if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
83 parse += 8; /* flags + filter info */
84 else
85 parse += 4; /* flags */
86
87 /*
88 * At least mode, mtime_low, filename length, and checksum must
89 * be left to be parsed. If also mtime_high is present, it's OK
90 * because the next input buffer check is after reading the
91 * filename length.
92 */
93 if (end - parse < 8 + 1 + 4)
94 return 0;
95
96 /* skip mode and mtime_low */
97 parse += 8;
98 if (version >= 0x0940)
99 parse += 4; /* skip mtime_high */
100
101 l = *parse++;
102 /* don't care about the file name, and skip checksum */
103 if (end - parse < l + 4)
104 return 0;
105 parse += l + 4;
106
107 *skip = parse - input;
108 return 1;
109 }
110
unlzo(u8 * input,int in_len,int (* fill)(void *,unsigned int),int (* flush)(void *,unsigned int),u8 * output,int * posp,void (* error)(char * x))111 STATIC inline int INIT unlzo(u8 *input, int in_len,
112 int (*fill) (void *, unsigned int),
113 int (*flush) (void *, unsigned int),
114 u8 *output, int *posp,
115 void (*error) (char *x))
116 {
117 u8 r = 0;
118 int skip = 0;
119 u32 src_len, dst_len;
120 size_t tmp;
121 u8 *in_buf, *in_buf_save, *out_buf;
122 int ret = -1;
123
124 if (output) {
125 out_buf = output;
126 } else if (!flush) {
127 error("NULL output pointer and no flush function provided");
128 goto exit;
129 } else {
130 out_buf = malloc(LZO_BLOCK_SIZE);
131 if (!out_buf) {
132 error("Could not allocate output buffer");
133 goto exit;
134 }
135 }
136
137 if (input && fill) {
138 error("Both input pointer and fill function provided, don't know what to do");
139 goto exit_1;
140 } else if (input) {
141 in_buf = input;
142 } else if (!fill) {
143 error("NULL input pointer and missing fill function");
144 goto exit_1;
145 } else {
146 in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
147 if (!in_buf) {
148 error("Could not allocate input buffer");
149 goto exit_1;
150 }
151 }
152 in_buf_save = in_buf;
153
154 if (posp)
155 *posp = 0;
156
157 if (fill) {
158 /*
159 * Start from in_buf + HEADER_SIZE_MAX to make it possible
160 * to use memcpy() to copy the unused data to the beginning
161 * of the buffer. This way memmove() isn't needed which
162 * is missing from pre-boot environments of most archs.
163 */
164 in_buf += HEADER_SIZE_MAX;
165 in_len = fill(in_buf, HEADER_SIZE_MAX);
166 }
167
168 if (!parse_header(in_buf, &skip, in_len)) {
169 error("invalid header");
170 goto exit_2;
171 }
172 in_buf += skip;
173 in_len -= skip;
174
175 if (fill) {
176 /* Move the unused data to the beginning of the buffer. */
177 memcpy(in_buf_save, in_buf, in_len);
178 in_buf = in_buf_save;
179 }
180
181 if (posp)
182 *posp = skip;
183
184 for (;;) {
185 /* read uncompressed block size */
186 if (fill && in_len < 4) {
187 skip = fill(in_buf + in_len, 4 - in_len);
188 if (skip > 0)
189 in_len += skip;
190 }
191 if (in_len < 4) {
192 error("file corrupted");
193 goto exit_2;
194 }
195 dst_len = get_unaligned_be32(in_buf);
196 in_buf += 4;
197 in_len -= 4;
198
199 /* exit if last block */
200 if (dst_len == 0) {
201 if (posp)
202 *posp += 4;
203 break;
204 }
205
206 if (dst_len > LZO_BLOCK_SIZE) {
207 error("dest len longer than block size");
208 goto exit_2;
209 }
210
211 /* read compressed block size, and skip block checksum info */
212 if (fill && in_len < 8) {
213 skip = fill(in_buf + in_len, 8 - in_len);
214 if (skip > 0)
215 in_len += skip;
216 }
217 if (in_len < 8) {
218 error("file corrupted");
219 goto exit_2;
220 }
221 src_len = get_unaligned_be32(in_buf);
222 in_buf += 8;
223 in_len -= 8;
224
225 if (src_len <= 0 || src_len > dst_len) {
226 error("file corrupted");
227 goto exit_2;
228 }
229
230 /* decompress */
231 if (fill && in_len < src_len) {
232 skip = fill(in_buf + in_len, src_len - in_len);
233 if (skip > 0)
234 in_len += skip;
235 }
236 if (in_len < src_len) {
237 error("file corrupted");
238 goto exit_2;
239 }
240 tmp = dst_len;
241
242 /* When the input data is not compressed at all,
243 * lzo1x_decompress_safe will fail, so call memcpy()
244 * instead */
245 if (unlikely(dst_len == src_len))
246 memcpy(out_buf, in_buf, src_len);
247 else {
248 r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
249 out_buf, &tmp);
250
251 if (r != LZO_E_OK || dst_len != tmp) {
252 error("Compressed data violation");
253 goto exit_2;
254 }
255 }
256
257 if (flush && flush(out_buf, dst_len) != dst_len)
258 goto exit_2;
259 if (output)
260 out_buf += dst_len;
261 if (posp)
262 *posp += src_len + 12;
263
264 in_buf += src_len;
265 in_len -= src_len;
266 if (fill) {
267 /*
268 * If there happens to still be unused data left in
269 * in_buf, move it to the beginning of the buffer.
270 * Use a loop to avoid memmove() dependency.
271 */
272 if (in_len > 0)
273 for (skip = 0; skip < in_len; ++skip)
274 in_buf_save[skip] = in_buf[skip];
275 in_buf = in_buf_save;
276 }
277 }
278
279 ret = 0;
280 exit_2:
281 if (!input)
282 free(in_buf_save);
283 exit_1:
284 if (!output)
285 free(out_buf);
286 exit:
287 return ret;
288 }
289
290 #define decompress unlzo
291