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 #define PREBOOT
35 #include "lzo/lzo1x_decompress_safe.c"
36 #else
37 #include <linux/decompress/unlzo.h>
38 #endif
39
40 #include <linux/types.h>
41 #include <linux/lzo.h>
42 #include <linux/decompress/mm.h>
43
44 #include <linux/compiler.h>
45 #include <asm/unaligned.h>
46
47 static const unsigned char lzop_magic[] = {
48 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
49
50 #define LZO_BLOCK_SIZE (256*1024l)
51 #define HEADER_HAS_FILTER 0x00000800L
52 #define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4)
53 #define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)
54
parse_header(u8 * input,long * skip,long in_len)55 STATIC inline long INIT parse_header(u8 *input, long *skip, long in_len)
56 {
57 int l;
58 u8 *parse = input;
59 u8 *end = input + in_len;
60 u8 level = 0;
61 u16 version;
62
63 /*
64 * Check that there's enough input to possibly have a valid header.
65 * Then it is possible to parse several fields until the minimum
66 * size may have been used.
67 */
68 if (in_len < HEADER_SIZE_MIN)
69 return 0;
70
71 /* read magic: 9 first bits */
72 for (l = 0; l < 9; l++) {
73 if (*parse++ != lzop_magic[l])
74 return 0;
75 }
76 /* get version (2bytes), skip library version (2),
77 * 'need to be extracted' version (2) and
78 * method (1) */
79 version = get_unaligned_be16(parse);
80 parse += 7;
81 if (version >= 0x0940)
82 level = *parse++;
83 if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
84 parse += 8; /* flags + filter info */
85 else
86 parse += 4; /* flags */
87
88 /*
89 * At least mode, mtime_low, filename length, and checksum must
90 * be left to be parsed. If also mtime_high is present, it's OK
91 * because the next input buffer check is after reading the
92 * filename length.
93 */
94 if (end - parse < 8 + 1 + 4)
95 return 0;
96
97 /* skip mode and mtime_low */
98 parse += 8;
99 if (version >= 0x0940)
100 parse += 4; /* skip mtime_high */
101
102 l = *parse++;
103 /* don't care about the file name, and skip checksum */
104 if (end - parse < l + 4)
105 return 0;
106 parse += l + 4;
107
108 *skip = parse - input;
109 return 1;
110 }
111
unlzo(u8 * input,long in_len,long (* fill)(void *,unsigned long),long (* flush)(void *,unsigned long),u8 * output,long * posp,void (* error)(char * x))112 STATIC int INIT unlzo(u8 *input, long in_len,
113 long (*fill)(void *, unsigned long),
114 long (*flush)(void *, unsigned long),
115 u8 *output, long *posp,
116 void (*error) (char *x))
117 {
118 u8 r = 0;
119 long skip = 0;
120 u32 src_len, dst_len;
121 size_t tmp;
122 u8 *in_buf, *in_buf_save, *out_buf;
123 int ret = -1;
124
125 if (output) {
126 out_buf = output;
127 } else if (!flush) {
128 error("NULL output pointer and no flush function provided");
129 goto exit;
130 } else {
131 out_buf = malloc(LZO_BLOCK_SIZE);
132 if (!out_buf) {
133 error("Could not allocate output buffer");
134 goto exit;
135 }
136 }
137
138 if (input && fill) {
139 error("Both input pointer and fill function provided, don't know what to do");
140 goto exit_1;
141 } else if (input) {
142 in_buf = input;
143 } else if (!fill) {
144 error("NULL input pointer and missing fill function");
145 goto exit_1;
146 } else {
147 in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
148 if (!in_buf) {
149 error("Could not allocate input buffer");
150 goto exit_1;
151 }
152 }
153 in_buf_save = in_buf;
154
155 if (posp)
156 *posp = 0;
157
158 if (fill) {
159 /*
160 * Start from in_buf + HEADER_SIZE_MAX to make it possible
161 * to use memcpy() to copy the unused data to the beginning
162 * of the buffer. This way memmove() isn't needed which
163 * is missing from pre-boot environments of most archs.
164 */
165 in_buf += HEADER_SIZE_MAX;
166 in_len = fill(in_buf, HEADER_SIZE_MAX);
167 }
168
169 if (!parse_header(in_buf, &skip, in_len)) {
170 error("invalid header");
171 goto exit_2;
172 }
173 in_buf += skip;
174 in_len -= skip;
175
176 if (fill) {
177 /* Move the unused data to the beginning of the buffer. */
178 memcpy(in_buf_save, in_buf, in_len);
179 in_buf = in_buf_save;
180 }
181
182 if (posp)
183 *posp = skip;
184
185 for (;;) {
186 /* read uncompressed block size */
187 if (fill && in_len < 4) {
188 skip = fill(in_buf + in_len, 4 - in_len);
189 if (skip > 0)
190 in_len += skip;
191 }
192 if (in_len < 4) {
193 error("file corrupted");
194 goto exit_2;
195 }
196 dst_len = get_unaligned_be32(in_buf);
197 in_buf += 4;
198 in_len -= 4;
199
200 /* exit if last block */
201 if (dst_len == 0) {
202 if (posp)
203 *posp += 4;
204 break;
205 }
206
207 if (dst_len > LZO_BLOCK_SIZE) {
208 error("dest len longer than block size");
209 goto exit_2;
210 }
211
212 /* read compressed block size, and skip block checksum info */
213 if (fill && in_len < 8) {
214 skip = fill(in_buf + in_len, 8 - in_len);
215 if (skip > 0)
216 in_len += skip;
217 }
218 if (in_len < 8) {
219 error("file corrupted");
220 goto exit_2;
221 }
222 src_len = get_unaligned_be32(in_buf);
223 in_buf += 8;
224 in_len -= 8;
225
226 if (src_len <= 0 || src_len > dst_len) {
227 error("file corrupted");
228 goto exit_2;
229 }
230
231 /* decompress */
232 if (fill && in_len < src_len) {
233 skip = fill(in_buf + in_len, src_len - in_len);
234 if (skip > 0)
235 in_len += skip;
236 }
237 if (in_len < src_len) {
238 error("file corrupted");
239 goto exit_2;
240 }
241 tmp = dst_len;
242
243 /* When the input data is not compressed at all,
244 * lzo1x_decompress_safe will fail, so call memcpy()
245 * instead */
246 if (unlikely(dst_len == src_len))
247 memcpy(out_buf, in_buf, src_len);
248 else {
249 r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
250 out_buf, &tmp);
251
252 if (r != LZO_E_OK || dst_len != tmp) {
253 error("Compressed data violation");
254 goto exit_2;
255 }
256 }
257
258 if (flush && flush(out_buf, dst_len) != dst_len)
259 goto exit_2;
260 if (output)
261 out_buf += dst_len;
262 if (posp)
263 *posp += src_len + 12;
264
265 in_buf += src_len;
266 in_len -= src_len;
267 if (fill) {
268 /*
269 * If there happens to still be unused data left in
270 * in_buf, move it to the beginning of the buffer.
271 * Use a loop to avoid memmove() dependency.
272 */
273 if (in_len > 0)
274 for (skip = 0; skip < in_len; ++skip)
275 in_buf_save[skip] = in_buf[skip];
276 in_buf = in_buf_save;
277 }
278 }
279
280 ret = 0;
281 exit_2:
282 if (!input)
283 free(in_buf_save);
284 exit_1:
285 if (!output)
286 free(out_buf);
287 exit:
288 return ret;
289 }
290
291 #ifdef PREBOOT
__decompress(unsigned char * buf,long len,long (* fill)(void *,unsigned long),long (* flush)(void *,unsigned long),unsigned char * out_buf,long olen,long * pos,void (* error)(char * x))292 STATIC int INIT __decompress(unsigned char *buf, long len,
293 long (*fill)(void*, unsigned long),
294 long (*flush)(void*, unsigned long),
295 unsigned char *out_buf, long olen,
296 long *pos,
297 void (*error)(char *x))
298 {
299 return unlzo(buf, len, fill, flush, out_buf, pos, error);
300 }
301 #endif
302