summaryrefslogtreecommitdiffstats
path: root/lib/decompress_unlzo.c
blob: 1f439a622076c10d9641ff4173162aea799da33b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * LZO decompressor for the Linux kernel. Code borrowed from the lzo
 * implementation by Markus Franz Xaver Johannes Oberhumer.
 *
 * Linux kernel adaptation:
 * Copyright (C) 2009
 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
 *
 * Original code:
 * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
 * All Rights Reserved.
 *
 * Markus F.X.J. Oberhumer
 * <markus@oberhumer.com>
 * http://www.oberhumer.com/opensource/lzop/
 */

#ifdef STATIC
#define PREBOOT
#include "lzo/lzo1x_decompress_safe.c"
#else
#include <linux/decompress/unlzo.h>
#endif

#include <linux/types.h>
#include <linux/lzo.h>
#include <linux/decompress/mm.h>

#include <linux/compiler.h>
#include <asm/unaligned.h>

static const unsigned char lzop_magic[] = {
	0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };

#define LZO_BLOCK_SIZE        (256*1024l)
#define HEADER_HAS_FILTER      0x00000800L
#define HEADER_SIZE_MIN       (9 + 7     + 4 + 8     + 1       + 4)
#define HEADER_SIZE_MAX       (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)

STATIC inline long INIT parse_header(u8 *input, long *skip, long in_len)
{
	int l;
	u8 *parse = input;
	u8 *end = input + in_len;
	u8 level = 0;
	u16 version;

	/*
	 * Check that there's enough input to possibly have a valid header.
	 * Then it is possible to parse several fields until the minimum
	 * size may have been used.
	 */
	if (in_len < HEADER_SIZE_MIN)
		return 0;

	/* read magic: 9 first bits */
	for (l = 0; l < 9; l++) {
		if (*parse++ != lzop_magic[l])
			return 0;
	}
	/* get version (2bytes), skip library version (2),
	 * 'need to be extracted' version (2) and
	 * method (1) */
	version = get_unaligned_be16(parse);
	parse += 7;
	if (version >= 0x0940)
		level = *parse++;
	if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
		parse += 8; /* flags + filter info */
	else
		parse += 4; /* flags */

	/*
	 * At least mode, mtime_low, filename length, and checksum must
	 * be left to be parsed. If also mtime_high is present, it's OK
	 * because the next input buffer check is after reading the
	 * filename length.
	 */
	if (end - parse < 8 + 1 + 4)
		return 0;

	/* skip mode and mtime_low */
	parse += 8;
	if (version >= 0x0940)
		parse += 4;	/* skip mtime_high */

	l = *parse++;
	/* don't care about the file name, and skip checksum */
	if (end - parse < l + 4)
		return 0;
	parse += l + 4;

	*skip = parse - input;
	return 1;
}

STATIC int INIT unlzo(u8 *input, long in_len,
				long (*fill)(void *, unsigned long),
				long (*flush)(void *, unsigned long),
				u8 *output, long *posp,
				void (*error) (char *x))
{
	u8 r = 0;
	long skip = 0;
	u32 src_len, dst_len;
	size_t tmp;
	u8 *in_buf, *in_buf_save, *out_buf;
	int ret = -1;

	if (output) {
		out_buf = output;
	} else if (!flush) {
		error("NULL output pointer and no flush function provided");
		goto exit;
	} else {
		out_buf = malloc(LZO_BLOCK_SIZE);
		if (!out_buf) {
			error("Could not allocate output buffer");
			goto exit;
		}
	}

	if (input && fill) {
		error("Both input pointer and fill function provided, don't know what to do");
		goto exit_1;
	} else if (input) {
		in_buf = input;
	} else if (!fill) {
		error("NULL input pointer and missing fill function");
		goto exit_1;
	} else {
		in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
		if (!in_buf) {
			error("Could not allocate input buffer");
			goto exit_1;
		}
	}
	in_buf_save = in_buf;

	if (posp)
		*posp = 0;

	if (fill) {
		/*
		 * Start from in_buf + HEADER_SIZE_MAX to make it possible
		 * to use memcpy() to copy the unused data to the beginning
		 * of the buffer. This way memmove() isn't needed which
		 * is missing from pre-boot environments of most archs.
		 */
		in_buf += HEADER_SIZE_MAX;
		in_len = fill(in_buf, HEADER_SIZE_MAX);
	}

	if (!parse_header(in_buf, &skip, in_len)) {
		error("invalid header");
		goto exit_2;
	}
	in_buf += skip;
	in_len -= skip;

	if (fill) {
		/* Move the unused data to the beginning of the buffer. */
		memcpy(in_buf_save, in_buf, in_len);
		in_buf = in_buf_save;
	}

	if (posp)
		*posp = skip;

	for (;;) {
		/* read uncompressed block size */
		if (fill && in_len < 4) {
			skip = fill(in_buf + in_len, 4 - in_len);
			if (skip > 0)
				in_len += skip;
		}
		if (in_len < 4) {
			error("file corrupted");
			goto exit_2;
		}
		dst_len = get_unaligned_be32(in_buf);
		in_buf += 4;
		in_len -= 4;

		/* exit if last block */
		if (dst_len == 0) {
			if (posp)
				*posp += 4;
			break;
		}

		if (dst_len > LZO_BLOCK_SIZE) {
			error("dest len longer than block size");
			goto exit_2;
		}

		/* read compressed block size, and skip block checksum info */
		if (fill && in_len < 8) {
			skip = fill(in_buf + in_len, 8 - in_len);
			if (skip > 0)
				in_len += skip;
		}
		if (in_len < 8) {
			error("file corrupted");
			goto exit_2;
		}
		src_len = get_unaligned_be32(in_buf);
		in_buf += 8;
		in_len -= 8;

		if (src_len <= 0 || src_len > dst_len) {
			error("file corrupted");
			goto exit_2;
		}

		/* decompress */
		if (fill && in_len < src_len) {
			skip = fill(in_buf + in_len, src_len - in_len);
			if (skip > 0)
				in_len += skip;
		}
		if (in_len < src_len) {
			error("file corrupted");
			goto exit_2;
		}
		tmp = dst_len;

		/* When the input data is not compressed at all,
		 * lzo1x_decompress_safe will fail, so call memcpy()
		 * instead */
		if (unlikely(dst_len == src_len))
			memcpy(out_buf, in_buf, src_len);
		else {
			r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
						out_buf, &tmp);

			if (r != LZO_E_OK || dst_len != tmp) {
				error("Compressed data violation");
				goto exit_2;
			}
		}

		if (flush && flush(out_buf, dst_len) != dst_len)
			goto exit_2;
		if (output)
			out_buf += dst_len;
		if (posp)
			*posp += src_len + 12;

		in_buf += src_len;
		in_len -= src_len;
		if (fill) {
			/*
			 * If there happens to still be unused data left in
			 * in_buf, move it to the beginning of the buffer.
			 * Use a loop to avoid memmove() dependency.
			 */
			if (in_len > 0)
				for (skip = 0; skip < in_len; ++skip)
					in_buf_save[skip] = in_buf[skip];
			in_buf = in_buf_save;
		}
	}

	ret = 0;
exit_2:
	if (!input)
		free(in_buf_save);
exit_1:
	if (!output)
		free(out_buf);
exit:
	return ret;
}

#ifdef PREBOOT
STATIC int INIT __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))
{
	return unlzo(buf, len, fill, flush, out_buf, pos, error);
}
#endif
OpenPOWER on IntegriCloud