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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * LZO decompressor for the Linux kernel. Code borrowed from the lzo
4 * implementation by Markus Franz Xaver Johannes Oberhumer.
5 *
6 * Linux kernel adaptation:
7 * Copyright (C) 2009
8 * Albin Tonnerre, Free Electrons <[email protected]>
9 *
10 * Original code:
11 * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
12 * All Rights Reserved.
13 *
14 * Markus F.X.J. Oberhumer
15 * <[email protected]>
16 * http://www.oberhumer.com/opensource/lzop/
17 */
18
19#ifdef STATIC
20#define PREBOOT
21#include "lzo/lzo1x_decompress_safe.c"
22#else
23#include <linux/decompress/unlzo.h>
24#endif
25
26#include <linux/types.h>
27#include <linux/lzo.h>
28#include <linux/decompress/mm.h>
29
30#include <linux/compiler.h>
31#include <linux/unaligned.h>
32
33static const unsigned char lzop_magic[] = {
34 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
35
36#define LZO_BLOCK_SIZE (256*1024l)
37#define HEADER_HAS_FILTER 0x00000800L
38#define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4)
39#define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)
40
41STATIC inline long INIT parse_header(u8 *input, long *skip, long in_len)
42{
43 int l;
44 u8 *parse = input;
45 u8 *end = input + in_len;
46 u16 version;
47
48 /*
49 * Check that there's enough input to possibly have a valid header.
50 * Then it is possible to parse several fields until the minimum
51 * size may have been used.
52 */
53 if (in_len < HEADER_SIZE_MIN)
54 return 0;
55
56 /* read magic: 9 first bits */
57 for (l = 0; l < 9; l++) {
58 if (*parse++ != lzop_magic[l])
59 return 0;
60 }
61 /* get version (2bytes), skip library version (2),
62 * 'need to be extracted' version (2) and
63 * method (1) */
64 version = get_unaligned_be16(parse);
65 parse += 7;
66 if (version >= 0x0940)
67 parse++;
68 if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
69 parse += 8; /* flags + filter info */
70 else
71 parse += 4; /* flags */
72
73 /*
74 * At least mode, mtime_low, filename length, and checksum must
75 * be left to be parsed. If also mtime_high is present, it's OK
76 * because the next input buffer check is after reading the
77 * filename length.
78 */
79 if (end - parse < 8 + 1 + 4)
80 return 0;
81
82 /* skip mode and mtime_low */
83 parse += 8;
84 if (version >= 0x0940)
85 parse += 4; /* skip mtime_high */
86
87 l = *parse++;
88 /* don't care about the file name, and skip checksum */
89 if (end - parse < l + 4)
90 return 0;
91 parse += l + 4;
92
93 *skip = parse - input;
94 return 1;
95}
96
97STATIC int INIT unlzo(u8 *input, long in_len,
98 long (*fill)(void *, unsigned long),
99 long (*flush)(void *, unsigned long),
100 u8 *output, long *posp,
101 void (*error) (char *x))
102{
103 u8 r = 0;
104 long skip = 0;
105 u32 src_len, dst_len;
106 size_t tmp;
107 u8 *in_buf, *in_buf_save, *out_buf;
108 int ret = -1;
109
110 if (output) {
111 out_buf = output;
112 } else if (!flush) {
113 error("NULL output pointer and no flush function provided");
114 goto exit;
115 } else {
116 out_buf = malloc(LZO_BLOCK_SIZE);
117 if (!out_buf) {
118 error("Could not allocate output buffer");
119 goto exit;
120 }
121 }
122
123 if (input && fill) {
124 error("Both input pointer and fill function provided, don't know what to do");
125 goto exit_1;
126 } else if (input) {
127 in_buf = input;
128 } else if (!fill) {
129 error("NULL input pointer and missing fill function");
130 goto exit_1;
131 } else {
132 in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
133 if (!in_buf) {
134 error("Could not allocate input buffer");
135 goto exit_1;
136 }
137 }
138 in_buf_save = in_buf;
139
140 if (posp)
141 *posp = 0;
142
143 if (fill) {
144 /*
145 * Start from in_buf + HEADER_SIZE_MAX to make it possible
146 * to use memcpy() to copy the unused data to the beginning
147 * of the buffer. This way memmove() isn't needed which
148 * is missing from pre-boot environments of most archs.
149 */
150 in_buf += HEADER_SIZE_MAX;
151 in_len = fill(in_buf, HEADER_SIZE_MAX);
152 }
153
154 if (!parse_header(in_buf, &skip, in_len)) {
155 error("invalid header");
156 goto exit_2;
157 }
158 in_buf += skip;
159 in_len -= skip;
160
161 if (fill) {
162 /* Move the unused data to the beginning of the buffer. */
163 memcpy(in_buf_save, in_buf, in_len);
164 in_buf = in_buf_save;
165 }
166
167 if (posp)
168 *posp = skip;
169
170 for (;;) {
171 /* read uncompressed block size */
172 if (fill && in_len < 4) {
173 skip = fill(in_buf + in_len, 4 - in_len);
174 if (skip > 0)
175 in_len += skip;
176 }
177 if (in_len < 4) {
178 error("file corrupted");
179 goto exit_2;
180 }
181 dst_len = get_unaligned_be32(in_buf);
182 in_buf += 4;
183 in_len -= 4;
184
185 /* exit if last block */
186 if (dst_len == 0) {
187 if (posp)
188 *posp += 4;
189 break;
190 }
191
192 if (dst_len > LZO_BLOCK_SIZE) {
193 error("dest len longer than block size");
194 goto exit_2;
195 }
196
197 /* read compressed block size, and skip block checksum info */
198 if (fill && in_len < 8) {
199 skip = fill(in_buf + in_len, 8 - in_len);
200 if (skip > 0)
201 in_len += skip;
202 }
203 if (in_len < 8) {
204 error("file corrupted");
205 goto exit_2;
206 }
207 src_len = get_unaligned_be32(in_buf);
208 in_buf += 8;
209 in_len -= 8;
210
211 if (src_len <= 0 || src_len > dst_len) {
212 error("file corrupted");
213 goto exit_2;
214 }
215
216 /* decompress */
217 if (fill && in_len < src_len) {
218 skip = fill(in_buf + in_len, src_len - in_len);
219 if (skip > 0)
220 in_len += skip;
221 }
222 if (in_len < src_len) {
223 error("file corrupted");
224 goto exit_2;
225 }
226 tmp = dst_len;
227
228 /* When the input data is not compressed at all,
229 * lzo1x_decompress_safe will fail, so call memcpy()
230 * instead */
231 if (unlikely(dst_len == src_len))
232 memcpy(out_buf, in_buf, src_len);
233 else {
234 r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
235 out_buf, &tmp);
236
237 if (r != LZO_E_OK || dst_len != tmp) {
238 error("Compressed data violation");
239 goto exit_2;
240 }
241 }
242
243 if (flush && flush(out_buf, dst_len) != dst_len)
244 goto exit_2;
245 if (output)
246 out_buf += dst_len;
247 if (posp)
248 *posp += src_len + 12;
249
250 in_buf += src_len;
251 in_len -= src_len;
252 if (fill) {
253 /*
254 * If there happens to still be unused data left in
255 * in_buf, move it to the beginning of the buffer.
256 * Use a loop to avoid memmove() dependency.
257 */
258 if (in_len > 0)
259 for (skip = 0; skip < in_len; ++skip)
260 in_buf_save[skip] = in_buf[skip];
261 in_buf = in_buf_save;
262 }
263 }
264
265 ret = 0;
266exit_2:
267 if (!input)
268 free(in_buf_save);
269exit_1:
270 if (!output)
271 free(out_buf);
272exit:
273 return ret;
274}
275
276#ifdef PREBOOT
277STATIC int INIT __decompress(unsigned char *buf, long len,
278 long (*fill)(void*, unsigned long),
279 long (*flush)(void*, unsigned long),
280 unsigned char *out_buf, long olen,
281 long *pos,
282 void (*error)(char *x))
283{
284 return unlzo(buf, len, fill, flush, out_buf, pos, error);
285}
286#endif