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