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 0x00000800L |
38 | #define (9 + 7 + 4 + 8 + 1 + 4) |
39 | #define (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4) |
40 | |
41 | STATIC inline long INIT (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(p: parse); |
65 | parse += 7; |
66 | if (version >= 0x0940) |
67 | parse++; |
68 | if (get_unaligned_be32(p: 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 | |
97 | STATIC 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(input: in_buf, skip: &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(p: 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(p: 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(src: (u8 *) in_buf, src_len, |
235 | dst: out_buf, dst_len: &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; |
266 | exit_2: |
267 | if (!input) |
268 | free(in_buf_save); |
269 | exit_1: |
270 | if (!output) |
271 | free(out_buf); |
272 | exit: |
273 | return ret; |
274 | } |
275 | |
276 | #ifdef PREBOOT |
277 | STATIC 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 |
287 | |