1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
4 *
5 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
6 */
7
8 #ifdef STATIC
9 #define PREBOOT
10 #include "lz4/lz4_decompress.c"
11 #else
12 #include <linux/decompress/unlz4.h>
13 #endif
14 #include <linux/types.h>
15 #include <linux/lz4.h>
16 #include <linux/decompress/mm.h>
17 #include <linux/compiler.h>
18
19 #include <asm/unaligned.h>
20
21 /*
22 * Note: Uncompressed chunk size is used in the compressor side
23 * (userspace side for compression).
24 * It is hardcoded because there is not proper way to extract it
25 * from the binary stream which is generated by the preliminary
26 * version of LZ4 tool so far.
27 */
28 #define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
29 #define ARCHIVE_MAGICNUMBER 0x184C2102
30
31 STATIC inline int INIT unlz4(u8 *input, long in_len,
32 long (*fill)(void *, unsigned long),
33 long (*flush)(void *, unsigned long),
34 u8 *output, long *posp,
35 void (*error) (char *x))
36 {
37 int ret = -1;
38 size_t chunksize = 0;
39 size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
40 u8 *inp;
41 u8 *inp_start;
42 u8 *outp;
43 long size = in_len;
44 #ifdef PREBOOT
45 size_t out_len = get_unaligned_le32(input + in_len);
46 #endif
47 size_t dest_len;
48
49
50 if (output) {
51 outp = output;
52 } else if (!flush) {
53 error("NULL output pointer and no flush function provided");
54 goto exit_0;
55 } else {
56 outp = large_malloc(uncomp_chunksize);
57 if (!outp) {
58 error("Could not allocate output buffer");
59 goto exit_0;
60 }
61 }
62
63 if (input && fill) {
64 error("Both input pointer and fill function provided,");
65 goto exit_1;
66 } else if (input) {
67 inp = input;
68 } else if (!fill) {
69 error("NULL input pointer and missing fill function");
70 goto exit_1;
71 } else {
72 inp = large_malloc(LZ4_compressBound(uncomp_chunksize));
73 if (!inp) {
74 error("Could not allocate input buffer");
75 goto exit_1;
76 }
77 }
78 inp_start = inp;
79
80 if (posp)
81 *posp = 0;
82
83 if (fill) {
84 size = fill(inp, 4);
85 if (size < 4) {
86 error("data corrupted");
87 goto exit_2;
88 }
89 }
90
91 chunksize = get_unaligned_le32(inp);
92 if (chunksize == ARCHIVE_MAGICNUMBER) {
93 if (!fill) {
94 inp += 4;
95 size -= 4;
96 }
97 } else {
98 error("invalid header");
99 goto exit_2;
100 }
101
102 if (posp)
103 *posp += 4;
104
105 for (;;) {
106
107 if (fill) {
108 size = fill(inp, 4);
109 if (size == 0)
110 break;
111 if (size < 4) {
112 error("data corrupted");
113 goto exit_2;
114 }
115 } else if (size < 4) {
116 /* empty or end-of-file */
117 goto exit_3;
118 }
119
120 chunksize = get_unaligned_le32(inp);
121 if (chunksize == ARCHIVE_MAGICNUMBER) {
122 if (!fill) {
123 inp += 4;
124 size -= 4;
125 }
126 if (posp)
127 *posp += 4;
128 continue;
129 }
130
131 if (!fill && chunksize == 0) {
132 /* empty or end-of-file */
133 goto exit_3;
134 }
135
136 if (posp)
137 *posp += 4;
138
139 if (!fill) {
140 inp += 4;
141 size -= 4;
142 } else {
143 if (chunksize > LZ4_compressBound(uncomp_chunksize)) {
144 error("chunk length is longer than allocated");
145 goto exit_2;
146 }
147 size = fill(inp, chunksize);
148 if (size < chunksize) {
149 error("data corrupted");
150 goto exit_2;
151 }
152 }
153 #ifdef PREBOOT
154 if (out_len >= uncomp_chunksize) {
155 dest_len = uncomp_chunksize;
156 out_len -= dest_len;
157 } else
158 dest_len = out_len;
159
160 ret = LZ4_decompress_fast(inp, outp, dest_len);
161 chunksize = ret;
162 #else
163 dest_len = uncomp_chunksize;
164
165 ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len);
166 dest_len = ret;
167 #endif
168 if (ret < 0) {
169 error("Decoding failed");
170 goto exit_2;
171 }
172
173 ret = -1;
174 if (flush && flush(outp, dest_len) != dest_len)
175 goto exit_2;
176 if (output)
177 outp += dest_len;
178 if (posp)
179 *posp += chunksize;
180
181 if (!fill) {
182 size -= chunksize;
183
184 if (size == 0)
185 break;
186 else if (size < 0) {
187 error("data corrupted");
188 goto exit_2;
189 }
190 inp += chunksize;
191 }
192 }
193
194 exit_3:
195 ret = 0;
196 exit_2:
197 if (!input)
198 large_free(inp_start);
199 exit_1:
200 if (!output)
201 large_free(outp);
202 exit_0:
203 return ret;
204 }
205
206 #ifdef PREBOOT
207 STATIC int INIT __decompress(unsigned char *buf, long in_len,
208 long (*fill)(void*, unsigned long),
209 long (*flush)(void*, unsigned long),
210 unsigned char *output, long out_len,
211 long *posp,
212 void (*error)(char *x)
213 )
214 {
215 return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
216 }
217 #endif
218
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