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 
unlz4(u8 * input,long in_len,long (* fill)(void *,unsigned long),long (* flush)(void *,unsigned long),u8 * output,long * posp,void (* error)(char * x))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
__decompress(unsigned char * buf,long in_len,long (* fill)(void *,unsigned long),long (* flush)(void *,unsigned long),unsigned char * output,long out_len,long * posp,void (* error)(char * x))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