xref: /openbmc/u-boot/lib/lzo/lzo1x_decompress.c (revision e89516f0) 
1 /*
2  *  LZO1X Decompressor from MiniLZO
3  *
4  *  Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus@oberhumer.com>
5  *
6  *  The full LZO package can be found at:
7  *  http://www.oberhumer.com/opensource/lzo/
8  *
9  *  Changed for kernel use by:
10  *  Nitin Gupta <nitingupta910@gmail.com>
11  *  Richard Purdie <rpurdie@openedhand.com>
12  */
13 
14 #include <common.h>
15 #include <linux/lzo.h>
16 #include <asm/byteorder.h>
17 #include <asm/unaligned.h>
18 #include "lzodefs.h"
19 
20 #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
21 #define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x))
22 #define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op)
23 
24 #define COPY4(dst, src)	\
25 		put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
26 
27 static const unsigned char lzop_magic[] = {
28 	0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a
29 };
30 
31 #define HEADER_HAS_FILTER	0x00000800L
32 
33 static inline const unsigned char *parse_header(const unsigned char *src)
34 {
35 	u8 level = 0;
36 	u16 version;
37 	int i;
38 
39 	/* read magic: 9 first bytes */
40 	for (i = 0; i < ARRAY_SIZE(lzop_magic); i++) {
41 		if (*src++ != lzop_magic[i])
42 			return NULL;
43 	}
44 	/* get version (2bytes), skip library version (2),
45 	 * 'need to be extracted' version (2) and
46 	 * method (1) */
47 	version = get_unaligned_be16(src);
48 	src += 7;
49 	if (version >= 0x0940)
50 		level = *src++;
51 	if (get_unaligned_be32(src) & HEADER_HAS_FILTER)
52 		src += 4; /* filter info */
53 
54 	/* skip flags, mode and mtime_low */
55 	src += 12;
56 	if (version >= 0x0940)
57 		src += 4;	/* skip mtime_high */
58 
59 	i = *src++;
60 	/* don't care about the file name, and skip checksum */
61 	src += i + 4;
62 
63 	return src;
64 }
65 
66 int lzop_decompress(const unsigned char *src, size_t src_len,
67 		    unsigned char *dst, size_t *dst_len)
68 {
69 	unsigned char *start = dst;
70 	const unsigned char *send = src + src_len;
71 	u32 slen, dlen;
72 	size_t tmp;
73 	int r;
74 
75 	src = parse_header(src);
76 	if (!src)
77 		return LZO_E_ERROR;
78 
79 	while (src < send) {
80 		/* read uncompressed block size */
81 		dlen = get_unaligned_be32(src);
82 		src += 4;
83 
84 		/* exit if last block */
85 		if (dlen == 0) {
86 			*dst_len = dst - start;
87 			return LZO_E_OK;
88 		}
89 
90 		/* read compressed block size, and skip block checksum info */
91 		slen = get_unaligned_be32(src);
92 		src += 8;
93 
94 		if (slen <= 0 || slen > dlen)
95 			return LZO_E_ERROR;
96 
97 		/* decompress */
98 		tmp = dlen;
99 		r = lzo1x_decompress_safe((u8 *) src, slen, dst, &tmp);
100 
101 		if (r != LZO_E_OK)
102 			return r;
103 
104 		if (dlen != tmp)
105 			return LZO_E_ERROR;
106 
107 		src += slen;
108 		dst += dlen;
109 	}
110 
111 	return LZO_E_INPUT_OVERRUN;
112 }
113 
114 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
115 			unsigned char *out, size_t *out_len)
116 {
117 	const unsigned char * const ip_end = in + in_len;
118 	unsigned char * const op_end = out + *out_len;
119 	const unsigned char *ip = in, *m_pos;
120 	unsigned char *op = out;
121 	size_t t;
122 
123 	*out_len = 0;
124 
125 	if (*ip > 17) {
126 		t = *ip++ - 17;
127 		if (t < 4)
128 			goto match_next;
129 		if (HAVE_OP(t, op_end, op))
130 			goto output_overrun;
131 		if (HAVE_IP(t + 1, ip_end, ip))
132 			goto input_overrun;
133 		do {
134 			*op++ = *ip++;
135 		} while (--t > 0);
136 		goto first_literal_run;
137 	}
138 
139 	while ((ip < ip_end)) {
140 		t = *ip++;
141 		if (t >= 16)
142 			goto match;
143 		if (t == 0) {
144 			if (HAVE_IP(1, ip_end, ip))
145 				goto input_overrun;
146 			while (*ip == 0) {
147 				t += 255;
148 				ip++;
149 				if (HAVE_IP(1, ip_end, ip))
150 					goto input_overrun;
151 			}
152 			t += 15 + *ip++;
153 		}
154 		if (HAVE_OP(t + 3, op_end, op))
155 			goto output_overrun;
156 		if (HAVE_IP(t + 4, ip_end, ip))
157 			goto input_overrun;
158 
159 		COPY4(op, ip);
160 		op += 4;
161 		ip += 4;
162 		if (--t > 0) {
163 			if (t >= 4) {
164 				do {
165 					COPY4(op, ip);
166 					op += 4;
167 					ip += 4;
168 					t -= 4;
169 				} while (t >= 4);
170 				if (t > 0) {
171 					do {
172 						*op++ = *ip++;
173 					} while (--t > 0);
174 				}
175 			} else {
176 				do {
177 					*op++ = *ip++;
178 				} while (--t > 0);
179 			}
180 		}
181 
182 first_literal_run:
183 		t = *ip++;
184 		if (t >= 16)
185 			goto match;
186 		m_pos = op - (1 + M2_MAX_OFFSET);
187 		m_pos -= t >> 2;
188 		m_pos -= *ip++ << 2;
189 
190 		if (HAVE_LB(m_pos, out, op))
191 			goto lookbehind_overrun;
192 
193 		if (HAVE_OP(3, op_end, op))
194 			goto output_overrun;
195 		*op++ = *m_pos++;
196 		*op++ = *m_pos++;
197 		*op++ = *m_pos;
198 
199 		goto match_done;
200 
201 		do {
202 match:
203 			if (t >= 64) {
204 				m_pos = op - 1;
205 				m_pos -= (t >> 2) & 7;
206 				m_pos -= *ip++ << 3;
207 				t = (t >> 5) - 1;
208 				if (HAVE_LB(m_pos, out, op))
209 					goto lookbehind_overrun;
210 				if (HAVE_OP(t + 3 - 1, op_end, op))
211 					goto output_overrun;
212 				goto copy_match;
213 			} else if (t >= 32) {
214 				t &= 31;
215 				if (t == 0) {
216 					if (HAVE_IP(1, ip_end, ip))
217 						goto input_overrun;
218 					while (*ip == 0) {
219 						t += 255;
220 						ip++;
221 						if (HAVE_IP(1, ip_end, ip))
222 							goto input_overrun;
223 					}
224 					t += 31 + *ip++;
225 				}
226 				m_pos = op - 1;
227 				m_pos -= get_unaligned_le16(ip) >> 2;
228 				ip += 2;
229 			} else if (t >= 16) {
230 				m_pos = op;
231 				m_pos -= (t & 8) << 11;
232 
233 				t &= 7;
234 				if (t == 0) {
235 					if (HAVE_IP(1, ip_end, ip))
236 						goto input_overrun;
237 					while (*ip == 0) {
238 						t += 255;
239 						ip++;
240 						if (HAVE_IP(1, ip_end, ip))
241 							goto input_overrun;
242 					}
243 					t += 7 + *ip++;
244 				}
245 				m_pos -= get_unaligned_le16(ip) >> 2;
246 				ip += 2;
247 				if (m_pos == op)
248 					goto eof_found;
249 				m_pos -= 0x4000;
250 			} else {
251 				m_pos = op - 1;
252 				m_pos -= t >> 2;
253 				m_pos -= *ip++ << 2;
254 
255 				if (HAVE_LB(m_pos, out, op))
256 					goto lookbehind_overrun;
257 				if (HAVE_OP(2, op_end, op))
258 					goto output_overrun;
259 
260 				*op++ = *m_pos++;
261 				*op++ = *m_pos;
262 				goto match_done;
263 			}
264 
265 			if (HAVE_LB(m_pos, out, op))
266 				goto lookbehind_overrun;
267 			if (HAVE_OP(t + 3 - 1, op_end, op))
268 				goto output_overrun;
269 
270 			if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
271 				COPY4(op, m_pos);
272 				op += 4;
273 				m_pos += 4;
274 				t -= 4 - (3 - 1);
275 				do {
276 					COPY4(op, m_pos);
277 					op += 4;
278 					m_pos += 4;
279 					t -= 4;
280 				} while (t >= 4);
281 				if (t > 0)
282 					do {
283 						*op++ = *m_pos++;
284 					} while (--t > 0);
285 			} else {
286 copy_match:
287 				*op++ = *m_pos++;
288 				*op++ = *m_pos++;
289 				do {
290 					*op++ = *m_pos++;
291 				} while (--t > 0);
292 			}
293 match_done:
294 			t = ip[-2] & 3;
295 			if (t == 0)
296 				break;
297 match_next:
298 			if (HAVE_OP(t, op_end, op))
299 				goto output_overrun;
300 			if (HAVE_IP(t + 1, ip_end, ip))
301 				goto input_overrun;
302 
303 			*op++ = *ip++;
304 			if (t > 1) {
305 				*op++ = *ip++;
306 				if (t > 2)
307 					*op++ = *ip++;
308 			}
309 
310 			t = *ip++;
311 		} while (ip < ip_end);
312 	}
313 
314 	*out_len = op - out;
315 	return LZO_E_EOF_NOT_FOUND;
316 
317 eof_found:
318 	*out_len = op - out;
319 	return (ip == ip_end ? LZO_E_OK :
320 		(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
321 input_overrun:
322 	*out_len = op - out;
323 	return LZO_E_INPUT_OVERRUN;
324 
325 output_overrun:
326 	*out_len = op - out;
327 	return LZO_E_OUTPUT_OVERRUN;
328 
329 lookbehind_overrun:
330 	*out_len = op - out;
331 	return LZO_E_LOOKBEHIND_OVERRUN;
332 }
333