xref: /openbmc/u-boot/lib/lzo/lzo1x_decompress.c (revision 23ff8633) 
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 	u16 version;
36 	int i;
37 
38 	/* read magic: 9 first bytes */
39 	for (i = 0; i < ARRAY_SIZE(lzop_magic); i++) {
40 		if (*src++ != lzop_magic[i])
41 			return NULL;
42 	}
43 	/* get version (2bytes), skip library version (2),
44 	 * 'need to be extracted' version (2) and
45 	 * method (1) */
46 	version = get_unaligned_be16(src);
47 	src += 7;
48 	if (version >= 0x0940)
49 		src++;
50 	if (get_unaligned_be32(src) & HEADER_HAS_FILTER)
51 		src += 4; /* filter info */
52 
53 	/* skip flags, mode and mtime_low */
54 	src += 12;
55 	if (version >= 0x0940)
56 		src += 4;	/* skip mtime_high */
57 
58 	i = *src++;
59 	/* don't care about the file name, and skip checksum */
60 	src += i + 4;
61 
62 	return src;
63 }
64 
65 int lzop_decompress(const unsigned char *src, size_t src_len,
66 		    unsigned char *dst, size_t *dst_len)
67 {
68 	unsigned char *start = dst;
69 	const unsigned char *send = src + src_len;
70 	u32 slen, dlen;
71 	size_t tmp, remaining;
72 	int r;
73 
74 	src = parse_header(src);
75 	if (!src)
76 		return LZO_E_ERROR;
77 
78 	remaining = *dst_len;
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 		/* abort if buffer ran out of room */
98 		if (dlen > remaining)
99 			return LZO_E_OUTPUT_OVERRUN;
100 
101 		/* decompress */
102 		tmp = dlen;
103 		r = lzo1x_decompress_safe((u8 *) src, slen, dst, &tmp);
104 
105 		if (r != LZO_E_OK) {
106 			*dst_len = dst - start;
107 			return r;
108 		}
109 
110 		if (dlen != tmp)
111 			return LZO_E_ERROR;
112 
113 		src += slen;
114 		dst += dlen;
115 		remaining -= dlen;
116 	}
117 
118 	return LZO_E_INPUT_OVERRUN;
119 }
120 
121 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
122 			unsigned char *out, size_t *out_len)
123 {
124 	const unsigned char * const ip_end = in + in_len;
125 	unsigned char * const op_end = out + *out_len;
126 	const unsigned char *ip = in, *m_pos;
127 	unsigned char *op = out;
128 	size_t t;
129 
130 	*out_len = 0;
131 
132 	if (*ip > 17) {
133 		t = *ip++ - 17;
134 		if (t < 4)
135 			goto match_next;
136 		if (HAVE_OP(t, op_end, op))
137 			goto output_overrun;
138 		if (HAVE_IP(t + 1, ip_end, ip))
139 			goto input_overrun;
140 		do {
141 			*op++ = *ip++;
142 		} while (--t > 0);
143 		goto first_literal_run;
144 	}
145 
146 	while ((ip < ip_end)) {
147 		t = *ip++;
148 		if (t >= 16)
149 			goto match;
150 		if (t == 0) {
151 			if (HAVE_IP(1, ip_end, ip))
152 				goto input_overrun;
153 			while (*ip == 0) {
154 				t += 255;
155 				ip++;
156 				if (HAVE_IP(1, ip_end, ip))
157 					goto input_overrun;
158 			}
159 			t += 15 + *ip++;
160 		}
161 		if (HAVE_OP(t + 3, op_end, op))
162 			goto output_overrun;
163 		if (HAVE_IP(t + 4, ip_end, ip))
164 			goto input_overrun;
165 
166 		COPY4(op, ip);
167 		op += 4;
168 		ip += 4;
169 		if (--t > 0) {
170 			if (t >= 4) {
171 				do {
172 					COPY4(op, ip);
173 					op += 4;
174 					ip += 4;
175 					t -= 4;
176 				} while (t >= 4);
177 				if (t > 0) {
178 					do {
179 						*op++ = *ip++;
180 					} while (--t > 0);
181 				}
182 			} else {
183 				do {
184 					*op++ = *ip++;
185 				} while (--t > 0);
186 			}
187 		}
188 
189 first_literal_run:
190 		t = *ip++;
191 		if (t >= 16)
192 			goto match;
193 		m_pos = op - (1 + M2_MAX_OFFSET);
194 		m_pos -= t >> 2;
195 		m_pos -= *ip++ << 2;
196 
197 		if (HAVE_LB(m_pos, out, op))
198 			goto lookbehind_overrun;
199 
200 		if (HAVE_OP(3, op_end, op))
201 			goto output_overrun;
202 		*op++ = *m_pos++;
203 		*op++ = *m_pos++;
204 		*op++ = *m_pos;
205 
206 		goto match_done;
207 
208 		do {
209 match:
210 			if (t >= 64) {
211 				m_pos = op - 1;
212 				m_pos -= (t >> 2) & 7;
213 				m_pos -= *ip++ << 3;
214 				t = (t >> 5) - 1;
215 				if (HAVE_LB(m_pos, out, op))
216 					goto lookbehind_overrun;
217 				if (HAVE_OP(t + 3 - 1, op_end, op))
218 					goto output_overrun;
219 				goto copy_match;
220 			} else if (t >= 32) {
221 				t &= 31;
222 				if (t == 0) {
223 					if (HAVE_IP(1, ip_end, ip))
224 						goto input_overrun;
225 					while (*ip == 0) {
226 						t += 255;
227 						ip++;
228 						if (HAVE_IP(1, ip_end, ip))
229 							goto input_overrun;
230 					}
231 					t += 31 + *ip++;
232 				}
233 				m_pos = op - 1;
234 				m_pos -= get_unaligned_le16(ip) >> 2;
235 				ip += 2;
236 			} else if (t >= 16) {
237 				m_pos = op;
238 				m_pos -= (t & 8) << 11;
239 
240 				t &= 7;
241 				if (t == 0) {
242 					if (HAVE_IP(1, ip_end, ip))
243 						goto input_overrun;
244 					while (*ip == 0) {
245 						t += 255;
246 						ip++;
247 						if (HAVE_IP(1, ip_end, ip))
248 							goto input_overrun;
249 					}
250 					t += 7 + *ip++;
251 				}
252 				m_pos -= get_unaligned_le16(ip) >> 2;
253 				ip += 2;
254 				if (m_pos == op)
255 					goto eof_found;
256 				m_pos -= 0x4000;
257 			} else {
258 				m_pos = op - 1;
259 				m_pos -= t >> 2;
260 				m_pos -= *ip++ << 2;
261 
262 				if (HAVE_LB(m_pos, out, op))
263 					goto lookbehind_overrun;
264 				if (HAVE_OP(2, op_end, op))
265 					goto output_overrun;
266 
267 				*op++ = *m_pos++;
268 				*op++ = *m_pos;
269 				goto match_done;
270 			}
271 
272 			if (HAVE_LB(m_pos, out, op))
273 				goto lookbehind_overrun;
274 			if (HAVE_OP(t + 3 - 1, op_end, op))
275 				goto output_overrun;
276 
277 			if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
278 				COPY4(op, m_pos);
279 				op += 4;
280 				m_pos += 4;
281 				t -= 4 - (3 - 1);
282 				do {
283 					COPY4(op, m_pos);
284 					op += 4;
285 					m_pos += 4;
286 					t -= 4;
287 				} while (t >= 4);
288 				if (t > 0)
289 					do {
290 						*op++ = *m_pos++;
291 					} while (--t > 0);
292 			} else {
293 copy_match:
294 				*op++ = *m_pos++;
295 				*op++ = *m_pos++;
296 				do {
297 					*op++ = *m_pos++;
298 				} while (--t > 0);
299 			}
300 match_done:
301 			t = ip[-2] & 3;
302 			if (t == 0)
303 				break;
304 match_next:
305 			if (HAVE_OP(t, op_end, op))
306 				goto output_overrun;
307 			if (HAVE_IP(t + 1, ip_end, ip))
308 				goto input_overrun;
309 
310 			*op++ = *ip++;
311 			if (t > 1) {
312 				*op++ = *ip++;
313 				if (t > 2)
314 					*op++ = *ip++;
315 			}
316 
317 			t = *ip++;
318 		} while (ip < ip_end);
319 	}
320 
321 	*out_len = op - out;
322 	return LZO_E_EOF_NOT_FOUND;
323 
324 eof_found:
325 	*out_len = op - out;
326 	return (ip == ip_end ? LZO_E_OK :
327 		(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
328 input_overrun:
329 	*out_len = op - out;
330 	return LZO_E_INPUT_OVERRUN;
331 
332 output_overrun:
333 	*out_len = op - out;
334 	return LZO_E_OUTPUT_OVERRUN;
335 
336 lookbehind_overrun:
337 	*out_len = op - out;
338 	return LZO_E_LOOKBEHIND_OVERRUN;
339 }
340