xref: /openbmc/u-boot/lib/lzo/lzo1x_decompress.c (revision ac1058fd) 
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 			return r;
107 
108 		if (dlen != tmp)
109 			return LZO_E_ERROR;
110 
111 		src += slen;
112 		dst += dlen;
113 		remaining -= dlen;
114 	}
115 
116 	return LZO_E_INPUT_OVERRUN;
117 }
118 
119 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
120 			unsigned char *out, size_t *out_len)
121 {
122 	const unsigned char * const ip_end = in + in_len;
123 	unsigned char * const op_end = out + *out_len;
124 	const unsigned char *ip = in, *m_pos;
125 	unsigned char *op = out;
126 	size_t t;
127 
128 	*out_len = 0;
129 
130 	if (*ip > 17) {
131 		t = *ip++ - 17;
132 		if (t < 4)
133 			goto match_next;
134 		if (HAVE_OP(t, op_end, op))
135 			goto output_overrun;
136 		if (HAVE_IP(t + 1, ip_end, ip))
137 			goto input_overrun;
138 		do {
139 			*op++ = *ip++;
140 		} while (--t > 0);
141 		goto first_literal_run;
142 	}
143 
144 	while ((ip < ip_end)) {
145 		t = *ip++;
146 		if (t >= 16)
147 			goto match;
148 		if (t == 0) {
149 			if (HAVE_IP(1, ip_end, ip))
150 				goto input_overrun;
151 			while (*ip == 0) {
152 				t += 255;
153 				ip++;
154 				if (HAVE_IP(1, ip_end, ip))
155 					goto input_overrun;
156 			}
157 			t += 15 + *ip++;
158 		}
159 		if (HAVE_OP(t + 3, op_end, op))
160 			goto output_overrun;
161 		if (HAVE_IP(t + 4, ip_end, ip))
162 			goto input_overrun;
163 
164 		COPY4(op, ip);
165 		op += 4;
166 		ip += 4;
167 		if (--t > 0) {
168 			if (t >= 4) {
169 				do {
170 					COPY4(op, ip);
171 					op += 4;
172 					ip += 4;
173 					t -= 4;
174 				} while (t >= 4);
175 				if (t > 0) {
176 					do {
177 						*op++ = *ip++;
178 					} while (--t > 0);
179 				}
180 			} else {
181 				do {
182 					*op++ = *ip++;
183 				} while (--t > 0);
184 			}
185 		}
186 
187 first_literal_run:
188 		t = *ip++;
189 		if (t >= 16)
190 			goto match;
191 		m_pos = op - (1 + M2_MAX_OFFSET);
192 		m_pos -= t >> 2;
193 		m_pos -= *ip++ << 2;
194 
195 		if (HAVE_LB(m_pos, out, op))
196 			goto lookbehind_overrun;
197 
198 		if (HAVE_OP(3, op_end, op))
199 			goto output_overrun;
200 		*op++ = *m_pos++;
201 		*op++ = *m_pos++;
202 		*op++ = *m_pos;
203 
204 		goto match_done;
205 
206 		do {
207 match:
208 			if (t >= 64) {
209 				m_pos = op - 1;
210 				m_pos -= (t >> 2) & 7;
211 				m_pos -= *ip++ << 3;
212 				t = (t >> 5) - 1;
213 				if (HAVE_LB(m_pos, out, op))
214 					goto lookbehind_overrun;
215 				if (HAVE_OP(t + 3 - 1, op_end, op))
216 					goto output_overrun;
217 				goto copy_match;
218 			} else if (t >= 32) {
219 				t &= 31;
220 				if (t == 0) {
221 					if (HAVE_IP(1, ip_end, ip))
222 						goto input_overrun;
223 					while (*ip == 0) {
224 						t += 255;
225 						ip++;
226 						if (HAVE_IP(1, ip_end, ip))
227 							goto input_overrun;
228 					}
229 					t += 31 + *ip++;
230 				}
231 				m_pos = op - 1;
232 				m_pos -= get_unaligned_le16(ip) >> 2;
233 				ip += 2;
234 			} else if (t >= 16) {
235 				m_pos = op;
236 				m_pos -= (t & 8) << 11;
237 
238 				t &= 7;
239 				if (t == 0) {
240 					if (HAVE_IP(1, ip_end, ip))
241 						goto input_overrun;
242 					while (*ip == 0) {
243 						t += 255;
244 						ip++;
245 						if (HAVE_IP(1, ip_end, ip))
246 							goto input_overrun;
247 					}
248 					t += 7 + *ip++;
249 				}
250 				m_pos -= get_unaligned_le16(ip) >> 2;
251 				ip += 2;
252 				if (m_pos == op)
253 					goto eof_found;
254 				m_pos -= 0x4000;
255 			} else {
256 				m_pos = op - 1;
257 				m_pos -= t >> 2;
258 				m_pos -= *ip++ << 2;
259 
260 				if (HAVE_LB(m_pos, out, op))
261 					goto lookbehind_overrun;
262 				if (HAVE_OP(2, op_end, op))
263 					goto output_overrun;
264 
265 				*op++ = *m_pos++;
266 				*op++ = *m_pos;
267 				goto match_done;
268 			}
269 
270 			if (HAVE_LB(m_pos, out, op))
271 				goto lookbehind_overrun;
272 			if (HAVE_OP(t + 3 - 1, op_end, op))
273 				goto output_overrun;
274 
275 			if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
276 				COPY4(op, m_pos);
277 				op += 4;
278 				m_pos += 4;
279 				t -= 4 - (3 - 1);
280 				do {
281 					COPY4(op, m_pos);
282 					op += 4;
283 					m_pos += 4;
284 					t -= 4;
285 				} while (t >= 4);
286 				if (t > 0)
287 					do {
288 						*op++ = *m_pos++;
289 					} while (--t > 0);
290 			} else {
291 copy_match:
292 				*op++ = *m_pos++;
293 				*op++ = *m_pos++;
294 				do {
295 					*op++ = *m_pos++;
296 				} while (--t > 0);
297 			}
298 match_done:
299 			t = ip[-2] & 3;
300 			if (t == 0)
301 				break;
302 match_next:
303 			if (HAVE_OP(t, op_end, op))
304 				goto output_overrun;
305 			if (HAVE_IP(t + 1, ip_end, ip))
306 				goto input_overrun;
307 
308 			*op++ = *ip++;
309 			if (t > 1) {
310 				*op++ = *ip++;
311 				if (t > 2)
312 					*op++ = *ip++;
313 			}
314 
315 			t = *ip++;
316 		} while (ip < ip_end);
317 	}
318 
319 	*out_len = op - out;
320 	return LZO_E_EOF_NOT_FOUND;
321 
322 eof_found:
323 	*out_len = op - out;
324 	return (ip == ip_end ? LZO_E_OK :
325 		(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
326 input_overrun:
327 	*out_len = op - out;
328 	return LZO_E_INPUT_OVERRUN;
329 
330 output_overrun:
331 	*out_len = op - out;
332 	return LZO_E_OUTPUT_OVERRUN;
333 
334 lookbehind_overrun:
335 	*out_len = op - out;
336 	return LZO_E_LOOKBEHIND_OVERRUN;
337 }
338