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64c70b1c RP |
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 <linux/module.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/lzo.h> | |
17 | #include <asm/byteorder.h> | |
18 | #include <asm/unaligned.h> | |
19 | #include "lzodefs.h" | |
20 | ||
21 | #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x)) | |
22 | #define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x)) | |
23 | #define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op) | |
24 | ||
25 | #define COPY4(dst, src) \ | |
26 | put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst)) | |
27 | ||
28 | int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, | |
29 | unsigned char *out, size_t *out_len) | |
30 | { | |
31 | const unsigned char * const ip_end = in + in_len; | |
32 | unsigned char * const op_end = out + *out_len; | |
33 | const unsigned char *ip = in, *m_pos; | |
34 | unsigned char *op = out; | |
35 | size_t t; | |
36 | ||
37 | *out_len = 0; | |
38 | ||
39 | if (*ip > 17) { | |
40 | t = *ip++ - 17; | |
41 | if (t < 4) | |
42 | goto match_next; | |
43 | if (HAVE_OP(t, op_end, op)) | |
44 | goto output_overrun; | |
45 | if (HAVE_IP(t + 1, ip_end, ip)) | |
46 | goto input_overrun; | |
47 | do { | |
48 | *op++ = *ip++; | |
49 | } while (--t > 0); | |
50 | goto first_literal_run; | |
51 | } | |
52 | ||
53 | while ((ip < ip_end)) { | |
54 | t = *ip++; | |
55 | if (t >= 16) | |
56 | goto match; | |
57 | if (t == 0) { | |
58 | if (HAVE_IP(1, ip_end, ip)) | |
59 | goto input_overrun; | |
60 | while (*ip == 0) { | |
61 | t += 255; | |
62 | ip++; | |
63 | if (HAVE_IP(1, ip_end, ip)) | |
64 | goto input_overrun; | |
65 | } | |
66 | t += 15 + *ip++; | |
67 | } | |
68 | if (HAVE_OP(t + 3, op_end, op)) | |
69 | goto output_overrun; | |
70 | if (HAVE_IP(t + 4, ip_end, ip)) | |
71 | goto input_overrun; | |
72 | ||
73 | COPY4(op, ip); | |
74 | op += 4; | |
75 | ip += 4; | |
76 | if (--t > 0) { | |
77 | if (t >= 4) { | |
78 | do { | |
79 | COPY4(op, ip); | |
80 | op += 4; | |
81 | ip += 4; | |
82 | t -= 4; | |
83 | } while (t >= 4); | |
84 | if (t > 0) { | |
85 | do { | |
86 | *op++ = *ip++; | |
87 | } while (--t > 0); | |
88 | } | |
89 | } else { | |
90 | do { | |
91 | *op++ = *ip++; | |
92 | } while (--t > 0); | |
93 | } | |
94 | } | |
95 | ||
96 | first_literal_run: | |
97 | t = *ip++; | |
98 | if (t >= 16) | |
99 | goto match; | |
100 | m_pos = op - (1 + M2_MAX_OFFSET); | |
101 | m_pos -= t >> 2; | |
102 | m_pos -= *ip++ << 2; | |
103 | ||
104 | if (HAVE_LB(m_pos, out, op)) | |
105 | goto lookbehind_overrun; | |
106 | ||
107 | if (HAVE_OP(3, op_end, op)) | |
108 | goto output_overrun; | |
109 | *op++ = *m_pos++; | |
110 | *op++ = *m_pos++; | |
111 | *op++ = *m_pos; | |
112 | ||
113 | goto match_done; | |
114 | ||
115 | do { | |
116 | match: | |
117 | if (t >= 64) { | |
118 | m_pos = op - 1; | |
119 | m_pos -= (t >> 2) & 7; | |
120 | m_pos -= *ip++ << 3; | |
121 | t = (t >> 5) - 1; | |
122 | if (HAVE_LB(m_pos, out, op)) | |
123 | goto lookbehind_overrun; | |
124 | if (HAVE_OP(t + 3 - 1, op_end, op)) | |
125 | goto output_overrun; | |
126 | goto copy_match; | |
127 | } else if (t >= 32) { | |
128 | t &= 31; | |
129 | if (t == 0) { | |
130 | if (HAVE_IP(1, ip_end, ip)) | |
131 | goto input_overrun; | |
132 | while (*ip == 0) { | |
133 | t += 255; | |
134 | ip++; | |
135 | if (HAVE_IP(1, ip_end, ip)) | |
136 | goto input_overrun; | |
137 | } | |
138 | t += 31 + *ip++; | |
139 | } | |
140 | m_pos = op - 1; | |
545e4006 | 141 | m_pos -= get_unaligned_le16(ip) >> 2; |
64c70b1c RP |
142 | ip += 2; |
143 | } else if (t >= 16) { | |
144 | m_pos = op; | |
145 | m_pos -= (t & 8) << 11; | |
146 | ||
147 | t &= 7; | |
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 += 7 + *ip++; | |
158 | } | |
545e4006 | 159 | m_pos -= get_unaligned_le16(ip) >> 2; |
64c70b1c RP |
160 | ip += 2; |
161 | if (m_pos == op) | |
162 | goto eof_found; | |
163 | m_pos -= 0x4000; | |
164 | } else { | |
165 | m_pos = op - 1; | |
166 | m_pos -= t >> 2; | |
167 | m_pos -= *ip++ << 2; | |
168 | ||
169 | if (HAVE_LB(m_pos, out, op)) | |
170 | goto lookbehind_overrun; | |
171 | if (HAVE_OP(2, op_end, op)) | |
172 | goto output_overrun; | |
173 | ||
174 | *op++ = *m_pos++; | |
175 | *op++ = *m_pos; | |
176 | goto match_done; | |
177 | } | |
178 | ||
179 | if (HAVE_LB(m_pos, out, op)) | |
180 | goto lookbehind_overrun; | |
181 | if (HAVE_OP(t + 3 - 1, op_end, op)) | |
182 | goto output_overrun; | |
183 | ||
184 | if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) { | |
185 | COPY4(op, m_pos); | |
186 | op += 4; | |
187 | m_pos += 4; | |
188 | t -= 4 - (3 - 1); | |
189 | do { | |
190 | COPY4(op, m_pos); | |
191 | op += 4; | |
192 | m_pos += 4; | |
193 | t -= 4; | |
194 | } while (t >= 4); | |
195 | if (t > 0) | |
196 | do { | |
197 | *op++ = *m_pos++; | |
198 | } while (--t > 0); | |
199 | } else { | |
200 | copy_match: | |
201 | *op++ = *m_pos++; | |
202 | *op++ = *m_pos++; | |
203 | do { | |
204 | *op++ = *m_pos++; | |
205 | } while (--t > 0); | |
206 | } | |
207 | match_done: | |
208 | t = ip[-2] & 3; | |
209 | if (t == 0) | |
210 | break; | |
211 | match_next: | |
212 | if (HAVE_OP(t, op_end, op)) | |
213 | goto output_overrun; | |
214 | if (HAVE_IP(t + 1, ip_end, ip)) | |
215 | goto input_overrun; | |
216 | ||
217 | *op++ = *ip++; | |
218 | if (t > 1) { | |
219 | *op++ = *ip++; | |
220 | if (t > 2) | |
221 | *op++ = *ip++; | |
222 | } | |
223 | ||
224 | t = *ip++; | |
225 | } while (ip < ip_end); | |
226 | } | |
227 | ||
228 | *out_len = op - out; | |
229 | return LZO_E_EOF_NOT_FOUND; | |
230 | ||
231 | eof_found: | |
232 | *out_len = op - out; | |
233 | return (ip == ip_end ? LZO_E_OK : | |
234 | (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN)); | |
235 | input_overrun: | |
236 | *out_len = op - out; | |
237 | return LZO_E_INPUT_OVERRUN; | |
238 | ||
239 | output_overrun: | |
240 | *out_len = op - out; | |
241 | return LZO_E_OUTPUT_OVERRUN; | |
242 | ||
243 | lookbehind_overrun: | |
244 | *out_len = op - out; | |
245 | return LZO_E_LOOKBEHIND_OVERRUN; | |
246 | } | |
247 | ||
248 | EXPORT_SYMBOL_GPL(lzo1x_decompress_safe); | |
249 | ||
250 | MODULE_LICENSE("GPL"); | |
251 | MODULE_DESCRIPTION("LZO1X Decompressor"); | |
252 |