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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
64c70b1c | 2 | /* |
8b975bd3 | 3 | * LZO1X Decompressor from LZO |
64c70b1c | 4 | * |
8b975bd3 | 5 | * Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com> |
64c70b1c RP |
6 | * |
7 | * The full LZO package can be found at: | |
8 | * http://www.oberhumer.com/opensource/lzo/ | |
9 | * | |
8b975bd3 | 10 | * Changed for Linux kernel use by: |
64c70b1c RP |
11 | * Nitin Gupta <nitingupta910@gmail.com> |
12 | * Richard Purdie <rpurdie@openedhand.com> | |
13 | */ | |
14 | ||
7dd65feb | 15 | #ifndef STATIC |
64c70b1c RP |
16 | #include <linux/module.h> |
17 | #include <linux/kernel.h> | |
7dd65feb | 18 | #endif |
64c70b1c | 19 | #include <asm/unaligned.h> |
7dd65feb | 20 | #include <linux/lzo.h> |
64c70b1c RP |
21 | #include "lzodefs.h" |
22 | ||
af958a38 WT |
23 | #define HAVE_IP(x) ((size_t)(ip_end - ip) >= (size_t)(x)) |
24 | #define HAVE_OP(x) ((size_t)(op_end - op) >= (size_t)(x)) | |
25 | #define NEED_IP(x) if (!HAVE_IP(x)) goto input_overrun | |
26 | #define NEED_OP(x) if (!HAVE_OP(x)) goto output_overrun | |
27 | #define TEST_LB(m_pos) if ((m_pos) < out) goto lookbehind_overrun | |
64c70b1c | 28 | |
72cf9012 WT |
29 | /* This MAX_255_COUNT is the maximum number of times we can add 255 to a base |
30 | * count without overflowing an integer. The multiply will overflow when | |
31 | * multiplying 255 by more than MAXINT/255. The sum will overflow earlier | |
32 | * depending on the base count. Since the base count is taken from a u8 | |
33 | * and a few bits, it is safe to assume that it will always be lower than | |
34 | * or equal to 2*255, thus we can always prevent any overflow by accepting | |
35 | * two less 255 steps. See Documentation/lzo.txt for more information. | |
36 | */ | |
37 | #define MAX_255_COUNT ((((size_t)~0) / 255) - 2) | |
38 | ||
64c70b1c | 39 | int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, |
8b975bd3 | 40 | unsigned char *out, size_t *out_len) |
64c70b1c | 41 | { |
8b975bd3 MO |
42 | unsigned char *op; |
43 | const unsigned char *ip; | |
44 | size_t t, next; | |
45 | size_t state = 0; | |
46 | const unsigned char *m_pos; | |
64c70b1c RP |
47 | const unsigned char * const ip_end = in + in_len; |
48 | unsigned char * const op_end = out + *out_len; | |
64c70b1c | 49 | |
5ee4014a DR |
50 | unsigned char bitstream_version; |
51 | ||
8b975bd3 MO |
52 | op = out; |
53 | ip = in; | |
64c70b1c | 54 | |
8b975bd3 MO |
55 | if (unlikely(in_len < 3)) |
56 | goto input_overrun; | |
5ee4014a | 57 | |
b11ed18e | 58 | if (likely(in_len >= 5) && likely(*ip == 17)) { |
5ee4014a DR |
59 | bitstream_version = ip[1]; |
60 | ip += 2; | |
5ee4014a DR |
61 | } else { |
62 | bitstream_version = 0; | |
63 | } | |
64 | ||
64c70b1c RP |
65 | if (*ip > 17) { |
66 | t = *ip++ - 17; | |
8b975bd3 MO |
67 | if (t < 4) { |
68 | next = t; | |
64c70b1c | 69 | goto match_next; |
64c70b1c | 70 | } |
8b975bd3 MO |
71 | goto copy_literal_run; |
72 | } | |
64c70b1c | 73 | |
8b975bd3 | 74 | for (;;) { |
64c70b1c | 75 | t = *ip++; |
8b975bd3 MO |
76 | if (t < 16) { |
77 | if (likely(state == 0)) { | |
78 | if (unlikely(t == 0)) { | |
72cf9012 WT |
79 | size_t offset; |
80 | const unsigned char *ip_last = ip; | |
81 | ||
8b975bd3 | 82 | while (unlikely(*ip == 0)) { |
64c70b1c | 83 | ip++; |
af958a38 | 84 | NEED_IP(1); |
64c70b1c | 85 | } |
72cf9012 WT |
86 | offset = ip - ip_last; |
87 | if (unlikely(offset > MAX_255_COUNT)) | |
88 | return LZO_E_ERROR; | |
89 | ||
90 | offset = (offset << 8) - offset; | |
91 | t += offset + 15 + *ip++; | |
64c70b1c | 92 | } |
8b975bd3 MO |
93 | t += 3; |
94 | copy_literal_run: | |
95 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) | |
af958a38 | 96 | if (likely(HAVE_IP(t + 15) && HAVE_OP(t + 15))) { |
8b975bd3 MO |
97 | const unsigned char *ie = ip + t; |
98 | unsigned char *oe = op + t; | |
99 | do { | |
100 | COPY8(op, ip); | |
101 | op += 8; | |
102 | ip += 8; | |
103 | COPY8(op, ip); | |
104 | op += 8; | |
105 | ip += 8; | |
106 | } while (ip < ie); | |
107 | ip = ie; | |
108 | op = oe; | |
109 | } else | |
110 | #endif | |
111 | { | |
af958a38 WT |
112 | NEED_OP(t); |
113 | NEED_IP(t + 3); | |
8b975bd3 MO |
114 | do { |
115 | *op++ = *ip++; | |
116 | } while (--t > 0); | |
64c70b1c | 117 | } |
8b975bd3 MO |
118 | state = 4; |
119 | continue; | |
120 | } else if (state != 4) { | |
121 | next = t & 3; | |
64c70b1c RP |
122 | m_pos = op - 1; |
123 | m_pos -= t >> 2; | |
124 | m_pos -= *ip++ << 2; | |
8b975bd3 | 125 | TEST_LB(m_pos); |
af958a38 | 126 | NEED_OP(2); |
8b975bd3 MO |
127 | op[0] = m_pos[0]; |
128 | op[1] = m_pos[1]; | |
129 | op += 2; | |
130 | goto match_next; | |
131 | } else { | |
132 | next = t & 3; | |
133 | m_pos = op - (1 + M2_MAX_OFFSET); | |
134 | m_pos -= t >> 2; | |
135 | m_pos -= *ip++ << 2; | |
136 | t = 3; | |
64c70b1c | 137 | } |
8b975bd3 MO |
138 | } else if (t >= 64) { |
139 | next = t & 3; | |
140 | m_pos = op - 1; | |
141 | m_pos -= (t >> 2) & 7; | |
142 | m_pos -= *ip++ << 3; | |
143 | t = (t >> 5) - 1 + (3 - 1); | |
144 | } else if (t >= 32) { | |
145 | t = (t & 31) + (3 - 1); | |
146 | if (unlikely(t == 2)) { | |
72cf9012 WT |
147 | size_t offset; |
148 | const unsigned char *ip_last = ip; | |
149 | ||
8b975bd3 | 150 | while (unlikely(*ip == 0)) { |
8b975bd3 | 151 | ip++; |
af958a38 | 152 | NEED_IP(1); |
8b975bd3 | 153 | } |
72cf9012 WT |
154 | offset = ip - ip_last; |
155 | if (unlikely(offset > MAX_255_COUNT)) | |
156 | return LZO_E_ERROR; | |
157 | ||
158 | offset = (offset << 8) - offset; | |
159 | t += offset + 31 + *ip++; | |
af958a38 | 160 | NEED_IP(2); |
8b975bd3 MO |
161 | } |
162 | m_pos = op - 1; | |
163 | next = get_unaligned_le16(ip); | |
164 | ip += 2; | |
165 | m_pos -= next >> 2; | |
166 | next &= 3; | |
167 | } else { | |
5ee4014a DR |
168 | NEED_IP(2); |
169 | next = get_unaligned_le16(ip); | |
170 | if (((next & 0xfffc) == 0xfffc) && | |
171 | ((t & 0xf8) == 0x18) && | |
172 | likely(bitstream_version)) { | |
173 | NEED_IP(3); | |
174 | t &= 7; | |
175 | t |= ip[2] << 3; | |
176 | t += MIN_ZERO_RUN_LENGTH; | |
177 | NEED_OP(t); | |
178 | memset(op, 0, t); | |
179 | op += t; | |
180 | next &= 3; | |
181 | ip += 3; | |
182 | goto match_next; | |
183 | } else { | |
184 | m_pos = op; | |
185 | m_pos -= (t & 8) << 11; | |
186 | t = (t & 7) + (3 - 1); | |
187 | if (unlikely(t == 2)) { | |
188 | size_t offset; | |
189 | const unsigned char *ip_last = ip; | |
72cf9012 | 190 | |
5ee4014a DR |
191 | while (unlikely(*ip == 0)) { |
192 | ip++; | |
193 | NEED_IP(1); | |
194 | } | |
195 | offset = ip - ip_last; | |
196 | if (unlikely(offset > MAX_255_COUNT)) | |
197 | return LZO_E_ERROR; | |
72cf9012 | 198 | |
5ee4014a DR |
199 | offset = (offset << 8) - offset; |
200 | t += offset + 7 + *ip++; | |
201 | NEED_IP(2); | |
202 | next = get_unaligned_le16(ip); | |
203 | } | |
204 | ip += 2; | |
205 | m_pos -= next >> 2; | |
206 | next &= 3; | |
207 | if (m_pos == op) | |
208 | goto eof_found; | |
209 | m_pos -= 0x4000; | |
8b975bd3 | 210 | } |
8b975bd3 MO |
211 | } |
212 | TEST_LB(m_pos); | |
213 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) | |
214 | if (op - m_pos >= 8) { | |
215 | unsigned char *oe = op + t; | |
af958a38 | 216 | if (likely(HAVE_OP(t + 15))) { |
64c70b1c | 217 | do { |
8b975bd3 MO |
218 | COPY8(op, m_pos); |
219 | op += 8; | |
220 | m_pos += 8; | |
221 | COPY8(op, m_pos); | |
222 | op += 8; | |
223 | m_pos += 8; | |
224 | } while (op < oe); | |
225 | op = oe; | |
af958a38 | 226 | if (HAVE_IP(6)) { |
8b975bd3 MO |
227 | state = next; |
228 | COPY4(op, ip); | |
229 | op += next; | |
230 | ip += next; | |
231 | continue; | |
232 | } | |
64c70b1c | 233 | } else { |
af958a38 | 234 | NEED_OP(t); |
64c70b1c RP |
235 | do { |
236 | *op++ = *m_pos++; | |
8b975bd3 | 237 | } while (op < oe); |
64c70b1c | 238 | } |
8b975bd3 MO |
239 | } else |
240 | #endif | |
241 | { | |
242 | unsigned char *oe = op + t; | |
af958a38 | 243 | NEED_OP(t); |
8b975bd3 MO |
244 | op[0] = m_pos[0]; |
245 | op[1] = m_pos[1]; | |
246 | op += 2; | |
247 | m_pos += 2; | |
248 | do { | |
249 | *op++ = *m_pos++; | |
250 | } while (op < oe); | |
251 | } | |
64c70b1c | 252 | match_next: |
8b975bd3 MO |
253 | state = next; |
254 | t = next; | |
255 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) | |
af958a38 | 256 | if (likely(HAVE_IP(6) && HAVE_OP(4))) { |
8b975bd3 MO |
257 | COPY4(op, ip); |
258 | op += t; | |
259 | ip += t; | |
260 | } else | |
261 | #endif | |
262 | { | |
af958a38 WT |
263 | NEED_IP(t + 3); |
264 | NEED_OP(t); | |
8b975bd3 | 265 | while (t > 0) { |
64c70b1c | 266 | *op++ = *ip++; |
8b975bd3 | 267 | t--; |
64c70b1c | 268 | } |
8b975bd3 | 269 | } |
64c70b1c RP |
270 | } |
271 | ||
64c70b1c RP |
272 | eof_found: |
273 | *out_len = op - out; | |
8b975bd3 MO |
274 | return (t != 3 ? LZO_E_ERROR : |
275 | ip == ip_end ? LZO_E_OK : | |
276 | ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN); | |
277 | ||
64c70b1c RP |
278 | input_overrun: |
279 | *out_len = op - out; | |
280 | return LZO_E_INPUT_OVERRUN; | |
281 | ||
282 | output_overrun: | |
283 | *out_len = op - out; | |
284 | return LZO_E_OUTPUT_OVERRUN; | |
285 | ||
286 | lookbehind_overrun: | |
287 | *out_len = op - out; | |
288 | return LZO_E_LOOKBEHIND_OVERRUN; | |
289 | } | |
7dd65feb | 290 | #ifndef STATIC |
64c70b1c RP |
291 | EXPORT_SYMBOL_GPL(lzo1x_decompress_safe); |
292 | ||
293 | MODULE_LICENSE("GPL"); | |
294 | MODULE_DESCRIPTION("LZO1X Decompressor"); | |
295 | ||
7dd65feb | 296 | #endif |