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