1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libdis.h"
#include "ia32_insn.h"
#include "ia32_invariant.h"
#include "x86_operand_list.h"
#ifdef _MSC_VER
#define snprintf _snprintf
#define inline __inline
#endif
unsigned int x86_disasm( unsigned char *buf, unsigned int buf_len,
uint32_t buf_rva, unsigned int offset,
x86_insn_t *insn ){
int len, size;
unsigned char bytes[MAX_INSTRUCTION_SIZE];
if ( ! buf || ! insn || ! buf_len ) {
/* caller screwed up somehow */
return 0;
}
/* ensure we are all NULLed up */
memset( insn, 0, sizeof(x86_insn_t) );
insn->addr = buf_rva + offset;
insn->offset = offset;
/* default to invalid insn */
insn->type = insn_invalid;
insn->group = insn_none;
if ( offset >= buf_len ) {
/* another caller screwup ;) */
x86_report_error(report_disasm_bounds, (void*)(long)buf_rva+offset);
return 0;
}
len = buf_len - offset;
/* copy enough bytes for disassembly into buffer : this
* helps prevent buffer overruns at the end of a file */
memset( bytes, 0, MAX_INSTRUCTION_SIZE );
memcpy( bytes, &buf[offset], (len < MAX_INSTRUCTION_SIZE) ? len :
MAX_INSTRUCTION_SIZE );
/* actually do the disassembly */
/* TODO: allow switching when more disassemblers are added */
size = ia32_disasm_addr( bytes, len, insn);
/* check and see if we had an invalid instruction */
if (! size ) {
x86_report_error(report_invalid_insn, (void*)(long)buf_rva+offset );
return 0;
}
/* check if we overran the end of the buffer */
if ( size > len ) {
x86_report_error( report_insn_bounds, (void*)(long)buf_rva + offset );
MAKE_INVALID( insn, bytes );
return 0;
}
/* fill bytes field of insn */
memcpy( insn->bytes, bytes, size );
return size;
}
unsigned int x86_disasm_range( unsigned char *buf, uint32_t buf_rva,
unsigned int offset, unsigned int len,
DISASM_CALLBACK func, void *arg ) {
x86_insn_t insn;
unsigned int buf_len, size, count = 0, bytes = 0;
/* buf_len is implied by the arguments */
buf_len = len + offset;
while ( bytes < len ) {
size = x86_disasm( buf, buf_len, buf_rva, offset + bytes,
&insn );
if ( size ) {
/* invoke callback if it exists */
if ( func ) {
(*func)( &insn, arg );
}
bytes += size;
count ++;
} else {
/* error */
bytes++; /* try next byte */
}
x86_oplist_free( &insn );
}
return( count );
}
static inline int follow_insn_dest( x86_insn_t *insn ) {
if ( insn->type == insn_jmp || insn->type == insn_jcc ||
insn->type == insn_call || insn->type == insn_callcc ) {
return(1);
}
return(0);
}
static inline int insn_doesnt_return( x86_insn_t *insn ) {
return( (insn->type == insn_jmp || insn->type == insn_return) ? 1: 0 );
}
static int32_t internal_resolver( x86_op_t *op, x86_insn_t *insn ){
int32_t next_addr = -1;
if ( x86_optype_is_address(op->type) ) {
next_addr = op->data.sdword;
} else if ( op->type == op_relative_near ) {
next_addr = insn->addr + insn->size + op->data.relative_near;
} else if ( op->type == op_relative_far ) {
next_addr = insn->addr + insn->size + op->data.relative_far;
}
return( next_addr );
}
unsigned int x86_disasm_forward( unsigned char *buf, unsigned int buf_len,
uint32_t buf_rva, unsigned int offset,
DISASM_CALLBACK func, void *arg,
DISASM_RESOLVER resolver, void *r_arg ){
x86_insn_t insn;
x86_op_t *op;
int32_t next_addr;
uint32_t next_offset;
unsigned int size, count = 0, bytes = 0, cont = 1;
while ( cont && bytes < buf_len ) {
size = x86_disasm( buf, buf_len, buf_rva, offset + bytes,
&insn );
if ( size ) {
/* invoke callback if it exists */
if ( func ) {
(*func)( &insn, arg );
}
bytes += size;
count ++;
} else {
/* error */
bytes++; /* try next byte */
}
if ( follow_insn_dest(&insn) ) {
op = x86_get_dest_operand( &insn );
next_addr = -1;
/* if caller supplied a resolver, use it to determine
* the address to disassemble */
if ( resolver ) {
next_addr = resolver(op, &insn, r_arg);
} else {
next_addr = internal_resolver(op, &insn);
}
if (next_addr != -1 ) {
next_offset = next_addr - buf_rva;
/* if offset is in this buffer... */
if ( next_offset >= 0 &&
next_offset < buf_len ) {
/* go ahead and disassemble */
count += x86_disasm_forward( buf,
buf_len,
buf_rva,
next_offset,
func, arg,
resolver, r_arg );
} else {
/* report unresolved address */
x86_report_error( report_disasm_bounds,
(void*)(long)next_addr );
}
}
} /* end follow_insn */
if ( insn_doesnt_return(&insn) ) {
/* stop disassembling */
cont = 0;
}
x86_oplist_free( &insn );
}
return( count );
}
/* invariant instruction representation */
size_t x86_invariant_disasm( unsigned char *buf, int buf_len,
x86_invariant_t *inv ){
if (! buf || ! buf_len || ! inv ) {
return(0);
}
return ia32_disasm_invariant(buf, buf_len, inv);
}
size_t x86_size_disasm( unsigned char *buf, unsigned int buf_len ) {
if (! buf || ! buf_len ) {
return(0);
}
return ia32_disasm_size(buf, buf_len);
}
|
