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
|
#include <sys/ptrace.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdint.h>
#include <sys/mman.h>
#include "vm.h"
#include "util.h"
static void strtrim (char *str)
{
char *begin = str;
while (isspace(*begin)) {
begin++;
}
size_t len = strlen(begin);
char *end = begin + len;
while (end > begin && isspace(*end)) {
end++;
}
memmove(str, begin, end - begin + 1);
}
VMMapping* parse_vmmap (int pid)
{
char fmaps_path[128];
sprintf(fmaps_path, "/proc/%d/maps", pid);
FILE *fmaps;
if ((fmaps = fopen(fmaps_path, "r")) == NULL) {
perror("fopen");
exit(1);
}
uint64_t begin, end;
char perms[16];
char filename[1024];
VMMapping *head = NULL;
VMMapping *cur = NULL;
while(
fscanf(fmaps, "%lx-%lx %15s %*x %*x:%*x %*u%1023[^\n]",
&begin, &end, perms, filename) != EOF) {
strtrim(filename);
VMMapping *new_mapping = xmalloc(sizeof(VMMapping));
*new_mapping = (VMMapping) {
.begin = (void*)begin,
.end = (void*)end,
.r = perms[0] == 'r',
.w = perms[1] == 'w',
.x = perms[2] == 'x',
.s = perms[3] == 's',
.p = perms[3] == 'p',
.name = strdup(filename),
.next = NULL,
};
if (head) {
cur->next = new_mapping;
cur = new_mapping;
} else {
head = cur = new_mapping;
}
}
return head;
}
static off_t memfind(const uint8_t *hay, size_t hay_size, const uint8_t *needle, size_t needle_size)
{
for (off_t i = 0 ; i < hay_size - needle_size; ++i) {
if (memcmp(&hay[i], needle, needle_size) == 0) {
return i;
}
}
return hay_size;
}
MemscanResult* memscan(int pid, uint8_t *byte_seq, uint64_t byte_seq_len)
{
char fmem_path[1024] = {0};
sprintf(fmem_path, "/proc/%d/mem", pid);
FILE *fmem = fopen(fmem_path, "rb");
VMMapping *vmmaps_head = parse_vmmap(pid);
VMMapping *cur_vmmap = vmmaps_head;
MemscanResult *cur = NULL, *head = NULL;
while (cur_vmmap) {
if (!cur_vmmap->r) {
cur_vmmap = cur_vmmap->next;
continue;
}
size_t region_size = cur_vmmap->end - cur_vmmap->begin;
uint8_t region_data[region_size];
fseek(fmem, (off_t)cur_vmmap->begin, SEEK_SET);
fread(region_data, 1, region_size, fmem);
off_t offset = 0;
while (offset += memfind(region_data + offset,
region_size - offset,
byte_seq,
byte_seq_len),
offset < region_size) {
LOG("Matched pattern at [%p]\n", cur_vmmap->begin + (off_t)offset);
MemscanResult *new_result = xmalloc(sizeof(MemscanResult));
*new_result = (MemscanResult) {
.mapping = cur_vmmap,
.offset = offset,
.next = NULL,
};
if (head) {
cur->next = new_result;
cur = new_result;
}
else {
head = cur = new_result;
}
offset += byte_seq_len;
}
cur_vmmap = cur_vmmap->next;
}
fclose(fmem);
return head;
}
void memwrite(int pid, void *address, uint8_t *data, size_t data_len)
{
char fmem_path[1024] = {0};
sprintf(fmem_path, "/proc/%d/mem", pid);
FILE *fmem = fopen(fmem_path, "rb+");
fseek(fmem, (off_t)address, SEEK_SET);
fwrite(data, 1, data_len, fmem);
fclose(fmem);
LOG("Data written successfully at address %p\n", address);
}
|
