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#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, Bytes aob)
{
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 = xmalloc(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,
aob.data,
aob.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 += aob.len;
}
free(region_data);
cur_vmmap = cur_vmmap->next;
}
fclose(fmem);
return head;
}
void memwrite(int pid, void *address, Bytes aob)
{
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(aob.data, 1, aob.len, fmem);
fclose(fmem);
LOG("Data written successfully at address %p\n", address);
}
Bytes memread(int pid, void *address, size_t nbytes)
{
Bytes result = {
.data = xmalloc(nbytes),
.len = nbytes,
};
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);
fread(result.data, 1, result.len, fmem);
fclose(fmem);
return result;
}
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