114 lines
2.8 KiB
C
114 lines
2.8 KiB
C
#include <stdio.h>
|
|
#include <sys/mman.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <elf.h>
|
|
|
|
#include "log.h"
|
|
#include "elf.h"
|
|
|
|
// Pad ELF File
|
|
static void *elf_pad(const char *target, size_t padding, size_t *out_size) {
|
|
// File Data
|
|
FILE *file_obj = NULL;
|
|
unsigned char *file_map = NULL;
|
|
long int file_size = 0;
|
|
|
|
// Return
|
|
unsigned char *out = NULL;
|
|
|
|
// Code
|
|
{
|
|
// Load Main Binary
|
|
file_obj = fopen(target, "rb");
|
|
|
|
// Verify Binary
|
|
if (!file_obj) {
|
|
ERR("Unable To Open: %s", target);
|
|
}
|
|
|
|
// Get File Size
|
|
fseek(file_obj, 0L, SEEK_END);
|
|
file_size = ftell(file_obj);
|
|
fseek(file_obj, 0L, SEEK_SET);
|
|
|
|
// Map File To Pointer
|
|
file_map = (unsigned char *) mmap(0, file_size, PROT_READ, MAP_PRIVATE, fileno(file_obj), 0);
|
|
|
|
// Check ELF Magic
|
|
if (file_map[EI_MAG0] != ELFMAG0 || file_map[EI_MAG1] != ELFMAG1 || file_map[EI_MAG2] != ELFMAG2 || file_map[EI_MAG3] != ELFMAG3) {
|
|
ERR("Not An ELF File: %s", target);
|
|
}
|
|
int is_64bit = file_map[EI_CLASS] != ELFCLASS32;
|
|
if (file_map[EI_DATA] != ELFDATA2LSB) {
|
|
ERR("ELF File Isn't Little-Endian: %s", target);
|
|
}
|
|
|
|
// Allocate New File
|
|
*out_size = file_size + padding;
|
|
out = malloc(*out_size);
|
|
ALLOC_CHECK(out);
|
|
|
|
// Copy Header
|
|
size_t header_size = is_64bit ? sizeof (Elf64_Ehdr) : sizeof (Elf32_Ehdr);
|
|
memcpy(out, file_map, header_size);
|
|
// Copy Everything Else
|
|
memcpy(out + header_size + padding, file_map + header_size, file_size - header_size);
|
|
// Zero Padding
|
|
memset(out + header_size, 0, padding);
|
|
|
|
// Fix Pointers
|
|
if (is_64bit) {
|
|
Elf64_pad(out, padding);
|
|
} else {
|
|
Elf32_pad(out, padding);
|
|
}
|
|
}
|
|
|
|
// Unmap And Close File
|
|
if (file_map != NULL) {
|
|
munmap(file_map, file_size);
|
|
}
|
|
if (file_obj != NULL) {
|
|
fclose(file_obj);
|
|
}
|
|
|
|
// Return
|
|
return out;
|
|
}
|
|
|
|
// Main
|
|
int main(int argc, char *argv[]) {
|
|
if (argc != 3) {
|
|
ERR("%s", "Invalid Arguments");
|
|
}
|
|
|
|
// Arguments
|
|
size_t padding = 0;
|
|
if (sscanf(argv[1], "%zu", &padding) != 1) {
|
|
ERR("%s", "Unable To Parse Padding Number");
|
|
}
|
|
char *target = argv[2];
|
|
|
|
// Align Padding To Page Boundary
|
|
{
|
|
long page_size = sysconf(_SC_PAGESIZE);
|
|
size_t old_padding = padding;
|
|
padding = (padding / page_size) * page_size;
|
|
if ((old_padding % page_size) != 0) {
|
|
padding += page_size;
|
|
}
|
|
}
|
|
INFO("Aligning Padding To Page Boundary: %zu", padding);
|
|
|
|
// Pad
|
|
size_t out_size = 0;
|
|
void *out = elf_pad(target, padding, &out_size);
|
|
|
|
// Print
|
|
fwrite(out, 1, out_size, stdout);
|
|
|
|
// Free
|
|
free(out);
|
|
}
|