91 lines
1.6 KiB
C
91 lines
1.6 KiB
C
// goal:
|
|
// replace "file" + "checksec"
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
|
|
#define MAX_FILENAME 256
|
|
#define EI_NIDENT 16
|
|
#define MAX_HEADER_LEN 2048
|
|
|
|
#define Elf32_Half uint16_t
|
|
#define Elf32_Word uint32_t
|
|
#define Elf32_Addr uint32_t
|
|
#define Elf32_Off uint32_t
|
|
|
|
struct Elf32_Ehdr
|
|
{
|
|
unsigned char e_ident[EI_NIDENT];
|
|
Elf32_Half e_type;
|
|
Elf32_Half e_machine;
|
|
Elf32_Word e_version;
|
|
Elf32_Addr e_entry;
|
|
Elf32_Off e_phoff;
|
|
Elf32_Off e_shoff;
|
|
Elf32_Word e_flags;
|
|
Elf32_Half e_ehsize;
|
|
Elf32_Half e_phentsize;
|
|
Elf32_Half e_phnum;
|
|
Elf32_Half e_shentsize;
|
|
Elf32_Half e_shnum;
|
|
Elf32_Half e_shstrndx;
|
|
};
|
|
|
|
int parse_elf_header32(struct Elf32_Ehdr* header, FILE* fp)
|
|
{
|
|
fread(header, sizeof(struct Elf32_Ehdr), 1, fp);
|
|
return EXIT_SUCCESS;
|
|
}
|
|
|
|
int main(int argc, char* argv[])
|
|
{
|
|
// Accessing file arg
|
|
if (argc < 2)
|
|
{
|
|
printf("Usage: %s <elf>\n", argv[0]);
|
|
return -EINVAL;
|
|
}
|
|
|
|
char* filename = argv[1];
|
|
|
|
// 0. is ELF32 or ELF64 ???
|
|
// 1. create ELF header struct
|
|
// 2. populate ELF header struct
|
|
// 3. display ELF header struct
|
|
|
|
if (!filename)
|
|
{
|
|
printf("Error parsing filename.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
FILE* elf_file = fopen(filename, "rb");
|
|
|
|
if (!elf_file)
|
|
{
|
|
printf("Couldn't open file '%s'\n", filename);
|
|
return -ENOENT;
|
|
}
|
|
|
|
struct Elf32_Ehdr elf_header = {0};
|
|
int res = parse_elf_header32(&elf_header, elf_file);
|
|
if (res)
|
|
{
|
|
printf("Error parsing ELF header.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!(memcmp(elf_header.e_ident, "\177ELF", 4) == 0))
|
|
{
|
|
printf("Not an ELF file..\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
printf("ELF file\n");
|
|
|
|
return EXIT_SUCCESS;
|
|
}
|