README.md

jsonelf

Describe an ELF file in JSON.

This is basically like readelf but with structured output appropriate for scripting or integration tests.

Compiling and installing

Compiling jsonelf requires the following dependencies:

• git
• gcc
• linux-headers
• python3
• json-c

Once you have the dependencies installed:

git clone https://github.com/briansteffens/jsonelf
cd jsonelf
make
sudo make install

Uninstall like this:

sudo make uninstall

Usage example

To run jsonelf on an ELF file called test.o, execute the following:

jsonelf test.o

In this case test.o is a minimal hello world object file produced by nasm. The output should look something like this:

{
   "e_ident": {
     "ei_class": "ELFCLASS64",
     "ei_data": "ELFDATA2LSB",
     "ei_version": "EV_CURRENT",
     "ei_osabi": "ELFOSABI_NONE | ELFOSABI_SYSV",
     "ei_abiversion": 0
   },
   "e_type": "ET_REL",
   "e_machine": "EM_X86_64",
   "e_version": "EV_CURRENT",
   "e_entry": 0,
   "e_phoff": 0,
   "e_shoff": 64,
   "e_flags": 0,
   "e_ehsize": 64,
   "e_phentsize": 0,
   "e_phnum": 0,
   "e_shentsize": 64,
   "e_shnum": 7,
   "e_shstrndx": 3,
   "program_headers": [
   ],
   "section_headers": [
     {
       "sh_name": "",
       "sh_type": "SHT_NULL",
       "sh_flags": "",
       "sh_addr": 0,
       "sh_offset": 0,
       "sh_size": 0,
       "sh_link": 0,
       "sh_info": 0,
       "sh_addralign": 0,
       "sh_entsize": 0
     },
     {
       "sh_name": ".data",
       "sh_type": "SHT_PROGBITS",
       "sh_flags": "SHF_WRITE | SHF_ALLOC",
       "sh_addr": 0,
       "sh_offset": 512,
       "sh_size": 11,
       "sh_link": 0,
       "sh_info": 0,
       "sh_addralign": 4,
       "sh_entsize": 0
     },
     {
       "sh_name": ".text",
       "sh_type": "SHT_PROGBITS",
       "sh_flags": "SHF_ALLOC | SHF_EXECINSTR",
       "sh_addr": 0,
       "sh_offset": 528,
       "sh_size": 39,
       "sh_link": 0,
       "sh_info": 0,
       "sh_addralign": 16,
       "sh_entsize": 0
     },
     {
       "sh_name": ".shstrtab",
       "sh_type": "SHT_STRTAB",
       "sh_flags": "SHF_ALLOC | SHF_EXECINSTR",
       "sh_addr": 0,
       "sh_offset": 576,
       "sh_size": 50,
       "sh_link": 0,
       "sh_info": 0,
       "sh_addralign": 1,
       "sh_entsize": 0,
       "strings": [
         "",
         ".data",
         ".text",
         ".shstrtab",
         ".symtab",
         ".strtab",
         ".rela.text",
         ""
       ]
     },
     {
       "sh_name": ".symtab",
       "sh_type": "SHT_SYMTAB",
       "sh_flags": "SHF_ALLOC | SHF_EXECINSTR",
       "sh_addr": 0,
       "sh_offset": 640,
       "sh_size": 168,
       "sh_link": 5,
       "sh_info": 6,
       "sh_addralign": 8,
       "sh_entsize": 24,
       "symbols": [
         {
           "st_name": "",
           "st_info": "STT_NOTYPE | STB_LOCAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": "UND",
           "st_value": 0,
           "st_size": 0
         },
         {
           "st_name": "test.asm",
           "st_info": "STT_FILE | STB_LOCAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": "ABS",
           "st_value": 0,
           "st_size": 0
         },
         {
           "st_name": "",
           "st_info": "STT_SECTION | STB_LOCAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": ".data",
           "st_value": 0,
           "st_size": 0
         },
         {
           "st_name": "",
           "st_info": "STT_SECTION | STB_LOCAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": "data",
           "st_value": 0,
           "st_size": 0
         },
         {
           "st_name": "msg",
           "st_info": "STT_NOTYPE | STB_LOCAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": ".data",
           "st_value": 0,
           "st_size": 0
         },
         {
           "st_name": "msg_len",
           "st_info": "STT_NOTYPE | STB_LOCAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": "ABS",
           "st_value": 11,
           "st_size": 0
         },
         {
           "st_name": "_start",
           "st_info": "STT_NOTYPE | STB_GLOBAL",
           "st_other": "STV_DEFAULT",
           "st_shndx": "data",
           "st_value": 0,
           "st_size": 0
         }
       ]
     },
     {
       "sh_name": ".strtab",
       "sh_type": "SHT_STRTAB",
       "sh_flags": "SHF_ALLOC | SHF_EXECINSTR",
       "sh_addr": 0,
       "sh_offset": 816,
       "sh_size": 29,
       "sh_link": 0,
       "sh_info": 0,
       "sh_addralign": 1,
       "sh_entsize": 0,
       "strings": [
         "",
         "test.asm",
         "msg",
         "msg_len",
         "_start",
         ""
       ]
     },
     {
       "sh_name": ".rela.text",
       "sh_type": "SHT_RELA",
       "sh_flags": "SHF_ALLOC | SHF_EXECINSTR",
       "sh_addr": 0,
       "sh_offset": 848,
       "sh_size": 24,
       "sh_link": 4,
       "sh_info": 2,
       "sh_addralign": 8,
       "sh_entsize": 24,
       "relocations": [
         {
           "r_offset": 12,
           "r_info": 1,
           "r_addend": 0,
           "__sym_table": 2,
           "__relo_type": "R_X86_64_64"
         }
       ]
     }
   ]
}