After adding a segment, the file size increases by a large amount

[yung1231]

I tried to add a Segment

Execute dummy can print hello world

import lief
from pwn import *

filename = './dummy'
bin = lief.parse(filename)

shellcode = asm("nop")*16

segment  = lief.ELF.Segment()
segment.type = lief.ELF.SEGMENT_TYPES.LOAD
segment.alignment = 0x100
segment.add(lief.ELF.SEGMENT_FLAGS.X)
segment.content   = bytearray(shellcode)
segment = bin.add(segment, base=0x1000)
bin.write(filename + "_infected")

I don't know why the file size changed from 8232 to 20520 ?

-rwxr-xr-x  1 root root  8232  1月  3 17:55 dummy*
-rw-rw-r--  1 root root 20520  1月  3 22:13 dummy_infected

Another question is, what does base in bin.add do and how do I set it up to be better?

[gogo2464]

[ZehMatt]

Sections are not mapped in the process space only segments are. He does not need to add sections if he wants to inject new code into the ELF binary.