Shellcode not working correctly

Question

I wrote a small program in assembly which is supposed to print "AAAA". It works fine when I run it directly, but when I run it as a shellcode in a c program, it doesn't work. Please help.

Here is the assembly code:

When I compile and execute the following code:

char shellcode[] = {0x31,0xc0,0xb0,0x04,0x31,0xdb,0xb3,0x01,0x68,0x41,0x41,0x41,0x41,0x89,0xe1,0x31,0xd2,0xb2,0x04,0xcd,0x80,0x31,0xc0,0xb0,0x01,0x31,0xdb,0xb3,0x01,0xcd,0x80};
int main(){
        (*(void(*)())shellcode)();
        return 0;
}

Compiled as:

$gcc -g -Wall -fno-stack-protector -z execstack code.c -o code

Execution:

$./code
$

Answer 1

You're showing x86 (32bit) shellcode, but are not compiling your program for that architecture, so gcc most likely creates an amd64 (64bit) executable instead. This can be fixed by adding the -m32 switch:

gcc -g -Wall -fno-stack-protector -z execstack -m32 code.c -o code

You can verify this by running file on the resulting file:

code: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), […]