Rootme ELF - No software breakpoints Cracking Challenge

keygen.c

#include <stdio.h>  
/*
 * Title: Rootme ELF - No software breakpoints Cracking Challenge
 * Author: Osanda Malith (@OsandaMalith)
 * Website: http://osandamalith.wordpress.com
 */
int main(int argc, char const *argv[]) {
	
	size_t i;  
	unsigned int checksum; 
	char pass;  
	char password[25];  
	
	unsigned int key_bytes[25] = {
		0x1e,0xcd,0x2a,0xd5,0x34,0x87,0xfc,0x78,      
		0x64,0x35,0x9d,0xec,0xde,0x15,0xac,0x97,  
		0x99,0xaf,0x96,0xda,0x79,0x26,0x4f,0x32,  
		0xe0  
	};  
	unsigned char shellcode[164] =
		"\xb8\x04\x00\x00\x00\xbb\x01\x00\x00\x00\xb9\xa1\x91\x04"
		"\x08\xba\x26\x00\x00\x00\xcd\x80\xb8\x03\x00\x00\x00\x31"
		"\xdb\xb9\x88\x91\x04\x08\xba\x33\x00\x00\x00\xcd\x80\x31"
		"\xc9\xb8\x80\x80\x04\x08\xbb\x23\x81\x04\x08\xe8\x5b\x00"
		"\x00\x00\x89\xca\xb9\x19\x00\x00\x00\xb8\x55\x91\x04\x08"
		"\xbb\x88\x91\x04\x08\xd1\xca\x8a\x44\x08\xff\x8a\x5c\x0b"
		"\xff\x30\xd8\x30\xd0\x75\x1b\x49\x75\xe3\xb8\x04\x00\x00"
		"\x00\xbb\x01\x00\x00\x00\xb9\x24\x91\x04\x08\xba\x26\x00"
		"\x00\x00\xcd\x80\xeb\x16\xb8\x04\x00\x00\x00\xbb\x01\x00"
		"\x00\x00\xb9\x4a\x91\x04\x08\xba\x0b\x00\x00\x00\xcd\x80"
		"\xb8\x01\x00\x00\x00\x31\xdb\xcd\x80\x29\xc3\x31\xc9\x02"
		"\x08\xc1\xc1\x03\x40\x4b\x75\xf7\xc3";
	
	puts(
	"\t------------------------------------------------------------\n"
	"\t[~] Rootme No software breakpoints Cracking Challenge\n"
	"\t[~] Author: Osanda Malith (@OsandaMalith)\n"
	"\t[~] Website: http://osandamalith.wordpress.com\n"
	"\t------------------------------------------------------------\n"
	);

#if defined(_MSC_VER)
	_asm {
		lea esi, [shellcode]
		mov ebx, 163
		mov ecx, 0
		
	_loop:
		add cl, [esi]
		rol ecx, 0x3
		inc esi
		dec ebx
		jnz _loop
		mov[checksum], ecx
	}

#elif defined(__GNUC__)	
	asm(  
		".intel_syntax noprefix;"
		"lea esi, [%1];"
		"mov ebx, 163;"
		"mov ecx, 0;"  
		
	"_loop:"
		"add cl, [esi];"         
		"rol ecx, 0x3;" 
		"inc esi;"
		"dec ebx;"
		"jnz _Loop;" 
		"mov %0, ecx;"  
		
		".att_syntax;"
		:"=r" (checksum)  
		:"r" (shellcode)
	);   

#endif
	printf("Checksum: %x\n\n", checksum);  
 
	for (i = 0; i < 25; i++) {
		checksum = (checksum >> 1) | (checksum << (32 - 1)); // ror by 1
		pass = checksum ^ key_bytes[24 - i];
		printf("%p xor %x = %c\n", checksum, key_bytes[24 - i], pass);
		password[24 - i] = pass;
	}
	printf("\n\nSerial: ");
	for (i = 0; i < 25; i++) printf("%c", *(password+i));
	return 0;
 }  

Isn't line 69 supposed to be "jnz _loop;"?

Isn't line 69 supposed to be "jnz _loop;"?

Yep. Thanks :)