Hi,
I am developing a client and server in C. Client encrypts some data and sends it to the server. The server receives the data and prints it out. I am using AES 128 bit encryption in CBC mode. But at the server side I am unable to receive any thing due to segmentation fault error.
Code is in the following:
Client Code:
#include "headerfiles.h"
#define MAXDATASIZE 256
int main(int argc, char *argv[])
{
int sockfd;
int numbytes;
int port;
int in_len;
int out_len;
char buf[MAXDATASIZE];
char source[]="shahab";
char *target;
char mykey[EVP_MAX_KEY_LENGTH]="hardtobreak";
char iv[EVP_MAX_IV_LENGTH] = "aniv";
EVP_CIPHER_CTX ctx;
target=malloc(sizeof(source));
in_len=strlen(source);
/*----------------------------------------------------------------------*/
EVP_CIPHER_CTX_init(&ctx);
EVP_EncryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,mykey,iv);
EVP_EncryptUpdate(&ctx,target,&out_len,source,in_len);
EVP_EncryptFinal_ex(&ctx,target,&out_len);
/*----------------------------------------------------------------------*/
struct hostent *he;
struct sockaddr_in serverAddress;
if (argc != 3) {
fprintf(stderr,"usage: client hostname\n");
exit(1);
}
serverAddress.sin_addr.s_addr = inet_addr(argv[1]);
he=gethostbyaddr((char *) &serverAddress.sin_addr.s_addr,sizeof(serverAddress.sin_addr.s_addr),AF_INET);
port=atoi(argv[2]);
if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(port);
serverAddress.sin_addr = *((struct in_addr *)he->h_addr);
memset(serverAddress.sin_zero, '\0', sizeof serverAddress.sin_zero);
if (connect(sockfd, (struct sockaddr *)&serverAddress,sizeof (serverAddress)) == -1) {
perror("connect");
exit(1);
}
/* if ((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
perror("recv");
exit(1);
}*/
if (send(sockfd, target, MAXDATASIZE, 0) == -1){
perror("send");
}
/* buf[numbytes] = '\0';
printf("Received: %s",buf);*/
close(sockfd);
return 0;
}2. Server Code
#include "headerfiles.h"
#define SERVER_PORT 9990
#define BACKLOG 10
#define MAX_SIZE 500
int main(void)
{
int listenSocket;
int activeSocket;
int numberOfBytes; /*printf("Works");*/
int socketOption;
int bindCheck;
int listenCheck;
int sendCheck;
int out_len,in_len;
int yes=1;
char buffer[MAX_SIZE];
char mykey[EVP_MAX_KEY_LENGTH]="hardtobreak";
char iv[EVP_MAX_IV_LENGTH] = "aniv";
char *output;
socklen_t client_size;
EVP_CIPHER_CTX ctx;
struct sockaddr_in serverAddress;
struct sockaddr_in clientAddress;
listenSocket = socket(AF_INET, SOCK_STREAM, 0);
if(listenSocket==-1){
perror("socket");
exit(1);
}
socketOption=setsockopt(listenSocket, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
if(socketOption==-1){
perror("setsockopt");
exit(1);
}
bzero(&serverAddress,sizeof(serverAddress));
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(SERVER_PORT);
serverAddress.sin_addr.s_addr = INADDR_ANY;
bindCheck=bind(listenSocket, (struct sockaddr *)&serverAddress, sizeof (serverAddress));
if(bindCheck==-1){
perror("bind");
exit(1);
}
listenCheck=listen(listenSocket, BACKLOG);
if(listenCheck==-1){
perror("listen");
exit(1);
}
for(;;) {
client_size = sizeof (clientAddress);
activeSocket = accept(listenSocket, (struct sockaddr *)&clientAddress, &client_size);
if(activeSocket==-1){
perror("accept");
continue;
}
/* sendCheck=send(activeSocket, "Hello, world From Server!\n", MAX_SIZE, MSG_DONTWAIT);
if(sendCheck==-1){
perror("send");
}*/
numberOfBytes=recv(activeSocket, buffer,MAX_SIZE-1, 0);
if(numberOfBytes==-1)
{
perror("recv");
exit(1);
}
in_len=sizeof(buffer);
/*-----------------------------------------------------------*/
EVP_CIPHER_CTX_init(&ctx);
EVP_DecryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,mykey,iv);
EVP_DecryptUpdate(&ctx,output,&out_len,buffer,in_len);
EVP_DecryptFinal_ex(&ctx,output,&out_len);
/*-----------------------------------------------------------*/
output[out_len] = '\0';
printf("Received: %s",output);
}
close(activeSocket);
return 0;
}Thanks in Advance for your help.
