SSL_accept hangs after calling fork() - c++

Question

I'm writing an app in C++ using openssl, and I can't seem to get the ssl socket connection to work.
I have an abstract class, with multiple functions implemented using various protocols by the inheriting classes and simple TCP and UDP ( posix sockets ) work fine.
I could not get the ssl working though and after some code browsing and tweaking I found out, that it is the fork() function which causes problems.
I wrote a very simple program to check things out, and this is what I get:
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <iostream>
#include <errno.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/timeb.h>
#include <netinet/in.h>
#include <sys/select.h>
#include <netdb.h>
#include <time.h>
#include </usr/local/include/ssl/ssl.h>
#include "SSL_CA.cpp"
int main( int argc, char **argv ) {
int retval;
SSL_CTX *ctx;
SSL *con;
int port = atoi(argv[1]);
sockaddr_in client_addr;
sockaddr_in serv_addr;
socklen_t client_len;
int max_clients = 40;
int serv_sock, client_sock;
if ( ( serv_sock = socket( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
return -12;
SSL_library_init();
int SSL_CA = NowySSL();
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = port;
cout << "Conf " << endl;
if ( bind( serv_sock, ( sockaddr * ) &serv_addr, sizeof( serv_addr ) ) < 0 )
return -1;
if ( listen( serv_sock, max_clients ) < 0 )
return -1;
while (1) {
cout << "Waiting" << endl;
if ( ( client_sock = accept( serv_sock, ( sockaddr * ) &client_addr, &client_len ) ) < 0 )
return -1;
pid_t pid = fork();
if ( pid = 0 ) {
con = NULL;
ctx = NULL;
ctx = (SSL_CTX *)SSL_CTX_new( SSLv23_server_method() );
con = (SSL *)SSL_new( (SSL_CTX *)ctx );
if (
!( ( ( !SSL_CA ) && ( SSL_NO_CA_RUN( con, ctx, client_sock, 0 ) ) ) ||
( ( SSL_CA ) && ( SSL_CA_RUN( con, ctx, client_sock, true ) ) ) )
)
return -1;
char buf[10];
if ( ( retval = SSL_read( con, buf, 10 ) ) <= 0 )
return -16;
cout << "Got msg " << buf << " " << retval << endl;
sprintf(buf, "12345" );
if ( ( retval = SSL_write( con, buf, strlen(buf) ) ) <= 0 )
return -1;
cout << "Sent" << endl;
}
else cout << "Parent " << endl;
}
return 0;
}
These are the SSL_CA_RUN and SSL_NO_CA_RUN functions - not written by me, but i have to use it
int SSL_NO_CA_RUN (SSL *con, SSL_CTX *ctx, int msgsock, int exit_now)
{
// printf ("SSL NO CA\n");
// SSL_library_init();
// ctx=(SSL_CTX *)SSL_CTX_new(SSLv23_server_method());
// con=(SSL *)SSL_new((SSL_CTX *)ctx);
if ((!SSL_set_fd (con,msgsock))||
(!SSL_use_RSAPrivateKey_file (con,"ktsa_u_linux.k",1))||
(!SSL_use_certificate_file (con,"ktsa_u_linux.c",1))||
(!SSL_accept (con)))
{
printf ("SSL ERROR (%s)\n",strerror(errno));
if (exit_now)
{
zamknij_polaczenie (con,ctx,msgsock);
exit(0);
}
return false;
}
// printf ("SSL NO CA OK!!!\n");
return true;
}
int SSL_CA_RUN (SSL *con, SSL_CTX *ctx, int msgsock, int exit_now)
{
int ret, ok=true;
X509 *peer;
FILE *fp;
char error[250];
// printf ("SSL CA\n");
//MARCIN (START)
//robimy linki do certyfikatow Marcin
certhash(CA_DIR,CRL_DIR,getpid());
//dostep_read (890);
// SSL_library_init();
// printf("\n");
// ctx=(SSL_CTX *)SSL_CTX_new(SSLv23_server_method());
// con=(SSL *)SSL_new((SSL_CTX *)ctx);
cb=pem_passwd_cb;
SSL_CTX_set_default_passwd_cb_userdata(ctx,haslo);
SSL_CTX_set_default_passwd_cb(ctx,cb);
//SSL_set_verify_depth(con,10); default = 9
SSL_set_verify(con,SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT,NULL);
// SSL_CTX_set_verify(ctx,SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT,NULL);
//SSL_CTX_set_cipher_list(ctx,"SHA1+3DES:+RSA:HIGH");
//SSL_set_cipher_list(con,"SHA1+3DES:+RSA:HIGH");
if ((!SSL_set_fd (con,msgsock))||
(!SSL_use_RSAPrivateKey_file (con,KEY_FILE,1))||
(!SSL_use_certificate_file (con,CERT_FILE,1))||
// (!SSL_CTX_load_verify_locations(ctx,CA_FILE,NULL))||
(!SSL_CTX_load_verify_locations(ctx,NULL,linkdir))||
(!SSL_accept (con))
)
{
if (exit_now)
{
remove_symdir(getpid());
// printf("error connect\n");
zamknij_polaczenie (con,ctx,msgsock);
exit(0);
} else remove_symdir(getpid());
ok=false;
}
if (ok)
{
peer=SSL_get_peer_certificate(con);
if(peer!=NULL)
{
//ret=1 - odwolany
//ret=0 - wszystko ok
//ret = inne - jakis inny blad, np. brak wlasciwej listy crl
//ret=check_peer_crl_dir(peer,error,CRL_DIR); //sprawdzenie odwolania certyfikatu przychodzacego
ret=check_peera(peer,error,0); //sprawdzenie odwolania certyfikatu przychodzacego
// printf("peer certyfikat:%s:%i\n",error,ret);
}
if ((peer==NULL)||(ret==1))
{
//nie akceptujemy polaczenia bo nie dostalismy certyfikatu lub certyfikat jest odwolany
// printf("polaczenie odrzucone - certyfikat peera odwolany, brak certyfikatu lub wystawiony przez inne CA \n");
if (exit_now)
{
remove_symdir(getpid());
zamknij_polaczenie (con,ctx,msgsock);
exit(2);
}
ok=false;
}
}
if (ok)
{
X509_free(peer); //potrzebne?
peer=NULL;
//mozna sprawdzic tez nasz certyfikat
if (!(fp = fopen (CERT_FILE, "r"))) //"/router/ssl/cert/sslcert.cer"
printf ("Error reading my certificate file\n");
if (!(peer = PEM_read_X509 (fp, NULL, NULL, NULL)))
printf ("Error reading my certificate in file\n");
if (fp)fclose (fp);
if(peer!=NULL)
{
//ret=1 - odwolany
//ret=0 - wszystko ok
//ret = inne - jakis inny blad, np. brak wlasciwej listy crl
//ret=check_peer_crl_dir(peer,error,CRL_DIR); //sprawdzenie odwolania certyfikatu przychodzacego
ret=check_peera(peer,error,0); //sprawdzenie odwolania certyfikatu naszego
// printf("nasz certyfikat:%s:%i\n",error,ret);
}
if ((peer==NULL)||(ret==1))
{
//nie akceptujemy polaczenia bo nasz certyfikat ma problem lub jest odwolany
// printf("polaczenie odrzucone- nasz certyfikat odwolany\n");
if (exit_now)
{
remove_symdir(getpid());
zamknij_polaczenie (con,ctx,msgsock);
exit(2);
}
ok=false;
}
}
if (ok)
{
X509_free(peer); //potrzebne?
peer=NULL;
}
// printf("connected...ok\n");
remove_symdir(getpid());
return ok;
}
If I don't call fork, all works fine, the message gets through, if the fork's there it gets stuck on ssl_accept.
Any help?

Answer 1

Not sure if this is just a typo or your real problem but this isn't going to do what you intend:
pid_t pid = fork();
if ( pid = 0 )
{
con = NULL;
//.............
Your child code is not going to execute.