Discussion :

[stanlagtan]

Bonjour a tous, j'essaie d'etablir une connexion securisee avec un serveur.
le serveur que j'ai implemente utilise SSLv3.
j'utilise l'api openssl pour ecrire mon programme client mais j'ai des tas d'erreurs du style: "undefined reference to ..."
voici mon code :

Code :

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#include <stdio.h>
#include <memory.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <openssl/crypto.h>
#include <openssl/x509.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <unistd.h>

#define CHK_NULL(x) if ((x)==NULL) exit (1)
#define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); }
#define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); }

int main ()
{


  int err;
  int sd;
  struct sockaddr_in sa;
  SSL_CTX* ctx;
  SSL*     ssl;
  X509*    server_cert;
  char*    str;
  char     buf [4096];
  

  SSLeay_add_ssl_algorithms();
  
  SSL_load_error_strings();
  ctx = SSL_CTX_new( SSLv3_client_method());                      CHK_NULL(ctx);

  CHK_SSL(err);
  
  /* ----------------------------------------------- */
  /* Create a socket and connect to server using normal socket calls. */
  
  sd = socket (AF_INET, SOCK_STREAM, 0);       CHK_ERR(sd, "socket");
 
  memset (&sa, '\0', sizeof(sa));
  sa.sin_family      = AF_INET;
  sa.sin_addr.s_addr = inet_addr ("127.0.0.1");   /* Server IP */
  sa.sin_port        = htons     (1111);          /* Server Port number */
  
  err = connect(sd, (struct sockaddr*) &sa,
		sizeof(sa));                   CHK_ERR(err, "connect");

  /* ----------------------------------------------- */
  /* Now we have TCP conncetion. Start SSL negotiation. */
  
  ssl = SSL_new (ctx);                         CHK_NULL(ssl);    
  SSL_set_fd (ssl, sd);
  err = SSL_connect (ssl);                     CHK_SSL(err);
    
  /* Following two steps are optional and not required for
     data exchange to be successful. */
  
  /* Get the cipher - opt */

  printf ("SSL connection using %s\n", SSL_get_cipher (ssl));
  
  /* Get server's certificate (note: beware of dynamic allocation) - opt */

  server_cert = SSL_get_peer_certificate (ssl);       CHK_NULL(server_cert);
  printf ("Server certificate:\n");
  
  str = X509_NAME_oneline (X509_get_subject_name (server_cert),0,0);
  CHK_NULL(str);
  printf ("\t subject: %s\n", str);
  OPENSSL_free (str);

  str = X509_NAME_oneline (X509_get_issuer_name  (server_cert),0,0);
  CHK_NULL(str);
  printf ("\t issuer: %s\n", str);
  OPENSSL_free (str);

  /* We could do all sorts of certificate verification stuff here before
     deallocating the certificate. */

  X509_free (server_cert);
  
  /* --------------------------------------------------- */
  /* DATA EXCHANGE - Send a message and receive a reply. */

  err = SSL_write (ssl, "Hello World!", strlen("Hello World!"));  CHK_SSL(err);
  
  err = SSL_read (ssl, buf, sizeof(buf) - 1);                     CHK_SSL(err);
  buf[err] = '\0';
  printf ("Got %d chars:'%s'\n", err, buf);
  SSL_shutdown (ssl);  /* send SSL/TLS close_notify */

  /* Clean up. */

  close (sd);
  SSL_free (ssl);
  SSL_CTX_free (ctx);
}
/* EOF - cli.cpp */

et voici les principaux message d'errerus que j'obtiens:

cli.cpp.text+0x1c): undefined reference to `SSL_library_init'
cli.cpp.text+0x21): undefined reference to `SSL_load_error_strings'
cli.cpp.text+0x26): undefined reference to `SSLv3_client_method'
cli.cpp.text+0x2e): undefined reference to `SSL_CTX_new'
cli.cpp.text+0x59): undefined reference to `ERR_print_errors_fp'
cli.cpp.text+0x145): undefined reference to `SSL_new'
cli.cpp.text+0x170): undefined reference to `SSL_set_fd'
cli.cpp.text+0x17c): undefined reference to `SSL_connect'
cli.cpp.text+0x194): undefined reference to `ERR_print_errors_fp'
cli.cpp.text+0x1ac): undefined reference to `SSL_get_current_cipher'
cli.cpp.text+0x1b4): undefined reference to `SSL_CIPHER_get_name'
cli.cpp.text+0x1d0): undefined reference to `SSL_get_peer_certificate'
cli.cpp.text+0x1ff): undefined reference to `X509_get_subject_name'
cli.cpp.text+0x217): undefined reference to `X509_NAME_oneline'
cli.cpp.text+0x24e): undefined reference to `CRYPTO_free'
cli.cpp.text+0x25a): undefined reference to `X509_get_issuer_name'
cli.cpp.text+0x272): undefined reference to `X509_NAME_oneline'
cli.cpp.text+0x2a9): undefined reference to `CRYPTO_free'
cli.cpp.text+0x2b5): undefined reference to `X509_free'
cli.cpp.text+0x2d1): undefined reference to `SSL_write'
cli.cpp.text+0x2e9): undefined reference to `ERR_print_errors_fp'
cli.cpp.text+0x311): undefined reference to `SSL_read'
cli.cpp.text+0x329): undefined reference to `ERR_print_errors_fp'
cli.cpp.text+0x368): undefined reference to `SSL_shutdown'
cli.cpp.text+0x380): undefined reference to `SSL_free'
cli.cpp.text+0x38c): undefined reference to `SSL_CTX_free'

pensez vous que c'est a cause d'une bibliotheque que je n'ai pas inclus?

toute aide est la bien venue.
merci!!!

[liberal1]

SSL est un protocole obsolète.

[BufferBob]

SSL est un protocole obsolète.

ça n'est absolument pas pertinent.

Code :

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cli.cpp:(.text+0x1c): undefined reference to `SSL_library_init'
cli.cpp:(.text+0x21): undefined reference to `SSL_load_error_strings'
cli.cpp:(.text+0x26): undefined reference to `SSLv3_client_method'
(...)

c'est typique d'un flag manquant, essaye de compiler en rajoutant -lssl au bon endroit
ç'aurait été plus avisé de poster la discussion dans le forum C/C++ à mon avis, c'est une question classique

[liberal1]

SSL est obsolète et ne doit pas être utilisé.