1 files changed, 467 insertions, 0 deletions

diff --git a/vchat-ssl.c b/vchat-ssl.c
new file mode 100755
index 0000000..5d68309
--- /dev/null
+++ b/vchat-ssl.c
@@ -0,0 +1,467 @@
+/*
+ * vchat-client - alpha version
+ * vchat-ssl.c - handling of SSL connection and X509 certificate
+ * verification
+ *
+ * Copyright (C) 2007 Thorsten Schroeder <ths@berlin.ccc.de>
+ *
+ * This program is free software. It can be redistributed and/or modified,
+ * provided that this copyright notice is kept intact. This program is
+ * distributed in the hope that it will be useful, but without any warranty;
+ * without even the implied warranty of merchantability or fitness for a
+ * particular purpose. In no event shall the copyright holder be liable for
+ * any direct, indirect, incidental or special damages arising in any way out
+ * of the use of this software. 
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/err.h>
+#include <openssl/ssl.h>
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/x509.h>
+#include <openssl/x509v3.h>
+#include <openssl/conf.h>
+
+#include "vchat.h"
+#include "vchat-ssl.h"
+
+char *vchat_ssl_version = "$Id$";
+
+static int ignore_ssl;
+
+#define VC_CTX_ERR_EXIT(se, cx) do { \
+      snprintf(tmpstr, TMPSTRSIZE, "CREATE CTX: %s", \
+            ERR_error_string (ERR_get_error (), NULL)); \
+      writecf(FS_ERR, tmpstr); \
+      if(se)  X509_STORE_free(se); \
+      if(cx) SSL_CTX_free(cx); \
+      return(0); \
+   } while(0)
+
+#define VC_SETCERT_ERR_EXIT(se, cx, err) do { \
+      snprintf(tmpstr, TMPSTRSIZE, "CREATE CTX: %s", err); \
+      writecf(FS_ERR, tmpstr); \
+      if(se)  X509_STORE_free(se); \
+      if(cx) SSL_CTX_free(cx); \
+      return(NULL); \
+   } while(0)
+
+SSL_CTX * vc_create_sslctx( vc_x509store_t *vc_store )
+{
+   int                  i                 = 0;
+   int                  n                 = 0;
+   int                  flags             = 0;
+   int                  r                 = 0;
+   SSL_CTX              *ctx              = NULL;
+   X509_STORE           *store            = NULL;
+   vc_x509verify_cb_t   verify_callback   = NULL;
+
+   if( !(ctx = SSL_CTX_new(SSLv3_method())) )
+      VC_CTX_ERR_EXIT(store, ctx);
+
+   if( !(store = vc_x509store_create(vc_store)) )
+      VC_CTX_ERR_EXIT(store, ctx);
+
+   SSL_CTX_set_cert_store(ctx, store);
+   store = NULL;
+   SSL_CTX_set_options(ctx, SSL_OP_ALL|SSL_OP_NO_SSLv2);
+   SSL_CTX_set_cipher_list(ctx, "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
+
+   SSL_CTX_set_verify_depth (ctx, 2);
+
+   if( !(verify_callback = vc_store->callback) )
+      verify_callback = vc_verify_callback;
+
+   if( !(vc_store->flags & VC_X509S_SSL_VERIFY_MASK) ) {
+      writecf(FS_DBG, tmpstr);
+      flags = SSL_VERIFY_NONE;
+   }
+   else {
+      if(vc_store->flags & VC_X509S_SSL_VERIFY_PEER)
+         flags |= SSL_VERIFY_PEER;
+      if(vc_store->flags & VC_X509S_SSL_VERIFY_FAIL_IF_NO_PEER_CERT)
+         flags |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
+      if(vc_store->flags & VC_X509S_SSL_VERIFY_CLIENT_ONCE)
+         flags |= SSL_VERIFY_CLIENT_ONCE;
+   }
+
+   SSL_CTX_set_verify(ctx, flags, verify_callback);
+
+   if(vc_store->flags & VC_X509S_USE_CERTIFICATE) {
+      if(vc_store->use_certfile)
+         SSL_CTX_use_certificate_chain_file(ctx, vc_store->use_certfile);
+      else {
+         SSL_CTX_use_certificate(ctx, 
+               sk_X509_value(vc_store->use_certs, 0));
+         for(i=0,n=sk_X509_num(vc_store->use_certs); i<n; i++)
+            SSL_CTX_add_extra_chain_cert(ctx, 
+                  sk_X509_value(vc_store->use_certs, i));
+      }
+
+      SSL_CTX_set_default_passwd_cb(ctx, vc_store->askpass_callback);
+
+      if(vc_store->use_keyfile) {
+         r=SSL_CTX_use_PrivateKey_file(ctx, vc_store->use_keyfile, 
+               SSL_FILETYPE_PEM);
+      } else if(vc_store->use_key)
+            r=SSL_CTX_use_PrivateKey(ctx, vc_store->use_key);
+
+      if(r!=1)
+         VC_SETCERT_ERR_EXIT(store, ctx, "Load private key failed");
+
+   }
+
+   SSL_CTX_set_app_data(ctx, vc_store);
+   return(ctx);
+}
+
+#define VC_CONNSSL_ERR_EXIT(_cx, cx, cn) do { \
+      snprintf(tmpstr, TMPSTRSIZE, "[SSL ERROR] %s", \
+            ERR_error_string (ERR_get_error (), NULL)); \
+      writecf(FS_ERR, tmpstr); \
+      if(cn)  BIO_free_all(cn); \
+      if(*cx) SSL_CTX_free(*cx); \
+      if(_cx) *cx = 0; \
+      return(0); \
+   } while(0)
+
+BIO * vc_connect_ssl(char *host, int port, vc_x509store_t *vc_store,
+      SSL_CTX **ctx)
+{
+   BIO *conn   = NULL;
+   int _ctx    = 0;
+   
+   if(*ctx) {
+      CRYPTO_add( &((*ctx)->references), 1, CRYPTO_LOCK_SSL_CTX );
+      if( vc_store && vc_store != SSL_CTX_get_app_data(*ctx) ) {
+         SSL_CTX_set_cert_store(*ctx, vc_x509store_create(vc_store));
+         SSL_CTX_set_app_data(*ctx, vc_store);
+      }
+   } else {
+      *ctx = vc_create_sslctx(vc_store);
+      _ctx = 1;
+   }
+
+   if( !(conn = BIO_new_ssl_connect(*ctx)) )
+      VC_CONNSSL_ERR_EXIT(_ctx, ctx, conn);
+
+   BIO_set_conn_hostname(conn, host);
+   BIO_set_conn_int_port(conn, &port);
+
+   fflush(stdout);
+   if(BIO_do_connect(conn) <= 0)
+      VC_CONNSSL_ERR_EXIT(_ctx, ctx, conn);
+
+   if(_ctx)
+      SSL_CTX_free(*ctx);
+
+   return(conn);
+}
+
+#define VC_CONN_ERR_EXIT(cn) do { \
+      snprintf(tmpstr, TMPSTRSIZE, "[SSL ERROR] %s", \
+            ERR_error_string(ERR_get_error(), NULL)); \
+      if(ERR_get_error()) \
+         writecf(FS_ERR, tmpstr); \
+      if(cn)  BIO_free_all(cn); \
+      return(NULL); \
+   } while(0)
+
+#define VC_VERIFICATION_ERR_EXIT(cn, err) do { \
+      snprintf(tmpstr, TMPSTRSIZE, \
+            "[SSL ERROR] certificate verify failed: %s", err); \
+      writecf(FS_ERR, tmpstr); \
+      if(cn && !ignore_ssl) { BIO_free_all(cn); return(NULL); } \
+   } while(0)
+
+BIO * vc_connect( char *host, int port, int use_ssl, 
+      vc_x509store_t *vc_store, SSL_CTX **ctx)
+{
+   BIO *conn   = NULL;
+   SSL *ssl    = NULL;
+
+   if(use_ssl) {
+      if( !(conn = vc_connect_ssl(host, port, vc_store, ctx)) )
+         VC_CONN_ERR_EXIT(conn);
+
+
+      BIO_get_ssl(conn, &ssl);
+      if(!vc_verify_cert_hostname(SSL_get_peer_certificate(ssl), host))
+         VC_VERIFICATION_ERR_EXIT(conn, "Hostname does not match!");
+
+      return(conn);
+   } 
+
+   *ctx = 0;
+
+   if( !(conn = BIO_new_connect(host)) )
+      VC_CONN_ERR_EXIT(conn);
+
+   BIO_set_conn_int_port(conn, &port);
+
+   if(BIO_do_connect(conn) <= 0)
+      VC_CONN_ERR_EXIT(conn);
+
+   return(conn);
+}
+
+int vc_verify_cert_hostname(X509 *cert, char *host)
+{
+   
+   int i          = 0;
+   int j          = 0;
+   int n          = 0;
+   int extcount   = 0;
+   int ok         = 0;
+
+   X509_NAME            *subj    = NULL;
+   const char           *extstr  = NULL;
+   CONF_VALUE           *nval    = NULL;
+   unsigned char        *data    = NULL;
+   X509_EXTENSION       *ext     = NULL;
+   X509V3_EXT_METHOD    *meth    = NULL;
+   STACK_OF(CONF_VALUE) *val     = NULL;
+
+   char name[256];
+   memset(&name, 0, sizeof(name));
+
+   if((extcount = X509_get_ext_count(cert)) > 0) {
+      
+      for(i=0; !ok && i < extcount; i++) {
+         
+         meth = NULL;
+
+         ext = X509_get_ext(cert, i);
+         extstr = OBJ_nid2sn(OBJ_obj2nid(X509_EXTENSION_get_object(ext)));
+
+         if(!strcasecmp(extstr, "subjectAltName")) {
+            
+            if( !(meth = X509V3_EXT_get(ext)) )
+               break;
+
+            if( !(meth->d2i) )
+               break;
+            
+            data = ext->value->data;
+
+            val = meth->i2v(meth, meth->d2i(0, &data, ext->value->length), 0);
+            for( j=0, n=sk_CONF_VALUE_num(val); j<n; j++ ) {
+               nval = sk_CONF_VALUE_value(val, j);
+               if( !strcasecmp(nval->name, "DNS") && 
+                     !strcasecmp(nval->value, host) ) {
+                  ok = 1;
+                  break;
+               }
+            } 
+         }
+      }
+   }
+
+   if( !ok && (subj = X509_get_subject_name(cert)) &&
+         X509_NAME_get_text_by_NID(subj, NID_commonName, 
+            name, sizeof(name)) > 0 ) {
+      name[sizeof(name)-1] = '\0';
+      if(!strcasecmp(name, host))
+         ok = 1;
+   }
+
+   //printf("[*] vc_verify_cert_hostname() return: %d\n", ok);
+   return(ok);
+}
+
+int vc_verify_cert(X509 *cert, vc_x509store_t *vc_store)
+{
+   int result           = -1;
+   X509_STORE  *store   = NULL;
+   X509_STORE_CTX *ctx  = NULL;
+
+   if( !(store = vc_x509store_create(vc_store)) )
+      return(result);
+
+   if( (ctx = X509_STORE_CTX_new()) != 0 ) {
+      if(X509_STORE_CTX_init(ctx, store, cert, 0) == 1)
+         result = (X509_verify_cert(ctx) == 1);
+      X509_STORE_CTX_free(ctx);
+   }
+
+   X509_STORE_free(store);
+   return(result);
+}
+
+#define VC_STORE_ERR_EXIT(s) do { \
+      fprintf(stderr, "[E] SSL_STORE: %s\n", ERR_error_string (ERR_get_error (), NULL)); \
+      if(s)  X509_STORE_free(s); \
+      return(0); \
+   } while(0)
+
+X509_STORE *vc_x509store_create(vc_x509store_t *vc_store)
+{
+   int i                = 0;
+   int n                = 0;
+   X509_STORE *store    = NULL;
+   X509_LOOKUP *lookup  = NULL;
+
+   store = X509_STORE_new();
+
+   if(vc_store->callback)
+      X509_STORE_set_verify_cb_func(store, vc_store->callback);
+   else
+      X509_STORE_set_verify_cb_func(store, vc_verify_callback);
+
+   if( !(lookup = X509_STORE_add_lookup(store, X509_LOOKUP_file())) )
+      VC_STORE_ERR_EXIT(store);
+
+   if(!vc_store->cafile) {
+      if( !(vc_store->flags & VC_X509S_NODEF_CAFILE) )
+         X509_LOOKUP_load_file(lookup, 0, X509_FILETYPE_DEFAULT);
+   } else if( !X509_LOOKUP_load_file(lookup, vc_store->cafile, 
+            X509_FILETYPE_PEM) )
+      VC_STORE_ERR_EXIT(store);
+
+   if(vc_store->crlfile) {
+      if( !X509_load_crl_file(lookup, vc_store->crlfile, 
+               X509_FILETYPE_PEM) )
+         VC_STORE_ERR_EXIT(store);
+
+      X509_STORE_set_flags( store, 
+            X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL );
+   }
+   
+   if( !(lookup = X509_STORE_add_lookup(store, X509_LOOKUP_hash_dir())) )
+      VC_STORE_ERR_EXIT(store);
+
+   if( !vc_store->capath ) {
+      if( !(vc_store->flags & VC_X509S_NODEF_CAPATH) )
+         X509_LOOKUP_add_dir(lookup, 0, X509_FILETYPE_DEFAULT);
+   } else if( !X509_LOOKUP_add_dir(lookup, vc_store->capath, 
+            X509_FILETYPE_PEM) )
+      VC_STORE_ERR_EXIT(store);
+
+   for( i=0, n=sk_X509_num(vc_store->certs); i<n; i++)
+      if( !X509_STORE_add_cert(store, sk_X509_value(vc_store->certs, i)) )
+         VC_STORE_ERR_EXIT(store);
+
+   for( i=0, n=sk_X509_CRL_num(vc_store->crls); i<n; i++)
+      if( !X509_STORE_add_crl(store, 
+               sk_X509_CRL_value(vc_store->crls, i)) ) 
+         VC_STORE_ERR_EXIT(store);
+
+   return(store);
+}
+
+int vc_verify_callback(int ok, X509_STORE_CTX *store)
+{
+   if(!ok) {
+      /* XXX handle action/abort */
+      if(!ignore_ssl)
+         snprintf(tmpstr, TMPSTRSIZE, "[SSL ERROR] %s", 
+               X509_verify_cert_error_string(store->error));
+      else
+         snprintf(tmpstr, TMPSTRSIZE, "[SSL ERROR] %s (ignored)", 
+               X509_verify_cert_error_string(store->error));
+
+      writecf(FS_ERR, tmpstr);
+      ok = ignore_ssl;
+   }
+   return(ok);
+}
+
+void vc_x509store_setflags(vc_x509store_t *store, int flags)
+{
+   store->flags |= flags;
+}
+
+void vc_x509store_setignssl(vc_x509store_t *store, int ignore)
+{
+   store->ignore_ssl |= ignore;
+   ignore_ssl = ignore;
+}
+
+void vc_x509store_clearflags(vc_x509store_t *store, int flags)
+{
+   store->flags &= ~flags;
+}
+
+void vc_x509store_setcb(vc_x509store_t *store, 
+      vc_x509verify_cb_t callback)
+{
+   store->callback = callback;
+}
+
+void vc_x509store_set_pkeycb(vc_x509store_t *store, 
+      vc_askpass_cb_t callback)
+{
+   store->askpass_callback = callback;
+}
+
+void vc_x509store_addcert(vc_x509store_t *store, X509 *cert)
+{
+   sk_X509_push(store->certs, cert);
+}
+
+void vc_x509store_setcafile(vc_x509store_t *store, char *file) 
+{
+   if( store->cafile) free(store->cafile);
+   store->cafile = ( file ? strdup(file) : 0 );
+}
+
+void vc_x509store_setcapath(vc_x509store_t *store, char *path) 
+{
+   if( store->capath) free(store->capath);
+   store->capath = ( path ? strdup(path) : 0 );
+}
+
+void vc_x509store_setcrlfile(vc_x509store_t *store, char *file) 
+{
+   if( store->crlfile) free(store->crlfile);
+   store->crlfile = ( file ? strdup(file) : 0 );
+}
+
+void vc_x509store_setkeyfile(vc_x509store_t *store, char *file) 
+{
+   if( store->use_keyfile) free(store->use_keyfile);
+   store->use_keyfile = ( file ? strdup(file) : 0 );
+}
+
+void vc_x509store_setcertfile(vc_x509store_t *store, char *file) 
+{
+   if( store->use_certfile) free(store->use_certfile);
+   store->use_certfile = ( file ? strdup(file) : 0 );
+}
+
+
+void vc_init_x509store(vc_x509store_t *s)
+{
+   s->cafile         = NULL;
+   s->capath         = NULL;
+   s->crlfile        = NULL;
+   s->callback       = NULL;
+   s->askpass_callback = NULL;
+   s->certs          = sk_X509_new_null();
+   s->crls           = sk_X509_CRL_new_null();
+   s->use_certfile   = NULL;
+   s->use_certs      = sk_X509_new_null();
+   s->use_keyfile    = NULL;
+   s->use_key        = NULL;
+   s->flags          = 0;
+   s->ignore_ssl     = 0;
+}
+
+void vc_cleanup_x509store(vc_x509store_t *s)
+{
+   if(s->cafile)        free(s->cafile);
+   if(s->capath)        free(s->capath);
+   if(s->crlfile)       free(s->crlfile);
+   if(s->use_certfile)  free(s->use_certfile);
+   if(s->use_keyfile)   free(s->use_keyfile);
+   if(s->use_key)       free(s->use_key);
+   sk_X509_free(s->certs);
+   sk_X509_free(s->crls);
+   sk_X509_free(s->use_certs);
+   s->ignore_ssl     = 0;
+}