[Development] os: add gnutls_x509_crt_print() implementation, older systems

don't have it and improve backward compatibility of TLS code.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4277 3789f03b-4d11-0410-bbf8-ca57d06f2519

common/os/CMakeLists.txt

@@ -3,4 +3,5 @@ include_directories(${CMAKE_SOURCE_DIR}/common)
 add_library(os STATIC
   print.c
   net.c
-  os.cxx)
+  os.cxx
+  tls.cxx)

common/os/Makefile.am

@@ -1,8 +1,8 @@
 noinst_LTLIBRARIES = libos.la
 
-HDRS = net.h print.h os.h
+HDRS = net.h print.h os.h tls.h
 
-libos_la_SOURCES = $(HDRS) print.c net.c os.cxx
+libos_la_SOURCES = $(HDRS) print.c net.c os.cxx tls.cxx
 
 libos_la_CPPFLAGS = -I$(top_srcdir)/common
 

common/os/tls.cxx

@@ -0,0 +1,193 @@
+/* Copyright (C) 2011 TightVNC Team.  All Rights Reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software 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.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <os/tls.h>
+
+#include <iomanip>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sstream>
+#include <sys/types.h>
+#include <time.h>
+
+using namespace std;
+
+#ifdef HAVE_GNUTLS
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#ifndef HAVE_GNUTLS_X509_CRT_PRINT
+
+#define UNKNOWN_SUBJECT(err) \
+	do { \
+		ss << "unknown subject (" << gnutls_strerror(err) << "), "; \
+	} while (0)
+
+#define UNKNOWN_ISSUER(err) \
+	do { \
+		ss << "unknown issuer (" << gnutls_strerror(err) << "), "; \
+	} while (0)
+
+
+static void
+hexprint(ostringstream &ss, const char *data, size_t len)
+{
+	size_t j;
+	char tmp[3];
+
+	if (len == 0)
+		ss << "00";
+	else {
+		for (j = 0; j < len; j++) {
+			snprintf(tmp, sizeof(tmp), "%.2x", (unsigned char) data[j]);
+			ss << tmp;
+		}
+	}
+}
+
+/* Implementation based on gnutls_x509_crt_print from GNUTLS */
+int
+gnutls_x509_crt_print(gnutls_x509_crt_t cert,
+		      gnutls_certificate_print_formats_t format,
+		      gnutls_datum_t * out)
+{
+	ostringstream ss;
+	
+	int err;
+
+	char *dn;
+	size_t dn_size = 0;
+
+	/* Subject */
+	err = gnutls_x509_crt_get_dn(cert, NULL, &dn_size);
+	if (err != GNUTLS_E_SHORT_MEMORY_BUFFER)
+		UNKNOWN_SUBJECT(err);
+	else {
+		dn = (char *)malloc(dn_size);
+		if (dn == NULL) {
+			UNKNOWN_SUBJECT(GNUTLS_E_MEMORY_ERROR);
+		} else {
+			err = gnutls_x509_crt_get_dn(cert, dn, &dn_size);
+			if (err < 0) {
+				UNKNOWN_SUBJECT(err);
+			} else
+				ss << "subject `" << dn << "', ";
+			free(dn);
+		}
+	}
+
+	/* Issuer */
+	dn = NULL;
+	dn_size = 0;
+	err = gnutls_x509_crt_get_issuer_dn(cert, NULL, &dn_size);
+	if (err != GNUTLS_E_SHORT_MEMORY_BUFFER)
+		UNKNOWN_ISSUER(err);
+	else {
+		dn = (char *)malloc(dn_size);
+		if (dn == NULL) {
+			UNKNOWN_ISSUER(GNUTLS_E_MEMORY_ERROR);
+		} else {
+			err = gnutls_x509_crt_get_issuer_dn(cert, dn, &dn_size);
+			if (err < 0)
+				UNKNOWN_ISSUER(err);
+			else
+				ss << "issuer `" << dn << "', ";
+			free(dn);
+		}
+	}
+
+	/* Key algorithm and size */
+	unsigned int bits;
+	const char *name;
+	name = gnutls_pk_algorithm_get_name( (gnutls_pk_algorithm_t)
+		gnutls_x509_crt_get_pk_algorithm(cert, &bits));
+	if (name == NULL)
+		name = "Unknown";
+	ss << name << " key " << bits << " bits, ";
+
+	/* Signature algorithm */
+	err = gnutls_x509_crt_get_signature_algorithm(cert);
+	if (err < 0) {
+		ss << "unknown signature algorithm (" << gnutls_strerror(err)
+		   << "), ";
+	} else {
+		const char *name;
+		name = gnutls_sign_algorithm_get_name((gnutls_sign_algorithm_t)err);
+		if (name == NULL)
+			name = "Unknown";
+
+		ss << "signed using " << name;
+		if (err == GNUTLS_SIGN_RSA_MD5 || err == GNUTLS_SIGN_RSA_MD2)
+			ss << " (broken!)";
+		ss << ", ";
+	}
+
+	/* Validity */
+	time_t tim;
+	char s[42];
+	size_t max = sizeof(s);
+	struct tm t;
+
+	tim = gnutls_x509_crt_get_activation_time(cert);
+	if (gmtime_r(&tim, &t) == NULL)
+		ss << "unknown activation (" << (unsigned long) tim << ")";
+	else if (strftime(s, max, "%Y-%m-%d %H:%M:%S UTC", &t) == 0)
+		ss << "failed activation (" << (unsigned long) tim << ")";
+	else
+		ss << "activated `" << s << "'";
+	ss << ", ";
+
+	tim = gnutls_x509_crt_get_expiration_time(cert);
+	if (gmtime_r(&tim, &t) == NULL)
+		ss << "unknown expiry (" << (unsigned long) tim << ")";
+	else if (strftime(s, max, "%Y-%m-%d %H:%M:%S UTC", &t) == 0)
+		ss << "failed expiry (" << (unsigned long) tim << ")";
+	else
+		ss << "expires `" << s << "'";
+	ss << ", ";
+
+	/* Fingerprint */
+	char buffer[20];
+	size_t size = sizeof(buffer);
+
+	err = gnutls_x509_crt_get_fingerprint(cert, GNUTLS_DIG_SHA1, buffer, &size);
+	if (err < 0)
+		ss << "unknown fingerprint (" << gnutls_strerror(err) << ")";
+	else {
+		ss << "SHA-1 fingerprint `";
+		hexprint(ss, buffer, size);
+		ss << "'";
+	}
+
+	out->data = (unsigned char *) strdup(ss.str().c_str());
+	if (out->data == NULL)
+		return GNUTLS_E_MEMORY_ERROR;
+	out->size = strlen((char *)out->data);
+
+	return 0;
+}
+
+#endif /* HAVE_GNUTLS_X509_CRT_PRINT */
+
+#endif /* HAVE_GNUTLS */
+

common/os/tls.h

@@ -0,0 +1,49 @@
+/* Copyright (C) 2011 TightVNC Team.  All Rights Reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software 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.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#ifndef OS_TLS_H
+#define OS_TLS_H
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifdef HAVE_GNUTLS
+#include <gnutls/gnutls.h>
+
+#ifndef HAVE_GNUTLS_X509_CRT_PRINT
+#ifdef WIN32
+#error "Please install more recent GNUTLS with gnutls_x509_crt_print() function"
+#endif
+
+typedef enum {
+	GNUTLS_CRT_PRINT_ONELINE = 1
+} gnutls_certificate_print_formats_t;
+
+/*
+ * Prints certificate in human-readable form.
+ */
+int
+gnutls_x509_crt_print(gnutls_x509_crt_t cert,
+		      gnutls_certificate_print_formats_t format,
+		      gnutls_datum_t * out);
+#endif /* HAVE_GNUTLS_X509_CRT_PRINT */
+#endif /* HAVE_GNUTLS */
+
+#endif /* OS_TLS_H */
+

common/rfb/CSecurityTLS.cxx

@@ -43,16 +43,18 @@
 #include <rdr/TLSOutStream.h>
 #include <os/os.h>
 #include <os/print.h>
+#include <os/tls.h>
 
 #include <gnutls/x509.h>
 
-#if !defined(GNUTLS_VERSION_NUMBER) || (GNUTLS_VERSION_NUMBER < 0x020708)
-#define GNUTLS_CERT_NOT_ACTIVATED 512
-#define GNUTLS_CERT_EXPIRED 1024
-#endif
-
-#if !defined(GNUTLS_VERSION_NUMBER) || (GNUTLS_VERSION_NUMBER < 0x020301)
-#define GNUTLS_CRT_PRINT_ONELINE 1
+/*
+ * GNUTLS 2.6.5 and older didn't have some variables defined so don't use them.
+ * GNUTLS 1.X.X defined LIBGNUTLS_VERSION_NUMBER so treat it as "old" gnutls as
+ * well
+ */
+#if (defined(GNUTLS_VERSION_NUMBER) && GNUTLS_VERSION_NUMBER < 0x020606) || \
+    defined(LIBGNUTLS_VERSION_NUMBER)
+#define WITHOUT_X509_TIMES
 #endif
 
 #define TLS_DEBUG
@@ -284,6 +286,7 @@ void CSecurityTLS::checkSession()
   if (status & GNUTLS_CERT_REVOKED)
     throw AuthFailureException("server certificate has been revoked");
 
+#ifndef WITHOUT_X509_TIMES
   if (status & GNUTLS_CERT_NOT_ACTIVATED)
     throw AuthFailureException("server certificate has not been activated");
 
@@ -294,6 +297,7 @@ void CSecurityTLS::checkSession()
 			 "do you want to continue?"))
       throw AuthFailureException("server certificate has expired");
   }
+#endif
   /* Process other errors later */
 
   cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
@@ -338,7 +342,6 @@ void CSecurityTLS::checkSession()
 
   vlog.debug("Saved server certificates don't match");
 
-  #if defined(GNUTLS_VERSION_NUMBER) && (GNUTLS_VERSION_NUMBER >= 0x010706)
   if (gnutls_x509_crt_print(crt, GNUTLS_CRT_PRINT_ONELINE, &info)) {
     /*
      * GNUTLS doesn't correctly export gnutls_free symbol which is
@@ -352,9 +355,8 @@ void CSecurityTLS::checkSession()
 #endif
     throw AuthFailureException("Could not find certificate to display");
   }
-  #endif
 
-  size_t out_size;
+  size_t out_size = 0;
   char *out_buf = NULL;
   char *certinfo = NULL;
   int len = 0;

configure.ac

@@ -107,6 +107,12 @@ if test "x$enable_gnutls" = xyes; then
 		       AC_MSG_RESULT(yes),
 		       [AC_DEFINE(HAVE_OLD_GNUTLS, 1, [Does gnutls lack the gnutls_transport_set_global_errno() function? ])
 			AC_MSG_RESULT(no)])
+	AC_MSG_CHECKING([for gnutls_x509_crt_print() function])
+	AC_LINK_IFELSE(AC_LANG_CALL([], gnutls_x509_crt_print),
+		       [AC_DEFINE(HAVE_GNUTLS_X509_CRT_PRINT, 1, [Is the gnutls_x509_crt_print() function present? ])
+			AC_MSG_RESULT(yes)],
+			AC_MSG_RESULT(no))
+	
 	LIBS=${SAVE_LIBS}
 fi
 AC_SUBST([GNUTLS_LIBS])