Imported Upstream version 2.3_rc1

1 files changed, 622 insertions, 0 deletions

diff --git a/src/openvpn/ssl_verify_openssl.c b/src/openvpn/ssl_verify_openssl.c
new file mode 100644
index 0000000..658f5f3
--- /dev/null
+++ b/src/openvpn/ssl_verify_openssl.c
@@ -0,0 +1,622 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single TCP/UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *  Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  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.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/**
+ * @file Control Channel Verification Module OpenSSL implementation
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#if defined(ENABLE_SSL) && defined(ENABLE_CRYPTO_OPENSSL)
+
+#include "ssl_verify.h"
+#include "ssl_verify_backend.h"
+#include "ssl_openssl.h"
+#include <openssl/x509v3.h>
+#include <openssl/err.h>
+
+int
+verify_callback (int preverify_ok, X509_STORE_CTX * ctx)
+{
+  int ret = 0;
+  struct tls_session *session;
+  SSL *ssl;
+  struct gc_arena gc = gc_new();
+
+  /* get the tls_session pointer */
+  ssl = X509_STORE_CTX_get_ex_data (ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
+  ASSERT (ssl);
+  session = (struct tls_session *) SSL_get_ex_data (ssl, mydata_index);
+  ASSERT (session);
+
+  cert_hash_remember (session, ctx->error_depth,
+      x509_get_sha1_hash(ctx->current_cert, &gc));
+
+  /* did peer present cert which was signed by our root cert? */
+  if (!preverify_ok)
+    {
+      /* get the X509 name */
+      char *subject = x509_get_subject(ctx->current_cert, &gc);
+
+      if (subject)
+	{
+	  /* Remote site specified a certificate, but it's not correct */
+	  msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, error=%s: %s",
+	      ctx->error_depth,
+	      X509_verify_cert_error_string (ctx->error),
+	      subject);
+	}
+
+      ERR_clear_error();
+
+      session->verified = false;
+      goto cleanup;
+    }
+
+  if (SUCCESS != verify_cert(session, ctx->current_cert, ctx->error_depth))
+    goto cleanup;
+
+  ret = 1;
+
+cleanup:
+  gc_free(&gc);
+
+  return ret;
+}
+
+#ifdef ENABLE_X509ALTUSERNAME
+static
+bool extract_x509_extension(X509 *cert, char *fieldname, char *out, int size)
+{
+  bool retval = false;
+  X509_EXTENSION *pExt;
+  char *buf = 0;
+  int length = 0;
+  GENERAL_NAMES *extensions;
+  int nid = OBJ_txt2nid(fieldname);
+
+  extensions = (GENERAL_NAMES *)X509_get_ext_d2i(cert, nid, NULL, NULL);
+  if ( extensions )
+    {
+      int numalts;
+      int i;
+      /* get amount of alternatives,
+       * RFC2459 claims there MUST be at least
+       * one, but we don't depend on it...
+       */
+
+      numalts = sk_GENERAL_NAME_num(extensions);
+
+      /* loop through all alternatives */
+      for (i=0; i<numalts; i++)
+        {
+          /* get a handle to alternative name number i */
+          const GENERAL_NAME *name = sk_GENERAL_NAME_value (extensions, i );
+
+          switch (name->type)
+            {
+              case GEN_EMAIL:
+                ASN1_STRING_to_UTF8((unsigned char**)&buf, name->d.ia5);
+                if ( strlen (buf) != name->d.ia5->length )
+                  {
+                    msg (D_TLS_ERRORS, "ASN1 ERROR: string contained terminating zero");
+                    OPENSSL_free (buf);
+                  } else {
+                    strncpynt(out, buf, size);
+                    OPENSSL_free(buf);
+                    retval = true;
+                  }
+                break;
+              default:
+                msg (D_TLS_ERRORS, "ASN1 ERROR: can not handle field type %i",
+                     name->type);
+                break;
+            }
+          }
+        sk_GENERAL_NAME_free (extensions);
+    }
+  return retval;
+}
+#endif /* ENABLE_X509ALTUSERNAME */
+
+/*
+ * Extract a field from an X509 subject name.
+ *
+ * Example:
+ *
+ * /C=US/ST=CO/L=Denver/O=ORG/CN=First-CN/CN=Test-CA/Email=jim@yonan.net
+ *
+ * The common name is 'Test-CA'
+ *
+ * Return true on success, false on error (insufficient buffer size in 'out'
+ * to contain result is grounds for error).
+ */
+static result_t
+extract_x509_field_ssl (X509_NAME *x509, const char *field_name, char *out,
+    int size)
+{
+  int lastpos = -1;
+  int tmp = -1;
+  X509_NAME_ENTRY *x509ne = 0;
+  ASN1_STRING *asn1 = 0;
+  unsigned char *buf = (unsigned char *)1; /* bug in OpenSSL 0.9.6b ASN1_STRING_to_UTF8 requires this workaround */
+  int nid = OBJ_txt2nid((char *)field_name);
+
+  ASSERT (size > 0);
+  *out = '\0';
+  do {
+    lastpos = tmp;
+    tmp = X509_NAME_get_index_by_NID(x509, nid, lastpos);
+  } while (tmp > -1);
+
+  /* Nothing found */
+  if (lastpos == -1)
+    return FAILURE;
+
+  x509ne = X509_NAME_get_entry(x509, lastpos);
+  if (!x509ne)
+    return FAILURE;
+
+  asn1 = X509_NAME_ENTRY_get_data(x509ne);
+  if (!asn1)
+    return FAILURE;
+  tmp = ASN1_STRING_to_UTF8(&buf, asn1);
+  if (tmp <= 0)
+    return FAILURE;
+
+  strncpynt(out, (char *)buf, size);
+
+  {
+    const result_t ret = (strlen ((char *)buf) < size) ? SUCCESS: FAILURE;
+    OPENSSL_free (buf);
+    return ret;
+  }
+}
+
+result_t
+x509_get_username (char *common_name, int cn_len,
+    char * x509_username_field, X509 *peer_cert)
+{
+#ifdef ENABLE_X509ALTUSERNAME
+  if (strncmp("ext:",x509_username_field,4) == 0)
+    {
+      if (!extract_x509_extension (peer_cert, x509_username_field+4, common_name, cn_len))
+	return FAILURE;
+    } else
+#endif
+  if (FAILURE == extract_x509_field_ssl (X509_get_subject_name (peer_cert),
+      x509_username_field, common_name, cn_len))
+      return FAILURE;
+
+  return SUCCESS;
+}
+
+char *
+x509_get_serial (openvpn_x509_cert_t *cert, struct gc_arena *gc)
+{
+  ASN1_INTEGER *asn1_i;
+  BIGNUM *bignum;
+  char *openssl_serial, *serial;
+
+  asn1_i = X509_get_serialNumber(cert);
+  bignum = ASN1_INTEGER_to_BN(asn1_i, NULL);
+  openssl_serial = BN_bn2dec(bignum);
+
+  serial = string_alloc(openssl_serial, gc);
+
+  BN_free(bignum);
+  OPENSSL_free(openssl_serial);
+
+  return serial;
+}
+
+unsigned char *
+x509_get_sha1_hash (X509 *cert, struct gc_arena *gc)
+{
+  char *hash = gc_malloc(SHA_DIGEST_LENGTH, false, gc);
+  memcpy(hash, cert->sha1_hash, SHA_DIGEST_LENGTH);
+  return hash;
+}
+
+char *
+x509_get_subject (X509 *cert, struct gc_arena *gc)
+{
+  BIO *subject_bio = NULL;
+  BUF_MEM *subject_mem;
+  char *subject = NULL;
+  int maxlen = 0;
+
+  /*
+   * Generate the subject string in OpenSSL proprietary format,
+   * when in --compat-names mode
+   */
+  if (compat_flag (COMPAT_FLAG_QUERY | COMPAT_NAMES))
+    {
+      subject = gc_malloc (256, false, gc);
+      X509_NAME_oneline (X509_get_subject_name (cert), subject, 256);
+      subject[255] = '\0';
+      return subject;
+    }
+
+  subject_bio = BIO_new (BIO_s_mem ());
+  if (subject_bio == NULL)
+    goto err;
+
+  X509_NAME_print_ex (subject_bio, X509_get_subject_name (cert),
+                      0, XN_FLAG_SEP_CPLUS_SPC | XN_FLAG_FN_SN |
+                      ASN1_STRFLGS_UTF8_CONVERT | ASN1_STRFLGS_ESC_CTRL);
+
+  if (BIO_eof (subject_bio))
+    goto err;
+
+  BIO_get_mem_ptr (subject_bio, &subject_mem);
+
+  maxlen = subject_mem->length + 1;
+  subject = gc_malloc (maxlen, false, gc);
+
+  memcpy (subject, subject_mem->data, maxlen);
+  subject[maxlen - 1] = '\0';
+
+err:
+  if (subject_bio)
+    BIO_free (subject_bio);
+
+  return subject;
+}
+
+
+#ifdef ENABLE_X509_TRACK
+
+void
+x509_track_add (const struct x509_track **ll_head, const char *name, int msglevel, struct gc_arena *gc)
+{
+  struct x509_track *xt;
+  ALLOC_OBJ_CLEAR_GC (xt, struct x509_track, gc);
+  if (*name == '+')
+    {
+      xt->flags |= XT_FULL_CHAIN;
+      ++name;
+    }
+  xt->name = name;
+  xt->nid = OBJ_txt2nid(name);
+  if (xt->nid != NID_undef)
+    {
+      xt->next = *ll_head;
+      *ll_head = xt;
+    }
+  else
+    msg(msglevel, "x509_track: no such attribute '%s'", name);
+}
+
+/* worker method for setenv_x509_track */
+static void
+do_setenv_x509 (struct env_set *es, const char *name, char *value, int depth)
+{
+  char *name_expand;
+  size_t name_expand_size;
+
+  string_mod (value, CC_ANY, CC_CRLF, '?');
+  msg (D_X509_ATTR, "X509 ATTRIBUTE name='%s' value='%s' depth=%d", name, value, depth);
+  name_expand_size = 64 + strlen (name);
+  name_expand = (char *) malloc (name_expand_size);
+  check_malloc_return (name_expand);
+  openvpn_snprintf (name_expand, name_expand_size, "X509_%d_%s", depth, name);
+  setenv_str (es, name_expand, value);
+  free (name_expand);
+}
+
+void
+x509_setenv_track (const struct x509_track *xt, struct env_set *es, const int depth, X509 *x509)
+{
+  X509_NAME *x509_name = X509_get_subject_name (x509);
+  const char nullc = '\0';
+  int i;
+
+  while (xt)
+    {
+      if (depth == 0 || (xt->flags & XT_FULL_CHAIN))
+	{
+	  i = X509_NAME_get_index_by_NID(x509_name, xt->nid, -1);
+	  if (i >= 0)
+	    {
+	      X509_NAME_ENTRY *ent = X509_NAME_get_entry(x509_name, i);
+	      if (ent)
+		{
+		  ASN1_STRING *val = X509_NAME_ENTRY_get_data (ent);
+		  unsigned char *buf;
+		  buf = (unsigned char *)1; /* bug in OpenSSL 0.9.6b ASN1_STRING_to_UTF8 requires this workaround */
+		  if (ASN1_STRING_to_UTF8 (&buf, val) > 0)
+		    {
+		      do_setenv_x509(es, xt->name, (char *)buf, depth);
+		      OPENSSL_free (buf);
+		    }
+		}
+	    }
+	  else
+	    {
+	      i = X509_get_ext_by_NID(x509, xt->nid, -1);
+	      if (i >= 0)
+		{
+		  X509_EXTENSION *ext = X509_get_ext(x509, i);
+		  if (ext)
+		    {
+		      BIO *bio = BIO_new(BIO_s_mem());
+		      if (bio)
+			{
+			  if (X509V3_EXT_print(bio, ext, 0, 0))
+			    {
+			      if (BIO_write(bio, &nullc, 1) == 1)
+				{
+				  char *str;
+				  BIO_get_mem_data(bio, &str);
+				  do_setenv_x509(es, xt->name, str, depth);
+				}
+			    }
+			  BIO_free(bio);
+			}
+		    }
+		}
+	    }
+	}
+      xt = xt->next;
+    }
+}
+#endif
+
+/*
+ * Save X509 fields to environment, using the naming convention:
+ *
+ *  X509_{cert_depth}_{name}={value}
+ */
+void
+x509_setenv (struct env_set *es, int cert_depth, openvpn_x509_cert_t *peer_cert)
+{
+  int i, n;
+  int fn_nid;
+  ASN1_OBJECT *fn;
+  ASN1_STRING *val;
+  X509_NAME_ENTRY *ent;
+  const char *objbuf;
+  unsigned char *buf;
+  char *name_expand;
+  size_t name_expand_size;
+  X509_NAME *x509 = X509_get_subject_name (peer_cert);
+
+  n = X509_NAME_entry_count (x509);
+  for (i = 0; i < n; ++i)
+    {
+      ent = X509_NAME_get_entry (x509, i);
+      if (!ent)
+	continue;
+      fn = X509_NAME_ENTRY_get_object (ent);
+      if (!fn)
+	continue;
+      val = X509_NAME_ENTRY_get_data (ent);
+      if (!val)
+	continue;
+      fn_nid = OBJ_obj2nid (fn);
+      if (fn_nid == NID_undef)
+	continue;
+      objbuf = OBJ_nid2sn (fn_nid);
+      if (!objbuf)
+	continue;
+      buf = (unsigned char *)1; /* bug in OpenSSL 0.9.6b ASN1_STRING_to_UTF8 requires this workaround */
+      if (ASN1_STRING_to_UTF8 (&buf, val) <= 0)
+	continue;
+      name_expand_size = 64 + strlen (objbuf);
+      name_expand = (char *) malloc (name_expand_size);
+      check_malloc_return (name_expand);
+      openvpn_snprintf (name_expand, name_expand_size, "X509_%d_%s", cert_depth,
+	  objbuf);
+      string_mod (name_expand, CC_PRINT, CC_CRLF, '_');
+      string_mod ((char*)buf, CC_PRINT, CC_CRLF, '_');
+      setenv_str (es, name_expand, (char*)buf);
+      free (name_expand);
+      OPENSSL_free (buf);
+    }
+}
+
+result_t
+x509_verify_ns_cert_type(const openvpn_x509_cert_t *peer_cert, const int usage)
+{
+  if (usage == NS_CERT_CHECK_NONE)
+    return SUCCESS;
+  if (usage == NS_CERT_CHECK_CLIENT)
+    return ((peer_cert->ex_flags & EXFLAG_NSCERT)
+	&& (peer_cert->ex_nscert & NS_SSL_CLIENT)) ? SUCCESS: FAILURE;
+  if (usage == NS_CERT_CHECK_SERVER)
+    return ((peer_cert->ex_flags & EXFLAG_NSCERT)
+	&& (peer_cert->ex_nscert & NS_SSL_SERVER))  ? SUCCESS: FAILURE;
+
+  return FAILURE;
+}
+
+#if OPENSSL_VERSION_NUMBER >= 0x00907000L
+
+result_t
+x509_verify_cert_ku (X509 *x509, const unsigned * const expected_ku,
+    int expected_len)
+{
+  ASN1_BIT_STRING *ku = NULL;
+  result_t fFound = FAILURE;
+
+  if ((ku = (ASN1_BIT_STRING *) X509_get_ext_d2i (x509, NID_key_usage, NULL,
+      NULL)) == NULL)
+    {
+      msg (D_HANDSHAKE, "Certificate does not have key usage extension");
+    }
+  else
+    {
+      unsigned nku = 0;
+      int i;
+      for (i = 0; i < 8; i++)
+	{
+	  if (ASN1_BIT_STRING_get_bit (ku, i))
+	    nku |= 1 << (7 - i);
+	}
+
+      /*
+       * Fixup if no LSB bits
+       */
+      if ((nku & 0xff) == 0)
+	{
+	  nku >>= 8;
+	}
+
+      msg (D_HANDSHAKE, "Validating certificate key usage");
+      for (i = 0; fFound != SUCCESS && i < expected_len; i++)
+	{
+	  if (expected_ku[i] != 0)
+	    {
+	      msg (D_HANDSHAKE, "++ Certificate has key usage  %04x, expects "
+		  "%04x", nku, expected_ku[i]);
+
+	      if (nku == expected_ku[i])
+		fFound = SUCCESS;
+	    }
+	}
+    }
+
+  if (ku != NULL)
+    ASN1_BIT_STRING_free (ku);
+
+  return fFound;
+}
+
+result_t
+x509_verify_cert_eku (X509 *x509, const char * const expected_oid)
+{
+  EXTENDED_KEY_USAGE *eku = NULL;
+  result_t fFound = FAILURE;
+
+  if ((eku = (EXTENDED_KEY_USAGE *) X509_get_ext_d2i (x509, NID_ext_key_usage,
+      NULL, NULL)) == NULL)
+    {
+      msg (D_HANDSHAKE, "Certificate does not have extended key usage extension");
+    }
+  else
+    {
+      int i;
+
+      msg (D_HANDSHAKE, "Validating certificate extended key usage");
+      for (i = 0; SUCCESS != fFound && i < sk_ASN1_OBJECT_num (eku); i++)
+	{
+	  ASN1_OBJECT *oid = sk_ASN1_OBJECT_value (eku, i);
+	  char szOid[1024];
+
+	  if (SUCCESS != fFound && OBJ_obj2txt (szOid, sizeof(szOid), oid, 0) != -1)
+	    {
+	      msg (D_HANDSHAKE, "++ Certificate has EKU (str) %s, expects %s",
+		  szOid, expected_oid);
+	      if (!strcmp (expected_oid, szOid))
+		fFound = SUCCESS;
+	    }
+	  if (SUCCESS != fFound && OBJ_obj2txt (szOid, sizeof(szOid), oid, 1) != -1)
+	    {
+	      msg (D_HANDSHAKE, "++ Certificate has EKU (oid) %s, expects %s",
+		  szOid, expected_oid);
+	      if (!strcmp (expected_oid, szOid))
+		fFound = SUCCESS;
+	    }
+	}
+    }
+
+  if (eku != NULL)
+    sk_ASN1_OBJECT_pop_free (eku, ASN1_OBJECT_free);
+
+  return fFound;
+}
+
+result_t
+x509_write_pem(FILE *peercert_file, X509 *peercert)
+{
+  if (PEM_write_X509(peercert_file, peercert) < 0)
+    {
+      msg (M_ERR, "Failed to write peer certificate in PEM format");
+      return FAILURE;
+    }
+  return SUCCESS;
+}
+
+#endif /* OPENSSL_VERSION_NUMBER */
+
+/*
+ * check peer cert against CRL
+ */
+result_t
+x509_verify_crl(const char *crl_file, X509 *peer_cert, const char *subject)
+{
+  X509_CRL *crl=NULL;
+  X509_REVOKED *revoked;
+  BIO *in=NULL;
+  int n,i;
+  result_t retval = FAILURE;
+
+  in = BIO_new_file (crl_file, "r");
+
+  if (in == NULL) {
+    msg (M_ERR, "CRL: cannot read: %s", crl_file);
+    goto end;
+  }
+  crl=PEM_read_bio_X509_CRL(in,NULL,NULL,NULL);
+  if (crl == NULL) {
+    msg (M_ERR, "CRL: cannot read CRL from file %s", crl_file);
+    goto end;
+  }
+
+  if (X509_NAME_cmp(X509_CRL_get_issuer(crl), X509_get_issuer_name(peer_cert)) != 0) {
+    msg (M_WARN, "CRL: CRL %s is from a different issuer than the issuer of "
+	"certificate %s", crl_file, subject);
+    retval = SUCCESS;
+    goto end;
+  }
+
+  n = sk_X509_REVOKED_num(X509_CRL_get_REVOKED(crl));
+  for (i = 0; i < n; i++) {
+    revoked = (X509_REVOKED *)sk_X509_REVOKED_value(X509_CRL_get_REVOKED(crl), i);
+    if (ASN1_INTEGER_cmp(revoked->serialNumber, X509_get_serialNumber(peer_cert)) == 0) {
+      msg (D_HANDSHAKE, "CRL CHECK FAILED: %s is REVOKED",subject);
+      goto end;
+    }
+  }
+
+  retval = SUCCESS;
+  msg (D_HANDSHAKE, "CRL CHECK OK: %s",subject);
+
+end:
+  BIO_free(in);
+  if (crl)
+    X509_CRL_free (crl);
+
+  return retval;
+}
+
+#endif /* defined(ENABLE_SSL) && defined(ENABLE_CRYPTO_OPENSSL) */