Extractor for named RDN element types from a certificate DN field.

4 files changed, 92 insertions, 33 deletions

diff --git a/src/src/functions.h b/src/src/functions.h
index 792f3df4d..741b632a9 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -62,6 +62,7 @@ extern void    tls_version_report(FILE *);
 #ifndef USE_GNUTLS
 extern BOOL    tls_openssl_options_parse(uschar *, long *);
 #endif
+extern uschar * tls_field_from_dn(uschar *, uschar *);
 #endif	/*SUPPORT_TLS*/
 
 
diff --git a/src/src/tls.c b/src/src/tls.c
index f0ac60308..75c46e9e4 100644
--- a/src/src/tls.c
+++ b/src/src/tls.c
@@ -196,4 +196,66 @@ modify_variable(US"tls_sni",                  &dest_tsp->sni);
 #endif
 }
 
+/************************************************
+*	TLS certificate name operations         *
+************************************************/
+
+/* Convert an rfc4514 DN to an exim comma-sep list.
+Backslashed commas need to be replaced by doublecomma
+for Exim's list quoting.  We modify the given string
+inplace.
+*/
+
+static void
+dn_to_list(uschar * dn)
+{
+uschar * cp;
+for (cp = dn; *cp; cp++)
+  if (cp[0] == '\\' && cp[1] == ',')
+    *cp++ = ',';
+}
+
+
+/* Extract fields of a given type from an RFC4514-
+format Distinguished Name.  Return an Exim list.
+NOTE: We modify the supplied dn string during operation.
+
+Arguments:
+	dn	Distinguished Name string
+	mod	string containing optional list-sep and
+		field selector match, comma-separated
+Return:
+	allocated string with list of matching fields,
+	field type stripped
+*/
+
+uschar *
+tls_field_from_dn(uschar * dn, uschar * mod)
+{
+int insep = ',';
+uschar outsep = '\n';
+uschar * ele;
+uschar * match = NULL;
+int len;
+uschar * list = NULL;
+
+while (ele = string_nextinlist(&mod, &insep, NULL, 0))
+  if (ele[0] != '>')
+    match = ele;	/* field tag to match */
+  else if (ele[1])
+    outsep = ele[1];	/* nondefault separator */
+
+dn_to_list(dn);
+insep = ',';
+len = Ustrlen(match);
+while (ele = string_nextinlist(&dn, &insep, NULL, 0))
+  if (Ustrncmp(ele, match, len) == 0 && ele[len] == '=')
+    list = string_append_listele(list, outsep, ele+len+1);
+return list;
+}
+
+
+
+/* vi: aw ai sw=2
+*/
 /* End of tls.c */
diff --git a/src/src/tlscert-gnu.c b/src/src/tlscert-gnu.c
index 3d255ee96..085e05689 100644
--- a/src/src/tlscert-gnu.c
+++ b/src/src/tlscert-gnu.c
@@ -77,8 +77,8 @@ gnutls_global_deinit();
 static uschar *
 g_err(const char * tag, const char * from, int gnutls_err)
 {
-expand_string_message = string_sprintf(stderr,
-  "%s: %s fail: %s\n", from, tag, gnutls_strerror(gnutls_err));
+expand_string_message = string_sprintf("%s: %s fail: %s\n",
+  from, tag, gnutls_strerror(gnutls_err));
 return NULL;
 }
 
@@ -97,10 +97,19 @@ return len > 0 ? cp : NULL;
 uschar *
 tls_cert_issuer(void * cert, uschar * mod)
 {
-uschar txt[256];
-size_t sz = sizeof(txt);
-return ( gnutls_x509_crt_get_issuer_dn(cert, CS txt, &sz) == 0 )
-  ? string_copy(txt) : NULL;
+uschar * cp = NULL;
+int ret;
+size_t siz = 0;
+
+if ((ret = gnutls_x509_crt_get_issuer_dn(cert, cp, &siz))
+    != GNUTLS_E_SHORT_MEMORY_BUFFER)
+  return g_err("gi0", __FUNCTION__, ret);
+
+cp = store_get(siz);
+if ((ret = gnutls_x509_crt_get_issuer_dn(cert, cp, &siz)) < 0)
+  return g_err("gi1", __FUNCTION__, ret);
+
+return mod ? tls_field_from_dn(cp, mod) : cp;
 }
 
 uschar *
@@ -143,20 +152,13 @@ uschar * cp3;
 size_t len = 0;
 int ret;
 
-if ((ret = gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len)) !=
-	GNUTLS_E_SHORT_MEMORY_BUFFER)
-  {
-  fprintf(stderr, "%s: gs0 fail: %s\n", __FUNCTION__, gnutls_strerror(ret));
-  return NULL;
-  }
+if ((ret = gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len))
+    != GNUTLS_E_SHORT_MEMORY_BUFFER)
+  return g_err("gs0", __FUNCTION__, ret);
 
 cp1 = store_get(len*4+1);
-
 if (gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len) != 0)
-  {
-  fprintf(stderr, "%s: gs1 fail\n", __FUNCTION__);
-  return NULL;
-  }
+  return g_err("gs1", __FUNCTION__, ret);
 
 for(cp3 = cp2 = cp1+len; cp1 < cp2; cp3 += 3, cp1++)
   sprintf(cp3, "%.2x ", *cp1);
@@ -180,23 +182,15 @@ uschar * cp = NULL;
 int ret;
 size_t siz = 0;
 
-ret = gnutls_x509_crt_get_dn(cert, cp, &siz);
-if (ret != GNUTLS_E_SHORT_MEMORY_BUFFER)
-  {
-  fprintf(stderr, "%s: gs0 fail: %s\n", __FUNCTION__, gnutls_strerror(ret));
-  return NULL;
-  }
+if ((ret = gnutls_x509_crt_get_dn(cert, cp, &siz))
+    != GNUTLS_E_SHORT_MEMORY_BUFFER)
+  return g_err("gs0", __FUNCTION__, ret);
 
 cp = store_get(siz);
+if ((ret = gnutls_x509_crt_get_dn(cert, cp, &siz)) < 0)
+  return g_err("gs1", __FUNCTION__, ret);
 
-ret = gnutls_x509_crt_get_dn(cert, cp, &siz);
-if (ret < 0)
-  {
-  fprintf(stderr, "%s: gs1 fail: %s\n", __FUNCTION__, gnutls_strerror(ret));
-  return NULL;
-  }
-
-return cp;
+return mod ? tls_field_from_dn(cp, mod) : cp;
 }
 
 uschar *
diff --git a/src/src/tlscert-openssl.c b/src/src/tlscert-openssl.c
index 9903f08f3..00a3cb555 100644
--- a/src/src/tlscert-openssl.c
+++ b/src/src/tlscert-openssl.c
@@ -111,7 +111,8 @@ return bio_string_copy(bp, len_good);
 uschar *
 tls_cert_issuer(void * cert, uschar * mod)
 {
-return x509_name_copy(X509_get_issuer_name((X509 *)cert));
+uschar * cp = x509_name_copy(X509_get_issuer_name((X509 *)cert));
+return mod ? tls_field_from_dn(cp, mod) : cp;
 }
 
 uschar *
@@ -170,7 +171,8 @@ return string_copy(US OBJ_nid2ln(X509_get_signature_type((X509 *)cert)));
 uschar *
 tls_cert_subject(void * cert, uschar * mod)
 {
-return x509_name_copy(X509_get_subject_name((X509 *)cert));
+uschar * cp = x509_name_copy(X509_get_subject_name((X509 *)cert));
+return mod ? tls_field_from_dn(cp, mod) : cp;
 }
 
 uschar *