1 files changed, 41 insertions, 1 deletions
diff --git a/src/openvpn/ssl_verify_polarssl.c b/src/openvpn/ssl_verify_polarssl.c
index 5db4f02..3fd861c 100644
--- a/src/openvpn/ssl_verify_polarssl.c
+++ b/src/openvpn/ssl_verify_polarssl.c
@@ -38,6 +38,8 @@
 #if defined(ENABLE_SSL) && defined(ENABLE_CRYPTO_POLARSSL)
 
 #include "ssl_verify.h"
+#include <polarssl/error.h>
+#include <polarssl/bignum.h>
 #include <polarssl/sha1.h>
 
 #define MAX_SUBJECT_LENGTH 256
@@ -123,11 +125,49 @@ x509_get_username (char *cn, int cn_len,
 }
 
 char *
-x509_get_serial (x509_cert *cert, struct gc_arena *gc)
+backend_x509_get_serial (openvpn_x509_cert_t *cert, struct gc_arena *gc)
 {
   int ret = 0;
   int i = 0;
   char *buf = NULL;
+  size_t buflen = 0;
+  mpi serial_mpi = { 0 };
+  int retval = 0;
+
+  /* Transform asn1 integer serial into PolarSSL MPI */
+  mpi_init(&serial_mpi);
+  retval = mpi_read_binary(&serial_mpi, cert->serial.p, cert->serial.len);
+  if (retval < 0)
+    {
+      char errbuf[128];
+      error_strerror(retval, errbuf, sizeof(errbuf));
+
+      msg(M_WARN, "Failed to retrieve serial from certificate: %s.", errbuf);
+      return NULL;
+    }
+
+  /* Determine decimal representation length, allocate buffer */
+  mpi_write_string(&serial_mpi, 10, buf, &buflen);
+  buf = gc_malloc(buflen, true, gc);
+
+  /* Write MPI serial as decimal string into buffer */
+  retval = mpi_write_string(&serial_mpi, 10, buf, &buflen);
+  if (retval < 0)
+    {
+      char errbuf[128];
+      error_strerror(retval, errbuf, sizeof(errbuf));
+
+      msg(M_WARN, "Failed to write serial to string: %s.", errbuf);
+      return NULL;
+    }
+
+  return buf;
+}
+
+char *
+backend_x509_get_serial_hex (openvpn_x509_cert_t *cert, struct gc_arena *gc)
+{
+  char *buf = NULL;
   size_t len = cert->serial.len * 3 + 1;
 
   buf = gc_malloc(len, true, gc);