sasl: Introduced Curl_sasl_build_spn() for building a SPN

Various parts of the libcurl source code build a SPN for inclusion in
authentication data. This information is either used by our own native
generation routines or passed to authentication functions in third-party
libraries such as SSPI. However, some of these instances use fixed
buffers rather than dynamically allocated ones and not all of those that
should, convert to wide character strings in Unicode builds.

Implemented a common function that generates a SPN and performs the
wide character conversion where necessary.

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/curl_sasl.c b/lib/curl_sasl.c
index a2dfe7755..75efca3e8 100644
--- a/lib/curl_sasl.c
+++ b/lib/curl_sasl.c
@@ -120,6 +120,26 @@ static CURLcode sasl_digest_get_qop_values(const char *options, int *value)
 }
 #endif
 
+#if !defined(USE_WINDOWS_SSPI)
+/*
+ * Curl_sasl_build_spn()
+ *
+ * This is used to build a SPN string in the format service/host.
+ *
+ * Parameters:
+ *
+ * serivce  [in] - The service type such as www, smtp, pop or imap.
+ * instance [in] - The instance name such as the host nme or realm.
+ *
+ * Returns a pointer to the newly allocated SPN.
+ */
+char *Curl_sasl_build_spn(const char *service, const char *host)
+{
+  /* Generate and return our SPN */
+  return aprintf("%s/%s", service, host);
+}
+#endif
+
 /*
  * Curl_sasl_create_plain_message()
  *