From 751c2b50d565108094934c74d718bae51b98e2f9 Mon Sep 17 00:00:00 2001
From: Luke Howard <lukeh@padl.com>
Date: Wed, 8 Sep 2010 12:29:13 +0200
Subject: [PATCH] gss_pseudo_random implementation

---
 mech_eap/pseudo_random.c | 112 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 110 insertions(+), 2 deletions(-)

diff --git a/mech_eap/pseudo_random.c b/mech_eap/pseudo_random.c
index c4918f5..105a0d1 100644
--- a/mech_eap/pseudo_random.c
+++ b/mech_eap/pseudo_random.c
@@ -29,16 +29,124 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+/*
+ * lib/gssapi/krb5/prf.c
+ *
+ * Copyright 2009 by the Massachusetts Institute of Technology.
+ * All Rights Reserved.
+ *
+ * Export of this software from the United States of America may
+ *   require a specific license from the United States Government.
+ *   It is the responsibility of any person or organization contemplating
+ *   export to obtain such a license before exporting.
+ *
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission.  Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ *
+ *
+ */
 
 #include "gssapiP_eap.h"
 
+#ifndef MIN             /* Usually found in <sys/param.h>. */
+#define MIN(_a,_b)  ((_a)<(_b)?(_a):(_b))
+#endif
+
 OM_uint32
 gss_pseudo_random(OM_uint32 *minor,
-                  gss_ctx_id_t context,
+                  gss_ctx_id_t ctx,
                   int prf_key,
                   const gss_buffer_t prf_in,
                   ssize_t desired_output_len,
                   gss_buffer_t prf_out)
 {
-    GSSEAP_NOT_IMPLEMENTED;
+    krb5_error_code code;
+    int i;
+    OM_uint32 tmpMinor;
+    size_t prflen;
+    krb5_data t, ns;
+    unsigned char *p;
+
+    prf_out->length = 0;
+    prf_out->value = NULL;
+
+    if (!CTX_IS_ESTABLISHED(ctx))
+        return GSS_S_NO_CONTEXT;
+
+    t.length = 0;
+    t.data = NULL;
+
+    ns.length = 0;
+    ns.data = NULL;
+
+    if (prf_key != GSS_C_PRF_KEY_FULL &&
+        prf_key != GSS_C_PRF_KEY_FULL) {
+        code = EINVAL;
+        goto cleanup;
+    }
+
+    prf_out->value = GSSEAP_MALLOC(desired_output_len);
+    if (prf_out->value == NULL) {
+        code = ENOMEM;
+        goto cleanup;
+    }
+    prf_out->length = desired_output_len;
+
+    code = krb5_c_prf_length(ctx->kerberosCtx,
+                             ctx->encryptionType,
+                             &prflen);
+    if (code != 0)
+        goto cleanup;
+
+    ns.length = 4 + prf_in->length;
+    ns.data = GSSEAP_MALLOC(ns.length);
+    if (ns.data == NULL) {
+        code = ENOMEM;
+        goto cleanup;
+    }
+
+    t.length = prflen;
+    t.data = GSSEAP_MALLOC(t.length);
+    if (t.data == NULL) {
+        code = ENOMEM;
+        goto cleanup;
+    }
+
+    memcpy(ns.data + 4, prf_in->value, prf_in->length);
+    i = 0;
+    p = (unsigned char *)prf_out->value;
+    while (desired_output_len > 0) {
+        store_uint32_be(i, ns.data);
+
+        code = krb5_c_prf(ctx->kerberosCtx, ctx->encryptionKey, &ns, &t);
+        if (code != 0)
+            goto cleanup;
+
+        memcpy(p, t.data, MIN(t.length, desired_output_len));
+
+        p += t.length;
+        desired_output_len -= t.length;
+        i++;
+    }
+
+cleanup:
+    if (code != 0)
+        gss_release_buffer(&tmpMinor, prf_out);
+    krb5_free_data_contents(ctx->kerberosCtx, &ns);
+    krb5_free_data_contents(ctx->kerberosCtx, &t);
+
+    *minor = code;
+    return (code == 0) ? GSS_S_COMPLETE : GSS_S_FAILURE;
 }
+
-- 
2.1.4