Recast encrypted challenge as linked built-ins

Since it has no external dependencies, split up encrypted preauth into
clpreauth and kdcpreauth chunks and link them directly into the
consumers.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@25227 dc483132-0cff-0310-8789-dd5450dbe970

4 files changed, 200 insertions, 3 deletions

diff --git a/src/lib/krb5/krb/Makefile.in b/src/lib/krb5/krb/Makefile.in
index 33f31fd38..ddef9e29a 100644
--- a/src/lib/krb5/krb/Makefile.in
+++ b/src/lib/krb5/krb/Makefile.in
@@ -77,6 +77,7 @@ STLIBOBJS= \
 	plugin.o	\
 	pr_to_salt.o	\
 	preauth2.o	\
+	preauth_ec.o	\
 	gic_opt_set_pa.o	\
 	princ_comp.o	\
 	privsafe.o	\
@@ -180,6 +181,7 @@ OBJS=	$(OUTPRE)addr_comp.$(OBJEXT)	\
 	$(OUTPRE)plugin.$(OBJEXT)	\
 	$(OUTPRE)pr_to_salt.$(OBJEXT)	\
 	$(OUTPRE)preauth2.$(OBJEXT)	\
+	$(OUTPRE)preauth_ec.$(OBJEXT)	\
 	$(OUTPRE)gic_opt_set_pa.$(OBJEXT)	\
 	$(OUTPRE)princ_comp.$(OBJEXT)	\
 	$(OUTPRE)privsafe.$(OBJEXT)	\
@@ -283,6 +285,7 @@ SRCS=	$(srcdir)/addr_comp.c	\
 	$(srcdir)/plugin.c	\
 	$(srcdir)/pr_to_salt.c	\
 	$(srcdir)/preauth2.c	\
+	$(srcdir)/preauth_ec.c	\
 	$(srcdir)/gic_opt_set_pa.c	\
 	$(srcdir)/princ_comp.c	\
 	$(srcdir)/privsafe.c	\
diff --git a/src/lib/krb5/krb/int-proto.h b/src/lib/krb5/krb/int-proto.h
index 9b975ab4a..7aebdb162 100644
--- a/src/lib/krb5/krb/int-proto.h
+++ b/src/lib/krb5/krb/int-proto.h
@@ -54,6 +54,10 @@ krb5_preauth_supply_preauth_data(krb5_context context,
                                  const char *value);
 
 krb5_error_code
+clpreauth_encrypted_challenge_initvt(krb5_context context, int maj_ver,
+                                     int min_ver, krb5_plugin_vtable vtable);
+
+krb5_error_code
 krb5int_construct_matching_creds(krb5_context context, krb5_flags options,
                                  krb5_creds *in_creds, krb5_creds *mcreds,
                                  krb5_flags *fields);
diff --git a/src/lib/krb5/krb/preauth2.c b/src/lib/krb5/krb/preauth2.c
index ef866b1a2..ed411e5dd 100644
--- a/src/lib/krb5/krb/preauth2.c
+++ b/src/lib/krb5/krb/preauth2.c
@@ -120,11 +120,12 @@ krb5_init_preauth_context(krb5_context kcontext)
     if (kcontext->preauth_context != NULL)
         return;
 
-    /* Auto-register pkinit and encrypted challenge if possible. */
+    /* Auto-register encrypted challenge and (if possible) pkinit. */
     k5_plugin_register_dyn(kcontext, PLUGIN_INTERFACE_CLPREAUTH, "pkinit",
                            "preauth");
-    k5_plugin_register_dyn(kcontext, PLUGIN_INTERFACE_CLPREAUTH,
-                           "encrypted_challenge", "preauth");
+    k5_plugin_register(kcontext, PLUGIN_INTERFACE_CLPREAUTH,
+                       "encrypted_challenge",
+                       clpreauth_encrypted_challenge_initvt);
 
     /* Get all available clpreauth vtables. */
     if (k5_plugin_load_all(kcontext, PLUGIN_INTERFACE_CLPREAUTH, &plugins))
diff --git a/src/lib/krb5/krb/preauth_ec.c b/src/lib/krb5/krb/preauth_ec.c
new file mode 100644
index 000000000..e56807a3a
--- /dev/null
+++ b/src/lib/krb5/krb/preauth_ec.c
@@ -0,0 +1,189 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/* lib/krb5/krb/preauth_ec.c - Encrypted Challenge clpreauth module */
+/*
+ * Copyright (C) 2009, 2011 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.
+ */
+
+/*
+ * Implement Encrypted Challenge fast factor from
+ * draft-ietf-krb-wg-preauth-framework
+ */
+
+#include <k5-int.h>
+#include <krb5/preauth_plugin.h>
+#include "fast_factor.h"
+#include "int-proto.h"
+
+static int
+preauth_flags(krb5_context context, krb5_preauthtype pa_type)
+{
+    return PA_REAL;
+}
+
+static krb5_error_code
+process_preauth(krb5_context context, krb5_clpreauth_moddata moddata,
+                krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt,
+                krb5_clpreauth_get_data_fn get_data_proc,
+                krb5_clpreauth_rock rock, krb5_kdc_req *request,
+                krb5_data *encoded_request_body,
+                krb5_data *encoded_previous_request, krb5_pa_data *padata,
+                krb5_prompter_fct prompter, void *prompter_data,
+                krb5_clpreauth_get_as_key_fn gak_fct, void *gak_data,
+                krb5_data *salt, krb5_data *s2kparams, krb5_keyblock *as_key,
+                krb5_pa_data ***out_padata)
+{
+    krb5_error_code retval = 0;
+    krb5_enctype enctype = 0;
+    krb5_keyblock *challenge_key = NULL, *armor_key = NULL;
+    krb5_data *etype_data = NULL;
+    krb5int_access kaccess;
+
+    if (krb5int_accessor(&kaccess, KRB5INT_ACCESS_VERSION) != 0)
+        return 0;
+    retval = fast_get_armor_key(context, get_data_proc, rock, &armor_key);
+    if (retval || armor_key == NULL)
+        return 0;
+    retval = get_data_proc(context, rock, krb5_clpreauth_get_etype,
+                           &etype_data);
+    if (retval == 0) {
+        enctype = *((krb5_enctype *)etype_data->data);
+        if (as_key->length == 0 ||as_key->enctype != enctype)
+            retval = gak_fct(context, request->client,
+                             enctype, prompter, prompter_data,
+                             salt, s2kparams,
+                             as_key, gak_data);
+    }
+    if (retval == 0 && padata->length) {
+        krb5_enc_data *enc = NULL;
+        krb5_data scratch;
+        scratch.length = padata->length;
+        scratch.data = (char *) padata->contents;
+        retval = krb5_c_fx_cf2_simple(context,armor_key, "kdcchallengearmor",
+                                      as_key, "challengelongterm",
+                                      &challenge_key);
+        if (retval == 0)
+            retval =kaccess.decode_enc_data(&scratch, &enc);
+        scratch.data = NULL;
+        if (retval == 0) {
+            scratch.data = malloc(enc->ciphertext.length);
+            scratch.length = enc->ciphertext.length;
+            if (scratch.data == NULL)
+                retval = ENOMEM;
+        }
+        if (retval == 0)
+            retval = krb5_c_decrypt(context, challenge_key,
+                                    KRB5_KEYUSAGE_ENC_CHALLENGE_KDC, NULL,
+                                    enc, &scratch);
+        /*
+         * Per draft 11 of the preauth framework, the client MAY but is not
+         * required to actually check the timestamp from the KDC other than to
+         * confirm it decrypts. This code does not perform that check.
+         */
+        if (scratch.data)
+            krb5_free_data_contents(context, &scratch);
+        if (retval == 0)
+            fast_set_kdc_verified(context, get_data_proc, rock);
+        if (enc)
+            kaccess.free_enc_data(context, enc);
+    } else if (retval == 0) { /*No padata; we send*/
+        krb5_enc_data enc;
+        krb5_pa_data *pa = NULL;
+        krb5_pa_data **pa_array = NULL;
+        krb5_data *encoded_ts = NULL;
+        krb5_pa_enc_ts ts;
+        enc.ciphertext.data = NULL;
+        retval = krb5_us_timeofday(context, &ts.patimestamp, &ts.pausec);
+        if (retval == 0)
+            retval = kaccess.encode_enc_ts(&ts, &encoded_ts);
+        if (retval == 0)
+            retval = krb5_c_fx_cf2_simple(context,
+                                          armor_key, "clientchallengearmor",
+                                          as_key, "challengelongterm",
+                                          &challenge_key);
+        if (retval == 0)
+            retval = kaccess.encrypt_helper(context, challenge_key,
+                                            KRB5_KEYUSAGE_ENC_CHALLENGE_CLIENT,
+                                            encoded_ts, &enc);
+        if (encoded_ts)
+            krb5_free_data(context, encoded_ts);
+        encoded_ts = NULL;
+        if (retval == 0) {
+            retval = kaccess.encode_enc_data(&enc, &encoded_ts);
+            krb5_free_data_contents(context, &enc.ciphertext);
+        }
+        if (retval == 0) {
+            pa = calloc(1, sizeof(krb5_pa_data));
+            if (pa == NULL)
+                retval = ENOMEM;
+        }
+        if (retval == 0) {
+            pa_array = calloc(2, sizeof(krb5_pa_data *));
+            if (pa_array == NULL)
+                retval = ENOMEM;
+        }
+        if (retval == 0) {
+            pa->length = encoded_ts->length;
+            pa->contents = (unsigned char *) encoded_ts->data;
+            pa->pa_type = KRB5_PADATA_ENCRYPTED_CHALLENGE;
+            free(encoded_ts);
+            encoded_ts = NULL;
+            pa_array[0] = pa;
+            pa = NULL;
+            *out_padata = pa_array;
+            pa_array = NULL;
+        }
+        if (pa)
+            free(pa);
+        if (encoded_ts)
+            krb5_free_data(context, encoded_ts);
+        if (pa_array)
+            free(pa_array);
+    }
+    if (challenge_key)
+        krb5_free_keyblock(context, challenge_key);
+    if (armor_key)
+        krb5_free_keyblock(context, armor_key);
+    if (etype_data != NULL)
+        get_data_proc(context, rock, krb5_clpreauth_free_etype, &etype_data);
+    return retval;
+}
+
+
+krb5_preauthtype supported_pa_types[] = {
+    KRB5_PADATA_ENCRYPTED_CHALLENGE, 0};
+
+krb5_error_code
+clpreauth_encrypted_challenge_initvt(krb5_context context, int maj_ver,
+                                     int min_ver, krb5_plugin_vtable vtable)
+{
+    krb5_clpreauth_vtable vt;
+
+    if (maj_ver != 1)
+        return KRB5_PLUGIN_VER_NOTSUPP;
+    vt = (krb5_clpreauth_vtable)vtable;
+    vt->name = "encrypted_challenge";
+    vt->pa_type_list = supported_pa_types;
+    vt->flags = preauth_flags;
+    vt->process = process_preauth;
+    return 0;
+}