From 3d11179707923b033fa413387a33296b673ff52d Mon Sep 17 00:00:00 2001

From: Robbie Harwood <rharwood@redhat.com>

Date: Thu, 14 Jan 2021 18:13:09 -0500

Subject: [PATCH] Add APIs for marshalling credentials

Faciliate KCM daemon implementations by providing functions to

deserialize and reserialize credentials in the FILE v4 format.

[ghudson@mit.edu: minor editorial changes]

ticket: 8980 (new)

(cherry picked from commit 18ea3bd2fca55b789b7de9c663624bc11d348fa6)

---

 doc/appdev/refs/api/index.rst   |  2 ++

 src/include/krb5/krb5.hin       | 36 ++++++++++++++++++++++

 src/lib/krb5/ccache/ccmarshal.c | 53 +++++++++++++++++++++++++++++++++

 src/lib/krb5/ccache/t_marshal.c | 15 +++++++++-

 src/lib/krb5/libkrb5.exports    |  2 ++

 src/lib/krb5_32.def             |  4 +++

 6 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/doc/appdev/refs/api/index.rst b/doc/appdev/refs/api/index.rst

index 727d9b492..9e03fd386 100644

--- a/doc/appdev/refs/api/index.rst

+++ b/doc/appdev/refs/api/index.rst

@@ -232,6 +232,7 @@ Rarely used public interfaces

    krb5_kt_remove_entry.rst

    krb5_kt_start_seq_get.rst

    krb5_make_authdata_kdc_issued.rst

+   krb5_marshal_credentials.rst

    krb5_merge_authdata.rst

    krb5_mk_1cred.rst

    krb5_mk_error.rst

@@ -285,6 +286,7 @@ Rarely used public interfaces

    krb5_tkt_creds_get_times.rst

    krb5_tkt_creds_init.rst

    krb5_tkt_creds_step.rst

+   krb5_unmarshal_credentials.rst

    krb5_verify_init_creds.rst

    krb5_verify_init_creds_opt_init.rst

    krb5_verify_init_creds_opt_set_ap_req_nofail.rst

diff --git a/src/include/krb5/krb5.hin b/src/include/krb5/krb5.hin

index 63e67a2ba..c26dde535 100644

--- a/src/include/krb5/krb5.hin

+++ b/src/include/krb5/krb5.hin

@@ -3125,6 +3125,42 @@ krb5_get_credentials(krb5_context context, krb5_flags options,

                      krb5_ccache ccache, krb5_creds *in_creds,

                      krb5_creds **out_creds);

+/**

+ * Serialize a @c krb5_creds object.

+ *

+ * @param [in]  context         Library context

+ * @param [in]  creds           The credentials object to serialize

+ * @param [out] data_out        The serialized credentials

+ *

+ * Serialize @a creds in the format used by the FILE ccache format (vesion 4)

+ * and KCM ccache protocol.

+ *

+ * Use krb5_free_data() to free @a data_out when it is no longer needed.

+ *

+ * @retval 0 Success; otherwise - Kerberos error codes

+ */

+krb5_error_code KRB5_CALLCONV

+krb5_marshal_credentials(krb5_context context, krb5_creds *in_creds,

+                         krb5_data **data_out);

+

+/**

+ * Deserialize a @c krb5_creds object.

+ *

+ * @param [in]  context         Library context

+ * @param [in]  data            The serialized credentials

+ * @param [out] creds_out       The resulting creds object

+ *

+ * Deserialize @a data to credentials in the format used by the FILE ccache

+ * format (vesion 4) and KCM ccache protocol.

+ *

+ * Use krb5_free_creds() to free @a creds_out when it is no longer needed.

+ *

+ * @retval 0 Success; otherwise - Kerberos error codes

+ */

+krb5_error_code KRB5_CALLCONV

+krb5_unmarshal_credentials(krb5_context context, const krb5_data *data,

+                           krb5_creds **creds_out);

+

 /** @deprecated Replaced by krb5_get_validated_creds. */

 krb5_error_code KRB5_CALLCONV

 krb5_get_credentials_validate(krb5_context context, krb5_flags options,

diff --git a/src/lib/krb5/ccache/ccmarshal.c b/src/lib/krb5/ccache/ccmarshal.c

index ae634ccab..ab284e721 100644

--- a/src/lib/krb5/ccache/ccmarshal.c

+++ b/src/lib/krb5/ccache/ccmarshal.c

@@ -515,3 +515,56 @@ k5_marshal_mcred(struct k5buf *buf, krb5_creds *mcred)

     if (mcred->second_ticket.length > 0)

         put_data(buf, version, &mcred->second_ticket);

 }

+

+krb5_error_code KRB5_CALLCONV

+krb5_marshal_credentials(krb5_context context, krb5_creds *in_creds,

+                         krb5_data **data_out)

+{

+    krb5_error_code ret;

+    krb5_data *data;

+    struct k5buf buf;

+

+    *data_out = NULL;

+

+    data = k5alloc(sizeof(krb5_data), &ret;;

+    if (ret)

+        return ret;

+

+    k5_buf_init_dynamic(&buf;;

+    k5_marshal_cred(&buf, 4, in_creds);

+

+    ret = k5_buf_status(&buf;;

+    if (ret) {

+        free(data);

+        return ret;

+    }

+

+    /* Steal payload from buf. */

+    *data = make_data(buf.data, buf.len);

+    *data_out = data;

+    return 0;

+}

+

+krb5_error_code KRB5_CALLCONV

+krb5_unmarshal_credentials(krb5_context context, const krb5_data *data,

+                           krb5_creds **creds_out)

+{

+    krb5_error_code ret;

+    krb5_creds *creds;

+

+    *creds_out = NULL;

+

+    creds = k5alloc(sizeof(krb5_creds), &ret;;

+    if (ret)

+        return ret;

+

+    ret = k5_unmarshal_cred((unsigned char *)data->data, data->length, 4,

+                            creds);

+    if (ret) {

+        free(creds);

+        return ret;

+    }

+

+    *creds_out = creds;

+    return 0;

+}

diff --git a/src/lib/krb5/ccache/t_marshal.c b/src/lib/krb5/ccache/t_marshal.c

index bd0284afa..96e0931a2 100644

--- a/src/lib/krb5/ccache/t_marshal.c

+++ b/src/lib/krb5/ccache/t_marshal.c

@@ -268,13 +268,14 @@ main(int argc, char **argv)

     krb5_context context;

     krb5_ccache cache;

     krb5_principal princ;

-    krb5_creds cred1, cred2;

+    krb5_creds cred1, cred2, *alloc_cred;

     krb5_cc_cursor cursor;

     const char *filename;

     char *ccname, filebuf[256];

     int version, fd;

     const struct test *t;

     struct k5buf buf;

+    krb5_data ser_data, *alloc_data;

     if (argc != 2)

         abort();

@@ -285,6 +286,18 @@ main(int argc, char **argv)

     if (krb5_init_context(&context) != 0)

         abort();

+    /* Test public functions for unmarshalling and marshalling. */

+    ser_data = make_data((char *)tests[3].cred1, tests[3].cred1len);

+    if (krb5_unmarshal_credentials(context, &ser_data, &alloc_cred) != 0)

+        abort();

+    verify_cred1(alloc_cred);

+    if (krb5_marshal_credentials(context, alloc_cred, &alloc_data) != 0)

+        abort();

+    assert(alloc_data->length == tests[3].cred1len);

+    assert(memcmp(tests[3].cred1, alloc_data->data, alloc_data->length) == 0);

+    krb5_free_data(context, alloc_data);

+    krb5_free_creds(context, alloc_cred);

+

     for (version = FIRST_VERSION; version <= 4; version++) {

         t = &tests[version - 1];

diff --git a/src/lib/krb5/libkrb5.exports b/src/lib/krb5/libkrb5.exports

index 2d9d56530..adbfa332b 100644

--- a/src/lib/krb5/libkrb5.exports

+++ b/src/lib/krb5/libkrb5.exports

@@ -489,6 +489,7 @@ krb5_lock_file

 krb5_make_authdata_kdc_issued

 krb5_make_full_ipaddr

 krb5_make_fulladdr

+krb5_marshal_credentials

 krb5_mcc_ops

 krb5_merge_authdata

 krb5_mk_1cred

@@ -592,6 +593,7 @@ krb5_timeofday

 krb5_timestamp_to_sfstring

 krb5_timestamp_to_string

 krb5_unlock_file

+krb5_unmarshal_credentials

 krb5_unpack_full_ipaddr

 krb5_unparse_name

 krb5_unparse_name_ext

diff --git a/src/lib/krb5_32.def b/src/lib/krb5_32.def

index 4953907aa..60b8dd311 100644

--- a/src/lib/krb5_32.def

+++ b/src/lib/krb5_32.def

@@ -503,3 +503,7 @@ EXPORTS

 ; new in 1.19

 	k5_cc_store_primary_cred			@470 ; PRIVATE

 	k5_kt_have_match				@471 ; PRIVATE GSSAPI

+

+; new in 1.20

+	krb5_marshal_credentials			@472

+	krb5_unmarshal_credentials			@473