krb5 commit [krb5-1.15]: Explicitly copy KDB vtable fields

[Greg Hudson]

https://github.com/krb5/krb5/commit/75b601f18fdccad40fead041ad9e23e41775caf5
commit 75b601f18fdccad40fead041ad9e23e41775caf5
Author: Greg Hudson <ghudson at mit.edu>
Date:   Wed Jan 18 11:40:49 2017 -0500

    Explicitly copy KDB vtable fields
    
    In preparation for bumping the kdb_vftabl minor version, use explicit
    field assignments when copying the module vtable to the internal copy,
    so that we can conditionalize assignments for minor versions greater
    than 0.
    
    (cherry picked from commit 50605efa5058583667227223a75ca44a512f4796)
    
    ticket: 8538
    version_fixed: 1.15.1

 src/lib/kdb/kdb5.c |   79 ++++++++++++++++++++++++++++++++++++++--------------
 1 files changed, 58 insertions(+), 21 deletions(-)

diff --git a/src/lib/kdb/kdb5.c b/src/lib/kdb/kdb5.c
index a3139a7..ee41272 100644
--- a/src/lib/kdb/kdb5.c
+++ b/src/lib/kdb/kdb5.c
@@ -283,24 +283,63 @@ clean_n_exit:
 }
 
 static void
-kdb_setup_opt_functions(db_library lib)
-{
-    if (lib->vftabl.fetch_master_key == NULL)
-        lib->vftabl.fetch_master_key = krb5_db_def_fetch_mkey;
-    if (lib->vftabl.fetch_master_key_list == NULL)
-        lib->vftabl.fetch_master_key_list = krb5_def_fetch_mkey_list;
-    if (lib->vftabl.store_master_key_list == NULL)
-        lib->vftabl.store_master_key_list = krb5_def_store_mkey_list;
-    if (lib->vftabl.dbe_search_enctype == NULL)
-        lib->vftabl.dbe_search_enctype = krb5_dbe_def_search_enctype;
-    if (lib->vftabl.change_pwd == NULL)
-        lib->vftabl.change_pwd = krb5_dbe_def_cpw;
-    if (lib->vftabl.decrypt_key_data == NULL)
-        lib->vftabl.decrypt_key_data = krb5_dbe_def_decrypt_key_data;
-    if (lib->vftabl.encrypt_key_data == NULL)
-        lib->vftabl.encrypt_key_data = krb5_dbe_def_encrypt_key_data;
-    if (lib->vftabl.rename_principal == NULL)
-        lib->vftabl.rename_principal = krb5_db_def_rename_principal;
+copy_vtable(const kdb_vftabl *in, kdb_vftabl *out)
+{
+    /* Copy fields for minor version 0. */
+    out->maj_ver = in->maj_ver;
+    out->min_ver = in->min_ver;
+    out->init_library = in->init_library;
+    out->fini_library = in->fini_library;
+    out->init_module = in->init_module;
+    out->fini_module = in->fini_module;
+    out->create = in->create;
+    out->destroy = in->destroy;
+    out->get_age = in->get_age;
+    out->lock = in->lock;
+    out->unlock = in->unlock;
+    out->get_principal = in->get_principal;
+    out->put_principal = in->put_principal;
+    out->delete_principal = in->delete_principal;
+    out->rename_principal = in->rename_principal;
+    out->iterate = in->iterate;
+    out->create_policy = in->create_policy;
+    out->get_policy = in->get_policy;
+    out->put_policy = in->put_policy;
+    out->iter_policy = in->iter_policy;
+    out->delete_policy = in->delete_policy;
+    out->fetch_master_key = in->fetch_master_key;
+    out->fetch_master_key_list = in->fetch_master_key_list;
+    out->store_master_key_list = in->store_master_key_list;
+    out->dbe_search_enctype = in->dbe_search_enctype;
+    out->change_pwd = in->change_pwd;
+    out->promote_db = in->promote_db;
+    out->decrypt_key_data = in->decrypt_key_data;
+    out->encrypt_key_data = in->encrypt_key_data;
+    out->sign_authdata = in->sign_authdata;
+    out->check_transited_realms = in->check_transited_realms;
+    out->check_policy_as = in->check_policy_as;
+    out->check_policy_tgs = in->check_policy_tgs;
+    out->audit_as_req = in->audit_as_req;
+    out->refresh_config = in->refresh_config;
+    out->check_allowed_to_delegate = in->check_allowed_to_delegate;
+
+    /* Set defaults for optional fields. */
+    if (out->fetch_master_key == NULL)
+        out->fetch_master_key = krb5_db_def_fetch_mkey;
+    if (out->fetch_master_key_list == NULL)
+        out->fetch_master_key_list = krb5_def_fetch_mkey_list;
+    if (out->store_master_key_list == NULL)
+        out->store_master_key_list = krb5_def_store_mkey_list;
+    if (out->dbe_search_enctype == NULL)
+        out->dbe_search_enctype = krb5_dbe_def_search_enctype;
+    if (out->change_pwd == NULL)
+        out->change_pwd = krb5_dbe_def_cpw;
+    if (out->decrypt_key_data == NULL)
+        out->decrypt_key_data = krb5_dbe_def_decrypt_key_data;
+    if (out->encrypt_key_data == NULL)
+        out->encrypt_key_data = krb5_dbe_def_encrypt_key_data;
+    if (out->rename_principal == NULL)
+        out->rename_principal = krb5_db_def_rename_principal;
 }
 
 #ifdef STATIC_PLUGINS
@@ -334,8 +373,7 @@ kdb_load_library(krb5_context kcontext, char *lib_name, db_library *libptr)
         return ENOMEM;
 
     strlcpy(lib->name, lib_name, sizeof(lib->name));
-    memcpy(&lib->vftabl, vftabl_addr, sizeof(kdb_vftabl));
-    kdb_setup_opt_functions(lib);
+    copy_vtable(vftabl_addr, &lib->vftabl);
 
     status = lib->vftabl.init_library();
     if (status)
@@ -433,8 +471,7 @@ kdb_load_library(krb5_context kcontext, char *lib_name, db_library *lib)
         goto clean_n_exit;
     }
 
-    memcpy(&(*lib)->vftabl, vftabl_addrs[0], sizeof(kdb_vftabl));
-    kdb_setup_opt_functions(*lib);
+    copy_vtable(vftabl_addrs[0], &(*lib)->vftabl);
 
     if ((status = (*lib)->vftabl.init_library()))
         goto clean_n_exit;