From c3bd400fa209422cb0dfedde5b7d5aeb8bdd229d Mon Sep 17 00:00:00 2001
From: Jeffrey Altman <jaltman@auristor.com>
Date: Wed, 16 Apr 2025 10:08:23 -0400
Subject: [PATCH] base: heim_config_parse_file_multi fix plist config parsing

4c34168b01913d592fb304903b2fd75d9d65644e ("base: Fix use of
HEIM_USE_PATH_TOKENS") relocated the expansion of path tokens
within heim_config_parse_file_multi() so it is only performed
for non-plist files.  However, parse_plist_config() does not
understand tokens and will treat them as path components.  As
a result, plist paths such as

  %{USERCONFIG}/Library/Preferences/com.apple.Kerberos.plist

will not be expanded. If parse_plist_config() fails with ENOENT,
then the plist configuration will be skipped and krb5_init_context()
will succeed.  However, if the current working directory is invalid,
then parse_plist_config() would return ENOMEM which is a fatal
error and krb5_init_context() would fail.

For example, on macOS, if the cwd is in /afs and the user's
tokens have expired:

  user@MacBookAir user % ~/src/heimdal/kuser/heimtools klist
  shell-init: error retrieving current directory:
  getcwd: cannot access parent directories: Permission denied
  chdir: error retrieving current directory:
  getcwd: cannot access parent directories: Permission denied
  heimtools: krb5_init_context failed: 12

With this change %{USERCONFIG} is expanded and parse_plist_config()
is called with an absolute path.  Even though the specified file
is inaccessible, the krb5_init_context() call succeeds.
---
 lib/base/config_file.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/lib/base/config_file.c b/lib/base/config_file.c
index e23c3391f..7ea7a99ca 100644
--- a/lib/base/config_file.c
+++ b/lib/base/config_file.c
@@ -576,6 +576,7 @@ heim_config_parse_file_multi(heim_context context,
 {
     const char *str;
     char *newfname = NULL;
+    char *exp_fname = NULL;
     unsigned lineno = 0;
     heim_error_code ret = 0;
     struct fileptr f;
@@ -608,6 +609,19 @@ heim_config_parse_file_multi(heim_context context,
         fname = newfname;
     }
 
+    /*
+     * Note that heim_config_parse_dir_multi() doesn't want tokens
+     * expanded here, but it happens to limit the names of files to
+     * include such that there can be no tokens to expand.  Don't
+     * add token expansion for tokens using _, say.
+     */
+    ret = heim_expand_path_tokens(context, fname, 1, &exp_fname, NULL);
+    if (ret)
+	goto out;
+    free(newfname);
+    fname = newfname = exp_fname;
+
+
     if (is_plist_file(fname)) {
 #if defined(HAVE_FRAMEWORK_COREFOUNDATION)
         ret = parse_plist_config(context, fname, res);
@@ -623,20 +637,6 @@ heim_config_parse_file_multi(heim_context context,
 	goto out;
 #endif
     } else {
-	char *exp_fname = NULL;
-
-        /*
-         * Note that heim_config_parse_dir_multi() doesn't want tokens
-         * expanded here, but it happens to limit the names of files to
-         * include such that there can be no tokens to expand.  Don't
-         * add token expansion for tokens using _, say.
-         */
-        ret = heim_expand_path_tokens(context, fname, 1, &exp_fname, NULL);
-        if (ret)
-            goto out;
-	free(newfname);
-        fname = newfname = exp_fname;
-
         f.context = context;
         f.f = fopen(fname, "r");
         f.s = NULL;