krb5: move template check to initializzation

The randomized template check realy only makes sense for the FILE ccache
which is the only one that normally needs to use randomizing chars.
Also it is better to warn the admin early rather than to warn 'when it
is too late'.
So move the check at initialization time when we determine what the
template actually is.

Resolves:
https://fedorahosted.org/sssd/ticket/2061

1 files changed, 17 insertions, 0 deletions

diff --git a/src/providers/krb5/krb5_common.c b/src/providers/krb5/krb5_common.c
index c7ce574d..de7ae0a8 100644
--- a/src/providers/krb5/krb5_common.c
+++ b/src/providers/krb5/krb5_common.c
@@ -144,6 +144,19 @@ static errno_t sss_get_system_ccname_template(TALLOC_CTX *mem_ctx,
 }
 #endif
 
+static void sss_check_cc_template(const char *cc_template)
+{
+    size_t template_len;
+
+    template_len = strlen(cc_template);
+    if (template_len >= 6 &&
+        strcmp(cc_template + (template_len - 6), "XXXXXX") != 0) {
+        DEBUG(SSSDBG_CONF_SETTINGS, ("ccache file name template [%s] doesn't "
+                   "contain randomizing characters (XXXXXX), file might not "
+                   "be rewritable\n", cc_template));
+    }
+}
+
 errno_t check_and_export_options(struct dp_option *opts,
                                  struct sss_domain_info *dom,
                                  struct krb5_ctx *krb5_ctx)
@@ -282,6 +295,10 @@ errno_t check_and_export_options(struct dp_option *opts,
     switch (cc_be) {
     case SSS_KRB5_TYPE_FILE:
         DEBUG(SSSDBG_CONF_SETTINGS, ("ccache is of type FILE\n"));
+        /* warn if the file type (which is usally created in a sticky bit
+         * laden directory) does not have randomizing chracters */
+        sss_check_cc_template(ccname);
+
         krb5_ctx->cc_be = &file_cc;
         if (ccname[0] != '/') {
             /* FILE:/path/to/cc */