[krbdev.mit.edu #3092] cpw protocol does not return the result string during "min pw life not expired"

[Shawn Emery via RT]

The result string is not being generated in the KRB-PRIV message by the 
MIT kadmin server.  The specific failure is when the password's minimum 
life has not expired.  This is from the fact that check_min_life() never 
generates the result string.  The causes the default (terse) error 
message to be returned to the user, with no indication of what the real 
problem is:

% kpasswd poe
kpasswd: Changing password for poe.
Old password:
New password:
New password (again):
kpasswd: Password change rejected

I would rather see something like this:

% kpasswd poe
kpasswd: Changing password for poe.
Old password:
New password:
New password (again):
kpasswd: Password change rejected: Password cannot be changed because it 
was changed too recently.
Please wait until Tue Jun  7 00:53:06 2005
 before you change it.
If you need to change your password before then, contact your system
security administrator.

The fix includes the following diffs based on MIT 1.4.1:

kadmin/server/misc.c:
@@ -41,11 +41,11 @@
                           krb5_key_salt_tuple *ks_tuple,
                           char *password)
 {
     kadm5_ret_t                        ret;
 
-    ret = check_min_life(server_handle, principal);
+    ret = check_min_life(server_handle, principal, NULL);
     if (ret)
         return ret;
 
     return kadm5_chpass_principal_3(server_handle, principal,
                                    keepold, n_ks_tuple, ks_tuple,
@@ -84,11 +84,11 @@
                            krb5_key_salt_tuple *ks_tuple,
                            krb5_keyblock **keys, int *n_keys)
 {
     kadm5_ret_t                        ret;
 
-    ret = check_min_life(server_handle, principal);
+    ret = check_min_life(server_handle, principal, NULL);
     if (ret)
         return ret;
     return kadm5_randkey_principal_3(server_handle, principal,
                                     keepold, n_ks_tuple, ks_tuple,
                                     keys, n_keys);
@@ -99,21 +99,21 @@
                    char *new_pw, char **ret_pw,
                    char *msg_ret, unsigned int msg_len)
 {
     kadm5_ret_t ret;
 
-    ret = check_min_life(server_handle, princ);
+    ret = check_min_life(server_handle, princ, msg_ret);
     if (ret)
        return ret;
 
     return kadm5_chpass_principal_util(server_handle, princ,
                                       new_pw, ret_pw,
                                       msg_ret, msg_len);
 }
 
 kadm5_ret_t
-check_min_life(void *server_handle, krb5_principal principal)
+check_min_life(void *server_handle, krb5_principal principal, char 
*msg_ret)
 {
     krb5_int32                 now;
     kadm5_ret_t                        ret;
     kadm5_policy_ent_rec       pol;
     kadm5_principal_ent_rec    princ;
@@ -133,10 +133,19 @@
            (void) kadm5_free_principal_ent(handle->lhandle, &princ);
            return ret;
        }
        if((now - princ.last_pwd_change) < pol.pw_min_life &&
           !(princ.attributes & KRB5_KDB_REQUIRES_PWCHANGE)) {
+           if (msg_ret != NULL) {
+               char    *time_string;
+               time_t  until;
+
+               until = princ.last_pwd_change + pol.pw_min_life;
+               time_string = ctime(&until);
+               sprintf(msg_ret, string_text(CHPASS_UTIL_PASSWORD_TOO_SOON),
+                       time_string);
+           }
            (void) kadm5_free_policy_ent(handle->lhandle, &pol);
            (void) kadm5_free_principal_ent(handle->lhandle, &princ);
            return KADM5_PASS_TOOSOON;
        }


kadmin/server/misc.h:
@@ -22,11 +22,12 @@
 kadm5_ret_t
 chpass_util_wrapper(void *server_handle, krb5_principal princ,
                    char *new_pw, char **ret_pw,
                    char *msg_ret, unsigned int msg_len);
 
-kadm5_ret_t check_min_life(void *server_handle, krb5_principal principal);
+kadm5_ret_t check_min_life(void *server_handle, krb5_principal principal,
+                          char *msg_ret);
 
 kadm5_ret_t kadm5_get_principal_v1(void *server_handle,
                                   krb5_principal principal,
                                   kadm5_principal_ent_t_v1 *ent);
 
@@ -39,8 +40,10 @@
                                     char *realm, int s,
                                     krb5_keytab keytab,
                                     struct sockaddr_in *sockin,
                                     krb5_data *req, krb5_data *rep);
 
+#define string_text error_message
+
 #ifdef SVC_GETARGS
 void  kadm_1(struct svc_req *, SVCXPRT *);
 #endif

Shawn.
--