Catching more principals in ads_keytab_verify_ticket()
Jeremy Allison
jra at samba.org
Sat Mar 12 01:25:46 GMT 2005
On Thu, Mar 10, 2005 at 03:56:03AM -0800, Doug VanLeuven wrote:
> Jeremy Allison wrote:
>
> >I'm not going to add either patch until you huys have both
> >agreed. When you do - re-mail me the patch you want going in
> >and I'll look at that.
> >
> >The kerberos keytab stuff is complex enough that the last
> >thing I want to see is "warring patches" that fix different
> >things for different people.
> >
> >
> The rc4-hmac works ok.
> The des-cbc-md5 works ok.
>
> After having studied it and run the experiments, it seems like a real
> good idea.
> I didn't change anything from his submittal except a couple debug
> statements. I'm finding it really handy to have a message all key
> matches failed. Sort of a heads up something is missing from the keytab.
>
> Thanks a lot Michael, it's a lot cleaner.
>
> Jeremy, I'm still working on what to do for libads/kerberos_keytab.c.
> Some issues came up during the des testing that have a direct bearing on
> bug 2414 you asked about.
>
> Regards, Doug
Ok, here's my version of Michael's patch. Re-coded for Samba keytab
requirements - also frees entries after reading. I'm going to check into
SAMBA_3_0 and HEAD SVN trees. Please test.
Thanks,
Jeremy.
-------------- next part --------------
Index: libads/kerberos_verify.c
===================================================================
--- libads/kerberos_verify.c (revision 5755)
+++ libads/kerberos_verify.c (working copy)
@@ -42,88 +42,122 @@
krb5_error_code ret = 0;
BOOL auth_ok = False;
krb5_keytab keytab = NULL;
- fstring my_fqdn, my_name;
- fstring my_Fqdn, my_NAME;
- char *p_fqdn;
- char *host_princ_s[18];
- krb5_principal host_princ;
+ krb5_kt_cursor kt_cursor;
+ krb5_keytab_entry kt_entry;
+ char *valid_princ_formats[7] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL };
+ char *entry_princ_s = NULL;
+ fstring my_name, my_fqdn;
int i;
+ int number_matched_principals = 0;
+ /* Generate the list of principal names which we expect
+ * clients might want to use for authenticating to the file
+ * service. We allow name$,{host,cifs}/{name,fqdn,name.REALM}. */
+
+ fstrcpy(my_name, global_myname());
+
+ my_fqdn[0] = '\0';
+ name_to_fqdn(my_fqdn, global_myname());
+
+ asprintf(&valid_princ_formats[0], "%s$@%s", my_name, lp_realm());
+ asprintf(&valid_princ_formats[1], "host/%s@%s", my_name, lp_realm());
+ asprintf(&valid_princ_formats[2], "host/%s@%s", my_fqdn, lp_realm());
+ asprintf(&valid_princ_formats[3], "host/%s.%s@%s", my_name, lp_realm(), lp_realm());
+ asprintf(&valid_princ_formats[4], "cifs/%s@%s", my_name, lp_realm());
+ asprintf(&valid_princ_formats[5], "cifs/%s@%s", my_fqdn, lp_realm());
+ asprintf(&valid_princ_formats[6], "cifs/%s.%s@%s", my_name, lp_realm(), lp_realm());
+
+ ZERO_STRUCT(kt_entry);
+ ZERO_STRUCT(kt_cursor);
+
ret = krb5_kt_default(context, &keytab);
if (ret) {
DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_default failed (%s)\n", error_message(ret)));
goto out;
}
- /* Generate the list of principal names which we expect clients might
- * want to use for authenticating to the file service. */
+ /* Iterate through the keytab. For each key, if the principal
+ * name case-insensitively matches one of the allowed formats,
+ * try verifying the ticket using that principal. */
- fstrcpy(my_name, global_myname());
- strlower_m(my_name);
+ ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
+ if (ret) {
+ DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_start_seq_get failed (%s)\n", error_message(ret)));
+ goto out;
+ }
+
+ ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
+ if (ret != KRB5_KT_END && ret != ENOENT ) {
+ while (!auth_ok && (krb5_kt_next_entry(context, keytab, &kt_entry, &kt_cursor) == 0)) {
+ ret = krb5_unparse_name(context, kt_entry.principal, &entry_princ_s);
+ if (ret) {
+ DEBUG(1, ("ads_keytab_verify_ticket: krb5_unparse_name failed (%s)\n", error_message(ret)));
+ goto out;
+ }
- fstrcpy(my_NAME, global_myname());
- strupper_m(my_NAME);
+ for (i = 0; i < sizeof(valid_princ_formats) / sizeof(valid_princ_formats[0]); i++) {
+ if (strequal(entry_princ_s, valid_princ_formats[i])) {
+ number_matched_principals++;
+ p_packet->length = ticket->length;
+ p_packet->data = (krb5_pointer)ticket->data;
+ *pp_tkt = NULL;
+ ret = krb5_rd_req(context, &auth_context, p_packet, kt_entry.principal, keytab, NULL, pp_tkt);
+ if (ret) {
+ DEBUG(10, ("ads_keytab_verify_ticket: krb5_rd_req(%s) failed: %s\n",
+ entry_princ_s, error_message(ret)));
+ } else {
+ DEBUG(3,("ads_keytab_verify_ticket: krb5_rd_req succeeded for principal %s\n",
+ entry_princ_s));
+ auth_ok = True;
+ break;
+ }
+ }
+ }
- my_fqdn[0] = '\0';
- name_to_fqdn(my_fqdn, global_myname());
- strlower_m(my_fqdn);
+ /* Free the name we parsed. */
+ krb5_free_unparsed_name(context, entry_princ_s);
+ entry_princ_s = NULL;
- p_fqdn = strchr_m(my_fqdn, '.');
- fstrcpy(my_Fqdn, my_NAME);
- if (p_fqdn) {
- fstrcat(my_Fqdn, p_fqdn);
+ /* Free the entry we just read. */
+ smb_krb5_kt_free_entry(context, &kt_entry);
+ ZERO_STRUCT(kt_entry);
+ }
+ krb5_kt_end_seq_get(context, keytab, &kt_cursor);
}
- asprintf(&host_princ_s[0], "%s$@%s", my_name, lp_realm());
- asprintf(&host_princ_s[1], "%s$@%s", my_NAME, lp_realm());
- asprintf(&host_princ_s[2], "host/%s@%s", my_name, lp_realm());
- asprintf(&host_princ_s[3], "host/%s@%s", my_NAME, lp_realm());
- asprintf(&host_princ_s[4], "host/%s@%s", my_fqdn, lp_realm());
- asprintf(&host_princ_s[5], "host/%s@%s", my_Fqdn, lp_realm());
- asprintf(&host_princ_s[6], "HOST/%s@%s", my_name, lp_realm());
- asprintf(&host_princ_s[7], "HOST/%s@%s", my_NAME, lp_realm());
- asprintf(&host_princ_s[8], "HOST/%s@%s", my_fqdn, lp_realm());
- asprintf(&host_princ_s[9], "HOST/%s@%s", my_Fqdn, lp_realm());
- asprintf(&host_princ_s[10], "cifs/%s@%s", my_name, lp_realm());
- asprintf(&host_princ_s[11], "cifs/%s@%s", my_NAME, lp_realm());
- asprintf(&host_princ_s[12], "cifs/%s@%s", my_fqdn, lp_realm());
- asprintf(&host_princ_s[13], "cifs/%s@%s", my_Fqdn, lp_realm());
- asprintf(&host_princ_s[14], "CIFS/%s@%s", my_name, lp_realm());
- asprintf(&host_princ_s[15], "CIFS/%s@%s", my_NAME, lp_realm());
- asprintf(&host_princ_s[16], "CIFS/%s@%s", my_fqdn, lp_realm());
- asprintf(&host_princ_s[17], "CIFS/%s@%s", my_Fqdn, lp_realm());
+ ZERO_STRUCT(kt_cursor);
- /* Now try to verify the ticket using the key associated with each of
- * the principals which we think clients will expect us to be
- * participating as. */
- for (i = 0; i < sizeof(host_princ_s) / sizeof(host_princ_s[0]); i++) {
- host_princ = NULL;
- ret = krb5_parse_name(context, host_princ_s[i], &host_princ);
- if (ret) {
- DEBUG(1, ("ads_keytab_verify_ticket: krb5_parse_name(%s) failed (%s)\n",
- host_princ_s[i], error_message(ret)));
- goto out;
+ out:
+
+ if (!auth_ok) {
+ if (!number_matched_principals) {
+ DEBUG(3, ("ads_keytab_verify_ticket: no keytab principals matched expected file service name.\n"));
+ } else {
+ DEBUG(3, ("ads_keytab_verify_ticket: krb5_rd_req failed for all %d matched keytab principals\n",
+ number_matched_principals));
}
- p_packet->length = ticket->length;
- p_packet->data = (krb5_pointer)ticket->data;
- *pp_tkt = NULL;
- ret = krb5_rd_req(context, &auth_context, p_packet, host_princ, keytab, NULL, pp_tkt);
- krb5_free_principal(context, host_princ);
- if (ret) {
- DEBUG(10, ("krb5_rd_req(%s) failed: %s\n", host_princ_s[i], error_message(ret)));
- } else {
- DEBUG(10,("krb5_rd_req succeeded for principal %s\n", host_princ_s[i]));
- auth_ok = True;
- break;
- }
}
- for (i = 0; i < sizeof(host_princ_s) / sizeof(host_princ_s[0]); i++) {
- SAFE_FREE(host_princ_s[i]);
+ if (entry_princ_s) {
+ krb5_free_unparsed_name(context, entry_princ_s);
}
- out:
+ {
+ krb5_keytab_entry zero_kt_entry;
+ ZERO_STRUCT(zero_kt_entry);
+ if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
+ smb_krb5_kt_free_entry(context, &kt_entry);
+ }
+ }
+ {
+ krb5_kt_cursor zero_csr;
+ ZERO_STRUCT(zero_csr);
+ if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
+ krb5_kt_end_seq_get(context, keytab, &kt_cursor);
+ }
+ }
+
if (keytab) {
krb5_kt_close(context, keytab);
}
More information about the samba-technical
mailing list