From a9278ff6f7b387c529c3b57251974403c5990d44 Mon Sep 17 00:00:00 2001
From: Jakub Hrozek <jhrozek@redhat.com>
Date: Tue, 18 Mar 2014 16:48:11 +0100
Subject: [PATCH] KRB5: Do not attempt to get a TGT after a password change
using OTP
https://fedorahosted.org/sssd/ticket/2271
The current krb5_child code attempts to get a TGT for the convenience of
the user using the new password after a password change operation.
However, an OTP should never be used twice, which means we can't perform
the kinit operation after chpass is finished. Instead, we only print a
PAM information instructing the user to log out and back in manually.
---
src/providers/krb5/krb5_auth.c | 21 ++++++++++++++++++---
src/providers/krb5/krb5_child.c | 12 ++++++++++++
src/sss_client/pam_sss.c | 19 +++++++++++++++++++
src/sss_client/sss_cli.h | 3 +++
4 files changed, 52 insertions(+), 3 deletions(-)
diff --git a/src/providers/krb5/krb5_auth.c b/src/providers/krb5/krb5_auth.c
index ce461f5adefc6e42fdc69726ff71d23526375c0c..48c0746efc3d136a1f13e8982384d503d8d20723 100644
--- a/src/providers/krb5/krb5_auth.c
+++ b/src/providers/krb5/krb5_auth.c
@@ -815,6 +815,7 @@ static void krb5_auth_done(struct tevent_req *subreq)
char *renew_interval_str;
time_t renew_interval_time = 0;
bool use_enterprise_principal;
+ uint32_t user_info_type;
ret = handle_child_recv(subreq, pd, &buf, &len);
talloc_zfree(subreq);
@@ -1062,9 +1063,23 @@ static void krb5_auth_done(struct tevent_req *subreq)
ret = sss_krb5_check_ccache_princ(kr->uid, kr->gid, kr->ccname, kr->upn);
if (ret) {
- DEBUG(SSSDBG_CRIT_FAILURE,
- ("No ccache for %s in %s?\n", kr->upn, kr->ccname));
- goto done;
+ if (res->otp == true && pd->cmd == SSS_PAM_CHAUTHTOK) {
+ DEBUG(SSSDBG_IMPORTANT_INFO,
+ ("Password change succeeded but currently "
+ "post-chpass kinit is not implemented\n"));
+
+ user_info_type = SSS_PAM_USER_INFO_OTP_CHPASS;
+ ret = pam_add_response(pd, SSS_PAM_USER_INFO, sizeof(uint32_t),
+ (const uint8_t *) &user_info_type);
+ if (ret != EOK) {
+ DEBUG(SSSDBG_CRIT_FAILURE, ("pam_add_response failed.\n"));
+ /* Not fatal */
+ }
+ } else {
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("No ccache for %s in %s?\n", kr->upn, kr->ccname));
+ goto done;
+ }
}
if (kr->old_ccname) {
diff --git a/src/providers/krb5/krb5_child.c b/src/providers/krb5/krb5_child.c
index d000d70167936b09bbaa39ec7a665089572d9aaa..3ee49e4678078d15dab98eeddf56d36f87955dcf 100644
--- a/src/providers/krb5/krb5_child.c
+++ b/src/providers/krb5/krb5_child.c
@@ -45,6 +45,7 @@ struct krb5_req {
krb5_principal princ;
char* name;
krb5_creds *creds;
+ bool otp;
krb5_get_init_creds_opt *options;
struct pam_data *pd;
@@ -370,6 +371,8 @@ static krb5_error_code answer_otp(krb5_context ctx,
goto done;
}
+ kr->otp = true;
+
/* Validate our assumptions about the contents of authtok. */
ret = sss_authtok_get_password(kr->pd->authtok, &pwd, &len);
if (ret != EOK)
@@ -694,6 +697,8 @@ static errno_t k5c_send_data(struct krb5_req *kr, int fd, errno_t error)
size_t len;
int ret;
+ DEBUG(SSSDBG_FUNC_DATA, ("Received error code %d\n", error));
+
ret = pack_response_packet(kr, error, kr->pd->resp_list, &buf, &len);
if (ret != EOK) {
DEBUG(1, ("pack_response_packet failed.\n"));
@@ -1110,6 +1115,8 @@ static errno_t changepw_child(struct krb5_req *kr, bool prelim)
prompter, kr, 0,
SSSD_KRB5_CHANGEPW_PRINCIPAL,
kr->options);
+ DEBUG(SSSDBG_TRACE_INTERNAL,
+ ("chpass is%s using OTP\n", kr->otp ? "" : " not"));
if (kerr != 0) {
ret = pack_user_info_chpass_error(kr->pd, "Old password not accepted.",
&msg_len, &msg);
@@ -1205,6 +1212,11 @@ static errno_t changepw_child(struct krb5_req *kr, bool prelim)
krb5_free_cred_contents(kr->ctx, kr->creds);
+ if (kr->otp == true) {
+ sss_authtok_set_empty(kr->pd->newauthtok);
+ return map_krb5_error(kerr);
+ }
+
/* We changed some of the gic options for the password change, now we have
* to change them back to get a fresh TGT. */
revert_changepw_options(kr->options);
diff --git a/src/sss_client/pam_sss.c b/src/sss_client/pam_sss.c
index 4ff38f299bec75a49c8aace06eecab5735ca9443..e629fc19bd705ac35c2fa1ea4946f40c5eb49079 100644
--- a/src/sss_client/pam_sss.c
+++ b/src/sss_client/pam_sss.c
@@ -771,6 +771,22 @@ static int user_info_offline_chpass(pam_handle_t *pamh)
return PAM_SUCCESS;
}
+static int user_info_otp_chpass(pam_handle_t *pamh)
+{
+ int ret;
+
+ ret = do_pam_conversation(pamh, PAM_TEXT_INFO,
+ _("After changing the OTP password, you need to "
+ "log out and back in order to acquire a ticket"),
+ NULL, NULL);
+ if (ret != PAM_SUCCESS) {
+ D(("do_pam_conversation failed."));
+ return PAM_SYSTEM_ERR;
+ }
+
+ return PAM_SUCCESS;
+}
+
static int user_info_chpass_error(pam_handle_t *pamh, size_t buflen,
uint8_t *buf)
{
@@ -856,6 +872,9 @@ static int eval_user_info_response(pam_handle_t *pamh, size_t buflen,
case SSS_PAM_USER_INFO_OFFLINE_CHPASS:
ret = user_info_offline_chpass(pamh);
break;
+ case SSS_PAM_USER_INFO_OTP_CHPASS:
+ ret = user_info_otp_chpass(pamh);
+ break;
case SSS_PAM_USER_INFO_CHPASS_ERROR:
ret = user_info_chpass_error(pamh, buflen, buf);
break;
diff --git a/src/sss_client/sss_cli.h b/src/sss_client/sss_cli.h
index 285a2979addb0c0677527b76b3b6755f2f173815..16a08e1869bb81ede2c1db87f1fb6d0a51087847 100644
--- a/src/sss_client/sss_cli.h
+++ b/src/sss_client/sss_cli.h
@@ -451,6 +451,9 @@ enum user_info_type {
* possible to change the password while
* the system is offline. This message
* is generated by the PAM responder. */
+ SSS_PAM_USER_INFO_OTP_CHPASS, /**< Tell the user that he needs to kinit
+ * or login and logout to get a TGT after
+ * an OTP password change */
SSS_PAM_USER_INFO_CHPASS_ERROR, /**< Tell the user that a password change
* failed and optionally give a reason.
* @param Size of the message as unsigned
--
1.8.5.3