sssd/0055-PAM-return-short-name-for-files-provider-users.patch

From dbd717fe5b7d8dd640b6ade435b49edb3db5280a Mon Sep 17 00:00:00 2001
From: Sumit Bose <sbose@redhat.com>
Date: Tue, 9 Oct 2018 13:25:35 +0200
Subject: [PATCH 70/83] PAM: return short name for files provider users

If the 'allow_missing_name' option is used with pam_sss and the user
name will be determined based on the certificate content and the mapping
rules the PAM responder will by default return the fully-qualified name
of the user which is then later used by other PAM modules as well.

For local users which are configured to use SSSD for Smartcard
authentication this might cause issues in other PAM modules because they
are not aware of the fully-qualified name and will treat the user as
unknown.

With this patch the PAM responder will return the short name for all
users handled by the files provider.

Related to https://pagure.io/SSSD/sssd/issue/3848

Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
---
 src/responder/pam/pamsrv.h     |  3 ++-
 src/responder/pam/pamsrv_cmd.c | 13 +++++++++----
 src/responder/pam/pamsrv_p11.c | 32 +++++++++++++++++++++++++++++---
 3 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/src/responder/pam/pamsrv.h b/src/responder/pam/pamsrv.h
index 60aa979..3a927bb 100644
--- a/src/responder/pam/pamsrv.h
+++ b/src/responder/pam/pamsrv.h
@@ -108,7 +108,8 @@ struct tevent_req *pam_check_cert_send(TALLOC_CTX *mem_ctx,
 errno_t pam_check_cert_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
                             struct cert_auth_info **cert_list);
 
-errno_t add_pam_cert_response(struct pam_data *pd, const char *sysdb_username,
+errno_t add_pam_cert_response(struct pam_data *pd, struct sss_domain_info *dom,
+                              const char *sysdb_username,
                               struct cert_auth_info *cert_info,
                               enum response_type type);
 
diff --git a/src/responder/pam/pamsrv_cmd.c b/src/responder/pam/pamsrv_cmd.c
index a22afd2..553bf8f 100644
--- a/src/responder/pam/pamsrv_cmd.c
+++ b/src/responder/pam/pamsrv_cmd.c
@@ -1645,7 +1645,8 @@ static void pam_forwarder_lookup_by_cert_done(struct tevent_req *req)
                      preq->current_cert != NULL;
                      preq->current_cert = sss_cai_get_next(preq->current_cert)) {
 
-                    ret = add_pam_cert_response(preq->pd, "",
+                    ret = add_pam_cert_response(preq->pd,
+                                       preq->cctx->rctx->domains, "",
                                        preq->current_cert,
                                        preq->cctx->rctx->domains->user_name_hint
                                             ? SSS_PAM_CERT_INFO_WITH_HINT
@@ -1699,7 +1700,8 @@ static void pam_forwarder_lookup_by_cert_done(struct tevent_req *req)
 
             if (preq->cctx->rctx->domains->user_name_hint
                     && preq->pd->cmd == SSS_PAM_PREAUTH) {
-                ret = add_pam_cert_response(preq->pd, cert_user,
+                ret = add_pam_cert_response(preq->pd,
+                                            preq->cctx->rctx->domains, cert_user,
                                             preq->cert_list,
                                             SSS_PAM_CERT_INFO_WITH_HINT);
                 preq->pd->pam_status = PAM_SUCCESS;
@@ -1725,7 +1727,8 @@ static void pam_forwarder_lookup_by_cert_done(struct tevent_req *req)
              * SSS_PAM_CERT_INFO message to send the name to the caller. */
             if (preq->pd->cmd == SSS_PAM_AUTHENTICATE
                     && preq->pd->logon_name == NULL) {
-                ret = add_pam_cert_response(preq->pd, cert_user,
+                ret = add_pam_cert_response(preq->pd,
+                                            preq->cctx->rctx->domains, cert_user,
                                             preq->cert_list,
                                             SSS_PAM_CERT_INFO);
                 if (ret != EOK) {
@@ -2117,7 +2120,9 @@ static void pam_dom_forwarder(struct pam_auth_req *preq)
                                   "the backend.\n");
                         }
 
-                        ret = add_pam_cert_response(preq->pd, cert_user,
+                        ret = add_pam_cert_response(preq->pd,
+                                                    preq->cctx->rctx->domains,
+                                                    cert_user,
                                                     preq->current_cert,
                                                     SSS_PAM_CERT_INFO);
                         if (ret != EOK) {
diff --git a/src/responder/pam/pamsrv_p11.c b/src/responder/pam/pamsrv_p11.c
index 491bd2b..785b29c 100644
--- a/src/responder/pam/pamsrv_p11.c
+++ b/src/responder/pam/pamsrv_p11.c
@@ -1145,7 +1145,8 @@ static errno_t pack_cert_data(TALLOC_CTX *mem_ctx, const char *sysdb_username,
  * used when running gdm-password. */
 #define PKCS11_LOGIN_TOKEN_ENV_NAME "PKCS11_LOGIN_TOKEN_NAME"
 
-errno_t add_pam_cert_response(struct pam_data *pd, const char *sysdb_username,
+errno_t add_pam_cert_response(struct pam_data *pd, struct sss_domain_info *dom,
+                              const char *sysdb_username,
                               struct cert_auth_info *cert_info,
                               enum response_type type)
 {
@@ -1153,6 +1154,10 @@ errno_t add_pam_cert_response(struct pam_data *pd, const char *sysdb_username,
     char *env = NULL;
     size_t msg_len;
     int ret;
+    char *short_name = NULL;
+    char *domain_name = NULL;
+    const char *cert_info_name = sysdb_username;
+
 
     if (type != SSS_PAM_CERT_INFO && type != SSS_PAM_CERT_INFO_WITH_HINT) {
         DEBUG(SSSDBG_CRIT_FAILURE, "Invalid response type [%d].\n", type);
@@ -1174,9 +1179,30 @@ errno_t add_pam_cert_response(struct pam_data *pd, const char *sysdb_username,
      * Smartcard. If this type of name is irritating at the PIN prompt or the
      * re_expression config option was set in a way that user@domain cannot be
      * handled anymore some more logic has to be added here. But for the time
-     * being I think using sysdb_username is fine. */
+     * being I think using sysdb_username is fine.
+     * As special case is the files provider which handles local users which
+     * by definition only have a short name. To avoid confusion by other
+     * modules on the PAM stack the short name is returned in this case. */
+
+    if (sysdb_username != NULL) {
+        ret = sss_parse_internal_fqname(pd, sysdb_username,
+                                        &short_name, &domain_name);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_CRIT_FAILURE, "Unable to parse name '%s' [%d]: %s, "
+                                       "using full name.\n",
+                                        sysdb_username, ret, sss_strerror(ret));
+        } else {
+            if (domain_name != NULL
+                    &&  is_files_provider(find_domain_by_name(dom, domain_name,
+                                                              false))) {
+                cert_info_name = short_name;
+            }
+        }
+    }
 
-    ret = pack_cert_data(pd, sysdb_username, cert_info, &msg, &msg_len);
+    ret = pack_cert_data(pd, cert_info_name, cert_info, &msg, &msg_len);
+    talloc_free(short_name);
+    talloc_free(domain_name);
     if (ret != EOK) {
         DEBUG(SSSDBG_OP_FAILURE, "pack_cert_data failed.\n");
         return ret;
-- 
2.9.5