SELINUX: Use getseuserbyname to get IPA seuser

The libselinux function getseuserbyname is more reliable method to retrieve
SELinux usernames then functions from libsemanage `semanage_user_query`
and is recommended by libsemanage developers.
Replace get_seuser function with getseuserbyname.

Resolves:
https://pagure.io/SSSD/sssd/issue/3308

Reviewed-by: Michal Židek <mzidek@redhat.com>
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
Reviewed-by: Petr Lautrbach <plautrba@redhat.com>

4 files changed, 7 insertions, 81 deletions

diff --git a/Makefile.am b/Makefile.am
index cb5c405a4..42d7e4a17 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -4107,6 +4107,7 @@ selinux_child_LDADD = \
     $(POPT_LIBS) \
     $(DHASH_LIBS) \
     $(SEMANAGE_LIBS) \
+    $(SELINUX_LIBS) \
     $(NULL)
 endif
 
diff --git a/src/providers/ipa/selinux_child.c b/src/providers/ipa/selinux_child.c
index f8dd3954a..073475094 100644
--- a/src/providers/ipa/selinux_child.c
+++ b/src/providers/ipa/selinux_child.c
@@ -27,6 +27,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 #include <popt.h>
+#include <selinux/selinux.h>
 
 #include "util/util.h"
 #include "util/child_common.h"
@@ -172,11 +173,10 @@ static bool seuser_needs_update(struct input_buffer *ibuf)
     char *db_mls_range = NULL;
     errno_t ret;
 
-    ret = get_seuser(ibuf, ibuf->username, &db_seuser, &db_mls_range);
+    ret = getseuserbyname(ibuf->username, &db_seuser, &db_mls_range);
     DEBUG(SSSDBG_TRACE_INTERNAL,
-          "get_seuser: ret: %d msg: [%s] seuser: %s mls: %s\n",
-          ret, sss_strerror(ret),
-          db_seuser ? db_seuser : "unknown",
+          "getseuserbyname: ret: %d seuser: %s mls: %s\n",
+          ret, db_seuser ? db_seuser : "unknown",
           db_mls_range ? db_mls_range : "unknown");
     if (ret == EOK && db_seuser && db_mls_range &&
             strcmp(db_seuser, ibuf->seuser) == 0 &&
@@ -188,8 +188,8 @@ static bool seuser_needs_update(struct input_buffer *ibuf)
         needs_update = false;
     }
 
-    talloc_free(db_seuser);
-    talloc_free(db_mls_range);
+    free(db_seuser);
+    free(db_mls_range);
     return needs_update;
 }
 
diff --git a/src/util/sss_semanage.c b/src/util/sss_semanage.c
index 0da97aad4..37278cc98 100644
--- a/src/util/sss_semanage.c
+++ b/src/util/sss_semanage.c
@@ -382,73 +382,6 @@ done:
     sss_semanage_close(handle);
     return ret;
 }
-
-int get_seuser(TALLOC_CTX *mem_ctx, const char *login_name,
-               char **_seuser, char **_mls_range)
-{
-    errno_t ret;
-    const char *seuser;
-    const char *mls_range;
-    semanage_handle_t *sm_handle = NULL;
-    semanage_seuser_t *sm_user = NULL;
-    semanage_seuser_key_t *sm_key = NULL;
-
-    ret = sss_semanage_init(&sm_handle);
-    if (ret == ERR_SELINUX_NOT_MANAGED) {
-        goto done;
-    } else if (ret != EOK) {
-        DEBUG(SSSDBG_CRIT_FAILURE, "Cannot create SELinux handle\n");
-        goto done;
-    }
-
-    ret = semanage_seuser_key_create(sm_handle, login_name, &sm_key);
-    if (ret != EOK) {
-        DEBUG(SSSDBG_CRIT_FAILURE, "Cannot create key for %s\n", login_name);
-        ret = EIO;
-        goto done;
-    }
-
-    ret = semanage_seuser_query(sm_handle, sm_key, &sm_user);
-    if (ret < 0) {
-        DEBUG(SSSDBG_CRIT_FAILURE, "Cannot query for %s\n", login_name);
-        ret = EIO;
-        goto done;
-    }
-
-    seuser = semanage_seuser_get_sename(sm_user);
-    if (seuser != NULL) {
-        *_seuser = talloc_strdup(mem_ctx, seuser);
-        if (*_seuser == NULL) {
-            ret = ENOMEM;
-            goto done;
-        }
-        DEBUG(SSSDBG_OP_FAILURE,
-              "SELinux user for %s: %s\n", login_name, *_seuser);
-    } else {
-        DEBUG(SSSDBG_CRIT_FAILURE, "Cannot get sename for %s\n", login_name);
-    }
-
-    mls_range = semanage_seuser_get_mlsrange(sm_user);
-    if (mls_range != NULL) {
-        *_mls_range = talloc_strdup(mem_ctx, mls_range);
-        if (*_mls_range == NULL) {
-            ret = ENOMEM;
-            goto done;
-        }
-        DEBUG(SSSDBG_OP_FAILURE,
-              "SELinux range for %s: %s\n", login_name, *_mls_range);
-    } else {
-        DEBUG(SSSDBG_CRIT_FAILURE, "Cannot get mlsrange for %s\n", login_name);
-    }
-
-    ret = EOK;
-done:
-    semanage_seuser_key_free(sm_key);
-    semanage_seuser_free(sm_user);
-    sss_semanage_close(sm_handle);
-    return ret;
-}
-
 #else /* HAVE_SEMANAGE */
 int set_seuser(const char *login_name, const char *seuser_name,
                const char *mls)
@@ -460,10 +393,4 @@ int del_seuser(const char *login_name)
 {
     return EOK;
 }
-
-int get_seuser(TALLOC_CTX *mem_ctx, const char *login_name,
-               char **_seuser, char **_mls_range)
-{
-    return EOK;
-}
 #endif  /* HAVE_SEMANAGE */
diff --git a/src/util/util.h b/src/util/util.h
index 3d8bfe479..373830117 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -650,8 +650,6 @@ errno_t restore_creds(struct sss_creds *saved_creds);
 int set_seuser(const char *login_name, const char *seuser_name,
                const char *mlsrange);
 int del_seuser(const char *login_name);
-int get_seuser(TALLOC_CTX *mem_ctx, const char *login_name,
-               char **_seuser, char **_mls_range);
 
 /* convert time from generalized form to unix time */
 errno_t sss_utc_to_time_t(const char *str, const char *format, time_t *unix_time);