diff --git a/checkpolicy/checkpolicy.c b/checkpolicy/checkpolicy.c
index fcec6e51d..d7cafaa4a 100644
--- a/checkpolicy/checkpolicy.c
+++ b/checkpolicy/checkpolicy.c
@@ -370,10 +370,9 @@ static int check_level(hashtab_key_t key, hashtab_datum_t datum, void *arg __att
 {
 	level_datum_t *levdatum = (level_datum_t *) datum;
 
-	if (!levdatum->isalias && !levdatum->defined) {
-		fprintf(stderr,
-			"Error:  sensitivity %s was not used in a level definition!\n",
-			key);
+	if (!levdatum->isalias && levdatum->notdefined) {
+		fprintf(stderr, "Error:  sensitivity %s was not used in a level definition!\n",
+				key);
 		return -1;
 	}
 	return 0;
diff --git a/checkpolicy/policy_define.c b/checkpolicy/policy_define.c
index ddfd4ee35..614b77066 100644
--- a/checkpolicy/policy_define.c
+++ b/checkpolicy/policy_define.c
@@ -770,6 +770,7 @@ int define_sens(void)
 	level_datum_init(datum);
 	datum->isalias = FALSE;
 	datum->level = level;
+	datum->notdefined = TRUE;
 
 	ret = declare_symbol(SYM_LEVELS, id, datum, &value, &value);
 	switch (ret) {
@@ -809,6 +810,7 @@ int define_sens(void)
 		level_datum_init(aliasdatum);
 		aliasdatum->isalias = TRUE;
 		aliasdatum->level = level;
+		aliasdatum->notdefined = TRUE;
 
 		ret = declare_symbol(SYM_LEVELS, id, aliasdatum, NULL, &value);
 		switch (ret) {
@@ -1037,9 +1039,10 @@ static int clone_level(hashtab_key_t key __attribute__ ((unused)), hashtab_datum
 	mls_level_t *level = (mls_level_t *) arg, *newlevel;
 
 	if (levdatum->level == level) {
-		levdatum->defined = 1;
-		if (!levdatum->isalias)
+		if (!levdatum->isalias) {
+			levdatum->notdefined = FALSE;
 			return 0;
+		}
 		newlevel = (mls_level_t *) malloc(sizeof(mls_level_t));
 		if (!newlevel)
 			return -1;
@@ -1048,6 +1051,7 @@ static int clone_level(hashtab_key_t key __attribute__ ((unused)), hashtab_datum
 			return -1;
 		}
 		levdatum->level = newlevel;
+		levdatum->notdefined = FALSE;
 	}
 	return 0;
 }
@@ -1088,8 +1092,6 @@ int define_level(void)
 	}
 	free(id);
 
-	levdatum->defined = 1;
-
 	while ((id = queue_remove(id_queue))) {
 		cat_datum_t *cdatum;
 		uint32_t range_start, range_end, i;
diff --git a/libsepol/cil/src/cil_binary.c b/libsepol/cil/src/cil_binary.c
index a8e3616a3..95bd18baa 100644
--- a/libsepol/cil/src/cil_binary.c
+++ b/libsepol/cil/src/cil_binary.c
@@ -907,7 +907,6 @@ static int cil_sensalias_to_policydb(policydb_t *pdb, struct cil_alias *cil_alia
 		goto exit;
 	}
 	sepol_alias->level = mls_level;
-	sepol_alias->defined = 1;
 	sepol_alias->isalias = 1;
 
 	return SEPOL_OK;
@@ -3163,8 +3162,6 @@ int cil_sepol_level_define(policydb_t *pdb, struct cil_sens *cil_sens)
 		}
 	}
 
-	sepol_level->defined = 1;
-
 	return SEPOL_OK;
 
 exit:
diff --git a/libsepol/include/sepol/policydb/policydb.h b/libsepol/include/sepol/policydb/policydb.h
index 6682069ea..56d2cb01d 100644
--- a/libsepol/include/sepol/policydb/policydb.h
+++ b/libsepol/include/sepol/policydb/policydb.h
@@ -217,7 +217,7 @@ typedef struct user_datum {
 typedef struct level_datum {
 	mls_level_t *level;	/* sensitivity and associated categories */
 	unsigned char isalias;	/* is this sensitivity an alias for another? */
-	unsigned char defined;
+	unsigned char notdefined; /* Only set to non-zero in checkpolicy */
 } level_datum_t;
 
 /* Category attributes */
diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
index f10a8a95a..0c23a7a22 100644
--- a/libsepol/src/policydb.c
+++ b/libsepol/src/policydb.c
@@ -1390,8 +1390,10 @@ static int sens_destroy(hashtab_key_t key, hashtab_datum_t datum, void *p
 	if (key)
 		free(key);
 	levdatum = (level_datum_t *) datum;
-	mls_level_destroy(levdatum->level);
-	free(levdatum->level);
+	if (!levdatum->isalias || !levdatum->notdefined) {
+		mls_level_destroy(levdatum->level);
+		free(levdatum->level);
+	}
 	level_datum_destroy(levdatum);
 	free(levdatum);
 	return 0;
diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
index d86f885e4..6e46f4266 100644
--- a/libsepol/src/policydb_validate.c
+++ b/libsepol/src/policydb_validate.c
@@ -618,12 +618,37 @@ static int validate_mls_level(const mls_level_t *level, const validate_t *sens,
 	return -1;
 }
 
-static int validate_level_datum(__attribute__ ((unused)) hashtab_key_t k, hashtab_datum_t d, void *args)
+static int validate_level_datum(sepol_handle_t *handle, const level_datum_t *level, validate_t flavors[], const policydb_t *p)
 {
-	level_datum_t *level = d;
-	validate_t *flavors = args;
+	if (level->notdefined != 0)
+		goto bad;
+
+	if (validate_mls_level(level->level, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
+		goto bad;
+
+	if (level->isalias) {
+		const mls_level_t *l1 = level->level;
+		const mls_level_t *l2;
+		const level_datum_t *actual = (level_datum_t *) hashtab_search(p->p_levels.table, p->p_sens_val_to_name[l1->sens - 1]);
+		if (!actual)
+			goto bad;
+		l2 = actual->level;
+		if (!ebitmap_cmp(&l1->cat, &l2->cat))
+			goto bad;
+	}
+
+	return 0;
+
+	bad:
+	ERR(handle, "Invalid level datum");
+	return -1;
+}
+
+static int validate_level_datum_wrapper(__attribute__ ((unused)) hashtab_key_t k, hashtab_datum_t d, void *args)
+{
+	map_arg_t *margs = args;
 
-	return validate_mls_level(level->level, &flavors[SYM_LEVELS], &flavors[SYM_CATS]);
+	return validate_level_datum(margs->handle, d, margs->flavors, margs->policy);
 }
 
 static int validate_mls_range(const mls_range_t *range, const validate_t *sens, const validate_t *cats)
@@ -774,7 +799,7 @@ static int validate_datum_array_entries(sepol_handle_t *handle, const policydb_t
 	if (hashtab_map(p->p_users.table, validate_user_datum_wrapper, &margs))
 		goto bad;
 
-	if (p->mls && hashtab_map(p->p_levels.table, validate_level_datum, flavors))
+	if (p->mls && hashtab_map(p->p_levels.table, validate_level_datum_wrapper, &margs))
 		goto bad;
 
 	if (hashtab_map(p->p_cats.table, validate_datum, &flavors[SYM_CATS]))