[PATCH] libsepol: Expand role attributes in constraint expressions

[James Carter <jwcart2@gmail.com>]

When creating the kernel binary policy, role attributes in constraint
expressions are not expanded. This causes the constraint expression
to refer to a non-existent role in the kernel policy. This can lead
to a segfault when converting the binary policy back to conf or CIL
source or when using policy tools such as seinfo.

Expand role attributes in constraint expressions when creating the
kernel binary policy.

Reported-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
---
 libsepol/src/expand.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c
index eac7e450..2d9cb566 100644
--- a/libsepol/src/expand.c
+++ b/libsepol/src/expand.c
@@ -71,6 +71,38 @@ static int map_ebitmap(ebitmap_t * src, ebitmap_t * dst, uint32_t * map)
 	return 0;
 }
 
+static int ebitmap_expand_roles(policydb_t *p, ebitmap_t *roles)
+{
+	ebitmap_node_t *node;
+	unsigned int bit;
+	role_datum_t *role;
+	ebitmap_t tmp;
+
+	ebitmap_init(&tmp);
+	ebitmap_for_each_positive_bit(roles, node, bit) {
+		role = p->role_val_to_struct[bit];
+		assert(role);
+		if (role->flavor != ROLE_ATTRIB) {
+			if (ebitmap_set_bit(&tmp, bit, 1)) {
+				ebitmap_destroy(&tmp);
+				return -1;
+			}
+		} else {
+			if (ebitmap_union(&tmp, &role->roles)) {
+				ebitmap_destroy(&tmp);
+				return -1;
+			}
+		}
+	}
+	ebitmap_destroy(roles);
+	if (ebitmap_cpy(roles, &tmp)) {
+		ebitmap_destroy(&tmp);
+		return -1;
+	}
+	ebitmap_destroy(&tmp);
+	return 0;
+}
+
 static int type_copy_callback(hashtab_key_t key, hashtab_datum_t datum,
 			      void *data)
 {
@@ -333,6 +365,9 @@ static int constraint_node_clone(constraint_node_t ** dst,
 					if (map_ebitmap(&expr->names, &new_expr->names, state->rolemap)) {
 						goto out_of_mem;
 					}
+					if (ebitmap_expand_roles(state->out, &new_expr->names)) {
+						goto out_of_mem;
+					}
 				} else if (new_expr->attr & CEXPR_USER) {
 					if (map_ebitmap(&expr->names, &new_expr->names, state->usermap)) {
 						goto out_of_mem;
-- 
2.26.2