[PATCH 4/6] libsepol/cil: Resolve anonymous class permission sets only once

[James Carter <jwcart2@gmail.com>]

Anonymous class permission sets can be passed as call arguments.
Anonymous call arguments are resolved when they are used in a
rule. [This is because all the information might not be present
(like common permissions being added to a class) when the call
itself is resolved.] If there is more than one rule using an
anonymous class permission set, then a memory leak will occur
when a new list for the permission datum expression is created
without destroying the old one.

When resolving the class and permissions, check if the class has
already been resolved. If it has, then the permissions have been
as well.

This bug was found by the secilc-fuzzer.

Signed-off-by: James Carter <jwcart2@gmail.com>
---
 libsepol/cil/src/cil_resolve_ast.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libsepol/cil/src/cil_resolve_ast.c b/libsepol/cil/src/cil_resolve_ast.c
index 242aea4a..865297fb 100644
--- a/libsepol/cil/src/cil_resolve_ast.c
+++ b/libsepol/cil/src/cil_resolve_ast.c
@@ -158,6 +158,10 @@ int cil_resolve_classperms(struct cil_tree_node *current, struct cil_classperms
 	symtab_t *common_symtab = NULL;
 	struct cil_class *class;
 
+	if (cp->class) {
+		return SEPOL_OK;
+	}
+
 	rc = cil_resolve_name(current, cp->class_str, CIL_SYM_CLASSES, extra_args, &datum);
 	if (rc != SEPOL_OK) {
 		goto exit;
-- 
2.26.3