[PATCH] selinux: fix another double free

[trix]

From: Tom Rix <trix@xxxxxxxxxx>

Clang static analysis reports this double free error

security/selinux/ss/conditional.c:139:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(node->expr.nodes);
        ^~~~~~~~~~~~~~~~~~~~~~~

When cond_read_node fails, it calls cond_node_destroy which frees the
node but does not poison the entry in the node list.  So when it
returns to its caller cond_read_list, cond_read_list deletes the
partial list.  The latest entry in the list will be deleted twice.

So instead of freeing the node in cond_read_node, let list freeing in
code_read_list handle the freeing the problem node along with all of the the
earlier nodes.

Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
 security/selinux/ss/conditional.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index da94a1b4bfda..ffb31af22f4f 100644
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -411,7 +411,6 @@ static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
 		goto err;
 	return 0;
 err:
-	cond_node_destroy(node);
 	return rc;
 }
 
-- 
2.18.1