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
earlier nodes.
Because cond_read_node no longer does any error handling, the goto's
the error case are redundant. Instead just return the error code.
Fixes a problem was introduced by commit
selinux: convert cond_list to array
Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
security/selinux/ss/conditional.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index da94a1b4bfda..d0d6668709f0 100644
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -392,26 +392,21 @@ static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
rc = next_entry(buf, fp, sizeof(u32) * 2);
if (rc)
- goto err;
+ return rc;
expr->expr_type = le32_to_cpu(buf[0]);
expr->bool = le32_to_cpu(buf[1]);
if (!expr_node_isvalid(p, expr)) {
rc = -EINVAL;
- goto err;
+ return rc;
}
}
rc = cond_read_av_list(p, fp, &node->true_list, NULL);
if (rc)
- goto err;
+ return rc;
rc = cond_read_av_list(p, fp, &node->false_list, &node->true_list);
- if (rc)
- goto err;
- return 0;
-err:
- cond_node_destroy(node);
return rc;
}
--
2.18.1
