From: Tom Rix <t...@redhat.com>
commit aa449a7965a6172a89d48844c313708962216f1f upstream.
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.
Cc: sta...@vger.kernel.org
Fixes: 60abd3181db2 ("selinux: convert cond_list to array")
Signed-off-by: Tom Rix <t...@redhat.com>
Reviewed-by: Ondrej Mosnacek <omosn...@redhat.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <p...@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
security/selinux/ss/conditional.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -392,27 +392,19 @@ static int cond_read_node(struct policyd
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;
- }
+ if (!expr_node_isvalid(p, expr))
+ return -EINVAL;
}
rc = cond_read_av_list(p, fp, &node->true_list, NULL);
if (rc)
- goto err;
- 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;
+ return rc;
+ return cond_read_av_list(p, fp, &node->false_list, &node->true_list);
}
int cond_read_list(struct policydb *p, void *fp)
