From: Tom Rix trix@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: stable@vger.kernel.org Fixes: 60abd3181db2 ("selinux: convert cond_list to array") Signed-off-by: Tom Rix trix@redhat.com Reviewed-by: Ondrej Mosnacek omosnace@redhat.com [PM: subject line tweaks] Signed-off-by: Paul Moore paul@paul-moore.com Signed-off-by: Greg Kroah-Hartman gregkh@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)