Audit: send signal info if selinux is disabled

Audit will not respond to signal requests if selinux is disabled since it is
unable to translate the 0 sid from the sending process to a context.  This
patch just doesn't send the context info if there isn't any.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/kernel/audit.c b/kernel/audit.c
index defc2e6..5feed23 100644 (file)
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -855,18 +855,24 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                break;
        }
        case AUDIT_SIGNAL_INFO:
-               err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
-               if (err)
-                       return err;
+               len = 0;
+               if (audit_sig_sid) {
+                       err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
+                       if (err)
+                               return err;
+               }
                sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
                if (!sig_data) {
-                       security_release_secctx(ctx, len);
+                       if (audit_sig_sid)
+                               security_release_secctx(ctx, len);
                        return -ENOMEM;
                }
                sig_data->uid = audit_sig_uid;
                sig_data->pid = audit_sig_pid;
-               memcpy(sig_data->ctx, ctx, len);
-               security_release_secctx(ctx, len);
+               if (audit_sig_sid) {
+                       memcpy(sig_data->ctx, ctx, len);
+                       security_release_secctx(ctx, len);
+               }
                audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
                                0, 0, sig_data, sizeof(*sig_data) + len);
                kfree(sig_data);