On Fri, Mar 22, 2019 at 9:15 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote:
> On Fri, Mar 22, 2019 at 10:14 AM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> Hi Arnd,
>
> Thanks for pointing this out and providing a fix. I think you're
> right in that the should be pretty harmless, but I also agree that we
> should fix it; some thoughts on the patch below ...
>
> > diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
> > index 186e727b737b..d0e549d4f486 100644
> > --- a/security/selinux/netlabel.c
> > +++ b/security/selinux/netlabel.c
> > @@ -288,7 +288,6 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
> > int rc;
> > struct netlbl_lsm_secattr secattr;
> > struct sk_security_struct *sksec = ep->base.sk->sk_security;
> > - struct sockaddr *addr;
> > struct sockaddr_in addr4;
> > #if IS_ENABLED(CONFIG_IPV6)
> > struct sockaddr_in6 addr6;
> > @@ -310,16 +309,15 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
> > if (ip_hdr(skb)->version == 4) {
> > addr4.sin_family = AF_INET;
> > addr4.sin_addr.s_addr = ip_hdr(skb)->saddr;
> > - addr = (struct sockaddr *)&addr4;
> > + rc = netlbl_conn_setattr(ep->base.sk, (void*)&addr4, &secattr);
> > #if IS_ENABLED(CONFIG_IPV6)
> > } else {
> > addr6.sin6_family = AF_INET6;
> > addr6.sin6_addr = ipv6_hdr(skb)->saddr;
> > - addr = (struct sockaddr *)&addr6;
> > + rc = netlbl_conn_setattr(ep->base.sk, (void*)&addr6, &secattr);
> > #endif
>
> While we are hardening the code a bit, I'm thinking we should probably
> refactor this if-else a bit, some pseudo code for example:
>
> if (ip_hdr == 4) {
> rc = netlbl_conn_setattr();
> #if CONFIG_IPV6
> } else if (ip_hdr == 6) {
> rc = netlbl_conn_setattr();
> #endif
> } else {
> rc = -EAFNOSUPPORT;
> }
>
> Thoughts?
>
Seems fine. We could go a step further and use IS_ENABLED()
as C code here to get rid of the two #ifdef checks as well, like
if (ip_hdr(skb)->version == 4 ) {
addr4.sin_family = AF_INET;
addr4.sin_addr.s_addr = ip_hdr(skb)->saddr;
rc = netlbl_conn_setattr(ep->base.sk, &addr4, &secattr);
} else if (IS_ENABLED(CONFIG_IPV6) && ip_hdr(skb)->version == 6) {
addr6.sin6_family = AF_INET6;
addr6.sin6_addr = ipv6_hdr(skb)->saddr;
rc = netlbl_conn_setattr(ep->base.sk, &addr6, &secattr);
} else {
rc = -EAFNOSUPPORT;
}
Arnd
