Re: [PATCH] selinux: avoid uninitialized variable warning

From: Paul Moore
Date: Fri Mar 22 2019 - 17:00:29 EST


On Fri, Mar 22, 2019 at 4:35 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> 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;
> }

Looks good to me. Can you send a revised patch?

--
paul moore
www.paul-moore.com