Re: [next] BUG: kernel NULL pointer dereference, address:: selinux_ip_postroute_compat

On Tue, Oct 19, 2021 at 9:10 AM Florian Westphal fw@strlen.de wrote:

Naresh Kamboju naresh.kamboju@linaro.org wrote:

...

Following kernel crash noticed on linux next 20211019 tag. on x86, i386 and other architectures.

Paul, this might be caused by 1d1e1ded13568be81a0e19d228e310a48997bec8 ("selinux: make better use of the nf_hook_state passed to the NF hooks"), in particular this hunk here:

•   if (sk == NULL)
  

•   if (state->sk == NULL)
            return NF_ACCEPT;
  

•   sk = skb_to_full_sk(skb);
    sksec = sk->sk_security;
  
  

state->sk might not be related to skb->sk. I suspect that this should instead be:

•   sk = skb_to_full_sk(skb);
    if (sk == NULL)
  
  

See 7026b1ddb6b8d4e6ee33dc2bd06c0ca8746fa7ab for the origin of this additional socket pointer.

Sure, I'll patch that up now.