Subject: Re: [PATCH net-next v2] net: bpf: make eBPF interpreter images read-only

From: Daniel Borkmann <[email-masked]>
Date: Tue, 02 Sep 2014 23:47:29 +0200

On 09/02/2014 11:31 PM, Alexei Starovoitov wrote:
...
>> +#ifdef CONFIG_DEBUG_SET_MODULE_RONX
>> +static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
>> +{
>> +       set_memory_ro((unsigned long)fp, fp->pages);
>
> since ronx are ifdef checked together,
> would probably make sense to set nx too?

In case of JITs, for example, we request pages that are
PAGE_KERNEL_EXEC via module_alloc(), but here we only need
PAGE_KERNEL. At least on x86_64, PAGE_NX is then set already.