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Re: [PATCH] Linux: Implement opensock using Netlink sockets
* Ben Hutchings:
> On Mon, 2018-06-18 at 12:50 +0200, Florian Weimer wrote:
>> inet/tst-inet6_scopeid_pton uses __opensock indirectly, to call ioctl
>> with SIOCGIFINDEX, and it still works after this change.
>>
>> 2018-06-18 Florian Weimer <fweimer@redhat.com>
>>
>> * sysdeps/unix/sysv/linux/opensock.c (__opensock): Unconditionally
>> return a Netlink socket.
>> * sysdeps/unix/sysv/linux/s390/opensock.c: Remove file.
> [...]
>
> I agree that we can assume the kernel implements AF_NETLINK, but the
> available socket address families might be restricted by a security
> policy (e.g. systemd's RestrictAddressFamilies property). I'm not sure
> whether it's safe to assume that they will always allow AF_NETLINK.
If it actually worked, the AF_NETLINK approach seems cleaner in this
regard. The current code goes hunting for information in /proc (to
avoid loading unwanted kernel modules), which requires a much larger
footprint and is harder to filter.