Re: [ANNOUNCE][PATCH] New fs to control access to system resources

Olaf Dietsche (olaf.dietsche--list.linux-kernel@exmail.de)
16 Jan 2002 18:18:50 +0100


Hi Ben,

I just managed to build and boot 2.5.2 plus my patch. My named starts
without any problem. So, sorry can't reproduce it here.

Ben Clifford <benc@hawaga.org.uk> writes:

> After applying your patch to 2.5.2, my named wouldn't start up (it
> couldn't bind to port 921)

This sounds weird. Normally, named binds to port 53 and some high
unprivileged port for replies from other DNS servers. Do you have some
'listen-on' and/or 'query-source' statements in your named.conf? If
you do, just change permissions of /mnt/net/ipv4/bind/921 appropriately.

> The below patch seems to have fixed that, and I think is probably the
> right thing to do.
[...]
> - if (snum && snum < PROT_SOCK && !accessfs_permitted(&bind_to_port[snum], MAY_EXEC))
> + if (snum && snum < PROT_SOCK && !accessfs_permitted(&bind_to_port[snum], MAY_EXEC) && !capable(CAP_NET_BIND_SERVICE))

You may use accessfs and capabilities in parallel, of course. But
currently, this is equivalent to "chown root/chmod u+x".

Regards, Olaf.
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