On 13.09.2014 8:29, Peter Wemm wrote:
> On Thursday, September 11, 2014 12:38:02 PM Patrick Kelsey wrote:
>> On Wed, Sep 10, 2014 at 3:00 AM, Andrey Chernov <a...@freebsd.org> wrote:
>>> On 09.09.2014 21:53, Patrick Kelsey wrote:
>>>> I don't think it is worth the trouble, as given the larger pattern of
>>>> libc routines requiring multiple capsicum rights, it seems one will in
>>>> general have to have libc implementation knowledge when using it in
>>>> concert with capsicum.  For example, consider the limitfd() routine in
>>>> kdump.c, which provides rights for the TIOCGETA ioctl to be used on
>>>> stdout so the eventual call to isatty() via printf() will work as
>>> intended.
>>>> I think the above kdump example is a good one for the subtle issues that
>>>> can arise when using capsicum with libc.  That call to isatty() is via a
>>>> widely-used internal libc routine __smakebuf().  __smakebuf() also calls
>>>> __swhatbuf(), which in turn calls _fstat(), all to make sure that output
>>>> to a tty is line buffered by default.  It would appear that programs
>>>> that restrict rights on stdout without allowing CAP_IOCTL and CAP_FSTAT
>>>> could be disabling the normally default line buffering when stdout is a
>>>> tty.  kdump goes the distance, but dhclient does not (restricting stdout
>>>> to CAP_WRITE only).
>>>> In any event, the patch attached to my first message is seeming like the
>>>> way to go.
>>> Well, then commit it (if capsicum team agrees).
>> Will do - thanks for the feedback.
>> -Patrick
> Is there any possibility that this is related to the problem we've recently 
> hit in the freebsd.org cluster with this month's refresh?
> After running for a while:
> Sep 10 02:39:44 ns2 unbound: [65258:0] notice: init module 0: validator
> Sep 10 02:39:44 ns2 unbound: [65258:0] notice: init module 1: iterator
> Sep 10 11:44:29 ns2 unbound: [65258:3] fatal error: event_dispatch returned 
> error -1, errno is Capabilities insufficient

unbound itself does not use capsicum, just grep cap_, ldns too, so the
problem can be somewhere else.


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