Date: Thu, 27 Jul 1995 18:36:57 -0700 From: Matt Dillon <dillon@blob.best.net> To: root@corbin.Root.COM Cc: bugs@freebsd.org Subject: Re: More on our shell2 crashes Message-ID: <199507280136.SAA19342@blob.best.net>
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>> This time around it crashed with a panic("nfsreq nogrps")
>
> That's a known bug. It is caused by someone doing the equivilent of
>"setgroups(0, &foo)". Old versions of Smail are alleged to do this. We haven't
>fixed this bug yet as there are several conflicting opinions about how it
>should be fixed. Since setgroups() can only be executed by the Superuser, it
>hasn't been a high priority thing to fix.
>
>> I am also seeing this:
>>
>>Jul 27 08:40:31 shell2 /kernel: vnode_pager_getpages: I/O read error
>>Jul 27 08:40:32 shell2 /kernel: vm_fault: pager input (probably hardware) error,
>> PID 690 failure
>>..
>
> I believe the problem here is that ftpd isn't allowed read permission on
>the server, yet the process is "root" on the client. This means that the
>client thinks it can exec the binary but the server refuses to allow reads to
>the file during the page fault (file read). One work-around for this is to add
>"-root=0" as an option in your server's exports file. Another is to fix the
>permissions on the file.
>
>-DG
FTPD is able to run.... the situation is that ftpd runs fine, in fact a
whole *bunch* of ftpd's are running along, but then a random period
of time later one of the running ftpd's starts to fail with the above
failure mode.
The permissions on ftpd are:
shell2:/home/ftpadmin/etc# ls -lda ftpd
-rwxr-x--- 1 root wheel 94651 Jun 21 22:14 ftpd
shell2:/home/ftpadmin/etc#
and we export it properly as far as I can tell:
/usr/home/ftpadmin -maproot=0 ...
Hmm... wait a moment.... ftpd setuid()'s itself to the user . Could it
be that a pagefault occuring after the setuid() is made can fail because
it is trying to access it using the user's uid? If not, then we are
back to a permissions-change-out-from-under problem of some sort.
-Matt
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