Re: [Vserver] "Abstract" (not FS based) UNIX sockets collision

From: Herbert Poetzl <herbert_at_13thfloor.at>
Date: Wed 25 Jan 2006 - 17:51:01 GMT
Message-ID: <20060125175101.GH10609@MAIL.13thfloor.at>

On Wed, Jan 25, 2006 at 07:27:11PM +0200, Alex Lyashkov wrote:
> ? ???, 25.01.2006, ? 19:07, Herbert Poetzl ?????:
> > On Wed, Jan 25, 2006 at 06:51:14PM +0200, Alex Lyashkov wrote:
> > > ? ???, 25.01.2006, ? 18:47, Herbert Poetzl ?????:
> > > > On Wed, Jan 25, 2006 at 03:35:23PM +0100, Andreas Schultz wrote:
> > > > > Hi,
> > > > >
> > > > > It seems that abstract UNIX sockets "leak" from a vserver. I'm trying to run
> > > > > the same java app inside two vservers and only the first one started succeeds.
> > > > >
> > > > > The critical piece from strace is:
> > > > >
> > > > > 20397 socket(PF_FILE, SOCK_STREAM, 0) = 5
> > > > > 20397 setsockopt(5, SOL_SOCKET, SO_PASSCRED, [7738151124464566273], 4) = 0
> > > > > 20397 bind(5, {sa_family=AF_FILE, path=@var/run/.php-java-bridge_socket}, 110) = -1 EADDRINUSE (Address already in use)
> > > > >
> > > > > Looking at unix_bind() in net/unix/af_unix.c, it would seem that the socket
> > > > > hashes are identical across all vservers and that no additional context check
> > > > > is used. There is a context check in include/net/af_unix.h, but this
> > > > > does not seem to be used when creating sockets from unix_bind().
> > > > >
> > > > > Any ideas?
> > > >
> > > > this should help ...
> > > >
> > > > --- linux-2.6.16-rc1/net/unix/af_unix.c 2006-01-21 18:28:17 +0100
> > > > +++ linux-2.6.16-rc1/net/unix/af_unix.c 2006-01-25 17:22:11 +0100
> > > > @@ -238,6 +238,8 @@ static struct sock *__unix_find_socket_b
> > > > sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
> > > > struct unix_sock *u = unix_sk(s);
> > > >
> > > > + if (!vx_check(s->sk_xid, VX_IDENT|VX_WATCH))
> > > > + continue;
> > > > if (u->addr->len == len &&
> > > > !memcmp(u->addr->name, sunname, len))
> > > > goto found;
> > > >
> > > > thanks for spotting this ...
> > > >
> > > this not a full fix.
> > > this not fix issue for FS based unix sockets.
> >
> > sorry Alex, but the filesystem case is already covered
> > by the namespaces, which you can verify easily ...
> >
> > so everything fine here ...
> >
> don`t. inode must have one context id (just are error or if
> unification), but access/bind from an other context.

could you provide an example where it fails for you?

TIA,
Herbert

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Received on Wed Jan 25 17:51:19 2006

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