Re: [PATCH v3 1/3] qio: add support for SO_PEERCRED for socket channel

[Daniel P . Berrangé]

On Mon, Jan 29, 2024 at 08:25:29PM +0100, Paolo Bonzini wrote:
> On Thu, Jan 25, 2024 at 5:38 PM Daniel P. Berrangé <berrange@redhat.com> 
> wrote:
> > > +static void
> > > +qio_channel_socket_get_peerpid(QIOChannel *ioc,
> > > +                               unsigned int *pid,
> > > +                               Error **errp)
> > > +{
> > > +#ifdef CONFIG_LINUX
> > > +    QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc);
> > > +    Error *err = NULL;
> > > +    socklen_t len = sizeof(struct ucred);
> > > +
> > > +    struct ucred cred;
> > > +    if (getsockopt(sioc->fd,
> > > +               SOL_SOCKET, SO_PEERCRED,
> > > +               &cred, &len) == -1) {
> > > +        error_setg_errno(&err, errno, "Unable to get peer credentials");
> > > +        error_propagate(errp, err);
> > > +    }
> > > +    *pid = (unsigned int)cred.pid;
> > > +#else
> > > +    *pid = 0;
> >
> > Defaulting 'pid' to 0 is potentially unsafe, because to a caller it
> > now appears that the remote party is 'root' and thus implied to be
> > a privileged account.
> 
> This is a pid, so 0 cannot be confused; however, I agree that
> returning an error is better.

Opps, face-palm  !



With regards,
Daniel
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