Re: [PATCH 1/4] chardev: fix qemu_chr_open_fd() being called with fd=-1

["Marc-André Lureau" <marcandre.lureau@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 2243 bytes --]

Hi

On Tue, Aug 3, 2021 at 12:41 PM Daniel P. Berrangé <berrange@redhat.com>
wrote:

> On Fri, Jul 23, 2021 at 02:28:22PM +0400, marcandre.lureau@redhat.com
> wrote:
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > The "file" chardev may call qemu_chr_open_fd() with fd_in=-1. This may
> > cause invalid system calls, as the QIOChannel is assumed to be properly
> > initialized later on.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  chardev/char-fd.c | 22 +++++++++++++---------
> >  1 file changed, 13 insertions(+), 9 deletions(-)
> >
> > diff --git a/chardev/char-fd.c b/chardev/char-fd.c
> > index 1cd62f2779..ee85a52c06 100644
> > --- a/chardev/char-fd.c
> > +++ b/chardev/char-fd.c
> > @@ -133,15 +133,19 @@ void qemu_chr_open_fd(Chardev *chr,
> >      FDChardev *s = FD_CHARDEV(chr);
> >      char *name;
> >
> > -    s->ioc_in = QIO_CHANNEL(qio_channel_file_new_fd(fd_in));
> > -    name = g_strdup_printf("chardev-file-in-%s", chr->label);
> > -    qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
> > -    g_free(name);
> > -    s->ioc_out = QIO_CHANNEL(qio_channel_file_new_fd(fd_out));
> > -    name = g_strdup_printf("chardev-file-out-%s", chr->label);
> > -    qio_channel_set_name(QIO_CHANNEL(s->ioc_out), name);
> > -    g_free(name);
> > -    qemu_set_nonblock(fd_out);
> > +    if (fd_in >= 0) {
> > +        s->ioc_in = QIO_CHANNEL(qio_channel_file_new_fd(fd_in));
> > +        name = g_strdup_printf("chardev-file-in-%s", chr->label);
> > +        qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
> > +        g_free(name);
> > +    }
> > +    if (fd_out >= 0) {
> > +        s->ioc_out = QIO_CHANNEL(qio_channel_file_new_fd(fd_out));
> > +        name = g_strdup_printf("chardev-file-out-%s", chr->label);
> > +        qio_channel_set_name(QIO_CHANNEL(s->ioc_out), name);
> > +        g_free(name);
> > +        qemu_set_nonblock(fd_out);
> > +    }
>
> Other code in this file assumes ioc_out is non-NULL, so this looks
> like an incomplete fix.
>
>
Right, I am adding a patch to correct the source watch creation, and fixing
this one handling !ioc_out condition.

thanks

-- 
Marc-André Lureau

[-- Attachment #2: Type: text/html, Size: 3260 bytes --]