| Message ID | 20180530055704-mutt-send-email-mst@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/29/2018 08:01 PM, Michael S. Tsirkin wrote: > On Tue, May 29, 2018 at 03:19:08PM -0700, Guenter Roeck wrote: >> On Fri, Apr 27, 2018 at 11:45:02AM -0400, Kevin Easton wrote: >>> The struct vhost_msg within struct vhost_msg_node is copied to userspace, >>> so it should be allocated with kzalloc() to ensure all structure padding >>> is zeroed. >>> >>> Signed-off-by: Kevin Easton <kevin@guarana.org> >>> Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com >> >> Is this patch going anywhere ? >> >> The patch fixes CVE-2018-1118. It would be useful to understand if and when >> this problem is going to be fixed. >> >> Thanks, >> Guenter >>> --- >>> drivers/vhost/vhost.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >>> index f3bd8e9..1b84dcff 100644 >>> --- a/drivers/vhost/vhost.c >>> +++ b/drivers/vhost/vhost.c >>> @@ -2339,7 +2339,7 @@ EXPORT_SYMBOL_GPL(vhost_disable_notify); >>> /* Create a new message. */ >>> struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) >>> { >>> - struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); >>> + struct vhost_msg_node *node = kzalloc(sizeof *node, GFP_KERNEL); >>> if (!node) >>> return NULL; >>> node->vq = vq; > > As I pointed out, we don't need to init the whole structure. The proper > fix is thus (I think) below. > > Could you use your testing infrastructure to confirm this fixes the issue? > Sorry, I don't have the means to test the fix. Guenter > Thanks! > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index f3bd8e941224..58d9aec90afb 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2342,6 +2342,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) > struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); > if (!node) > return NULL; > + > + /* Make sure all padding within the structure is initialized. */ > + memset(&node->msg, 0, sizeof node->msg); > node->vq = vq; > node->msg.type = type; > return node; >
On Wed, May 30, 2018 at 5:01 AM, Michael S. Tsirkin <mst@redhat.com> wrote: > On Tue, May 29, 2018 at 03:19:08PM -0700, Guenter Roeck wrote: >> On Fri, Apr 27, 2018 at 11:45:02AM -0400, Kevin Easton wrote: >> > The struct vhost_msg within struct vhost_msg_node is copied to userspace, >> > so it should be allocated with kzalloc() to ensure all structure padding >> > is zeroed. >> > >> > Signed-off-by: Kevin Easton <kevin@guarana.org> >> > Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com >> >> Is this patch going anywhere ? >> >> The patch fixes CVE-2018-1118. It would be useful to understand if and when >> this problem is going to be fixed. >> >> Thanks, >> Guenter >> > --- >> > drivers/vhost/vhost.c | 2 +- >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> > >> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >> > index f3bd8e9..1b84dcff 100644 >> > --- a/drivers/vhost/vhost.c >> > +++ b/drivers/vhost/vhost.c >> > @@ -2339,7 +2339,7 @@ EXPORT_SYMBOL_GPL(vhost_disable_notify); >> > /* Create a new message. */ >> > struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) >> > { >> > - struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); >> > + struct vhost_msg_node *node = kzalloc(sizeof *node, GFP_KERNEL); >> > if (!node) >> > return NULL; >> > node->vq = vq; > > As I pointed out, we don't need to init the whole structure. The proper > fix is thus (I think) below. > > Could you use your testing infrastructure to confirm this fixes the issue? Hi Michael, syzbot is self-service, see: https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches > Thanks! > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index f3bd8e941224..58d9aec90afb 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2342,6 +2342,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) > struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); > if (!node) > return NULL; > + > + /* Make sure all padding within the structure is initialized. */ > + memset(&node->msg, 0, sizeof node->msg); > node->vq = vq; > node->msg.type = type; > return node; > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20180530055704-mutt-send-email-mst%40kernel.org. > For more options, visit https://groups.google.com/d/optout.
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index f3bd8e941224..58d9aec90afb 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2342,6 +2342,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); if (!node) return NULL; + + /* Make sure all padding within the structure is initialized. */ + memset(&node->msg, 0, sizeof node->msg); node->vq = vq; node->msg.type = type; return node;