#syz test: https://github.com/google/kmsan.git/master d2d741e5d1898dfde1a75ea3d29a9a3e2edf0617 Subject: vhost: fix info leak Fixes: CVE-2018-1118 Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index f0be5f35ab28..9beefa6ed1ce 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2345,6 +2345,9 @@ 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 Thu, Jun 7, 2018 at 5:38 PM, Michael S. Tsirkin <mst at redhat.com> wrote:> #syz test: https://github.com/google/kmsan.git/master d2d741e5d1898dfde1a75ea3d29a9a3e2edf0617Hi Michael, We need: #syz test: https://github.com/google/kmsan.git master here. Please see https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches for more info. Please also add the Reported-by tag when mailing the patch for review. Thanks> Subject: vhost: fix info leak > > Fixes: CVE-2018-1118 > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index f0be5f35ab28..9beefa6ed1ce 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2345,6 +2345,9 @@ 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 at googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20180607183627-mutt-send-email-mst%40kernel.org. > For more options, visit https://groups.google.com/d/optout.-------------- next part -------------- A non-text attachment was scrubbed... Name: patch Type: application/octet-stream Size: 517 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20180607/71388af3/attachment.obj>
On Thu, Jun 07, 2018 at 06:38:48PM +0300, Michael S. Tsirkin wrote:> #syz test: https://github.com/google/kmsan.git/master d2d741e5d1898dfde1a75ea3d29a9a3e2edf0617 > > Subject: vhost: fix info leak > > Fixes: CVE-2018-1118 > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index f0be5f35ab28..9beefa6ed1ce 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2345,6 +2345,9 @@ 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);Umm... Maybe kzalloc(), then? You have struct vhost_msg_node { struct vhost_msg msg; struct vhost_virtqueue *vq; struct list_head node; }; and that's what, 68 bytes in msg, then either 4 bytes pointer or 4 bytes padding + 8 bytes pointer, then two pointers? How much does explicit partial memset() save you here?> node->vq = vq; > node->msg.type = type; > return node;
On Thu, Jun 07, 2018 at 06:43:55PM +0100, Al Viro wrote:> On Thu, Jun 07, 2018 at 06:38:48PM +0300, Michael S. Tsirkin wrote: > > #syz test: https://github.com/google/kmsan.git/master d2d741e5d1898dfde1a75ea3d29a9a3e2edf0617 > > > > Subject: vhost: fix info leak > > > > Fixes: CVE-2018-1118 > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > index f0be5f35ab28..9beefa6ed1ce 100644 > > --- a/drivers/vhost/vhost.c > > +++ b/drivers/vhost/vhost.c > > @@ -2345,6 +2345,9 @@ 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); > > Umm... Maybe kzalloc(), then? You have > > struct vhost_msg_node { > struct vhost_msg msg; > struct vhost_virtqueue *vq; > struct list_head node; > }; > > and that's what, 68 bytes in msg, then either 4 bytes pointer or > 4 bytes padding + 8 bytes pointer, then two pointers? How much > does explicit partial memset() save you here?Yes but 0 isn't a nop here so if this struct is used without a sensible initialization, it will crash elsewhere. I prefer KASAN to catch such uses.> > node->vq = vq; > > node->msg.type = type; > > return node;