vhost: fix info leak due to uninitialized memory
commit 670ae9caac
upstream.
struct vhost_msg within struct vhost_msg_node is copied to userspace.
Unfortunately it turns out on 64 bit systems vhost_msg has padding after
type which gcc doesn't initialize, leaking 4 uninitialized bytes to
userspace.
This padding also unfortunately means 32 bit users of this interface are
broken on a 64 bit kernel which will need to be fixed separately.
Fixes: CVE-2018-1118
Cc: stable@vger.kernel.org
Reported-by: Kevin Easton <kevin@guarana.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
d37c95f529
commit
7446344baa
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@ -2382,6 +2382,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
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struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
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if (!node)
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return NULL;
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/* Make sure all padding within the structure is initialized. */
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memset(&node->msg, 0, sizeof node->msg);
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node->vq = vq;
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node->msg.type = type;
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return node;
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