On 2018年09月28日 01:04, Michael S. Tsirkin wrote:
On Thu, Sep 27, 2018 at 08:22:04PM +0800, Jason Wang wrote:The access of vsock is not protected by vhost_vsock_lock. This may lead to use after free since vhost_vsock_dev_release() may free the pointer at the same time. Fix this by holding the lock during the access. Reported-by:syzbot+e3e074963495f92a89ed@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 16320f363ae1 ("vhost-vsock: add pkt cancel capability") Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") Cc: Stefan Hajnoczi<stefanha@xxxxxxxxxx> Signed-off-by: Jason Wang<jasowang@xxxxxxxxxx>Wow is that really the best we can do?
For net/stable, probably yes.
A global lock on a data path operation?
It's already there, and the patch only increase the critical section.
Granted use after free is nasty but Stefan said he sees a way to fix it using a per socket refcount. He's on vacation until Oct 4 though ...
Stefan has acked the pacth, so I think it's ok? We can do optimization for -next on top.
Thanks
