From df18fa14629ae3ae10f51577642113ccc8ce87d1 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Fri, 13 Dec 2019 19:48:00 +0100 Subject: vsock/virtio: fix null-pointer dereference in virtio_transport_recv_listen() With multi-transport support, listener sockets are not bound to any transport. So, calling virtio_transport_reset(), when an error occurs, on a listener socket produces the following null-pointer dereference: BUG: kernel NULL pointer dereference, address: 00000000000000e8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 20 Comm: kworker/0:1 Not tainted 5.5.0-rc1-ste-00003-gb4be21f316ac-dirty #56 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 Workqueue: virtio_vsock virtio_transport_rx_work [vmw_vsock_virtio_transport] RIP: 0010:virtio_transport_send_pkt_info+0x20/0x130 [vmw_vsock_virtio_transport_common] Code: 1f 84 00 00 00 00 00 0f 1f 00 55 48 89 e5 41 57 41 56 41 55 49 89 f5 41 54 49 89 fc 53 48 83 ec 10 44 8b 76 20 e8 c0 ba fe ff <48> 8b 80 e8 00 00 00 e8 64 e3 7d c1 45 8b 45 00 41 8b 8c 24 d4 02 RSP: 0018:ffffc900000b7d08 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88807bf12728 RCX: 0000000000000000 RDX: ffff88807bf12700 RSI: ffffc900000b7d50 RDI: ffff888035c84000 RBP: ffffc900000b7d40 R08: ffff888035c84000 R09: ffffc900000b7d08 R10: ffff8880781de800 R11: 0000000000000018 R12: ffff888035c84000 R13: ffffc900000b7d50 R14: 0000000000000000 R15: ffff88807bf12724 FS: 0000000000000000(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000e8 CR3: 00000000790f4004 CR4: 0000000000160ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: virtio_transport_reset+0x59/0x70 [vmw_vsock_virtio_transport_common] virtio_transport_recv_pkt+0x5bb/0xe50 [vmw_vsock_virtio_transport_common] ? detach_buf_split+0xf1/0x130 virtio_transport_rx_work+0xba/0x130 [vmw_vsock_virtio_transport] process_one_work+0x1c0/0x300 worker_thread+0x45/0x3c0 kthread+0xfc/0x130 ? current_work+0x40/0x40 ? kthread_park+0x90/0x90 ret_from_fork+0x35/0x40 Modules linked in: sunrpc kvm_intel kvm vmw_vsock_virtio_transport vmw_vsock_virtio_transport_common irqbypass vsock virtio_rng rng_core CR2: 00000000000000e8 ---[ end trace e75400e2ea2fa824 ]--- This happens because virtio_transport_reset() calls virtio_transport_send_pkt_info() that can be used only on connecting/connected sockets. This patch fixes the issue, using virtio_transport_reset_no_sock() instead of virtio_transport_reset() when we are handling a listener socket. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller --- net/vmw_vsock/virtio_transport_common.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/vmw_vsock') diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index e5ea29c6bca7..f5991006190e 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1021,18 +1021,18 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt, int ret; if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_REQUEST) { - virtio_transport_reset(vsk, pkt); + virtio_transport_reset_no_sock(t, pkt); return -EINVAL; } if (sk_acceptq_is_full(sk)) { - virtio_transport_reset(vsk, pkt); + virtio_transport_reset_no_sock(t, pkt); return -ENOMEM; } child = vsock_create_connected(sk); if (!child) { - virtio_transport_reset(vsk, pkt); + virtio_transport_reset_no_sock(t, pkt); return -ENOMEM; } @@ -1054,7 +1054,7 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt, */ if (ret || vchild->transport != &t->transport) { release_sock(child); - virtio_transport_reset(vsk, pkt); + virtio_transport_reset_no_sock(t, pkt); sock_put(child); return ret; } -- cgit v1.2.3 From 4aaf596148f4b518244cf2b02fafc53ad586dd6b Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Fri, 13 Dec 2019 19:48:01 +0100 Subject: vsock/virtio: add WARN_ON check on virtio_transport_get_ops() virtio_transport_get_ops() and virtio_transport_send_pkt_info() can only be used on connecting/connected sockets, since a socket assigned to a transport is required. This patch adds a WARN_ON() on virtio_transport_get_ops() to check this requirement, a comment and a returned error on virtio_transport_send_pkt_info(), Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller --- net/vmw_vsock/virtio_transport_common.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'net/vmw_vsock') diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index f5991006190e..6abec3fc81d1 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -34,6 +34,9 @@ virtio_transport_get_ops(struct vsock_sock *vsk) { const struct vsock_transport *t = vsock_core_get_transport(vsk); + if (WARN_ON(!t)) + return NULL; + return container_of(t, struct virtio_transport, transport); } @@ -161,15 +164,25 @@ void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt) } EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt); +/* This function can only be used on connecting/connected sockets, + * since a socket assigned to a transport is required. + * + * Do not use on listener sockets! + */ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, struct virtio_vsock_pkt_info *info) { u32 src_cid, src_port, dst_cid, dst_port; + const struct virtio_transport *t_ops; struct virtio_vsock_sock *vvs; struct virtio_vsock_pkt *pkt; u32 pkt_len = info->pkt_len; - src_cid = virtio_transport_get_ops(vsk)->transport.get_local_cid(); + t_ops = virtio_transport_get_ops(vsk); + if (unlikely(!t_ops)) + return -EFAULT; + + src_cid = t_ops->transport.get_local_cid(); src_port = vsk->local_addr.svm_port; if (!info->remote_cid) { dst_cid = vsk->remote_addr.svm_cid; @@ -202,7 +215,7 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, virtio_transport_inc_tx_pkt(vvs, pkt); - return virtio_transport_get_ops(vsk)->send_pkt(pkt); + return t_ops->send_pkt(pkt); } static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs, -- cgit v1.2.3