From d7b0ff5a866724c3ad21f2628c22a63336deec3f Mon Sep 17 00:00:00 2001 From: Michal Luczaj Date: Thu, 7 Nov 2024 21:46:12 +0100 Subject: [PATCH] virtio/vsock: Fix accept_queue memory leak As the final stages of socket destruction may be delayed, it is possible that virtio_transport_recv_listen() will be called after the accept_queue has been flushed, but before the SOCK_DONE flag has been set. As a result, sockets enqueued after the flush would remain unremoved, leading to a memory leak. vsock_release __vsock_release lock virtio_transport_release virtio_transport_close schedule_delayed_work(close_work) sk_shutdown = SHUTDOWN_MASK (!) flush accept_queue release virtio_transport_recv_pkt vsock_find_bound_socket lock if flag(SOCK_DONE) return virtio_transport_recv_listen child = vsock_create_connected (!) vsock_enqueue_accept(child) release close_work lock virtio_transport_do_close set_flag(SOCK_DONE) virtio_transport_remove_sock vsock_remove_sock vsock_remove_bound release Introduce a sk_shutdown check to disallow vsock_enqueue_accept() during socket destruction. unreferenced object 0xffff888109e3f800 (size 2040): comm "kworker/5:2", pid 371, jiffies 4294940105 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 28 00 0b 40 00 00 00 00 00 00 00 00 00 00 00 00 (..@............ backtrace (crc 9e5f4e84): [] kmem_cache_alloc_noprof+0x2c1/0x360 [] sk_prot_alloc+0x30/0x120 [] sk_alloc+0x2c/0x4b0 [] __vsock_create.constprop.0+0x2a/0x310 [] virtio_transport_recv_pkt+0x4dc/0x9a0 [] vsock_loopback_work+0xfd/0x140 [] process_one_work+0x20c/0x570 [] worker_thread+0x1bf/0x3a0 [] kthread+0xdd/0x110 [] ret_from_fork+0x2d/0x50 [] ret_from_fork_asm+0x1a/0x30 Fixes: 3fe356d58efa ("vsock/virtio: discard packets only when socket is really closed") Reviewed-by: Stefano Garzarella Signed-off-by: Michal Luczaj Signed-off-by: Paolo Abeni --- net/vmw_vsock/virtio_transport_common.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index ccbd2bc0d210..cd075f608d4f 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1512,6 +1512,14 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb, return -ENOMEM; } + /* __vsock_release() might have already flushed accept_queue. + * Subsequent enqueues would lead to a memory leak. + */ + if (sk->sk_shutdown == SHUTDOWN_MASK) { + virtio_transport_reset_no_sock(t, skb); + return -ESHUTDOWN; + } + child = vsock_create_connected(sk); if (!child) { virtio_transport_reset_no_sock(t, skb);