From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B560DEB64DC for ; Wed, 12 Jul 2023 03:20:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229945AbjGLDUF (ORCPT ); Tue, 11 Jul 2023 23:20:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229742AbjGLDUE (ORCPT ); Tue, 11 Jul 2023 23:20:04 -0400 Received: from mail-m11875.qiye.163.com (mail-m11875.qiye.163.com [115.236.118.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 159F7133 for ; Tue, 11 Jul 2023 20:20:01 -0700 (PDT) Received: from localhost.localdomain (unknown [IPV6:240e:3b7:3270:4fa0:68e8:99a6:210:534d]) by mail-m11875.qiye.163.com (Hmail) with ESMTPA id B1FDA280F80; Wed, 12 Jul 2023 11:12:37 +0800 (CST) From: Ding Hui To: stable@vger.kernel.org Cc: chuck.lever@oracle.com, gregkh@linuxfoundation.org, Ding Hui Subject: [PATCH 4.14.y] SUNRPC: Fix UAF in svc_tcp_listen_data_ready() Date: Wed, 12 Jul 2023 11:12:01 +0800 Message-Id: <20230712031201.13103-1-dinghui@sangfor.com.cn> X-Mailer: git-send-email 2.17.1 In-Reply-To: <2023071119-underdone-monotype-f516@gregkh> References: <2023071119-underdone-monotype-f516@gregkh> X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlCS00fVh5CH09KSEtJGEpDTlUTARMWGhIXJBQOD1 lXWRgSC1lBWUlPSx5BSBlMQUhJTEtBTx0aS0FNQx5DQUJCGk1BSUpLQU5ITx9ZV1kWGg8SFR0UWU FZT0tIVUpKS0hKTFVKS0tVS1kG X-HM-Tid: 0a89481623d32eb1kusnb1fda280f80 X-HM-MType: 1 X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Nww6Mxw*GD1PTBgyF0sUKw8U NyMaFAtVSlVKTUNCSkhKTk5DQkpNVTMWGhIXVR8SFRwTDhI7CBoVHB0UCVUYFBZVGBVFWVdZEgtZ QVlJT0seQUgZTEFISUxLQU8dGktBTUMeQ0FCQhpNQUlKS0FOSE8fWVdZCAFZQU5NSE43Bg++ Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org After the listener svc_sock is freed, and before invoking svc_tcp_accept() for the established child sock, there is a window that the newsock retaining a freed listener svc_sock in sk_user_data which cloning from parent. In the race window, if data is received on the newsock, we will observe use-after-free report in svc_tcp_listen_data_ready(). Reproduce by two tasks: 1. while :; do rpc.nfsd 0 ; rpc.nfsd; done 2. while :; do echo "" | ncat -4 127.0.0.1 2049 ; done KASAN report: ================================================================== BUG: KASAN: slab-use-after-free in svc_tcp_listen_data_ready+0x1cf/0x1f0 [sunrpc] Read of size 8 at addr ffff888139d96228 by task nc/102553 CPU: 7 PID: 102553 Comm: nc Not tainted 6.3.0+ #18 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 Call Trace: dump_stack_lvl+0x33/0x50 print_address_description.constprop.0+0x27/0x310 print_report+0x3e/0x70 kasan_report+0xae/0xe0 svc_tcp_listen_data_ready+0x1cf/0x1f0 [sunrpc] tcp_data_queue+0x9f4/0x20e0 tcp_rcv_established+0x666/0x1f60 tcp_v4_do_rcv+0x51c/0x850 tcp_v4_rcv+0x23fc/0x2e80 ip_protocol_deliver_rcu+0x62/0x300 ip_local_deliver_finish+0x267/0x350 ip_local_deliver+0x18b/0x2d0 ip_rcv+0x2fb/0x370 __netif_receive_skb_one_core+0x166/0x1b0 process_backlog+0x24c/0x5e0 __napi_poll+0xa2/0x500 net_rx_action+0x854/0xc90 __do_softirq+0x1bb/0x5de do_softirq+0xcb/0x100 ... Allocated by task 102371: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x7b/0x90 svc_setup_socket+0x52/0x4f0 [sunrpc] svc_addsock+0x20d/0x400 [sunrpc] __write_ports_addfd+0x209/0x390 [nfsd] write_ports+0x239/0x2c0 [nfsd] nfsctl_transaction_write+0xac/0x110 [nfsd] vfs_write+0x1c3/0xae0 ksys_write+0xed/0x1c0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc Freed by task 102551: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x50 __kasan_slab_free+0x106/0x190 __kmem_cache_free+0x133/0x270 svc_xprt_free+0x1e2/0x350 [sunrpc] svc_xprt_destroy_all+0x25a/0x440 [sunrpc] nfsd_put+0x125/0x240 [nfsd] nfsd_svc+0x2cb/0x3c0 [nfsd] write_threads+0x1ac/0x2a0 [nfsd] nfsctl_transaction_write+0xac/0x110 [nfsd] vfs_write+0x1c3/0xae0 ksys_write+0xed/0x1c0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc Fix the UAF by simply doing nothing in svc_tcp_listen_data_ready() if state != TCP_LISTEN, that will avoid dereferencing svsk for all child socket. Link: https://lore.kernel.org/lkml/20230507091131.23540-1-dinghui@sangfor.com.cn/ Fixes: fa9251afc33c ("SUNRPC: Call the default socket callbacks instead of open coding") Signed-off-by: Ding Hui Cc: Signed-off-by: Chuck Lever (cherry picked from commit fc80fc2d4e39137869da3150ee169b40bf879287) Signed-off-by: Ding Hui --- net/sunrpc/svcsock.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index d6771f3b715b..1f717654b4cb 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -766,12 +766,6 @@ static void svc_tcp_listen_data_ready(struct sock *sk) dprintk("svc: socket %p TCP (listen) state change %d\n", sk, sk->sk_state); - if (svsk) { - /* Refer to svc_setup_socket() for details. */ - rmb(); - svsk->sk_odata(sk); - } - /* * This callback may called twice when a new connection * is established as a child socket inherits everything @@ -780,15 +774,20 @@ static void svc_tcp_listen_data_ready(struct sock *sk) * when one of child sockets become ESTABLISHED. * 2) data_ready method of the child socket may be called * when it receives data before the socket is accepted. - * In case of 2, we should ignore it silently. + * In case of 2, we should ignore it silently and DO NOT + * dereference svsk. */ - if (sk->sk_state == TCP_LISTEN) { - if (svsk) { - set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags); - svc_xprt_enqueue(&svsk->sk_xprt); - } else - printk("svc: socket %p: no user data\n", sk); - } + if (sk->sk_state != TCP_LISTEN) + return; + + if (svsk) { + /* Refer to svc_setup_socket() for details. */ + rmb(); + svsk->sk_odata(sk); + set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags); + svc_xprt_enqueue(&svsk->sk_xprt); + } else + printk("svc: socket %p: no user data\n", sk); } /* -- 2.17.1