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 29F2DC433F5 for ; Mon, 2 May 2022 18:53:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229822AbiEBS5A (ORCPT ); Mon, 2 May 2022 14:57:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230318AbiEBS47 (ORCPT ); Mon, 2 May 2022 14:56:59 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9232B7EF for ; Mon, 2 May 2022 11:53:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A9A2DB819C5 for ; Mon, 2 May 2022 18:53:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54A97C385A4; Mon, 2 May 2022 18:53:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651517606; bh=Jfsd4PUF0ciE5X1Wi7rW5eE0zJAxYmzwYypB397PGro=; h=Subject:To:Cc:From:Date:From; b=Ga6Ly4NwSqLglpHGa9HTK2Kp7H2XCTzamJHwYXb9gWP4bvY6XEH1Bz6nsfGKF42wm IsWc3g+92VD5AGNP7kUxnJqJ1/YUtSvqAQJdgyYIMx9Cxlkm7/L/dtFM+WbblCbYam z+nPqyqU6i4hnQU2mS7EKYIMEtmI4lmQSwsE5CGc= Subject: FAILED: patch "[PATCH] net/smc: Fix slab-out-of-bounds issue in fallback" failed to apply to 5.17-stable tree To: guwen@linux.alibaba.com, kgraul@linux.ibm.com, kuba@kernel.org Cc: From: Date: Mon, 02 May 2022 20:53:25 +0200 Message-ID: <1651517605157232@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 0558226cebee256aa3f8ec0cc5a800a10bf120a6 Mon Sep 17 00:00:00 2001 From: Wen Gu Date: Fri, 22 Apr 2022 15:56:19 +0800 Subject: [PATCH] net/smc: Fix slab-out-of-bounds issue in fallback syzbot reported a slab-out-of-bounds/use-after-free issue, which was caused by accessing an already freed smc sock in fallback-specific callback functions of clcsock. This patch fixes the issue by restoring fallback-specific callback functions to original ones and resetting clcsock sk_user_data to NULL before freeing smc sock. Meanwhile, this patch introduces sk_callback_lock to make the access and assignment to sk_user_data mutually exclusive. Reported-by: syzbot+b425899ed22c6943e00b@syzkaller.appspotmail.com Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Link: https://lore.kernel.org/r/00000000000013ca8105d7ae3ada@google.com/ Signed-off-by: Wen Gu Acked-by: Karsten Graul Signed-off-by: Jakub Kicinski diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index d8433f17c5c9..fce16b9d6e1a 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -243,11 +243,27 @@ struct proto smc_proto6 = { }; EXPORT_SYMBOL_GPL(smc_proto6); +static void smc_fback_restore_callbacks(struct smc_sock *smc) +{ + struct sock *clcsk = smc->clcsock->sk; + + write_lock_bh(&clcsk->sk_callback_lock); + clcsk->sk_user_data = NULL; + + smc_clcsock_restore_cb(&clcsk->sk_state_change, &smc->clcsk_state_change); + smc_clcsock_restore_cb(&clcsk->sk_data_ready, &smc->clcsk_data_ready); + smc_clcsock_restore_cb(&clcsk->sk_write_space, &smc->clcsk_write_space); + smc_clcsock_restore_cb(&clcsk->sk_error_report, &smc->clcsk_error_report); + + write_unlock_bh(&clcsk->sk_callback_lock); +} + static void smc_restore_fallback_changes(struct smc_sock *smc) { if (smc->clcsock->file) { /* non-accepted sockets have no file yet */ smc->clcsock->file->private_data = smc->sk.sk_socket; smc->clcsock->file = NULL; + smc_fback_restore_callbacks(smc); } } @@ -745,48 +761,57 @@ static void smc_fback_forward_wakeup(struct smc_sock *smc, struct sock *clcsk, static void smc_fback_state_change(struct sock *clcsk) { - struct smc_sock *smc = - smc_clcsock_user_data(clcsk); + struct smc_sock *smc; - if (!smc) - return; - smc_fback_forward_wakeup(smc, clcsk, smc->clcsk_state_change); + read_lock_bh(&clcsk->sk_callback_lock); + smc = smc_clcsock_user_data(clcsk); + if (smc) + smc_fback_forward_wakeup(smc, clcsk, + smc->clcsk_state_change); + read_unlock_bh(&clcsk->sk_callback_lock); } static void smc_fback_data_ready(struct sock *clcsk) { - struct smc_sock *smc = - smc_clcsock_user_data(clcsk); + struct smc_sock *smc; - if (!smc) - return; - smc_fback_forward_wakeup(smc, clcsk, smc->clcsk_data_ready); + read_lock_bh(&clcsk->sk_callback_lock); + smc = smc_clcsock_user_data(clcsk); + if (smc) + smc_fback_forward_wakeup(smc, clcsk, + smc->clcsk_data_ready); + read_unlock_bh(&clcsk->sk_callback_lock); } static void smc_fback_write_space(struct sock *clcsk) { - struct smc_sock *smc = - smc_clcsock_user_data(clcsk); + struct smc_sock *smc; - if (!smc) - return; - smc_fback_forward_wakeup(smc, clcsk, smc->clcsk_write_space); + read_lock_bh(&clcsk->sk_callback_lock); + smc = smc_clcsock_user_data(clcsk); + if (smc) + smc_fback_forward_wakeup(smc, clcsk, + smc->clcsk_write_space); + read_unlock_bh(&clcsk->sk_callback_lock); } static void smc_fback_error_report(struct sock *clcsk) { - struct smc_sock *smc = - smc_clcsock_user_data(clcsk); + struct smc_sock *smc; - if (!smc) - return; - smc_fback_forward_wakeup(smc, clcsk, smc->clcsk_error_report); + read_lock_bh(&clcsk->sk_callback_lock); + smc = smc_clcsock_user_data(clcsk); + if (smc) + smc_fback_forward_wakeup(smc, clcsk, + smc->clcsk_error_report); + read_unlock_bh(&clcsk->sk_callback_lock); } static void smc_fback_replace_callbacks(struct smc_sock *smc) { struct sock *clcsk = smc->clcsock->sk; + write_lock_bh(&clcsk->sk_callback_lock); clcsk->sk_user_data = (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY); smc_clcsock_replace_cb(&clcsk->sk_state_change, smc_fback_state_change, @@ -797,6 +822,8 @@ static void smc_fback_replace_callbacks(struct smc_sock *smc) &smc->clcsk_write_space); smc_clcsock_replace_cb(&clcsk->sk_error_report, smc_fback_error_report, &smc->clcsk_error_report); + + write_unlock_bh(&clcsk->sk_callback_lock); } static int smc_switch_to_fallback(struct smc_sock *smc, int reason_code) @@ -2370,17 +2397,20 @@ static void smc_tcp_listen_work(struct work_struct *work) static void smc_clcsock_data_ready(struct sock *listen_clcsock) { - struct smc_sock *lsmc = - smc_clcsock_user_data(listen_clcsock); + struct smc_sock *lsmc; + read_lock_bh(&listen_clcsock->sk_callback_lock); + lsmc = smc_clcsock_user_data(listen_clcsock); if (!lsmc) - return; + goto out; lsmc->clcsk_data_ready(listen_clcsock); if (lsmc->sk.sk_state == SMC_LISTEN) { sock_hold(&lsmc->sk); /* sock_put in smc_tcp_listen_work() */ if (!queue_work(smc_tcp_ls_wq, &lsmc->tcp_listen_work)) sock_put(&lsmc->sk); } +out: + read_unlock_bh(&listen_clcsock->sk_callback_lock); } static int smc_listen(struct socket *sock, int backlog) @@ -2412,10 +2442,12 @@ static int smc_listen(struct socket *sock, int backlog) /* save original sk_data_ready function and establish * smc-specific sk_data_ready function */ + write_lock_bh(&smc->clcsock->sk->sk_callback_lock); smc->clcsock->sk->sk_user_data = (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY); smc_clcsock_replace_cb(&smc->clcsock->sk->sk_data_ready, smc_clcsock_data_ready, &smc->clcsk_data_ready); + write_unlock_bh(&smc->clcsock->sk->sk_callback_lock); /* save original ops */ smc->ori_af_ops = inet_csk(smc->clcsock->sk)->icsk_af_ops; @@ -2430,9 +2462,11 @@ static int smc_listen(struct socket *sock, int backlog) rc = kernel_listen(smc->clcsock, backlog); if (rc) { + write_lock_bh(&smc->clcsock->sk->sk_callback_lock); smc_clcsock_restore_cb(&smc->clcsock->sk->sk_data_ready, &smc->clcsk_data_ready); smc->clcsock->sk->sk_user_data = NULL; + write_unlock_bh(&smc->clcsock->sk->sk_callback_lock); goto out; } sk->sk_max_ack_backlog = backlog; diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c index 7bd1ef55b9df..31db7438857c 100644 --- a/net/smc/smc_close.c +++ b/net/smc/smc_close.c @@ -214,9 +214,11 @@ int smc_close_active(struct smc_sock *smc) sk->sk_state = SMC_CLOSED; sk->sk_state_change(sk); /* wake up accept */ if (smc->clcsock && smc->clcsock->sk) { + write_lock_bh(&smc->clcsock->sk->sk_callback_lock); smc_clcsock_restore_cb(&smc->clcsock->sk->sk_data_ready, &smc->clcsk_data_ready); smc->clcsock->sk->sk_user_data = NULL; + write_unlock_bh(&smc->clcsock->sk->sk_callback_lock); rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR); } smc_close_cleanup_listen(sk);