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 682E0CCA481 for ; Mon, 13 Jun 2022 12:00:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358045AbiFML7P (ORCPT ); Mon, 13 Jun 2022 07:59:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356841AbiFMLvh (ORCPT ); Mon, 13 Jun 2022 07:51:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F1291F2DB; Mon, 13 Jun 2022 03:55:21 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 57C9460F00; Mon, 13 Jun 2022 10:55:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 654D9C34114; Mon, 13 Jun 2022 10:55:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655117719; bh=nXbVtZBMYdh1/mCRCl45kEoYAqILv+JAoJaQO+5rpLA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rqFmqEPSJ6kAoqp+BTViUMmarS782qCSxLVdasouxkZH0qBfh3CVjzwMa+J8Y4dQw 9FLO7l4UTGJJZmCISOpLqCiTn9Wlf3ek49jptfS+ei5zhTjsM2jxnRY1yIwDbtQL7s rCrJZTD0V6PRWTAUBdUDng6Xl8Khunb7ZxCpq4PM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Dionne , David Howells , linux-afs@lists.infradead.org, "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 107/287] rxrpc: Fix listen() setting the bar too high for the prealloc rings Date: Mon, 13 Jun 2022 12:08:51 +0200 Message-Id: <20220613094927.122139585@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094923.832156175@linuxfoundation.org> References: <20220613094923.832156175@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells [ Upstream commit 88e22159750b0d55793302eeed8ee603f5c1a95c ] AF_RXRPC's listen() handler lets you set the backlog up to 32 (if you bump up the sysctl), but whilst the preallocation circular buffers have 32 slots in them, one of them has to be a dead slot because we're using CIRC_CNT(). This means that listen(rxrpc_sock, 32) will cause an oops when the socket is closed because rxrpc_service_prealloc_one() allocated one too many calls and rxrpc_discard_prealloc() won't then be able to get rid of them because it'll think the ring is empty. rxrpc_release_calls_on_socket() then tries to abort them, but oopses because call->peer isn't yet set. Fix this by setting the maximum backlog to RXRPC_BACKLOG_MAX - 1 to match the ring capacity. BUG: kernel NULL pointer dereference, address: 0000000000000086 ... RIP: 0010:rxrpc_send_abort_packet+0x73/0x240 [rxrpc] Call Trace: ? __wake_up_common_lock+0x7a/0x90 ? rxrpc_notify_socket+0x8e/0x140 [rxrpc] ? rxrpc_abort_call+0x4c/0x60 [rxrpc] rxrpc_release_calls_on_socket+0x107/0x1a0 [rxrpc] rxrpc_release+0xc9/0x1c0 [rxrpc] __sock_release+0x37/0xa0 sock_close+0x11/0x20 __fput+0x89/0x240 task_work_run+0x59/0x90 do_exit+0x319/0xaa0 Fixes: 00e907127e6f ("rxrpc: Preallocate peers, conns and calls for incoming service requests") Reported-by: Marc Dionne Signed-off-by: David Howells cc: linux-afs@lists.infradead.org Link: https://lists.infradead.org/pipermail/linux-afs/2022-March/005079.html Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/rxrpc/sysctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c index d75bd15151e6..50f825f55c21 100644 --- a/net/rxrpc/sysctl.c +++ b/net/rxrpc/sysctl.c @@ -17,7 +17,7 @@ static struct ctl_table_header *rxrpc_sysctl_reg_table; static const unsigned int one = 1; static const unsigned int four = 4; -static const unsigned int thirtytwo = 32; +static const unsigned int max_backlog = RXRPC_BACKLOG_MAX - 1; static const unsigned int n_65535 = 65535; static const unsigned int n_max_acks = RXRPC_RXTX_BUFF_SIZE - 1; static const unsigned long one_jiffy = 1; @@ -111,7 +111,7 @@ static struct ctl_table rxrpc_sysctl_table[] = { .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = (void *)&four, - .extra2 = (void *)&thirtytwo, + .extra2 = (void *)&max_backlog, }, { .procname = "rx_window_size", -- 2.35.1