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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACC97C433F5 for ; Mon, 27 Sep 2021 17:24:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9534A6108E for ; Mon, 27 Sep 2021 17:24:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237549AbhI0R0b (ORCPT ); Mon, 27 Sep 2021 13:26:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:38056 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237216AbhI0RWb (ORCPT ); Mon, 27 Sep 2021 13:22:31 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A4DA861356; Mon, 27 Sep 2021 17:14:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632762860; bh=wrxX2eap+yMjhNiAV493M40hjD0C94S0mhDnQ1OmbMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b3ozN5fA+S4FH+lBWfuLsUGfQGJ28hI3dtPqtDtAHINOy/EytIVe0nrq3gq7AACBj BI7b6tSxvoJjXiUxL7d4e979rt1vWEuO0EQSPEkUZmNVXJyCZ/39GiXNHpYGT6fTaK EgTZipeh1BNNlnpsp3+GPQ6x7CVmAuwa6ZLZ4CMk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefan Raspl , Julian Wiedmann , Alexandra Winter , Jakub Kicinski , Sasha Levin , Heiko Carstens Subject: [PATCH 5.14 078/162] s390/qeth: fix NULL deref in qeth_clear_working_pool_list() Date: Mon, 27 Sep 2021 19:02:04 +0200 Message-Id: <20210927170236.156926418@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210927170233.453060397@linuxfoundation.org> References: <20210927170233.453060397@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: Julian Wiedmann [ Upstream commit 248f064af222a1f97ee02c84a98013dfbccad386 ] When qeth_set_online() calls qeth_clear_working_pool_list() to roll back after an error exit from qeth_hardsetup_card(), we are at risk of accessing card->qdio.in_q before it was allocated by qeth_alloc_qdio_queues() via qeth_mpc_initialize(). qeth_clear_working_pool_list() then dereferences NULL, and by writing to queue->bufs[i].pool_entry scribbles all over the CPU's lowcore. Resulting in a crash when those lowcore areas are used next (eg. on the next machine-check interrupt). Such a scenario would typically happen when the device is first set online and its queues aren't allocated yet. An early IO error or certain misconfigs (eg. mismatched transport mode, bad portno) then cause us to error out from qeth_hardsetup_card() with card->qdio.in_q still being NULL. Fix it by checking the pointer for NULL before accessing it. Note that we also have (rare) paths inside qeth_mpc_initialize() where a configuration change can cause us to free the existing queues, expecting that subsequent code will allocate them again. If we then error out before that re-allocation happens, the same bug occurs. Fixes: eff73e16ee11 ("s390/qeth: tolerate pre-filled RX buffer") Reported-by: Stefan Raspl Root-caused-by: Heiko Carstens Signed-off-by: Julian Wiedmann Reviewed-by: Alexandra Winter Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/s390/net/qeth_core_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 62f88ccbd03f..51f7f4e680c3 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -207,6 +207,9 @@ static void qeth_clear_working_pool_list(struct qeth_card *card) &card->qdio.in_buf_pool.entry_list, list) list_del(&pool_entry->list); + if (!queue) + return; + for (i = 0; i < ARRAY_SIZE(queue->bufs); i++) queue->bufs[i].pool_entry = NULL; } -- 2.33.0