From nobody Wed Dec 17 09:14:25 2025 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 4B9D8C49EC5 for ; Tue, 23 Aug 2022 10:47:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356437AbiHWKrX (ORCPT ); Tue, 23 Aug 2022 06:47:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356067AbiHWKlZ (ORCPT ); Tue, 23 Aug 2022 06:41:25 -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 F121065272; Tue, 23 Aug 2022 02:08:35 -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 3F7A9B81C53; Tue, 23 Aug 2022 09:08:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87E71C43145; Tue, 23 Aug 2022 09:08:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661245712; bh=kT4S0FkdxQREl8KpWC8Zu8gJ7tAnQVe/AqEwUxUa6v0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z7yyIIiAJoJ+HOGOaIBsJ2Zfbei5mb/jikT7mzmpoRlNSRxPn3ajdRRmJ2Do7amxU +4KzqVIBqFX1AGcsNDgimbN9do7kHT7rjG8aGAwgBUrbfUHjajeiZm6fTUIHmlxU5v uFGft0y5GW+RTkrGKG1ShKNXOJybi+5ipLPWPhVY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthew Wilcox , Heiko Carstens , Alexander Egorenkov , Alexander Gordeev , Sasha Levin Subject: [PATCH 4.19 165/287] s390/zcore: fix race when reading from hardware system area Date: Tue, 23 Aug 2022 10:25:34 +0200 Message-Id: <20220823080106.292878681@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080100.268827165@linuxfoundation.org> References: <20220823080100.268827165@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Alexander Gordeev [ Upstream commit 9ffed254d938c9e99eb7761c7f739294c84e0367 ] Memory buffer used for reading out data from hardware system area is not protected against concurrent access. Reported-by: Matthew Wilcox Fixes: 411ed3225733 ("[S390] zfcpdump support.") Acked-by: Heiko Carstens Tested-by: Alexander Egorenkov Link: https://lore.kernel.org/r/e68137f0f9a0d2558f37becc20af18e2939934f6.16= 58206891.git.agordeev@linux.ibm.com Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin --- drivers/s390/char/zcore.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c index 76d3c50bf078..ba8fc756264b 100644 --- a/drivers/s390/char/zcore.c +++ b/drivers/s390/char/zcore.c @@ -53,6 +53,7 @@ static struct dentry *zcore_reipl_file; static struct dentry *zcore_hsa_file; static struct ipl_parameter_block *ipl_block; =20 +static DEFINE_MUTEX(hsa_buf_mutex); static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE); =20 /* @@ -69,19 +70,24 @@ int memcpy_hsa_user(void __user *dest, unsigned long sr= c, size_t count) if (!hsa_available) return -ENODATA; =20 + mutex_lock(&hsa_buf_mutex); while (count) { if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { TRACE("sclp_sdias_copy() failed\n"); + mutex_unlock(&hsa_buf_mutex); return -EIO; } offset =3D src % PAGE_SIZE; bytes =3D min(PAGE_SIZE - offset, count); - if (copy_to_user(dest, hsa_buf + offset, bytes)) + if (copy_to_user(dest, hsa_buf + offset, bytes)) { + mutex_unlock(&hsa_buf_mutex); return -EFAULT; + } src +=3D bytes; dest +=3D bytes; count -=3D bytes; } + mutex_unlock(&hsa_buf_mutex); return 0; } =20 @@ -99,9 +105,11 @@ int memcpy_hsa_kernel(void *dest, unsigned long src, si= ze_t count) if (!hsa_available) return -ENODATA; =20 + mutex_lock(&hsa_buf_mutex); while (count) { if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { TRACE("sclp_sdias_copy() failed\n"); + mutex_unlock(&hsa_buf_mutex); return -EIO; } offset =3D src % PAGE_SIZE; @@ -111,6 +119,7 @@ int memcpy_hsa_kernel(void *dest, unsigned long src, si= ze_t count) dest +=3D bytes; count -=3D bytes; } + mutex_unlock(&hsa_buf_mutex); return 0; } =20 --=20 2.35.1