From patchwork Mon Jul 24 12:02:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksandr Natalenko X-Patchwork-Id: 706088 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 1D5E4C001DE for ; Mon, 24 Jul 2023 12:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230157AbjGXMDl (ORCPT ); Mon, 24 Jul 2023 08:03:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230120AbjGXMDg (ORCPT ); Mon, 24 Jul 2023 08:03:36 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F0BEE73 for ; Mon, 24 Jul 2023 05:02:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690200168; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5cbGLzsOpszIW29iDt5MpDYjv/Oe38KhgfInWeAU+S0=; b=CGxtagzbetqpcfp+JSkcrTjOurfbYFMs+DN87HvbeWvfsqxAFnyIqsLy7gr66VSzNwVC5N ggOjCFF7DgCjbpETHDbRlMlHINjMrZ93zwLdmWLI5Ad6R9wXfl2yuqCUW3ypAKifeLVtbI 9SKM9HvkO7+GGkd/KAKv2jT6Osfpvso= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-513-oPGyuEgjOnOPAtmfaLM47g-1; Mon, 24 Jul 2023 08:02:44 -0400 X-MC-Unique: oPGyuEgjOnOPAtmfaLM47g-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0DB3E809F8F; Mon, 24 Jul 2023 12:02:44 +0000 (UTC) Received: from localhost (dhcp-10-40-5-80.brq.redhat.com [10.40.5.80]) by smtp.corp.redhat.com (Postfix) with ESMTP id C3337492C13; Mon, 24 Jul 2023 12:02:43 +0000 (UTC) From: Oleksandr Natalenko To: linux-kernel@vger.kernel.org Cc: linux-scsi@vger.kernel.org, Saurav Kashyap , Javed Hasan , GR-QLogic-Storage-Upstream@marvell.com, "James E.J. Bottomley" , "Martin K. Petersen" , Jozef Bacik , Laurence Oberman , Rob Evers Subject: [RFC PATCH 2/3] scsi: qedf: do not touch __user pointer in qedf_dbg_debug_cmd_read() directly Date: Mon, 24 Jul 2023 14:02:40 +0200 Message-ID: <20230724120241.40495-3-oleksandr@redhat.com> In-Reply-To: <20230724120241.40495-1-oleksandr@redhat.com> References: <20230724120241.40495-1-oleksandr@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org The qedf_dbg_debug_cmd_read() function invokes sprintf() directly on a __user pointer, which may crash the kernel. Avoid doing that by using a small on-stack buffer for sprintf() and then calling simple_read_from_buffer() which does a proper copy_to_user() call. Signed-off-by: Oleksandr Natalenko --- drivers/scsi/qedf/qedf_debugfs.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c index 4d1b99569d490..f910af0029a2c 100644 --- a/drivers/scsi/qedf/qedf_debugfs.c +++ b/drivers/scsi/qedf/qedf_debugfs.c @@ -138,15 +138,14 @@ qedf_dbg_debug_cmd_read(struct file *filp, char __user *buffer, size_t count, loff_t *ppos) { int cnt; + char cbuf[35]; struct qedf_dbg_ctx *qedf_dbg = (struct qedf_dbg_ctx *)filp->private_data; QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "debug mask=0x%x\n", qedf_debug); - cnt = sprintf(buffer, "debug mask = 0x%x\n", qedf_debug); + cnt = sprintf(cbuf, "debug mask = 0x%x\n", qedf_debug); - cnt = min_t(int, count, cnt - *ppos); - *ppos += cnt; - return cnt; + return simple_read_from_buffer(buffer, count, ppos, cbuf, cnt); } static ssize_t