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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A8B6C35E1C for ; Thu, 27 Feb 2020 14:03:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D17220801 for ; Thu, 27 Feb 2020 14:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812208; bh=wYM9V+zsA6wV02SA+dp3+ev3gngYIW00NpH86KDIBTg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qLU+8VOsX37rZjglfeUfLzhZac0OASy6dxAlyqcb+KRpZj+ohhIZ76rcxI6fC783+ PtV9CL9QR4z8L8SnyMdaKTPAbZu1G1+nF+PMZivsk7yvABdMPCo0TV7H2vRlcQcwOk foGJJCjOSJjtktxRd/8Y/pTzmvOhomlnr5EyMI6s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387431AbgB0OD1 (ORCPT ); Thu, 27 Feb 2020 09:03:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:38620 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387414AbgB0ODY (ORCPT ); Thu, 27 Feb 2020 09:03:24 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 41950246B7; Thu, 27 Feb 2020 14:03:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812203; bh=wYM9V+zsA6wV02SA+dp3+ev3gngYIW00NpH86KDIBTg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nA5dLnJMvmv/TiZZnhbNgbDUoo7HfpRz2ts+lHRiJD1BSV1LH+PxDcqYdtRmT4Vo8 9zlTdasy27xN7p7U8/IUSAtauSYt2bzyTStGHHU1mf54cnJqAlOI0dBphVO4Gytl8/ QbWLDR5K4tnzxvG2vKKCQANJBMQ9SRLLVDU2bXO0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicholas Johnson , Mika Westerberg Subject: [PATCH 4.19 08/97] thunderbolt: Prevent crash if non-active NVMem file is read Date: Thu, 27 Feb 2020 14:36:16 +0100 Message-Id: <20200227132215.936905449@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132214.553656188@linuxfoundation.org> References: <20200227132214.553656188@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mika Westerberg commit 03cd45d2e219301880cabc357e3cf478a500080f upstream. The driver does not populate .reg_read callback for the non-active NVMem because the file is supposed to be write-only. However, it turns out NVMem subsystem does not yet support this and expects that the .reg_read callback is provided. If user reads the binary attribute it triggers NULL pointer dereference like this one: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: bin_attr_nvmem_read+0x64/0x80 kernfs_fop_read+0xa7/0x180 vfs_read+0xbd/0x170 ksys_read+0x5a/0xd0 do_syscall_64+0x43/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this in the driver by providing .reg_read callback that always returns an error. Reported-by: Nicholas Johnson Fixes: e6b245ccd524 ("thunderbolt: Add support for host and device NVM firmware upgrade") Signed-off-by: Mika Westerberg Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200213095604.1074-1-mika.westerberg@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/thunderbolt/switch.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -264,6 +264,12 @@ static int tb_switch_nvm_read(void *priv return ret; } +static int tb_switch_nvm_no_read(void *priv, unsigned int offset, void *val, + size_t bytes) +{ + return -EPERM; +} + static int tb_switch_nvm_write(void *priv, unsigned int offset, void *val, size_t bytes) { @@ -309,6 +315,7 @@ static struct nvmem_device *register_nvm config.read_only = true; } else { config.name = "nvm_non_active"; + config.reg_read = tb_switch_nvm_no_read; config.reg_write = tb_switch_nvm_write; config.root_only = true; }