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[209.132.180.67]) by mx.google.com with ESMTP id c18si2300810ots.317.2020.02.27.06.24.57; Thu, 27 Feb 2020 06:25:09 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=0mcypYgo; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389423AbgB0OYP (ORCPT + 99 others); Thu, 27 Feb 2020 09:24:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:52118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388954AbgB0ONN (ORCPT ); Thu, 27 Feb 2020 09:13:13 -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 DE1F7246AC; Thu, 27 Feb 2020 14:13:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812793; bh=jTvwhF4KjEeGmTKvwo1HGhYhl0LBnNBc2sIqXvNxEEY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0mcypYgoYT1sgwQNLBgEEWJfatHUGtQtuMtJie805P4CFa7t+rLqKwdiaCrkpLHrz HLTGv+xT5xiBDn44xbwMK+2OHt10sK1HsihfkRGE9IbCF/bxhftkuU4bBAwXNAnAtm nE/lb2+Urvt6o77SnSi8xPZMRH2edD3kwD0xQOno= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicholas Johnson , Mika Westerberg Subject: [PATCH 5.5 019/150] thunderbolt: Prevent crash if non-active NVMem file is read Date: Thu, 27 Feb 2020 14:35:56 +0100 Message-Id: <20200227132235.531755428@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132232.815448360@linuxfoundation.org> References: <20200227132232.815448360@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 @@ -274,6 +274,12 @@ out: 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) { @@ -319,6 +325,7 @@ 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; }