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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 11794C10F11 for ; Mon, 22 Apr 2019 19:47:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CAA4421906 for ; Mon, 22 Apr 2019 19:47:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555962452; bh=3thwNhU9wWzxyaOnplzcDqjz1+lmuPcL/tkQJ0lATxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=h38LX3zxPZyHqBDy9j3Iuode3vnZ+r3ZqzQl5/DxfOqw/iWAVmTen/sJt0kDQs4vw DmyXWR3++NLAR72P8J+EvkkQFDfe3BQJJG4Ecf9cx3FOvRXIdId/w6mn+MvtG43224 1l4P0T4qsb79cFtWVSjMTU0wzBJ8P1wdPCQu2NDU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730290AbfDVTrb (ORCPT ); Mon, 22 Apr 2019 15:47:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:50238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730276AbfDVTr2 (ORCPT ); Mon, 22 Apr 2019 15:47:28 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5A6C521904; Mon, 22 Apr 2019 19:47:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555962447; bh=3thwNhU9wWzxyaOnplzcDqjz1+lmuPcL/tkQJ0lATxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qeXvDGoDvRICXEc2p1A7T45SmrC7qznd77EoaB7I/IWg34UK76WeeuF32EFZaVchs nx//57eKqOeZpIev6ZgRImEuBPhpKiLq7TvxcNTzk7qW8tyZScRw0h64QdEy7Axvyw cvK/uEnszdmJ3PpsuDgmtDPERhmWok1FVdgEYePA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Rasmus Villemoes , Jacek Anaszewski , Sasha Levin , linux-leds@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 68/68] leds: trigger: netdev: use memcpy in device_name_store Date: Mon, 22 Apr 2019 15:45:16 -0400 Message-Id: <20190422194516.11634-68-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190422194516.11634-1-sashal@kernel.org> References: <20190422194516.11634-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rasmus Villemoes [ Upstream commit 909346433064b8d840dc82af26161926b8d37558 ] If userspace doesn't end the input with a newline (which can easily happen if the write happens from a C program that does write(fd, iface, strlen(iface))), we may end up including garbage from a previous, longer value in the device_name. For example # cat device_name # printf 'eth12' > device_name # cat device_name eth12 # printf 'eth3' > device_name # cat device_name eth32 I highly doubt anybody is relying on this behaviour, so switch to simply copying the bytes (we've already checked that size is < IFNAMSIZ) and unconditionally zero-terminate it; of course, we also still have to strip a trailing newline. This is also preparation for future patches. Fixes: 06f502f57d0d ("leds: trigger: Introduce a NETDEV trigger") Signed-off-by: Rasmus Villemoes Acked-by: Pavel Machek Signed-off-by: Jacek Anaszewski Signed-off-by: Sasha Levin (Microsoft) --- drivers/leds/trigger/ledtrig-netdev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c index 167a94c02d05..136f86a1627d 100644 --- a/drivers/leds/trigger/ledtrig-netdev.c +++ b/drivers/leds/trigger/ledtrig-netdev.c @@ -122,7 +122,8 @@ static ssize_t device_name_store(struct device *dev, trigger_data->net_dev = NULL; } - strncpy(trigger_data->device_name, buf, size); + memcpy(trigger_data->device_name, buf, size); + trigger_data->device_name[size] = 0; if (size > 0 && trigger_data->device_name[size - 1] == '\n') trigger_data->device_name[size - 1] = 0; -- 2.19.1