From patchwork Thu Aug 15 18:41:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 819589 Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A0F49476; Thu, 15 Aug 2024 18:41:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.53 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723747318; cv=none; b=dE+wXRbl6pFdtJv2US+AOBp+qvv3lrk/oCgvGUp0BRhGaIXcxpusVIBqVQkkr0p4McCCpH5hEyJcLzsWbsxA5eZofA/3EvR9HXNfsagFjpIt741KAOCSryPoo62QyWyOhdRcAf9xVut7LNsFDMAUxYtI5hr3WAoxlf7k6OpdHLA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723747318; c=relaxed/simple; bh=fJxjOf2MfGSK/AT/Ea1N0ZQk5bOuxtfJpyomWoZ4dKI=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=eQbWZcrrqe6T46XMX2w93quPNinBBHfeJkk3m5pKzvtpQrt/cQDId+3zwZq9PDi5PZEGRJdaWWxl615T7WVlaBenFtzktQxG8rqxKskVLWGDt52HgZ3lniDA34Avjo9MFjDh+7Dq9bolapYh59fLKe733LvVp8ONvvj5AnYRZ8Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QjVCgEhH; arc=none smtp.client-ip=209.85.216.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QjVCgEhH" Received: by mail-pj1-f53.google.com with SMTP id 98e67ed59e1d1-2d1fe3754f4so921641a91.1; Thu, 15 Aug 2024 11:41:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1723747316; x=1724352116; darn=vger.kernel.org; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=nudRwsYKSTD0hk/5DSgrxE/mZ2qKAs3hXnjaPSiojfk=; b=QjVCgEhHzvsHC0X+KW3Q4zdAiYf8tZQ6iLmPZvbh1op6giFK1qTO21C6lnGYrK8v83 i574/nxUvqZalOiLbN7LAt9zkakph3s6yhhK8NAnWJNn15GQJRdPPtW1WgR54vCKMkUP nnki70Uc7x5pGNGrSZpKEQBbMDPtw0NtxA4vwBpvJ8xbd2Gijuo+wLtZXaC1VyPIdGJH nISOt0kDu1uw/YXBNM59lTyDxu83Ee7h+mlL91nJURcyAPqLuguNiKI6pQzkIbahueOb 2SwKOUJNfEl7KMbsqlv/pv/+k0xuPG7UhCakCT/BttHlLUW+kCv9ObtSbRfYXFwethIt c2Ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723747316; x=1724352116; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nudRwsYKSTD0hk/5DSgrxE/mZ2qKAs3hXnjaPSiojfk=; b=Qw7jwaqcUlksWmvkcwIdyDl5SdJ7EK95bGf7SomgC9cwKFscJ9qukp7Ah8YnaSaWgF sG23JUm+HBaFDu7Im/1MkISOzVXFOMb2iXIrE+IISSiO2FIVDOBcUldIsIN637iSu03R GpcXz+zOhej86HhwSrUuNvRLhidj0h8gspQBYi9ZBXA2dH81FBnDJRC0qlC7Jx7gwqdu n8PxaAxn9ZWeOzMFCFaD0WDTl2FhuYl76f9ztDKTfXXt+rHQMKdkL6EVbCQ2aFElNF/L EczUVUqnkmZg7rAQGHqazrdmVGEzfL8CnGf1vIqy/Phr+2v+5eac8g8RcdGXfBcEpBVH n45A== X-Forwarded-Encrypted: i=1; AJvYcCWlUmd5Ufi7nNrJwayO6cIfLHNTrwiFG4S+H8wHfVmxPFb7B/yjZ/PpTpZ/41NCtcMzjcG9irrMcSWFg2lN1IshZYQQXMZ4DmZMT507 X-Gm-Message-State: AOJu0YxHRsOofpC6ZHsRUfyWQpaDeDrwWUhq+Jh7NLzckCoVLiy2HiRU 7edY4xVNkLtclZjQdQ8SqDXTFzsfwEBaPdgMKY8N6s2w6nQS2qrzTcii0Q== X-Google-Smtp-Source: AGHT+IFuME9oQtZtMkOeAb6ToaT8paZRdzoGAc4uXJ53mRhHFxE01+m/GuQjsSeIonmUskhydbKQ7g== X-Received: by 2002:a17:90b:8c:b0:2d3:d68e:e8d8 with SMTP id 98e67ed59e1d1-2d3e040f199mr503942a91.40.1723747316086; Thu, 15 Aug 2024 11:41:56 -0700 (PDT) Received: from google.com ([2620:15c:9d:2:1ffe:470a:d451:c59]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2d3e2b65aa7sm113540a91.5.2024.08.15.11.41.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Aug 2024 11:41:55 -0700 (PDT) Date: Thu, 15 Aug 2024 11:41:53 -0700 From: Dmitry Torokhov To: linux-input@vger.kernel.org Cc: Jeff LaBundy , Benjamin Tissoires , linux-kernel@vger.kernel.org, Hans de Goede , Peter Hutterer Subject: [PATCH] Input: evdev - limit amount of data for writes Message-ID: Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Limit amount of data that can be written into an evdev instance at a given time to 4096 bytes (170 input events) to avoid holding evdev->mutex for too long and starving other users. Signed-off-by: Dmitry Torokhov Reviewed-by: Peter Hutterer Reviewed-by: Jeff LaBundy --- drivers/input/evdev.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index a8ce3d140722..eb4906552ac8 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -498,6 +498,13 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer, struct input_event event; int retval = 0; + /* + * Limit amount of data we inject into the input subsystem so that + * we do not hold evdev->mutex for too long. 4096 bytes corresponds + * to 170 input events. + */ + count = min(count, 4096); + if (count != 0 && count < input_event_size()) return -EINVAL;