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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2425C47089 for ; Fri, 2 Dec 2022 15:04:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233657AbiLBPEx (ORCPT ); Fri, 2 Dec 2022 10:04:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229523AbiLBPEv (ORCPT ); Fri, 2 Dec 2022 10:04:51 -0500 Received: from mail-wr1-x436.google.com (mail-wr1-x436.google.com [IPv6:2a00:1450:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D36BD37BB for ; Fri, 2 Dec 2022 07:04:50 -0800 (PST) Received: by mail-wr1-x436.google.com with SMTP id bs21so8206891wrb.4 for ; Fri, 02 Dec 2022 07:04:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=sWntLOso8o9063LNWZJJYme5vULdsehktJiTEafe5Yc=; b=MmZs8WNLZzH3Ve3COf6jKgg0XAxCoWHQv2IqCRK21J8mLyeCIdMPubL2Fk2aaQ4ZTP M3AKunN+njwVmA50iIJuPBcJAEdb/gegAESDznvqboZoz/rxyjxqO2mq6l+bT1GBAXj+ DVuewhC3diXchlw5TYaX5ZbqiYWB8q69xChbZrDfZzwUDLPGMzxZ+kY+4Uk+SshOhhP8 /0uThk/DhMR9Yw1Y4IzSPYmQKoopKiXJOnsbmODzZ/ukv59T+RMLVqSZzzRSJY/nXSuj kouoaMwT0HnxVnPDd5mdqLrB0ZY3ifFV5WDozB1MeaMHaw1acaxrqQp/ZLugB+r0EmFP IomA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=sWntLOso8o9063LNWZJJYme5vULdsehktJiTEafe5Yc=; b=ssCTPm5/+iQ+JYhsQ5OJmqqjx3JTUWvIYFpHCuq5ELvbjL7hrodJsRXhlKO0iKDLYJ UOTLMfkwc4KfR4+kbIk8gvEb9GsSyZNFAKLnHlP0fhZ88jTUVJEl9+3kvQRvzSjsu5vL nNM69BEnfAlVBeA9j5C5zNFDenNcXCauDaVUuexI+5RFgv1gSJEfj28KHsoblbkK1KG/ JVkhlLMpg83ByUaJHl4Q7lzeazNHQrJtVMihDsnEiNcNpujB8IdGceiU60HKtdcMqIHb 9ZjfQ2XiIte7eR0hI9Rttno8MBw4EOEgiUM1cAQWMQId7slAHIgoPAo42TFhNtqpqKMo WhEw== X-Gm-Message-State: ANoB5pnRWveocda1UiypNuxO3zlqJZgcbjEHuFui0B/AK+DDyBcgifkM NmrhTUWm27qwSo3YxtYpD1EpIQ== X-Google-Smtp-Source: AA0mqf5hO0RpjKqzK0vhPgDx3wdWpQKvjtLG+kMNnN+zODPNKQTp6qFMFXmdD/G9WL6LfhBHImiGWA== X-Received: by 2002:adf:ea0a:0:b0:241:fcd5:6b94 with SMTP id q10-20020adfea0a000000b00241fcd56b94mr25889868wrm.592.1669993488778; Fri, 02 Dec 2022 07:04:48 -0800 (PST) Received: from brgl-uxlite.home ([2a01:cb1d:334:ac00:29a4:6f04:ddb1:1ed7]) by smtp.gmail.com with ESMTPSA id v6-20020adfe286000000b00241f467f888sm7218237wri.74.2022.12.02.07.04.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Dec 2022 07:04:48 -0800 (PST) From: Bartosz Golaszewski To: Kent Gibson , Linus Walleij , Andy Shevchenko , Nick Hainke Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v7 0/2] gpiolib: don't allow user-space to crash the kernel with hot-unplugs Date: Fri, 2 Dec 2022 16:04:42 +0100 Message-Id: <20221202150444.244313-1-brgl@bgdev.pl> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bartosz Golaszewski I need to respin this series after Nick Hainke reported a build failure when the v1 uAPI for character device is disabled. I also noticed that we need to lower the semaphore when opening the character device file as well. v6 -> v7: - fix a build issue with CDEV_V1 code disabled (giving credit to Nick Hainke) - protect the gdev->chip also in gpio_chrdev_open() v5 -> v6: - signal an error in poll callbacks instead of returning 0 which would make the user-space assume a timeout occurred (which could lead to user-space spinning a timeout loop forever) v4 -> v5: - try to acquire the semaphore for reading and bail out of syscall callbacks immediately in case of lock contention v3 -> v4: - use function typedefs to make code cleaner - add a blank line after down_write() v2 -> v3: - drop the helper variable in patch 1/2 as we won't be using it in 2/2 - refactor patch 2/2 to use locking wrappers around the syscall callbacks v1 -> v2: - add missing gdev->chip checks in patch 1/2 - add a second patch that protects the structures that can be accessed by user-space calls against concurrent removal Bartosz Golaszewski (2): gpiolib: cdev: fix NULL-pointer dereferences gpiolib: protect the GPIO device against being dropped while in use by user-space drivers/gpio/gpiolib-cdev.c | 207 +++++++++++++++++++++++++++++++----- drivers/gpio/gpiolib.c | 4 + drivers/gpio/gpiolib.h | 5 + 3 files changed, 191 insertions(+), 25 deletions(-) -- 2.37.2