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[2620:137:e000::1:20]) by mx.google.com with ESMTP id h26-20020a1709066d9a00b0078ca7bbf616si595160ejt.746.2022.11.30.01.14.40; Wed, 30 Nov 2022 01:15:03 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@bgdev-pl.20210112.gappssmtp.com header.s=20210112 header.b=GpQ96fxp; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230006AbiK3JGE (ORCPT + 99 others); Wed, 30 Nov 2022 04:06:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229892AbiK3JGB (ORCPT ); Wed, 30 Nov 2022 04:06:01 -0500 Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [IPv6:2a00:1450:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4680412098 for ; Wed, 30 Nov 2022 01:06:00 -0800 (PST) Received: by mail-wm1-x329.google.com with SMTP id j5-20020a05600c410500b003cfa9c0ea76so872470wmi.3 for ; Wed, 30 Nov 2022 01:06:00 -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=fseEas+14xAFQxVLUfGfLUvuzNka2Dj76aCyMrxyJlY=; b=GpQ96fxp4whTMGCYqs8TBy1BcNSIrYVuSZjU9RaukJvnf7q7O8L1T4gUNrnq8/73/D n+IcaLAKz+DRd7jAFLITQOAzzNTFuTymRHrS0cTLHykFs2NL5vZvCSDuiWDemod3Y/Cr znwbr/SEj0XqEUZ+sh3rYDz/qjmdRxyAX90WJ/LuEjJitkZcmJWBpl7WnG/vb/ukzHXS pQ24vdtxd0G0C4OqBBqNsrkzCH4SWcq2OUV/1VyV4Wljj3Ix8UGR7zYgPTsBQvd4DaXR pQKrTmmV2BAUEo4a45wxh68TQf/AS6Zxokyx2kaOkFkMf9tijb02+epZxjL2wgATopnL LpFg== 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=fseEas+14xAFQxVLUfGfLUvuzNka2Dj76aCyMrxyJlY=; b=hBnxXBgQFmoTKxR9sxsICwh3BN4sL/Acj4DFeNyyMC1BdliighnqVj+GapOXbOShkW gInxtt0YF7h9qHs6VpXgiABCUXSWULvlZMEo+dEX+sQEPCyNXk/7Jl30NPbz3cfty9+Y 7qtSIUB4OIpwbKas7idFnB5NcGwX4KaNYd30fIOX7kP4ycvijP2zkZrbCb4wt6cGb6mC APU956Y9jhvi2L4LWcZj2HZl9GyLKxldH+qfuB1mUdrauvRgSIEBEZl9wqE155euwKyO zkeAUu+noaQIcZ3/tJT9gDvZ4EiishYmKw0ETV9cW2tacrDQeje9yQSKMk6LPYVVZWBn MPNA== X-Gm-Message-State: ANoB5pkDz2uAZyIBlyFN2ud7Xmo6+XkbJPQJCcswiVz/NXWhRmTYMc9A N6PN2M37wEJWruBjzwqpwHeS58+ZlvJEqg== X-Received: by 2002:a05:600c:3514:b0:3cf:e0ef:1f6c with SMTP id h20-20020a05600c351400b003cfe0ef1f6cmr36475633wmq.75.1669799158797; Wed, 30 Nov 2022 01:05:58 -0800 (PST) Received: from brgl-uxlite.home ([2a01:cb1d:334:ac00:458c:6db9:e033:a468]) by smtp.gmail.com with ESMTPSA id v24-20020a05600c4d9800b003cfbe1da539sm1168841wmp.36.2022.11.30.01.05.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Nov 2022 01:05:58 -0800 (PST) From: Bartosz Golaszewski To: Kent Gibson , Linus Walleij , Andy Shevchenko Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v4 0/2] gpiolib: don't allow user-space to crash the kernel with hot-unplugs Date: Wed, 30 Nov 2022 10:05:54 +0100 Message-Id: <20221130090556.40280-1-brgl@bgdev.pl> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1750911894414279597?= X-GMAIL-MSGID: =?utf-8?q?1750911894414279597?= From: Bartosz Golaszewski Sending it once more with some more tweaks and review tags collected. Will apply shortly. --- This is the final iteration of the changes that aim at fixing the situation in which the user-space can provoke a NULL-pointer derefence in the kernel when a GPIO device that's in use by user-space is removed. 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 | 190 +++++++++++++++++++++++++++++++----- drivers/gpio/gpiolib.c | 4 + drivers/gpio/gpiolib.h | 5 + 3 files changed, 177 insertions(+), 22 deletions(-)