From patchwork Fri Sep 2 13:13:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Abel Vesa X-Patchwork-Id: 12964180 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 AEE9FC38145 for ; Fri, 2 Sep 2022 13:53:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237067AbiIBNxS (ORCPT ); Fri, 2 Sep 2022 09:53:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236976AbiIBNwr (ORCPT ); Fri, 2 Sep 2022 09:52:47 -0400 Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [IPv6:2a00:1450:4864:20::332]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99D6724BF7 for ; Fri, 2 Sep 2022 06:27:05 -0700 (PDT) Received: by mail-wm1-x332.google.com with SMTP id bd26-20020a05600c1f1a00b003a5e82a6474so1413850wmb.4 for ; Fri, 02 Sep 2022 06:27:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=GsvQueQuCTUrKAHOrPXoQPRv2C01zYCjLMtVZuJnKZk=; b=PCk9KUCqb/mq9dLj7ZTKK3yD9RQLUT3BM/3S0+OKecwlv8d8Jx2Fh7MSUCA4LvN13S Lzu4UCX9NaAOnjnUrHpZqX79A+uhnVTA4cQiXQIcZrVpW2rx5yCrQdbksA2cIqfaJJMH q78+lkxPOYJUgwVWeinqlJgYeWunDBPSLbiciT0wMMKYuBbRP9/ebV+TgGIffXwRMp/k DZibjJHbKI81hF7STFHVjTxFwlOT0+edHalYGoTWz+Li++4qxMqXQ+50JlygJ+o5Uv4L /HHVQWOBwIOuGSu2KsFvOHMWSTqNrX48Qd/Gu7ymNflipM7tVLpW+dmY4TvRNyYLkJ43 HAaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=GsvQueQuCTUrKAHOrPXoQPRv2C01zYCjLMtVZuJnKZk=; b=PXhc/lD5C3EkhpQu+Qow1a+thb37LBa4s76Q4aSbApRZgeTL6/3mG52x1zPbWCI3XO xjayDDCM/Dy4lRXNg6kasCRdSI6nmkWRaTMLSgBgfLGQt6ly5qQ13K8tNdECZ+1N+pSn gqKzX9SIoDxNb4y456+3xjQzbyl0g8ttQBv2ISugtxhf/Rdp8Jg41nUKIosUjhilunpA nmmgcde4qPZLWiyC1OGQhPo5pOzKIarLbWou4oaPOfNLA7s8nEk10UOyq9WrX2I0hBOO 5lFUXNqlHoHeNFtgJNQjefN7q29jbLGufguhUsndi/rZELLYnh8dC05XG2jDH/M+RiUo HtNw== X-Gm-Message-State: ACgBeo3ZX1qLg8spUo2kOKRFiSekTEhvAJJexyaVQXUj4MJo7mLqU9ba VNgMXdZqu44akgUTbkoYEZMigNNakrGSms9X X-Google-Smtp-Source: AA6agR7ctgyVF+7Fp5xZ/ldtg0xNTR57lgO0mN4bcjBdcgcRGSGK8/aPmh8jDH664AV8gtaFa6q4Rg== X-Received: by 2002:a05:600c:3ac9:b0:3a5:f114:1f8 with SMTP id d9-20020a05600c3ac900b003a5f11401f8mr2755993wms.204.1662124461131; Fri, 02 Sep 2022 06:14:21 -0700 (PDT) Received: from hackbox.lan ([94.52.112.99]) by smtp.gmail.com with ESMTPSA id v14-20020a5d43ce000000b002253fd19a6asm1766253wrr.18.2022.09.02.06.14.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Sep 2022 06:14:20 -0700 (PDT) From: Abel Vesa To: Andy Gross , Bjorn Andersson , Konrad Dybcio , Srinivas Kandagatla , Amol Maheshwari , Rob Herring , Krzysztof Kozlowski , Ekansh Gupta Cc: Arnd Bergmann , Greg Kroah-Hartman , linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, Linux Kernel Mailing List , Ola Jeppsson Subject: [PATCH 01/14] misc: fastrpc: Fix use-after-free and race in fastrpc_map_find Date: Fri, 2 Sep 2022 16:13:31 +0300 Message-Id: <20220902131344.3029826-2-abel.vesa@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220902131344.3029826-1-abel.vesa@linaro.org> References: <20220902131344.3029826-1-abel.vesa@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Currently, there is a race window between the point when the mutex is unlocked in fastrpc_map_lookup and the reference count increasing (fastrpc_map_get) in fastrpc_map_find, which can also lead to use-after-free. So lets merge fastrpc_map_find into fastrpc_map_lookup which allows us to both protect the maps list by also taking the &fl->lock spinlock and the reference count, since the spinlock will be released only after. Add take_ref argument to make this suitable for all callers. Co-developed-by: Ola Jeppsson Signed-off-by: Ola Jeppsson Signed-off-by: Abel Vesa --- drivers/misc/fastrpc.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 93ebd174d848..0c816a11eeec 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -333,30 +333,31 @@ static void fastrpc_map_get(struct fastrpc_map *map) static int fastrpc_map_lookup(struct fastrpc_user *fl, int fd, - struct fastrpc_map **ppmap) + struct fastrpc_map **ppmap, bool take_ref) { + struct fastrpc_session_ctx *sess = fl->sctx; struct fastrpc_map *map = NULL; + int ret = -ENOENT; - mutex_lock(&fl->mutex); + spin_lock(&fl->lock); list_for_each_entry(map, &fl->maps, node) { - if (map->fd == fd) { - *ppmap = map; - mutex_unlock(&fl->mutex); - return 0; - } - } - mutex_unlock(&fl->mutex); - - return -ENOENT; -} + if (map->fd != fd) + continue; -static int fastrpc_map_find(struct fastrpc_user *fl, int fd, - struct fastrpc_map **ppmap) -{ - int ret = fastrpc_map_lookup(fl, fd, ppmap); + if (take_ref) { + ret = fastrpc_map_get(map); + if (ret) { + dev_dbg(sess->dev, "%s: Failed to get map fd=%d ret=%d\n", + __func__, fd, ret); + break; + } + } - if (!ret) - fastrpc_map_get(*ppmap); + *ppmap = map; + ret = 0; + break; + } + spin_unlock(&fl->lock); return ret; } @@ -703,7 +704,7 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, struct fastrpc_map *map = NULL; int err = 0; - if (!fastrpc_map_find(fl, fd, ppmap)) + if (!fastrpc_map_lookup(fl, fd, ppmap, true)) return 0; map = kzalloc(sizeof(*map), GFP_KERNEL); @@ -1026,7 +1027,7 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx, for (i = 0; i < FASTRPC_MAX_FDLIST; i++) { if (!fdlist[i]) break; - if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap)) + if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap, false)) fastrpc_map_put(mmap); }