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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 8358FC2B9F4 for ; Tue, 15 Jun 2021 02:49:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 549C9611CE for ; Tue, 15 Jun 2021 02:49:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230081AbhFOCvS (ORCPT ); Mon, 14 Jun 2021 22:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229829AbhFOCvQ (ORCPT ); Mon, 14 Jun 2021 22:51:16 -0400 Received: from mail-oi1-x22c.google.com (mail-oi1-x22c.google.com [IPv6:2607:f8b0:4864:20::22c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F062C061574 for ; Mon, 14 Jun 2021 19:49:12 -0700 (PDT) Received: by mail-oi1-x22c.google.com with SMTP id t140so16627266oih.0 for ; Mon, 14 Jun 2021 19:49:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=5mB54G1f2BMqsk/PpgeMUBY34ptNTL2FTGaPiB4Yuzg=; b=JzJ8Iuxsx3z0run2VPvrs1YOCVAzy6p5rjt9trA8nj1oMCeAxaymq8i1lqihTyDhND q6K1IHpI/90SVIdLxLBFQPB0ZMPoM6zrIos9JGmck2Ji0fNnP/Ps+D6Cv4gh9ZItgNGv P09JhtSZzvWj89m1762Z9KXmlYdtsJbgqbvquBWdVPzrcSqlS6eyBOlANiSOis6c+73l Fh0ObkTayhLnCBkqp5P7WimHEIscsVqu2tWE9BZseZtEFMRT5FEdEcDhN2Fef0LS2gou D6efwLz6SxohFFRI6dPeGQL/dZ6TgP5AL6jbsLcSMQFnZ1lmI0aWkQFHZNVL8FOmmPuH 0wFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=5mB54G1f2BMqsk/PpgeMUBY34ptNTL2FTGaPiB4Yuzg=; b=cdkPYXvZ2Xn46/PIRzbElaLh+RdxTOuQIhGxadvKQy6jkDOalcD6GunCKGwXe+Pver 4R9lF5d69ApKfkuZqrPkIdLRrBMt/Exzofm1pKjzYwHFtjtsVss6d8gGBFRq0Zfu1Ov+ ALDwVQV8fJYRuac0+ZfoWdu2QMLFxbjAZndG7FSaecPkV9/6y7/El7+9kl8RAx251wUY EsWQFjrlfQgQdP1NrsmfR0NFvdSp/WtGyc77n6aeUnxJp2wkSt5PK9XR+rLh5k6PNJcb fSdLmhwiiGklDgruyY+0mGkgX6fColt10eyG7u6wwmMxT4jvFuPvANRrwLGxtcRjo72g fJjQ== X-Gm-Message-State: AOAM531+9Jdr0kMOBhYmqI/ywvUi1STKqvQ4Bozvk/Sd9plvC6gAX6CH 1bxs6YlFMsqM+ndLSqXVOcFypS/YFXUHPKEzO4E= X-Google-Smtp-Source: ABdhPJwKHBPhRor0uBHBiT3Sc9lmWQ4R/sBqLW16QjtJF3wH74+3EGUShH6H4OB2pSMYnNl6znN5ag== X-Received: by 2002:a17:90a:ae15:: with SMTP id t21mr2445346pjq.55.1623724747504; Mon, 14 Jun 2021 19:39:07 -0700 (PDT) Received: from localhost.localdomain ([118.200.190.93]) by smtp.gmail.com with ESMTPSA id b133sm14102623pfb.36.2021.06.14.19.39.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Jun 2021 19:39:07 -0700 (PDT) From: Desmond Cheong Zhi Xi To: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@linux.ie, daniel@ffwll.ch Cc: Desmond Cheong Zhi Xi , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, emil.l.velikov@gmail.com, Daniel Vetter Subject: [PATCH v2 2/2] drm: Protect drm_master pointers in drm_lease.c Date: Tue, 15 Jun 2021 10:36:45 +0800 Message-Id: <20210615023645.6535-3-desmondcheongzx@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210615023645.6535-1-desmondcheongzx@gmail.com> References: <20210615023645.6535-1-desmondcheongzx@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch ensures that the device's master mutex is acquired before accessing pointers to struct drm_master that are subsequently dereferenced. Without the mutex, the struct drm_master may be freed concurrently by another process calling drm_setmaster_ioctl(). This could then lead to use-after-free errors. Reported-by: Daniel Vetter Signed-off-by: Desmond Cheong Zhi Xi Reviewed-by: Emil Velikov --- drivers/gpu/drm/drm_lease.c | 58 +++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c index da4f085fc09e..3e6f689236e5 100644 --- a/drivers/gpu/drm/drm_lease.c +++ b/drivers/gpu/drm/drm_lease.c @@ -107,10 +107,16 @@ static bool _drm_has_leased(struct drm_master *master, int id) */ bool _drm_lease_held(struct drm_file *file_priv, int id) { + bool ret; + if (!file_priv || !file_priv->master) return true; - return _drm_lease_held_master(file_priv->master, id); + mutex_lock(&file_priv->master->dev->master_mutex); + ret = _drm_lease_held_master(file_priv->master, id); + mutex_unlock(&file_priv->master->dev->master_mutex); + + return ret; } /** @@ -132,10 +138,12 @@ bool drm_lease_held(struct drm_file *file_priv, int id) if (!file_priv || !file_priv->master || !file_priv->master->lessor) return true; + mutex_lock(&file_priv->master->dev->master_mutex); master = file_priv->master; mutex_lock(&master->dev->mode_config.idr_mutex); ret = _drm_lease_held_master(master, id); mutex_unlock(&master->dev->mode_config.idr_mutex); + mutex_unlock(&file_priv->master->dev->master_mutex); return ret; } @@ -158,6 +166,7 @@ uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in) if (!file_priv || !file_priv->master || !file_priv->master->lessor) return crtcs_in; + mutex_lock(&file_priv->master->dev->master_mutex); master = file_priv->master; dev = master->dev; @@ -177,6 +186,7 @@ uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in) count_in++; } mutex_unlock(&master->dev->mode_config.idr_mutex); + mutex_unlock(&file_priv->master->dev->master_mutex); return crtcs_out; } @@ -490,7 +500,7 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, size_t object_count; int ret = 0; struct idr leases; - struct drm_master *lessor = lessor_priv->master; + struct drm_master *lessor; struct drm_master *lessee = NULL; struct file *lessee_file = NULL; struct file *lessor_file = lessor_priv->filp; @@ -502,12 +512,6 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; - /* Do not allow sub-leases */ - if (lessor->lessor) { - DRM_DEBUG_LEASE("recursive leasing not allowed\n"); - return -EINVAL; - } - /* need some objects */ if (cl->object_count == 0) { DRM_DEBUG_LEASE("no objects in lease\n"); @@ -519,12 +523,23 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, return -EINVAL; } + mutex_lock(&dev->master_mutex); + lessor = lessor_priv->master; + /* Do not allow sub-leases */ + if (lessor->lessor) { + DRM_DEBUG_LEASE("recursive leasing not allowed\n"); + ret = -EINVAL; + goto unlock; + } + object_count = cl->object_count; object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), array_size(object_count, sizeof(__u32))); - if (IS_ERR(object_ids)) - return PTR_ERR(object_ids); + if (IS_ERR(object_ids)) { + ret = PTR_ERR(object_ids); + goto unlock; + } idr_init(&leases); @@ -535,14 +550,15 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, if (ret) { DRM_DEBUG_LEASE("lease object lookup failed: %i\n", ret); idr_destroy(&leases); - return ret; + goto unlock; } /* Allocate a file descriptor for the lease */ fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK)); if (fd < 0) { idr_destroy(&leases); - return fd; + ret = fd; + goto unlock; } DRM_DEBUG_LEASE("Creating lease\n"); @@ -578,6 +594,7 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, /* Hook up the fd */ fd_install(fd, lessee_file); + mutex_unlock(&dev->master_mutex); DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n"); return 0; @@ -587,6 +604,8 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, out_leases: put_unused_fd(fd); +unlock: + mutex_unlock(&dev->master_mutex); DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret); return ret; } @@ -609,7 +628,7 @@ int drm_mode_list_lessees_ioctl(struct drm_device *dev, struct drm_mode_list_lessees *arg = data; __u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr); __u32 count_lessees = arg->count_lessees; - struct drm_master *lessor = lessor_priv->master, *lessee; + struct drm_master *lessor, *lessee; int count; int ret = 0; @@ -620,6 +639,8 @@ int drm_mode_list_lessees_ioctl(struct drm_device *dev, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; + mutex_lock(&dev->master_mutex); + lessor = lessor_priv->master; DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id); mutex_lock(&dev->mode_config.idr_mutex); @@ -643,6 +664,7 @@ int drm_mode_list_lessees_ioctl(struct drm_device *dev, arg->count_lessees = count; mutex_unlock(&dev->mode_config.idr_mutex); + mutex_unlock(&dev->master_mutex); return ret; } @@ -662,7 +684,7 @@ int drm_mode_get_lease_ioctl(struct drm_device *dev, struct drm_mode_get_lease *arg = data; __u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr); __u32 count_objects = arg->count_objects; - struct drm_master *lessee = lessee_priv->master; + struct drm_master *lessee; struct idr *object_idr; int count; void *entry; @@ -676,6 +698,8 @@ int drm_mode_get_lease_ioctl(struct drm_device *dev, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; + mutex_lock(&dev->master_mutex); + lessee = lessee_priv->master; DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id); mutex_lock(&dev->mode_config.idr_mutex); @@ -703,6 +727,7 @@ int drm_mode_get_lease_ioctl(struct drm_device *dev, arg->count_objects = count; mutex_unlock(&dev->mode_config.idr_mutex); + mutex_unlock(&dev->master_mutex); return ret; } @@ -721,7 +746,7 @@ int drm_mode_revoke_lease_ioctl(struct drm_device *dev, void *data, struct drm_file *lessor_priv) { struct drm_mode_revoke_lease *arg = data; - struct drm_master *lessor = lessor_priv->master; + struct drm_master *lessor; struct drm_master *lessee; int ret = 0; @@ -731,8 +756,10 @@ int drm_mode_revoke_lease_ioctl(struct drm_device *dev, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; + mutex_lock(&dev->master_mutex); mutex_lock(&dev->mode_config.idr_mutex); + lessor = lessor_priv->master; lessee = _drm_find_lessee(lessor, arg->lessee_id); /* No such lessee */ @@ -751,6 +778,7 @@ int drm_mode_revoke_lease_ioctl(struct drm_device *dev, fail: mutex_unlock(&dev->mode_config.idr_mutex); + mutex_unlock(&dev->master_mutex); return ret; } -- 2.25.1