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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 F3BBBC43457 for ; Tue, 21 Jul 2020 08:18:44 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C7D6521702 for ; Tue, 21 Jul 2020 08:18:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="eFkuws/N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7D6521702 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 03D1E89CDB; Tue, 21 Jul 2020 08:18:23 +0000 (UTC) Received: from mail29.static.mailgun.info (mail29.static.mailgun.info [104.130.122.29]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6CF566E088 for ; Mon, 20 Jul 2020 22:31:29 +0000 (UTC) DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1595284289; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=bxR7ijxZKMOnXI/AhQULBlr08uvy6ovR5LTV4Tax43k=; b=eFkuws/NnDz5DdZJxoUom4r0vfejZx2xZ71rg3lDcalgvyhMV3pgF0iaTHS9PqBjo5i53I4D gq5XoRxarHksGMBBp8vPR/NO+/4EtZoKkjUfkiSQvms0t/G31p1vY8z6wsBvB2QwE4TraeKD 3oCUZyLjkWcvlsH18TUxeVejvdw= X-Mailgun-Sending-Ip: 104.130.122.29 X-Mailgun-Sid: WyJkOTU5ZSIsICJkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n14.prod.us-east-1.postgun.com with SMTP id 5f161b40d3d6508422c44389 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 20 Jul 2020 22:31:28 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id BBA03C433CB; Mon, 20 Jul 2020 22:31:27 +0000 (UTC) Received: from cohens-linux.qualcomm.com (Global_NAT1_IAD_FW.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: cohens) by smtp.codeaurora.org (Postfix) with ESMTPSA id BB439C433C9; Mon, 20 Jul 2020 22:31:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org BB439C433C9 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=cohens@codeaurora.org From: Steve Cohen To: dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org Subject: [PATCH V2] drm: hold gem reference until object is no longer accessed Date: Mon, 20 Jul 2020 18:30:50 -0400 Message-Id: <1595284250-31580-1-git-send-email-cohens@codeaurora.org> X-Mailer: git-send-email 2.7.4 X-Mailman-Approved-At: Tue, 21 Jul 2020 08:18:03 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: adelva@google.com, Steve Cohen , pdhaval@codeaurora.org, seanpaul@chromium.org, sam@ravnborg.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" A use-after-free in drm_gem_open_ioctl can happen if the GEM object handle is closed between the idr lookup and retrieving the size from said object since a local reference is not being held at that point. Hold the local reference while the object can still be accessed to fix this and plug the potential security hole. Signed-off-by: Steve Cohen --- drivers/gpu/drm/drm_gem.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 7bf628e..ee2058a 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -871,9 +871,6 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data, * @file_priv: drm file-private structure * * Open an object using the global name, returning a handle and the size. - * - * This handle (of course) holds a reference to the object, so the object - * will not go away until the handle is deleted. */ int drm_gem_open_ioctl(struct drm_device *dev, void *data, @@ -898,14 +895,15 @@ drm_gem_open_ioctl(struct drm_device *dev, void *data, /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */ ret = drm_gem_handle_create_tail(file_priv, obj, &handle); - drm_gem_object_put_unlocked(obj); if (ret) - return ret; + goto err; args->handle = handle; args->size = obj->size; - return 0; +err: + drm_gem_object_put_unlocked(obj); + return ret; } /** -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel