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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 5CB68C43381 for ; Tue, 26 Feb 2019 22:09:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 29BAC21873 for ; Tue, 26 Feb 2019 22:09:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551218971; bh=nAWKJVnGFlVIF8CgK1I4DdB1l4VNvxVN31ahu5HL3UA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Yp1Qm0EQ7wgHJGtng2PfBXRvXqkSpkU8T97WZKXwf56py6geoy9jB2f1FVI4c0wf5 l0MjRZLlCX3IVlELYGhmbVGB5/J4LPeuwPcYOB2W7XBUN+mxTwZtG2dhd+6/ixqN4n 0uupo93varsIPA7zR5XffV9Pti8s0vwFJGPuwJ6g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729030AbfBZWJa (ORCPT ); Tue, 26 Feb 2019 17:09:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:44714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728766AbfBZWJa (ORCPT ); Tue, 26 Feb 2019 17:09:30 -0500 Received: from ebiggers-linuxstation.mtv.corp.google.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 254D72146F; Tue, 26 Feb 2019 22:09:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551218969; bh=nAWKJVnGFlVIF8CgK1I4DdB1l4VNvxVN31ahu5HL3UA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=05h2ohzKBEH0wwOHfZ44YT4D6kdeU9zel4+3F1iNAS4IFmmEvO9IrtRZ5UJ1/IeyL r/PO5PTMP92OX0FXUa9Va/OQ1viQUcCp1YEsIoHep8fACc8wzPzTG4qg+YHXf95HYn Oz+Rx2Cpyx1fozuVkL2gczCb5y4aCl7bIXtFeoaw= From: Eric Biggers To: dri-devel@lists.freedesktop.org Cc: syzkaller-bugs , linux-kernel@vger.kernel.org, Rodrigo Siqueira , Haneen Mohammed , Daniel Vetter , Chris Wilson , stable@vger.kernel.org Subject: [PATCH] drm/vkms: fix use-after-free when drm_gem_handle_create() fails Date: Tue, 26 Feb 2019 14:08:58 -0800 Message-Id: <20190226220858.214438-1-ebiggers@kernel.org> X-Mailer: git-send-email 2.21.0.rc2.261.ga7da99ff1b-goog In-Reply-To: <20190226213053.GC218103@gmail.com> References: <20190226213053.GC218103@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Biggers If drm_gem_handle_create() fails in vkms_gem_create(), then the vkms_gem_object is freed twice: once when the reference is dropped by drm_gem_object_put_unlocked(), and again by the extra calls to drm_gem_object_release() and kfree(). Fix it by skipping the second release and free. This bug was originally found in the vgem driver by syzkaller using fault injection, but I noticed it's also present in the vkms driver. Fixes: 559e50fd34d1 ("drm/vkms: Add dumb operations") Cc: Rodrigo Siqueira Cc: Haneen Mohammed Cc: Daniel Vetter Cc: Chris Wilson Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers --- drivers/gpu/drm/vkms/vkms_gem.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c index 138b0bb325cf9..69048e73377dc 100644 --- a/drivers/gpu/drm/vkms/vkms_gem.c +++ b/drivers/gpu/drm/vkms/vkms_gem.c @@ -111,11 +111,8 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev, ret = drm_gem_handle_create(file, &obj->gem, handle); drm_gem_object_put_unlocked(&obj->gem); - if (ret) { - drm_gem_object_release(&obj->gem); - kfree(obj); + if (ret) return ERR_PTR(ret); - } return &obj->gem; } -- 2.21.0.rc2.261.ga7da99ff1b-goog