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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F41CC433F5 for ; Mon, 30 May 2022 14:43:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240618AbiE3Onf (ORCPT ); Mon, 30 May 2022 10:43:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242230AbiE3OSe (ORCPT ); Mon, 30 May 2022 10:18:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50D38A3384; Mon, 30 May 2022 06:49:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6568961013; Mon, 30 May 2022 13:49:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9D89C385B8; Mon, 30 May 2022 13:49:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653918567; bh=kvqrbJKmFfnxAX+OzuSYqbmtTFwFrYPjGCVXwam8KDA=; h=From:To:Cc:Subject:Date:From; b=n9RrhDZr0RsY6qIMwygYNbIgKoRY2E4KdLE0M/quMGAkAAQKxaIWa8gy79i+OJWKR BudJwETEJgagVUfSB5vRyFyeckGELc7/OcvC2qU53/vJ7t8EvLAp8dYQniUv1zR4+i u1ClaUhIEJLrGiyV2xY8mDNZ33/KKmkv/gOHNxEkm6Mmp5HdJJgMdfR4YS4W5Y/sXD Wu5iqfEw9+kCzBFJv9e4nPHbvAtdOOAt3AFwFX1HzNcKehcqpGd5QGSz8b500umjZi NglARfIAk1Wycf8XPUdWLJ34fXWJIQ31vZsW7DNqAJl2fuygzDoRzQSrW8/OjWrudp 0nKEhAU1WZi7w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Liu Zixian , Gerd Hoffmann , Sasha Levin , airlied@linux.ie, daniel@ffwll.ch, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Subject: [PATCH AUTOSEL 4.19 01/38] drm/virtio: fix NULL pointer dereference in virtio_gpu_conn_get_modes Date: Mon, 30 May 2022 09:48:47 -0400 Message-Id: <20220530134924.1936816-1-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liu Zixian [ Upstream commit 194d250cdc4a40ccbd179afd522a9e9846957402 ] drm_cvt_mode may return NULL and we should check it. This bug is found by syzkaller: FAULT_INJECTION stacktrace: [ 168.567394] FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 [ 168.567403] CPU: 1 PID: 6425 Comm: syz Kdump: loaded Not tainted 4.19.90-vhulk2201.1.0.h1035.kasan.eulerosv2r10.aarch64 #1 [ 168.567406] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 168.567408] Call trace: [ 168.567414] dump_backtrace+0x0/0x310 [ 168.567418] show_stack+0x28/0x38 [ 168.567423] dump_stack+0xec/0x15c [ 168.567427] should_fail+0x3ac/0x3d0 [ 168.567437] __should_failslab+0xb8/0x120 [ 168.567441] should_failslab+0x28/0xc0 [ 168.567445] kmem_cache_alloc_trace+0x50/0x640 [ 168.567454] drm_mode_create+0x40/0x90 [ 168.567458] drm_cvt_mode+0x48/0xc78 [ 168.567477] virtio_gpu_conn_get_modes+0xa8/0x140 [virtio_gpu] [ 168.567485] drm_helper_probe_single_connector_modes+0x3a4/0xd80 [ 168.567492] drm_mode_getconnector+0x2e0/0xa70 [ 168.567496] drm_ioctl_kernel+0x11c/0x1d8 [ 168.567514] drm_ioctl+0x558/0x6d0 [ 168.567522] do_vfs_ioctl+0x160/0xf30 [ 168.567525] ksys_ioctl+0x98/0xd8 [ 168.567530] __arm64_sys_ioctl+0x50/0xc8 [ 168.567536] el0_svc_common+0xc8/0x320 [ 168.567540] el0_svc_handler+0xf8/0x160 [ 168.567544] el0_svc+0x10/0x218 KASAN stacktrace: [ 168.567561] BUG: KASAN: null-ptr-deref in virtio_gpu_conn_get_modes+0xb4/0x140 [virtio_gpu] [ 168.567565] Read of size 4 at addr 0000000000000054 by task syz/6425 [ 168.567566] [ 168.567571] CPU: 1 PID: 6425 Comm: syz Kdump: loaded Not tainted 4.19.90-vhulk2201.1.0.h1035.kasan.eulerosv2r10.aarch64 #1 [ 168.567573] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 168.567575] Call trace: [ 168.567578] dump_backtrace+0x0/0x310 [ 168.567582] show_stack+0x28/0x38 [ 168.567586] dump_stack+0xec/0x15c [ 168.567591] kasan_report+0x244/0x2f0 [ 168.567594] __asan_load4+0x58/0xb0 [ 168.567607] virtio_gpu_conn_get_modes+0xb4/0x140 [virtio_gpu] [ 168.567612] drm_helper_probe_single_connector_modes+0x3a4/0xd80 [ 168.567617] drm_mode_getconnector+0x2e0/0xa70 [ 168.567621] drm_ioctl_kernel+0x11c/0x1d8 [ 168.567624] drm_ioctl+0x558/0x6d0 [ 168.567628] do_vfs_ioctl+0x160/0xf30 [ 168.567632] ksys_ioctl+0x98/0xd8 [ 168.567636] __arm64_sys_ioctl+0x50/0xc8 [ 168.567641] el0_svc_common+0xc8/0x320 [ 168.567645] el0_svc_handler+0xf8/0x160 [ 168.567649] el0_svc+0x10/0x218 Signed-off-by: Liu Zixian Link: http://patchwork.freedesktop.org/patch/msgid/20220322091730.1653-1-liuzixian4@huawei.com Signed-off-by: Gerd Hoffmann Signed-off-by: Sasha Levin --- drivers/gpu/drm/virtio/virtgpu_display.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c index 25503b933599..7511f416eb67 100644 --- a/drivers/gpu/drm/virtio/virtgpu_display.c +++ b/drivers/gpu/drm/virtio/virtgpu_display.c @@ -180,6 +180,8 @@ static int virtio_gpu_conn_get_modes(struct drm_connector *connector) DRM_DEBUG("add mode: %dx%d\n", width, height); mode = drm_cvt_mode(connector->dev, width, height, 60, false, false, false); + if (!mode) + return count; mode->type |= DRM_MODE_TYPE_PREFERRED; drm_mode_probed_add(connector, mode); count++; -- 2.35.1