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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLACK,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 8C55BC3B1A4 for ; Fri, 14 Feb 2020 16:56:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 619F320656 for ; Fri, 14 Feb 2020 16:56:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581699373; bh=1IYZIfU70ec8hHglYytP/Ugx41NvVCmlHGf0FflTfys=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2F57s4DivFeehV9C7AZ5rB5cgBEooQEClXcDG7g8wBDnKDvg+IT89BXDxkoFasv68 UIxf4j4xlgapvMAzfGAuXU47DvQFcVLEC47nmoU71t1T7H444aGRgcivjsSsKbDanr HSYleGclhkCYxSnf3Y1n292EDeOMKfl0AmxLVUdk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388980AbgBNQ4M (ORCPT ); Fri, 14 Feb 2020 11:56:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:49822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404624AbgBNQSF (ORCPT ); Fri, 14 Feb 2020 11:18:05 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 16D58246F9; Fri, 14 Feb 2020 16:18:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581697085; bh=1IYZIfU70ec8hHglYytP/Ugx41NvVCmlHGf0FflTfys=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BRiz0p9mpmTwMr4pBHo/kvoFyw4JzvUQRHpUDtMty/Nwp7N5lHFk1O9LqW6GGhyS5 RVslHIvBYCHgUVxKJ5epUgFozj34YA2V32lE60JsugfdlsqyDYm53B9Sku8D+UqsEX HNJMg42fW2U+6JEHZs47GvNhtHJSAgtn1kFrNMDU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tyrel Datwyler , Tyrel Datwyler , Alexey Kardashevskiy , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.14 038/186] powerpc/pseries/vio: Fix iommu_table use-after-free refcount warning Date: Fri, 14 Feb 2020 11:14:47 -0500 Message-Id: <20200214161715.18113-38-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214161715.18113-1-sashal@kernel.org> References: <20200214161715.18113-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tyrel Datwyler [ Upstream commit aff8c8242bc638ba57247ae1ec5f272ac3ed3b92 ] Commit e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to iommu_table") missed an iommu_table allocation in the pseries vio code. The iommu_table is allocated with kzalloc and as a result the associated kref gets a value of zero. This has the side effect that during a DLPAR remove of the associated virtual IOA the iommu_tce_table_put() triggers a use-after-free underflow warning. Call Trace: [c0000002879e39f0] [c00000000071ecb4] refcount_warn_saturate+0x184/0x190 (unreliable) [c0000002879e3a50] [c0000000000500ac] iommu_tce_table_put+0x9c/0xb0 [c0000002879e3a70] [c0000000000f54e4] vio_dev_release+0x34/0x70 [c0000002879e3aa0] [c00000000087cfa4] device_release+0x54/0xf0 [c0000002879e3b10] [c000000000d64c84] kobject_cleanup+0xa4/0x240 [c0000002879e3b90] [c00000000087d358] put_device+0x28/0x40 [c0000002879e3bb0] [c0000000007a328c] dlpar_remove_slot+0x15c/0x250 [c0000002879e3c50] [c0000000007a348c] remove_slot_store+0xac/0xf0 [c0000002879e3cd0] [c000000000d64220] kobj_attr_store+0x30/0x60 [c0000002879e3cf0] [c0000000004ff13c] sysfs_kf_write+0x6c/0xa0 [c0000002879e3d10] [c0000000004fde4c] kernfs_fop_write+0x18c/0x260 [c0000002879e3d60] [c000000000410f3c] __vfs_write+0x3c/0x70 [c0000002879e3d80] [c000000000415408] vfs_write+0xc8/0x250 [c0000002879e3dd0] [c0000000004157dc] ksys_write+0x7c/0x120 [c0000002879e3e20] [c00000000000b278] system_call+0x5c/0x68 Further, since the refcount was always zero the iommu_tce_table_put() fails to call the iommu_table release function resulting in a leak. Fix this issue be initilizing the iommu_table kref immediately after allocation. Fixes: e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to iommu_table") Signed-off-by: Tyrel Datwyler Reviewed-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1579558202-26052-1-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/platforms/pseries/vio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c index d86938260a867..fc778865a4124 100644 --- a/arch/powerpc/platforms/pseries/vio.c +++ b/arch/powerpc/platforms/pseries/vio.c @@ -1195,6 +1195,8 @@ static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev) if (tbl == NULL) return NULL; + kref_init(&tbl->it_kref); + of_parse_dma_window(dev->dev.of_node, dma_window, &tbl->it_index, &offset, &size); -- 2.20.1