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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 2C8C8C43215 for ; Fri, 22 Nov 2019 11:22:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEBBC2072D for ; Fri, 22 Nov 2019 11:22:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574421772; bh=ekjUL9iEKKF0msi9brH469zdJuKPgU6PU/D6LgKa3SA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=r9xPZYUq6QNRKxf+FAEZ0/z2K5a9l5LQs8pIIR8aBB1U4tblS82o5YbbgB17sP5GG eBdToXeJOEVyFHnnzton+mURnhe452jk/fSVe/WVo9K3z2BRAWKOw5pj3ZlrELaAi4 0Uag7rHPNH4UtHn2hvOqFctGxWukRXcn9mrajlFI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729126AbfKVKme (ORCPT ); Fri, 22 Nov 2019 05:42:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:47694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728151AbfKVKmb (ORCPT ); Fri, 22 Nov 2019 05:42:31 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2A03F20637; Fri, 22 Nov 2019 10:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574419350; bh=ekjUL9iEKKF0msi9brH469zdJuKPgU6PU/D6LgKa3SA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fjQIKV+O7GvJCFdPaccEDyRwvp1Qnpl8kYXpD6nJ+Ubz22lK6D/ixTtMiRKW0fBG5 1WTqwdvSzHfTvC7ROdIIZjKt6Q6m+2eBR1GMC15cXSVafrpOR1bMZCdAVVNvDD9/Gd duZt9rRQsN3AShVC52tTENQMSPAuol/hLjmfKi80= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Breno Leitao , Michael Ellerman , Sasha Levin Subject: [PATCH 4.9 083/222] powerpc/iommu: Avoid derefence before pointer check Date: Fri, 22 Nov 2019 11:27:03 +0100 Message-Id: <20191122100909.462170357@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191122100830.874290814@linuxfoundation.org> References: <20191122100830.874290814@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Breno Leitao [ Upstream commit 984ecdd68de0fa1f63ce205d6c19ef5a7bc67b40 ] The tbl pointer is being derefenced by IOMMU_PAGE_SIZE prior the check if it is not NULL. Just moving the dereference code to after the check, where there will be guarantee that 'tbl' will not be NULL. Signed-off-by: Breno Leitao Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- arch/powerpc/kernel/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 5f202a566ec5f..9bfdd2510fd5e 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -765,9 +765,9 @@ dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl, vaddr = page_address(page) + offset; uaddr = (unsigned long)vaddr; - npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl)); if (tbl) { + npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl)); align = 0; if (tbl->it_page_shift < PAGE_SHIFT && size >= PAGE_SIZE && ((unsigned long)vaddr & ~PAGE_MASK) == 0) -- 2.20.1