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=-8.6 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_BLOCKED,USER_AGENT_SANE_1 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 3AE72C742BD for ; Fri, 12 Jul 2019 14:07:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 067CB208E4 for ; Fri, 12 Jul 2019 14:07:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562940475; bh=WI9/V+ZKiQt8N2ZXkmgG410vHGUKy60lwdIntaFOAvM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=sm/eEKoyKaxchJ4Dn8mLM0xYNx3eSW9NeymGarsEFvA8p4YBi2hBwBOfY7p8jWwfa TnI/eQ+NQ/pNW6y+nMBKTawfFtmCkgb9454SdjTOqU3Pmt+qC84XuIzbDHC0RYqUoG lb6UWTpsAIrsVkMtUKbuZiPTnuSFXHOqjLuaB4dw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbfGLOHy (ORCPT ); Fri, 12 Jul 2019 10:07:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:48842 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726266AbfGLOHy (ORCPT ); Fri, 12 Jul 2019 10:07:54 -0400 Received: from localhost (173-25-83-245.client.mchsi.com [173.25.83.245]) (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 CF3AD206B8; Fri, 12 Jul 2019 14:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562940474; bh=WI9/V+ZKiQt8N2ZXkmgG410vHGUKy60lwdIntaFOAvM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TaocqWa1LwZBshmqZLXcMcYGa1EH4XaJ9rHBAhR7BVJQOgIPhYR1uzHx6a9n2gSXM YMHHF/5/LwZuwvr3bem/r0KGFycDEmgMEeNUNU8SBwaUEijIlmO1PrVhHwzlerwfZR JxuzHn4UsVkNUl9Ti/RDV8bPf2Vnb9IymrMNyByA= Date: Fri, 12 Jul 2019 09:07:52 -0500 From: Bjorn Helgaas To: Lucas Stach Cc: Jingoo Han , Gustavo Pimentel , Lorenzo Pieralisi , linux-pci@vger.kernel.org, patchwork-lst@pengutronix.de, kernel@pengutronix.de Subject: Re: [PATCH] PCI: dwc: avoid OOB read in find_next_bit Message-ID: <20190712140752.GE46935@google.com> References: <20190712132611.3374-1-l.stach@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190712132611.3374-1-l.stach@pengutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Fri, Jul 12, 2019 at 03:26:11PM +0200, Lucas Stach wrote: > Find_next_bit works on a long type, which causes a OOB read on the > u32 input when used on ARM64. s/Find_next_bit/find_next_bit()/ so it's obviously a function name and we can directly grep for it (in subject also, and capitalize "Avoid"). Please spell out "OOB"; I *assume* that means "out of bounds"? > Signed-off-by: Lucas Stach > --- > drivers/pci/controller/dwc/pcie-designware-host.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > index 77db32529319..81a2139d68d6 100644 > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > @@ -78,15 +78,16 @@ static struct msi_domain_info dw_pcie_msi_domain_info = { > irqreturn_t dw_handle_msi_irq(struct pcie_port *pp) > { > int i, pos, irq; > - u32 val, num_ctrls; > + u32 num_ctrls; > irqreturn_t ret = IRQ_NONE; > + unsigned long val; > > num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL; > > for (i = 0; i < num_ctrls; i++) { > dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS + > (i * MSI_REG_CTRL_BLOCK_SIZE), > - 4, &val); > + 4, (u32 *)&val); I agree that the "val" we pass to find_next_bit() needs to be an "unsigned long", so I like that part. It's not completely obvious to me that it's safe to cast "val" to "u32 *" here; does that do the right thing regardless of byte order? Doing something like: u32 status; unsigned long val; dw_pcie_rd_own_conf(..., &status); val = status; find_next_bit(&val, ...); would be more obvious to me. > if (!val) > continue; > > -- > 2.20.1 >