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 6AC42C54EAA for ; Mon, 30 Jan 2023 14:10:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237235AbjA3OKh (ORCPT ); Mon, 30 Jan 2023 09:10:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237247AbjA3OK1 (ORCPT ); Mon, 30 Jan 2023 09:10:27 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8EFC3C285 for ; Mon, 30 Jan 2023 06:10:09 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 5D1C8B811C7 for ; Mon, 30 Jan 2023 14:10:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0075C433D2; Mon, 30 Jan 2023 14:10:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675087807; bh=oe1vOrC3J2wIMZvCNfvW0PTVXGscd+F91npwP/L0YFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XLVN45GOQqiQBmj7gme8jM01+IkAjn1UdGTCZDWli4ihi5HCI0tA+W0O3B8+LxdGl uJOysoCdW8LQQiRp5xzojGj5uJKb/HhlvDOWERoJ49449GdOABbRsYBson8acp0Jrk C6RnnMOlNSlpM+47RxdSjszg4uEnqr7JsBRpYeMk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cristian Marussi , Sudeep Holla , Sasha Levin Subject: [PATCH 5.15 017/204] firmware: arm_scmi: Harden shared memory access in fetch_response Date: Mon, 30 Jan 2023 14:49:42 +0100 Message-Id: <20230130134317.050136616@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134316.327556078@linuxfoundation.org> References: <20230130134316.327556078@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Cristian Marussi [ Upstream commit ad78b81a1077f7d956952cd8bdfe1e61504e3eb8 ] A misbheaving SCMI platform firmware could reply with out-of-spec messages, shorter than the mimimum size comprising a header and a status field. Harden shmem_fetch_response to properly truncate such a bad messages. Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221222183823.518856-3-cristian.marussi@arm.com Signed-off-by: Sudeep Holla Signed-off-by: Sasha Levin --- drivers/firmware/arm_scmi/shmem.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index 0e3eaea5d852..415ef7df8fc3 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -58,10 +58,11 @@ u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem) void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, struct scmi_xfer *xfer) { + size_t len = ioread32(&shmem->length); + xfer->hdr.status = ioread32(shmem->msg_payload); /* Skip the length of header and status in shmem area i.e 8 bytes */ - xfer->rx.len = min_t(size_t, xfer->rx.len, - ioread32(&shmem->length) - 8); + xfer->rx.len = min_t(size_t, xfer->rx.len, len > 8 ? len - 8 : 0); /* Take a copy to the rx buffer.. */ memcpy_fromio(xfer->rx.buf, shmem->msg_payload + 4, xfer->rx.len); -- 2.39.0