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 6DE79C61DA4 for ; Mon, 30 Jan 2023 14:10:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235531AbjA3OKk (ORCPT ); Mon, 30 Jan 2023 09:10:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237204AbjA3OK3 (ORCPT ); Mon, 30 Jan 2023 09:10:29 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8EE273C292 for ; Mon, 30 Jan 2023 06:10:12 -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 4003BB8117E for ; Mon, 30 Jan 2023 14:10:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91C69C433EF; Mon, 30 Jan 2023 14:10:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675087809; bh=JWV/LZ4M/HhUsHtYVWN7lXThWaXbYb+kb5ffyuLctmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L9Dbupe/RFVuRdTmNO4K+Km2DztYAowfouTM/o4WW+SoKah0q1mN9ofvNDnqmOKYW oyicT1nuyjxwWzLkhrn3VDSmsIE8CbEVTnU7OEKQS9D1csxJzHj55rwF5lA2Hsd9Sk xJALQX3G6IbdN8D+Ns62cmaJrwZAWijtIt8fYKo4= 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 5.15 018/204] firmware: arm_scmi: Harden shared memory access in fetch_notification Date: Mon, 30 Jan 2023 14:49:43 +0100 Message-Id: <20230130134317.091667812@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 9bae076cd4e3e3c3dc185cae829d80b2dddec86e ] A misbheaving SCMI platform firmware could reply with out-of-spec notifications, shorter than the mimimum size comprising a header. Fixes: d5141f37c42e ("firmware: arm_scmi: Add notifications support in transport layer") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221222183823.518856-4-cristian.marussi@arm.com Signed-off-by: Sudeep Holla Signed-off-by: Sasha Levin --- drivers/firmware/arm_scmi/shmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index 415ef7df8fc3..56a1f61aa3ff 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -71,8 +71,10 @@ void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem, size_t max_len, struct scmi_xfer *xfer) { + size_t len = ioread32(&shmem->length); + /* Skip only the length of header in shmem area i.e 4 bytes */ - xfer->rx.len = min_t(size_t, max_len, ioread32(&shmem->length) - 4); + xfer->rx.len = min_t(size_t, max_len, len > 4 ? len - 4 : 0); /* Take a copy to the rx buffer.. */ memcpy_fromio(xfer->rx.buf, shmem->msg_payload, xfer->rx.len); -- 2.39.0