From patchwork Mon Oct 4 19:27:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marijn Suijten X-Patchwork-Id: 12534617 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A94AEC4167B for ; Mon, 4 Oct 2021 19:27:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9041161354 for ; Mon, 4 Oct 2021 19:27:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239063AbhJDT3p (ORCPT ); Mon, 4 Oct 2021 15:29:45 -0400 Received: from relay01.th.seeweb.it ([5.144.164.162]:51377 "EHLO relay01.th.seeweb.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238932AbhJDT3i (ORCPT ); Mon, 4 Oct 2021 15:29:38 -0400 Received: from Marijn-Arch-PC.localdomain (94-209-165-62.cable.dynamic.v4.ziggo.nl [94.209.165.62]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by m-r1.th.seeweb.it (Postfix) with ESMTPSA id 85F901F6A2; Mon, 4 Oct 2021 21:27:47 +0200 (CEST) From: Marijn Suijten To: phone-devel@vger.kernel.org, Andy Gross , Bjorn Andersson , Lee Jones , Daniel Thompson , Jingoo Han Cc: ~postmarketos/upstreaming@lists.sr.ht, AngeloGioacchino Del Regno , Konrad Dybcio , Martin Botka , Jami Kettunen , Pavel Dubrova , Marijn Suijten , Kiran Gunda , Courtney Cavin , Bryan Wu , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 05/10] backlight: qcom-wled: Fix off-by-one maximum with default num_strings Date: Mon, 4 Oct 2021 21:27:36 +0200 Message-Id: <20211004192741.621870-6-marijn.suijten@somainline.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004192741.621870-1-marijn.suijten@somainline.org> References: <20211004192741.621870-1-marijn.suijten@somainline.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org When not specifying num-strings in the DT the default is used, but +1 is added to it which turns wled3 into 4 and wled4/5 into 5 strings instead of 3 and 4 respectively, causing out of bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by allowing one extra iteration of the wled_var_cfg function parsing this particular property. Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten Reviewed-by: AngeloGioacchino Del Regno --- drivers/video/backlight/qcom-wled.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 27e8949c7922..66ce77ee3099 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1255,17 +1255,17 @@ static const struct wled_var_cfg wled5_ovp_cfg = { static u32 wled3_num_strings_values_fn(u32 idx) { - return idx + 1; + return idx; } static const struct wled_var_cfg wled3_num_strings_cfg = { .fn = wled3_num_strings_values_fn, - .size = 3, + .size = 4, /* [0, 3] */ }; static const struct wled_var_cfg wled4_num_strings_cfg = { .fn = wled3_num_strings_values_fn, - .size = 4, + .size = 5, /* [0, 4] */ }; static u32 wled3_switch_freq_values_fn(u32 idx) @@ -1520,8 +1520,6 @@ static int wled_configure(struct wled *wled) *bool_opts[i].val_ptr = true; } - cfg->num_strings = cfg->num_strings + 1; - string_len = of_property_count_elems_of_size(dev->of_node, "qcom,enabled-strings", sizeof(u32));