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 6B28FC43217 for ; Mon, 24 Jan 2022 22:31:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344638AbiAXWan (ORCPT ); Mon, 24 Jan 2022 17:30:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1456471AbiAXVjV (ORCPT ); Mon, 24 Jan 2022 16:39:21 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 91C9BC034008; Mon, 24 Jan 2022 12:24:20 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 31A8B6090A; Mon, 24 Jan 2022 20:24:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E93A3C340E7; Mon, 24 Jan 2022 20:24:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643055859; bh=aoIkoXL+IbHeCwVZEZ3+5rPr3k+SkHRQnWmKrVQ5fs4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LAmi5WSmIFMmpUvl0hitK6M4+oluQufY6EL96im2wBpWsIPCfJCDMbqov3jFF8Zmk RK/E9/5sTU6xdcsJbmsOJIFLEwY81q4C2iY4j1xeLpqwM4fDKDnO8ripwrVLAvVLsS 8K6PVVT3pd1uxLmu3z34SnnA9QOmGu12UHDwzPzM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marijn Suijten , AngeloGioacchino Del Regno , Daniel Thompson , Lee Jones , Sasha Levin Subject: [PATCH 5.15 288/846] backlight: qcom-wled: Fix off-by-one maximum with default num_strings Date: Mon, 24 Jan 2022 19:36:45 +0100 Message-Id: <20220124184110.867517566@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marijn Suijten [ Upstream commit 5ada78b26f935f8751852dffa24f6b545b1d2517 ] 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 parsing the property separately much like qcom,enabled-strings. This also enables more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT, by parsing num-strings after enabled-strings to allow it to check against (and in a subsequent patch override) the length of enabled-strings: it is invalid to set num-strings higher than that. The DT currently utilizes it to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch) by setting a lower num-strings where desired. Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten Reviewed-By: AngeloGioacchino Del Regno Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20211115203459.1634079-5-marijn.suijten@somainline.org Signed-off-by: Sasha Levin --- drivers/video/backlight/qcom-wled.c | 48 ++++++++++------------------- 1 file changed, 16 insertions(+), 32 deletions(-) diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index d413b913fef32..dbcbeda655192 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1256,21 +1256,6 @@ static const struct wled_var_cfg wled5_ovp_cfg = { .size = 16, }; -static u32 wled3_num_strings_values_fn(u32 idx) -{ - return idx + 1; -} - -static const struct wled_var_cfg wled3_num_strings_cfg = { - .fn = wled3_num_strings_values_fn, - .size = 3, -}; - -static const struct wled_var_cfg wled4_num_strings_cfg = { - .fn = wled3_num_strings_values_fn, - .size = 4, -}; - static u32 wled3_switch_freq_values_fn(u32 idx) { return 19200 / (2 * (1 + idx)); @@ -1344,11 +1329,6 @@ static int wled_configure(struct wled *wled) .val_ptr = &cfg->switch_freq, .cfg = &wled3_switch_freq_cfg, }, - { - .name = "qcom,num-strings", - .val_ptr = &cfg->num_strings, - .cfg = &wled3_num_strings_cfg, - }, }; const struct wled_u32_opts wled4_opts[] = { @@ -1372,11 +1352,6 @@ static int wled_configure(struct wled *wled) .val_ptr = &cfg->switch_freq, .cfg = &wled3_switch_freq_cfg, }, - { - .name = "qcom,num-strings", - .val_ptr = &cfg->num_strings, - .cfg = &wled4_num_strings_cfg, - }, }; const struct wled_u32_opts wled5_opts[] = { @@ -1400,11 +1375,6 @@ static int wled_configure(struct wled *wled) .val_ptr = &cfg->switch_freq, .cfg = &wled3_switch_freq_cfg, }, - { - .name = "qcom,num-strings", - .val_ptr = &cfg->num_strings, - .cfg = &wled4_num_strings_cfg, - }, { .name = "qcom,modulator-sel", .val_ptr = &cfg->mod_sel, @@ -1523,8 +1493,6 @@ 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)); @@ -1555,6 +1523,22 @@ static int wled_configure(struct wled *wled) } } + rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val); + if (!rc) { + if (val < 1 || val > wled->max_string_count) { + dev_err(dev, "qcom,num-strings must be between 1 and %d\n", + wled->max_string_count); + return -EINVAL; + } + + if (string_len > 0 && val > string_len) { + dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n"); + return -EINVAL; + } + + cfg->num_strings = val; + } + return 0; } -- 2.34.1