From patchwork Mon Jan 24 18:39:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 536026 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 A764AC433FE for ; Mon, 24 Jan 2022 19:53:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344417AbiAXTxp (ORCPT ); Mon, 24 Jan 2022 14:53:45 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:47408 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350884AbiAXTud (ORCPT ); Mon, 24 Jan 2022 14:50:33 -0500 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 D563660B43; Mon, 24 Jan 2022 19:50:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A6D9C340E5; Mon, 24 Jan 2022 19:50:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643053830; bh=02qCKii77kOqjfN+HoEomacGxd5qMKcREHO1H1Kj6rU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lDF+wsI9vd8kd/qcU4Wm/GCMcnNEHe0RmR+eo0F8Dp58SKneoPcVmiAE35hkWJspx OtFvdg6ERWlz1OT99DmeepVHhQr7rNoWlqEpu7tSEOrvSbx2gkj57ucjxDKBJ9FNLn YMepiXtiYpHCqtQHoENVxsRPLsHrNjEHv6hty1S8= 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 5.10 191/563] backlight: qcom-wled: Fix off-by-one maximum with default num_strings Date: Mon, 24 Jan 2022 19:39:16 +0100 Message-Id: <20220124184031.029770158@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184024.407936072@linuxfoundation.org> References: <20220124184024.407936072@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 92df5a9f6ae51..9e09165984b48 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; }