From patchwork Mon Nov 15 20:34:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marijn Suijten X-Patchwork-Id: 12620391 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 1C608C433F5 for ; Mon, 15 Nov 2021 20:35:18 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E20E9619E3 for ; Mon, 15 Nov 2021 20:35:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E20E9619E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=somainline.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3FDAD6E44D; Mon, 15 Nov 2021 20:35:15 +0000 (UTC) Received: from relay04.th.seeweb.it (relay04.th.seeweb.it [IPv6:2001:4b7a:2000:18::165]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4335589FC8 for ; Mon, 15 Nov 2021 20:35:11 +0000 (UTC) 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 C7CE8200D2; Mon, 15 Nov 2021 21:35:08 +0100 (CET) From: Marijn Suijten To: phone-devel@vger.kernel.org, Andy Gross , Bjorn Andersson , Rob Herring , Lee Jones , Daniel Thompson , Jingoo Han Subject: [PATCH v3 4/9] backlight: qcom-wled: Fix off-by-one maximum with default num_strings Date: Mon, 15 Nov 2021 21:34:54 +0100 Message-Id: <20211115203459.1634079-5-marijn.suijten@somainline.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115203459.1634079-1-marijn.suijten@somainline.org> References: <20211115203459.1634079-1-marijn.suijten@somainline.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, linux-fbdev@vger.kernel.org, Kiran Gunda , Pavel Dubrova , Courtney Cavin , Jami Kettunen , linux-arm-msm@vger.kernel.org, Bryan Wu , Konrad Dybcio , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Martin Botka , ~postmarketos/upstreaming@lists.sr.ht, AngeloGioacchino Del Regno , Marijn Suijten Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 --- 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 9d883e702134..ab10910971e9 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1255,21 +1255,6 @@ 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)); @@ -1343,11 +1328,6 @@ 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[] = { @@ -1371,11 +1351,6 @@ 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[] = { @@ -1399,11 +1374,6 @@ 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, @@ -1522,8 +1492,6 @@ 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)); @@ -1554,6 +1522,22 @@ 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; }