From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-vs2-f25.google.com (mail-vs2-f25.google.com [74.125.227.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4531236C0C8 for ; Tue, 15 Sep 2026 04:26:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.25 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789446362; cv=none; b=jz5cwQlLNV9j6sZLzvfIGgVlrjQrBNu2V8fjziBFKH1VXs63EubIhaZvWUMWIwNbAIrFoOwWWH9q7MRUQLkWywxIGAijyHKptnU2Tuf1Es+pDrdqBuEZ+Doah5g/svjwsTeNwTK9pDfdNvMti1XzJkG6BPhREnESE20RVt4Ybf8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789446362; c=relaxed/simple; bh=goGTypsi29JZv923WshNeFTqi7KVaLuvDV7JqWYQbF0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MImn05tvU++6ibL7Ceo2S5l+EuxIqeBX3MerDqbp5IO+QW7z/LWKskkChyJUENt6b1ehRCykQbno8P/rzzPyMPwG+rWU173qem2JGD2PJ1acvY/emOtMSwSB2sQUlHtjl2jgV7cftPjrPJbCdtJ6COvdRXF/hdPO6baHnPao+G8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=UZuuuQPA; arc=none smtp.client-ip=74.125.227.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UZuuuQPA" Received: by mail-vs2-f25.google.com with SMTP id 71dfb90a1353d-5c67e5059fbso800608e0c.3 for ; Mon, 14 Sep 2026 21:26:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789446359; x=1790051159; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=xgksxHZM5YdiC9WvlT9cN3WzyS9QqUuMDDleGgoWHKM=; b=UZuuuQPA6Qlo0gkEqBrOZn0itUkGeSpcCdDculk8DEHH9whyEc+HdMu3XKcK/T/hre 4LRIOKa6XuWhbue/cKrE7engVZDUdpzuoiX3U59+lvuXOLn3CDXFQNfBuPSLcqxMi+2I sn1T6TAZyLU1SFWDJydgeTt3T8LnNQucSyBSfIMA5GyM0ZUwoNbP7MMDmhFUObJ7Msnw tV5XXzMSCLbL40Jumlw+zXTVeoS1MhP6EZyilfwz5E9rmqEQlxWqGyguxKC6p/1Y2DMc KRwfFHO7lP6KyJb6lxmwDom3BwKa6kd6KSVNww+H/JIDVs7YC2iDlCTS3b1N3eHoCF9Q rCLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789446359; x=1790051159; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=xgksxHZM5YdiC9WvlT9cN3WzyS9QqUuMDDleGgoWHKM=; b=nvz9Qn1rTsUVzbXgH/oKB8t+TztgEEBNInJOjNAvrASdKSmgTCXLpKsj0x+CFIBSPg qOreQcMs5yocknZcxdz/XHduKaypujYdm6Pcwj6aM02ktF2Uwof+VIY0qiZJT1adiCEa rT10d/rQ0SK7E5UNRyry4PX6eND2ZVLYpjWwqfycBYlE5pQHNq6XM9aG9ayyPnzNOJWe Ak7HUN22FMLL9Z0w75v0E//vuw0MaOtTpCdPsWCsytRHqLQvD2JZ4IHmfyOr7tZYbb4f nuz8crfqUX0qy7LKS8ifWFBDnGcN7wZGIc1U88DiHeEH8ouOE1YULIG/v9OhhbZBPitw 1aow== X-Forwarded-Encrypted: i=1; AKwUvBwudm0cGM62xxCA8I/Df7/fw3y5lXk6IMg3maHc6tncAoA1jYT8CP1jGiaFvuLPrgGsPSw8EJE23LYK5CA=@vger.kernel.org X-Gm-Message-State: AFuF++lwxAjK+YGgEFwGQA7gaRCU10MHK41f/VTTl/LNe5HhS3m2Eibv pChOz1x/KHbS6G/VTiOfPvllC5PfNC0GZgMImQH7XNRxO09pbcbEufuZ X-Gm-Gg: AYBFou0+9bWTrEtXsoTZ7rPebYkDYoGLMNvRYKMqG2j71t18Nkm3+ofcv5cV8awMWHT bShL3NaSH4Zuf6QKozZPuKoalj1NHf/5ovRfvfkObYacjvP4VqiWw51JNB0wNTjmaCsnSNomLoq bSd67cAiI5hhs49gqKJzQX+4s6yUNnG944cxq6JpNN4e6kPla49KQ9fA3svz8yqGkLzcarQfJsU YEFeXGT9fKDqeKigSMR4h0bOQBHb0xmGacOVVF+pKUw0A9wpNetxKIZ2frFUE4LGQXKsEWoxYux xc3Dw0bjDEq+E6V4ka71sJG9mvPMN7xon9HNWYct/peUj0GYuBOagYngWe4cpu1FUVoWr2yBX2m +gt4wn95AhQFJ8PQCDi1Wj/3Ih7veeqzNMI9sYLZUIJuNcibGokgV7W1Ctc2Bhg9JR5mk6Zu2Qg G3yMKNkS8wQ6uWGoGvrPytI+Glie1asXjK2B2Ds0ysEjaDlk1UTRxp1DZUkLxvHKzz X-Received: by 2002:a05:6122:e266:b0:5bf:a179:b2be with SMTP id 71dfb90a1353d-5c9820e55eamr8036213e0c.7.1789446359087; Mon, 14 Sep 2026 21:25:59 -0700 (PDT) Received: from beelink.. ([187.13.206.89]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-5c8470e7ef4sm14528090e0c.9.2026.09.14.21.25.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2026 21:25:58 -0700 (PDT) From: Aldo Ariel Panzardo To: Jiri Kosina , Benjamin Tissoires Cc: Ping Cheng , Jason Gerecke , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Aldo Ariel Panzardo Subject: [PATCH v2] HID: wacom: validate battery range before scaling Date: Tue, 15 Sep 2026 01:25:46 -0300 Message-ID: <20260915042546.2454238-1-qwe.aldo@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260915041248.2432629-1-qwe.aldo@gmail.com> References: <20260915041248.2432629-1-qwe.aldo@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Battery events divide by the difference between the logical maximum and minimum without validating the range. A malformed HID descriptor with equal limits can therefore trigger a divide-by-zero exception. Move percentage conversion to a helper that widens the arithmetic, rejects non-positive ranges, and accounts for a nonzero logical minimum. Clamp the result to [0, 100] instead of rejecting out-of-range values, so that real hardware whose ADC occasionally reports slightly beyond its declared limits still registers its battery and updates capacity normally. Fixes: 37d160193834 ("HID: wacom: generic: Scale battery capacity measurements to percentages") Cc: stable@vger.kernel.org Signed-off-by: Aldo Ariel Panzardo --- Changes in v2: - Clamp the computed percentage to [0, 100] instead of returning false, so that slightly out-of-range ADC values do not prevent battery registration (WACOM_QUIRK_BATTERY) or silently drop updates. Reported by Sashiko AI review. drivers/hid/wacom_wac.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c index da1f0ea85..XXXXXXX 100644 --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -7,6 +7,7 @@ #include "wacom.h" #include #include +#include /* resolution for penabled devices */ #define WACOM_PL_RES 20 @@ -1937,6 +1938,22 @@ static void wacom_wac_battery_usage_mapping(struct hid_device *hdev, return; } +static __s32 wacom_wac_battery_percentage(struct hid_field *field, __s32 value) +{ + s64 range = (s64)field->logical_maximum - field->logical_minimum; + s64 result; + + if (range <= 0) + return 0; + + result = div64_s64(((s64)value - field->logical_minimum) * 100, + range); + + return clamp_val(result, 0, 100); +} + static void wacom_wac_battery_event(struct hid_device *hdev, struct hid_field *field, struct hid_usage *usage, __s32 value) { @@ -1950,7 +1967,8 @@ static void wacom_wac_battery_event(struct hid_device *hdev, struct hid_field *f wacom_wac->hid_data.bat_status = POWER_SUPPLY_STATUS_UNKNOWN; } else { - value = value * 100 / (field->logical_maximum - field->logical_minimum); + value = wacom_wac_battery_percentage(field, value); wacom_wac->hid_data.battery_capacity = value; wacom_wac->hid_data.bat_connected = 1; wacom_wac->hid_data.bat_status = WACOM_POWER_SUPPLY_STATUS_AUTO; @@ -1958,7 +1976,8 @@ static void wacom_wac_battery_event(struct hid_device *hdev, struct hid_field *f wacom_wac->features.quirks |= WACOM_QUIRK_BATTERY; break; case WACOM_HID_WD_BATTERY_LEVEL: - value = value * 100 / (field->logical_maximum - field->logical_minimum); + value = wacom_wac_battery_percentage(field, value); wacom_wac->hid_data.battery_capacity = value; wacom_wac->hid_data.bat_connected = 1; wacom_wac->hid_data.bat_status = WACOM_POWER_SUPPLY_STATUS_AUTO; -- 2.43.0