From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f48.google.com (mail-wm1-f48.google.com [209.85.128.48]) (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 76EC12E5B29 for ; Sun, 28 Jun 2026 09:37:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782639468; cv=none; b=h1Uz9Dy4ZXmYHdPHXIubGvbZfeh29g5RgNCevQQ77wyfXZqWam7WYHTZ/4SCwMTTcpDguhbzawmues4WOuyL+YBX+Ges+16/P2Kv/aQAVhWq3RA0H0vTMp8CD2v0/3z2rvSvYUmFiTBO/avubdqJr7tMruJTYZVHfXfBbyP0fRc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782639468; c=relaxed/simple; bh=KUxc5s+Ozy/mh8LcygImhFbcgR+t8ibAmyTyILx/d9Q=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Wt8DVm35HKZUg9wzgJ/zc0OVYnhym9HwZYZQ/u58joEh9N9/jiOqeApYb8d4E5QZPaYiLmWDY6OXeAAe4c1aQYqllJoyYevnvAHGnoxwtk3juE6hdnSbXpTpMYTiDQYmn7IQyd9weR0dBf8M4ZqMCCWYg8lphaCrmyZs5mkDPaI= 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=lX4F6utV; arc=none smtp.client-ip=209.85.128.48 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="lX4F6utV" Received: by mail-wm1-f48.google.com with SMTP id 5b1f17b1804b1-4938d60c035so7857335e9.0 for ; Sun, 28 Jun 2026 02:37:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1782639466; x=1783244266; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=6FQzT0Pfxjs6kdPKaUfr6F0wexDd7Xo9qWKJhKghTGM=; b=lX4F6utViTkAkMfBZWiugZaSidMyROeH2ORe4flDMRrXPEq03BFE8YqO48noC7ORgJ KS/Djl5Jtzy17C+BWenVMkQwLcEAdm6418RhwTzY9JsmVeMuBOnsDohcHeIA23w3tSBb VvkY2Xr5wY7GYNc32dBJR2JH8rTWWPAFcyxV5SkxAQJ5IS1qvcuUAkAkvU8iIklv9lFG oNIlNlBuFfiuf3Hk0XLfITZwaEc61CZWlV4IlF643fFK3tV+NiMwOiH8f7VZh75NtFFc KDvfnY925GCE7N7wR1+lSRsv68SwpjNL+ltfc273yfoYlHR33HLbDj9MDiNLyt/Dag0s gYJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782639466; x=1783244266; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=6FQzT0Pfxjs6kdPKaUfr6F0wexDd7Xo9qWKJhKghTGM=; b=NUJdQ/K8OlzszHp+d3iTO2Dm68QrPtcuWP+vX3UC9Ec6tZpSH4J2gwdQfWZsXdwVA+ ztK3X7Ow+Oj2BWKbs9oALCwrhYf8vaxfGt2xrNzldtLWkOne4hK6xFAN5PVqV4jwYB2C Y6t7dNBhqc7nrF6AOj7nwMcMSL2+tTvT9HHXW48Z5VFa/8Io4jST/WMoltkbeH2I2Jzh 14HblSxhUZfDTvVc9JNhYB4wni4orpTE0PjqqcuA3zlLiJR3gXkE1gPd6IPWoy3XIqJb Sbo7LYzCJbW6ntifjcGCaCt1SZP/28kQdO3/P5oDzrLzzL6uNdzEH68IgdbKwRyBon0e glYQ== X-Forwarded-Encrypted: i=1; AFNElJ9mLlZTrV2PXaiRawaJbR9cZAp3jv8uILzWb8/G+pilezR0a0js8uDqVIYEdaPH7kMTYUTr9xFtRkZpWA==@vger.kernel.org X-Gm-Message-State: AOJu0YxEeMb10Msu2eX0BmK4cZRX+4lUh6AhDrU+YzLdGOZXBY2cmqR6 4V7ysLONw3BlSFRhZlAD+hON3kACAeRQ3POc+lH6/SNibulH6tSjmkm2 X-Gm-Gg: AfdE7cnbtHRWI2pu6JijEgP3VRj6/SLbNtWWdLoguU/nI9z7BFjk+YDtm/N6tVp+Ltd ZHNegisTv96ibN7qU6h8In7GIuO/RfUNShY0gv6OV4TyQh8miI+5kGeGKSwlZVT5F6DfxhGbS56 q79I/ReNGzPHXl/Ac1VeADX/3AnL08orOkAotqzJPrJKep8xF3qo18YUuLM3T23LIV+m3DvK0Xn u80GGpACaUh0mRKudzu/TZf4zMPBnZvUA3PQVPxgo8vZbDb/3cLWjfZUEBKG16Evwz6T65gdZPa ETRLkZlnROAdJ9bvxPNvdaKVhnyid5+rYBvgUamY0E5WrenrWHq9LTHcj5Ydl9b3gWnl67i+M0y L90DeQtNbIpJqqG0YFq7RvAZwmjY+fb0y7gRtvYwcMhK9UzTebvNn8JAUdWDeEbrvbyf84Mg14I VBo6XTcSy0yz+Ko3ep8oMFgFaFzg== X-Received: by 2002:a05:600c:1c17:b0:492:7019:caca with SMTP id 5b1f17b1804b1-4927019cb17mr131689195e9.26.1782639465516; Sun, 28 Jun 2026 02:37:45 -0700 (PDT) Received: from Dev-Null-MSI ([2a0d:3344:52ac:a808:98a4:4381:be45:536f]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-492690988e0sm246657585e9.14.2026.06.28.02.37.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Jun 2026 02:37:45 -0700 (PDT) From: Yousef Alhouseen To: Rishi Gupta , Jiri Kosina , Benjamin Tissoires Cc: linux-i2c@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+1018672fe70298606e5f@syzkaller.appspotmail.com, Yousef Alhouseen Subject: [PATCH] HID: mcp2221: reject short input reports Date: Sun, 28 Jun 2026 11:36:58 +0200 Message-ID: <20260628093658.43445-1-alhouseenyousef@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The MCP2221 raw-event callback reads fixed offsets from the 64-byte input report, including data[50] and a variable payload beginning at data[4]. Raw-event callbacks run before HID core extends short reports to their declared size, so a malformed USB device can make these accesses run past the received buffer. Reject reports whose size does not match the protocol and complete the pending command with -EMSGSIZE so its caller does not wait for a timeout. Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Reported-by: syzbot+1018672fe70298606e5f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=1018672fe70298606e5f Cc: stable@vger.kernel.org Signed-off-by: Yousef Alhouseen --- drivers/hid/hid-mcp2221.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index e4ddd8e9293b..311b51c17b4e 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -861,6 +861,12 @@ static int mcp2221_raw_event(struct hid_device *hdev, u8 *buf; struct mcp2221 *mcp = hid_get_drvdata(hdev); + if (size != sizeof(mcp->txbuf)) { + mcp->status = -EMSGSIZE; + complete(&mcp->wait_in_report); + return 1; + } + switch (data[0]) { case MCP2221_I2C_WR_DATA: -- 2.54.0