From nobody Sat Feb 7 21:24:28 2026 Received: from mail-qt1-f177.google.com (mail-qt1-f177.google.com [209.85.160.177]) (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 E222B42050 for ; Sat, 10 Jan 2026 19:22:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.177 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768072965; cv=none; b=NPBkpOBVFHtNUIqRT9Ov2OgPtORY1kDgeTuNBr/chJ6HzdwPjn5t/R/D8wbwZNn5GNhugCPSMWRk/SAKaujyE5sVIW85nXO7YyUDOHGq32J4Cq5tQ+FCL/+yqO3azpJ/a6KHLRLW+LHOtHCWH9i9XUMmYTJHgPLpkFCuKZBTSzM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768072965; c=relaxed/simple; bh=Yro/EFaDcrJHJUaHkqAFe4SvLolOsKDoHa8f6Ty2G5Q=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=l5fYNrTdqRuT/0daXSroPKx0txL//rAYS38aKwSFdumTBXqt3VqtIenNK5YqygnRaSLtjdCW0FMC7VyX1sGC68C9B0GZZ9hCfqSe+SXTJexk7pvjoX44kLoVWtf7rFC/y4ZRqyo+5B7nwsjPGFvL96IHkNcEurbn9Q7xEAbE/3U= 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=iDHreQ5Z; arc=none smtp.client-ip=209.85.160.177 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="iDHreQ5Z" Received: by mail-qt1-f177.google.com with SMTP id d75a77b69052e-4ffc0ddefc4so46738081cf.3 for ; Sat, 10 Jan 2026 11:22:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1768072963; x=1768677763; 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=n2qOKSN2/LKplz5xDT7OJ6TqAkcGsvuYaO3IpAITyX8=; b=iDHreQ5Z92ecI5m6oELO7DpXU+SUwGmuPzPt+qJXE0hn1d/69YZ1k+uURhfFRdXnks Kt7/NV76UCc7fmQUx4XuNB/UH66Sn1QaLKvl/DUHisnsI5HYBSKnxA0wT7tvhv32FYZi Ze/eNG90bsXu7/cBcRFgpXVTaEzVJQKzaFvHZ42vtlpdh0Bg7O6ib4+A+2y526L7EB62 su8Q8910rhyOFF2fnvCJfU6AcbL1H6xofXGiRhsMoPFcDQoJmcWX+eFleFJ6X5L17DJp Wbil135kkxJCatQbKOYzfbzUruiPnDOB2uTd0to9V2Gr45j/LLNSNoSjiJ/31Pwko/GE usiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768072963; x=1768677763; 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=n2qOKSN2/LKplz5xDT7OJ6TqAkcGsvuYaO3IpAITyX8=; b=k/0enYtFujOZOJPV9zgHNPiu9UywpbNIgT+DVVIR+wmOrA+dYTjeaGgdrBD9nO1dXm NN8HNLRwdXha35lKMuwy48phRzOiivVjuE0UPXjx26O6RJ8QxXqFmnx5ToT0ETC213CQ b9dR7XU8sSg2Lsn5BxY1rfL25utQcHQjrZUy26Et0bmkAnmrxrpk63jeHg6l4xkWgBEz iRRGSAyq2TTwbk6xdmVTg5xrU8M0o0Mx5TkshUZP/zmgEpOEFnmoBVf2NbI5jZI0UbUj rnRCOoi57IjOwd6Qcnf5uhpwZJj4OflbOZVyKjUb0ik9skyMeW2N5MAsWpFNckvDiRKi W0SQ== X-Forwarded-Encrypted: i=1; AJvYcCUGirntD6Dfra9oXefNQrzkH4b0+NoGOtFL5XalOsV2g3i6+I8wGh0P850T6m4+WqSlvJTZmF6dxL0W8VU=@vger.kernel.org X-Gm-Message-State: AOJu0Yzshn1EZDwXAuFEHrkPocmpYF3mZ/O9YG78pzX5V/iDcPIvg+hi +umLSH5Kd374hak8cIYm2tVIqy1KB2X5HpoVhWlPS1cGJXqjUMG8o9gX X-Gm-Gg: AY/fxX5x+UwBWNppcITjSmEpoL0BOPtRVE8op6PrI9yXCn0e6V5fd5Ps/XmYa/SlSf3 84pgI9t9jGYUpvhdZo5RrKIc3cTnRwi6C3rXYs8fe+XVMFiToW/ZHlSxELZ7uicHLz6ecU7RfpB B12IyCjFuEVrnqk4jf4m9+gUl91rB7d5RA60lvloDBxWtMpCoMV7JURPMRsZjQXYlX6yWNh0svj AE2bWTjm6VhZg3gzide8AEceswJqIz2tqOAaVBOk3GMopCGOlMi8adcv1Gz3qVyJtd6pe9EMG2s TFU1opOTsZpT8rKLBh6d9uAmrIscsjoGgQjfRWDroAzhMCUEMTvQgEwHkKZbAGDgBW/pMQqDx+5 dEGprXSFRXP3A6Nvvp+IjhaPaV1Kgx2aCZwggCjXSrn39Jb8wxOvCJ5U0am1uYJeqfJAoIfkyMP z4H8TnWw5xyvULswg8ntIKD6mWqNEzd9ks0LXSUR/FVt4iOCCPvRtxJPOZuDNaoZh512QVE402h 2lTmIc+J7guCqJoFIy5zUNPhp1Br3CIsY93iOQeNbU= X-Google-Smtp-Source: AGHT+IFtvlg+AGl8bD3EOoMS9DmbAkw1cVPMjy8S5I7lwgoYs9TBiwZ8k/bKK9L7O0+LPRsBvl6T2Q== X-Received: by 2002:a05:622a:c7:b0:4e8:93a1:7464 with SMTP id d75a77b69052e-4ffb47f0f1cmr162748961cf.15.1768072962892; Sat, 10 Jan 2026 11:22:42 -0800 (PST) Received: from seungjin-HP-ENVY-Desktop-TE02-0xxx.dartmouth.edu ([129.170.197.124]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4ffa8e6257esm92419021cf.31.2026.01.10.11.22.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 10 Jan 2026 11:22:41 -0800 (PST) From: pip-izony To: Greg Kroah-Hartman , Ingo Molnar , Thomas Gleixner Cc: Seungjin Bae , Kyungtae Kim , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] usb: r8a66597-hcd: fix potential divide-by-zero in prepare_packet_read() Date: Sat, 10 Jan 2026 14:22:33 -0500 Message-ID: <20260110192233.31955-1-eeodqql09@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Seungjin Bae The `prepare_packet_read()` function calculates the number of packets required for a transfer by dividing the transfer buffer length by the maximum packet size (`td->maxpacket`). The `td->maxpacket` is initialized in `r8a66597_make_td()` function based on the endpoint descriptor. However, it does not validate whether `td->maxpacket` is zero before using it in the `DIV_ROUND_UP` macro. If a malicious USB device sends a descriptor with `wMaxPacketSize` set to 0, it triggers a divide-by-zero exception (kernel panic). Fix this by ensuring `td->maxpacket` is greater than 0 before performing the division. Fixes: 5d3043586db4 ("USB: r8a66597-hcd: host controller driver for R8A6659= 7") Signed-off-by: Seungjin Bae --- drivers/usb/host/r8a66597-hcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/r8a66597-hcd.c b/drivers/usb/host/r8a66597-hc= d.c index d21a03cf5c17..445551b4b05f 100644 --- a/drivers/usb/host/r8a66597-hcd.c +++ b/drivers/usb/host/r8a66597-hcd.c @@ -1097,7 +1097,7 @@ static void prepare_packet_read(struct r8a66597 *r8a6= 6597, pipe_start(r8a66597, td->pipe); pipe_irq_enable(r8a66597, urb, td->pipenum); } else { - if (urb->actual_length =3D=3D 0) { + if (urb->actual_length =3D=3D 0 && td->maxpacket > 0) { pipe_irq_disable(r8a66597, td->pipenum); pipe_setting(r8a66597, td); pipe_stop(r8a66597, td->pipe); --=20 2.43.0