From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 06CF14A1393; Wed, 13 May 2026 15:52:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778687571; cv=none; b=OLf/RsvA+U+mC2I6NqSqRb2ynGJ+4tp/v0ng1HObQ7b3s3al/X6JXirPx7/HG7Fs6HN8v9bfNcGZlZ+zOVON0ZbrtMaRr+fXldOk4p/w4f/V209oVxA0l/3XJApDYEK3lAMGS0tB+AOyFi7drBSlf68SGa+zGYA+qmaGBxdBLh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778687571; c=relaxed/simple; bh=TQGYx9tV/qbPtt5vfAgvV49UdYNB0mdmVEcUsQhaHKs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IGHo8xBAtdn6XISb3AO/8A5OxFKwdeovYyl476LuSB+1m6OFSmuQx9EjaypiqdFsWXm6XAL5HjBRgPWDkupfIZDxK7/YwOsKTgdfzOuj35vH1H3h0QIkVdCn0hQoLvMWv69Q9ld3JFVwqOb9+GwlNavZwAHSOib88JDNn17/XRg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jcaJoWBL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jcaJoWBL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60664C2BCC6; Wed, 13 May 2026 15:52:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778687570; bh=TQGYx9tV/qbPtt5vfAgvV49UdYNB0mdmVEcUsQhaHKs=; h=From:To:Cc:Subject:Date:From; b=jcaJoWBLLJqft4XHdVa0btLbuhFk696Bvx60y6iCSpz9c12tQnIBXP3v/AmDzST3x 3IkcxxeIkaA3GDvv3qi8AkEGpUIlJg7A1g4To744paoGp0gnbCPMWXLg9E2i+MKLQg UFY5pq1BH4mMi37tdg2wuOTnTcE3V8drJiJrxUuU= From: Greg Kroah-Hartman To: linux-usb@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Heikki Krogerus , stable Subject: [PATCH 1/8] usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer() Date: Wed, 13 May 2026 17:52:48 +0200 Message-ID: <2026051347-clustered-deflected-9543@gregkh> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2858; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=TQGYx9tV/qbPtt5vfAgvV49UdYNB0mdmVEcUsQhaHKs=; b=owGbwMvMwCRo6H6F97bub03G02pJDFks8wI2FcwpktC26Ob23uZQF/dP5+9lzvevrW3c7P2MW jcvcDncEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABPRMGGYK7hQPtv66SKzqQab PZt/v5mjpviig2F+nu3RfY+0xcx0P+U997XW2yBf+PgbAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit wcove_read_rx_buffer() copies the PD RX FIFO into the caller's struct pd_message with for (i = 0; i < USBC_RXINFO_RXBYTES(info); i++) regmap_read(wcove->regmap, USBC_RX_DATA + i, msg + i); which has two problems: USBC_RXINFO_RXBYTES() is a 5-bit field (max 31) while struct pd_message is 30 bytes (__le16 header + __le32 payload[PD_MAX_PAYLOAD], packed). The byte count latched in RXINFO is the number of bytes the port partner put on the wire, so a malicious partner that transmits a 31-byte frame can drive the loop one byte past the destination if the WCOVE BMC receiver does not enforce the PD object-count limit in hardware. The existing FIXME flagged this as unverified. Independently, regmap_read() takes an unsigned int * and stores a full unsigned int at the destination. Passing the byte pointer msg + i means each iteration writes four bytes; the high three are zero (val_bits is 8) and are normally overwritten by the next iteration, but the final iteration's high bytes are not. With RXBYTES == 30 the i == 29 iteration already writes three zero bytes past msg, which sits on the IRQ thread's stack in wcove_typec_irq(). Clamp the loop to sizeof(struct pd_message) and read each register into a local before storing only its low byte, so the copy can never exceed the destination regardless of what RXINFO reports. Assisted-by: gkh_clanker_t1000 Cc: Heikki Krogerus Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/tcpm/wcove.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/usb/typec/tcpm/wcove.c b/drivers/usb/typec/tcpm/wcove.c index 759c982bb16a..0e5a3e277c3e 100644 --- a/drivers/usb/typec/tcpm/wcove.c +++ b/drivers/usb/typec/tcpm/wcove.c @@ -444,9 +444,11 @@ static int wcove_start_toggling(struct tcpc_dev *tcpc, return regmap_write(wcove->regmap, USBC_CONTROL1, usbc_ctrl); } -static int wcove_read_rx_buffer(struct wcove_typec *wcove, void *msg) +static int wcove_read_rx_buffer(struct wcove_typec *wcove, + struct pd_message *msg) { - unsigned int info; + unsigned int info, val, len; + u8 *buf = (u8 *)msg; int ret; int i; @@ -454,12 +456,13 @@ static int wcove_read_rx_buffer(struct wcove_typec *wcove, void *msg) if (ret) return ret; - /* FIXME: Check that USBC_RXINFO_RXBYTES(info) matches the header */ + len = min(USBC_RXINFO_RXBYTES(info), sizeof(*msg)); - for (i = 0; i < USBC_RXINFO_RXBYTES(info); i++) { - ret = regmap_read(wcove->regmap, USBC_RX_DATA + i, msg + i); + for (i = 0; i < len; i++) { + ret = regmap_read(wcove->regmap, USBC_RX_DATA + i, &val); if (ret) return ret; + buf[i] = val; } return regmap_write(wcove->regmap, USBC_RXSTATUS, -- 2.54.0