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 1C8084CA26A; Wed, 13 May 2026 15:53:04 +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=1778687584; cv=none; b=R8L7O/R3FARIJSRRobpGLDBipKme7ZgdePUo4SdfbT8obKG/Fk7x/awFc/Vl00xuMykcOyXAkoRfOsDAbGH4RSkG3DxJ1ncCkT6VVNkGlj6eMUA6Q2NYBRDe07VEtRSEQmhfNnFSBvfdovJqgocGFemL6xi1TmOSx0SSsIk3QrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778687584; c=relaxed/simple; bh=akf8xDcTf6ajKnNwVn/PvFJIgvoWufWJiAQPWRW9tJI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=seYZylSCxRSQoUuVH4INqxlLGGU9E6CjHArBPdKsBbThRrvbEdSuQW2PPJcpDpIsz6OqR32YPiKpf3ms4OzF8VihLnj2b7PwVXxvaIhUrDAijOuaqG2+mBPVvDKTcrvULYxE8VqOH9QY1Xm8nctIz+le49/l9KFwmOyF8qZEOXE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=T9M3BDHe; 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="T9M3BDHe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D8D2C2BCB7; Wed, 13 May 2026 15:53:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778687583; bh=akf8xDcTf6ajKnNwVn/PvFJIgvoWufWJiAQPWRW9tJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T9M3BDHeg5fS7bFbzDl48om0uTDG8DWlZ4ByGUL74Ab7CrkPojkbbeV0Zs7abaoS2 cqrvIsIUSGFfMgABma9FDvSXkSbbC7yHG11R4xoAe/9o+UYo4XDmkB5agTRcOMQ5OP pWfR3NACyK6vQretYxpPN/NADCS6NPKqFt7+QAvQ= From: Greg Kroah-Hartman To: linux-usb@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Badhri Jagan Sridharan , Heikki Krogerus , stable Subject: [PATCH 6/8] usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() Date: Wed, 13 May 2026 17:52:53 +0200 Message-ID: <2026051351-reshuffle-skillful-90af@gregkh> X-Mailer: git-send-email 2.54.0 In-Reply-To: <2026051347-clustered-deflected-9543@gregkh> References: <2026051347-clustered-deflected-9543@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2581; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=akf8xDcTf6ajKnNwVn/PvFJIgvoWufWJiAQPWRW9tJI=; b=kA0DAAIRMUfUDdst+ykByyZiAGoEnlPIHSclk1biT1GizZkf/bYl7LVkT6//4M9XKGwhJUa+M ohdBAARAgAdFiEE9LYMxb94wiFKMT3LMUfUDdst+ykFAmoEnlMACgkQMUfUDdst+ym0zACdFNRn HyKfz+UfOFoigZqU3nIFlk0AoIbxR9zVoJtHj2bDWwp4iVR0sTgv X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX modes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX]. But the CMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming ACK with any request the port actually sent. Once port->partner is set, an unsolicited Discover Modes ACK is consumed unconditionally. A broken or malicious port partner can therefore drive altmodes to ALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra Discover Modes ACK with seven VDOs. Because the pre-loop check passes, the loop could then writes up to five entries past altmode_desc[]. For mode_data_prime the next field in struct tcpm_port is the partner_altmode[] pointer array, which then receives partner-chosen SVID/VDO bytes. Move the bound check inside the loop so the array can never be indexed past ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner supplies or how the function was reached. Assisted-by: gkh_clanker_t1000 Cc: Badhri Jagan Sridharan Cc: Heikki Krogerus Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/tcpm/tcpm.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 2cab74ed71a7..8d904a9013fb 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -1992,23 +1992,19 @@ static void svdm_consume_modes(struct tcpm_port *port, const u32 *p, int cnt, switch (rx_sop_type) { case TCPC_TX_SOP_PRIME: pmdata = &port->mode_data_prime; - if (pmdata->altmodes >= ARRAY_SIZE(port->plug_prime_altmode)) { - /* Already logged in svdm_consume_svids() */ - return; - } break; case TCPC_TX_SOP: pmdata = &port->mode_data; - if (pmdata->altmodes >= ARRAY_SIZE(port->partner_altmode)) { - /* Already logged in svdm_consume_svids() */ - return; - } break; default: return; } for (i = 1; i < cnt; i++) { + if (pmdata->altmodes >= ALTMODE_DISCOVERY_MAX) { + /* Already logged in svdm_consume_svids() */ + return; + } paltmode = &pmdata->altmode_desc[pmdata->altmodes]; memset(paltmode, 0, sizeof(*paltmode)); -- 2.54.0