From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794325134; b=Nzh+N+lOj8qoqDBR+Oxdqut5rNXj0svUtRzUQO/x3rmkMfatuauTCYWaZ/gzmzrnuwt9 EyptxZK0lH0NbO+n04Ynsi3vPDqmjvNask+8sPA1vGP7FvSbvV6BokkDqqxo58TbkIWWX CXdQ1ZnkXy629yg4cr7+f/5hofVaWjg3A4jlqcBizbw9Up2F2rTutxAJVtM1C4OP9fork w49hN/lG9SJLqXepCo0irvpXWrN1RpuT5qNmTN0RUskySYTNbyXIm7tVY9hTcCbQ88dYS r4MYpvusWBDedgppRyfNrfUPLyvEOgmkfNkgO3LrleKzsqEQ7ji2jVXWe/+looESHSw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794325134; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=yAlpTTVXGCkpoAqWyQzQF2/xAkRbjAwy9xer0+8/rzo=; b=iWjV3wMwRHONG85lV1nuheDrr0GCGth78RX9Jm0DjB4/dShOBAkq2fcPuVyLPiIcFwoP 5U9di02BQQWGqE9oLeC4E8e3Ea6+AgywurxMVl2Moahtq6tY4LSiHjrdQa3/QuavcS4tH SnfRpFOZDgSM3dF6ZG3Ka8uUmj2yWc7owZ13BJUWZlYojzxE8hjyEM7ZYbVN/O0l9fh9H 5hvT5yKtLUkQEFWw5LyaDY9banmTJIXP0xk2Cr+ZlfkxywHHJAKtCNyPaK0W9He5TqLMl x9GvDRe/XG7O0VnoRKp/QqzSiHIGOtV/GLoirKzxHESca6o0rL4dBIEPFeA+5IKSPgA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gQhavh7v; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4FBC2606A323 for ; Tue, 10 Nov 2026 15:38:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gQhavh7v Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A71B1F008A3; Tue, 10 Nov 2026 15:38:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794325133; bh=yAlpTTVXGCkpoAqWyQzQF2/xAkRbjAwy9xer0+8/rzo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gQhavh7vde0i7kHlyd/Kip0MzW376FeTi+dwJXYKNKY1pPzdBVjmItWxiDjFCMErk P9yvF+81KluJO2vJKYPFBoVIKOFaltKV0KGBZA4bcP7Bu/RcdiSokENHAxxDBh32QC POpupRHvk2Efb9Yynw4QI8fy587taSJ7mum55jnoC8O8kdC02Rxb1qcG5wxFbXVSC6 U0Tn2nxvIMmH3+QOSCMbKVbKl3SOH4PJeYdEoZZYzYfkioqGNAC1azuvhcAhdmdchk 40/H55Rg5IUQm9zkRM1OQtAy3fuDHIwEtfzYujYal+AAj91uqwgjcHQN9GKTfE5v/P iWXVHr5SK0xxw== From: Sasha Levin To: stable@vger.kernel.org Cc: Seungjin Bae , stable , Nathan Rebello , Heikki Krogerus , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.1.y] usb: typec: ucsi: ccg: Validate altmode index in GET_CURRENT_CAM response Date: Tue, 10 Nov 2026 10:38:52 -0500 Message-ID: <20261110153828.2328698-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107054636-failed-6.1-02ee864e8d21@kernel.org> References: <20261107054636-failed-6.1-02ee864e8d21@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Seungjin Bae [ Upstream commit 02ee864e8d2142c5648998944c3306ea6a763c26 ] When the PPM reports more than one DisplayPort alternate mode for a connector, ucsi_ccg_update_altmodes() merges them into a single entry in uc->updated[] and sets uc->has_multiple_dp. In that case, ucsi_ccg_update_get_current_cam_cmd() rewrites the response of the GET_CURRENT_CAM command. The response is a single byte holding the index of the currently active alternate mode, and it is provided by the PPM firmware. The function uses this byte directly as an index into uc->orig[], and then uses the linked_idx read from that entry as the translated index into uc->updated[]. Both arrays have UCSI_MAX_ALTMODES entries, but neither index is checked against that size. If a malicious or buggy PPM reports a value of UCSI_MAX_ALTMODES or larger, e.g. 0xFF, uc->orig[cam].linked_idx reads over the end of uc->orig[]. The byte read from there is then used as the index for writing cam into uc->updated[new_cam].active_idx, so the out-of-bounds read is followed by an out-of-bounds write. This happens without any userspace action, since the UCSI core issues GET_CURRENT_CAM on its own when handling connector changes. Fix this by rejecting responses whose index is out of range, printing an error and returning -EPROTO, so that the caller cannot accept this. Also check linked_idx before using it as an index, so that the write into uc->updated[] is always within bounds. The response is now only processed when the command completed without an error. ucsi_sync_control_common() only reads the response when the CCI reports command completion, so otherwise the buffer is not filled and must not be mistaken for an invalid index. This bug was found with a Python script that traces where firmware input is used. Fixes: 170a6726d0e2 ("usb: typec: ucsi: add support for separate DP altmode devices") Cc: stable Reported-by: Nathan Rebello Assisted-by: LLM Signed-off-by: Seungjin Bae Reviewed-by: Heikki Krogerus Link: https://patch.msgid.link/20261003215520.611083-2-eeodqql09@gmail.com Signed-off-by: Greg Kroah-Hartman [ sashal: adapted error propagation to ucsi_ccg_read() instead of ucsi_ccg_sync_control() ] Signed-off-by: Sasha Levin --- drivers/usb/typec/ucsi/ucsi_ccg.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c index 20f7f87a92f2c..1ee2f4d9de4b5 100644 --- a/drivers/usb/typec/ucsi/ucsi_ccg.c +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c @@ -356,14 +356,28 @@ static int ucsi_ccg_init(struct ucsi_ccg *uc) return -ETIMEDOUT; } -static void ucsi_ccg_update_get_current_cam_cmd(struct ucsi_ccg *uc, u8 *data) +static int ucsi_ccg_update_get_current_cam_cmd(struct ucsi_ccg *uc, u8 *data) { u8 cam, new_cam; cam = data[0]; + if (cam >= UCSI_MAX_ALTMODES) { + dev_err(uc->dev, "PPM returned invalid alternate mode index %u\n", + cam); + return -EPROTO; + } + new_cam = uc->orig[cam].linked_idx; + if (new_cam >= UCSI_MAX_ALTMODES) { + dev_err(uc->dev, "invalid linked alternate mode index %u for %u\n", + new_cam, cam); + return -EPROTO; + } + uc->updated[new_cam].active_idx = cam; data[0] = new_cam; + + return 0; } static bool ucsi_ccg_update_altmodes(struct ucsi *ucsi, @@ -547,7 +561,7 @@ static int ucsi_ccg_read(struct ucsi *ucsi, unsigned int offset, switch (UCSI_COMMAND(uc->last_cmd_sent)) { case UCSI_GET_CURRENT_CAM: if (uc->has_multiple_dp) - ucsi_ccg_update_get_current_cam_cmd(uc, (u8 *)val); + ret = ucsi_ccg_update_get_current_cam_cmd(uc, (u8 *)val); break; case UCSI_GET_ALTERNATE_MODES: if (UCSI_ALTMODE_RECIPIENT(uc->last_cmd_sent) == -- 2.53.0