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=1794324958; b=13wuF97YYD+27Q66H200PMW8/5AANWfs75JUL59DIjuQoLPMEI8RZXwuy6esCKWDYpNn mNkwwiz3RQfo/daReYuYfCf+/cXB2OigBHzmemY9QsaZOca6AAbh7bSDmg8XljCJvFUuq fbrFytwJN/KiI/Bw0vEMbSYAkzO5+YE/yNOWLK5V3GZqAJOWNvq/tpzL75fWWN9ujZcVu 6CMqpWr7Ft4ZvK62AxcbQodCKLiz2Ib6nAQ1wFEXGIvOKugXXNXR58MTwipmU+/7zNMkp //imyeIdZsTGbXuf8JmvApSZxbqnwsOwLRE1BWHv0Q3k4WOyPxnIzFH94B1vcTb31uQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794324958; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=CV1hc6svwVAS3O8OrlNNSC7DbrfRyraOcLOf+TgmL/0=; b=ns1Ebx3wNQSBma+OumK2z5vXRbTW3x0B6yJLfxG6tLZE4yW4ENciTOI3SAQL4x5tsmGK tTTfPCXy2KbzVYT/LcjIFj27Ila3SLWWGuYvYkJ8aKzOPyBbD5TonoCIZ4YX12OOMgQ9q mSIYDrGfOlLc/8ur/zYRW8wUoS7IUIz4VUJ5qDkfaZ5AGdfDM/3soL0ak5FXrzuu694gY dilInNp9KYszgt/lBXJ44fgyi9n2C2wVx0ErGMtIAFW1Vet7a/EVfftGsE43y/Vvkz7/J 6XviMVbL1wArkEekRDQl5xas5V0/nEu4niJ94mwSClYp0Y8gVe3cWNSWKSCPCBuMFfw== 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=aiDaUA7G; 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 0F06B606A32D for ; Tue, 10 Nov 2026 15:35:57 +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=aiDaUA7G Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3B051F0089F; Tue, 10 Nov 2026 15:35:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794324957; bh=CV1hc6svwVAS3O8OrlNNSC7DbrfRyraOcLOf+TgmL/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aiDaUA7GBpMEwR4Pw/fqedl5HOKVwNNNvWyd+uuy70V6+aWk2MrLdU/l68NrVma84 Cfbqx3qarj/HSwqjAiKBVBFFKgmttG++vizOXBMh5wA4JFfqCDEqyOmxylchub3O5g kKcKR9XOtkleSmJ+IxNum+18grMrdsmJgg0XA9+raa8rRhNrx4FwAUdiqEM05VpYKQ CaeR8RSbJSBKAdWQ64lDleJ2ilVDc6RYjK5HviiBynV0yOuCoBLSiDj3kkO/Pd35tq jkxjD4vf3ViZQBPyv2M3/mvUTDHy9MaiZZMwrg4ZmgUwupAzFFSl0q5iV2kEwg90DM V4ceDYgOxft9Q== From: Sasha Levin To: stable@vger.kernel.org Cc: Seungjin Bae , stable , Nathan Rebello , Heikki Krogerus , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.6.y] usb: typec: ucsi: ccg: Validate altmode index in GET_CURRENT_CAM response Date: Tue, 10 Nov 2026 10:35:55 -0500 Message-ID: <20261110153533.2135248-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107053328-failed-6.6-02ee864e8d21@kernel.org> References: <20261107053328-failed-6.6-02ee864e8d21@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 ucsi_ccg_sync_control() changes to ucsi_ccg_read(), relying on existing core completion and error checks ] 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 623094cba276e..dde65e740bd8d 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