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=1794063260; b=gi7ajinZYLm28QaNT9C+K5u+XBsFZ6nYwL589IZPya8svAkhjsVG8xQ9NiW9nb1/MsGt qtg9fIGaX7v5+YYJP50D3F0+ITMgPolJ5GU0ZLKonXG1Mu7DnEfiCgOe0tH3c+P882yHg Dc0G5FbZENvK2eO7YQ/ccQoj3cWkqSEk7mBUzwaD5/rD+O+D4KpnwzBZAbIRrbNiV+bgO N5E8F4RuMgqmtinsMSZdoLT3f+jqdq6KVyvQ7mXnGeAYVKoLSzxRNf4w7gpv3NeAelijl RLlzpdd6eLelyUH1pH81vlyfqX3Q8zsyYPBy2j4lQm2nUcwTnLDr5Y6SuhUErvUwFwQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063260; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=Oez1XYfl6F+k0FWfTkgVHRG13rsZsDZwG6VhqyoAUnA=; b=XaEMfHaUU1VfwwPkv0pEPavw9KnZ74Y/+OYajjeJ7JSR2qNTsAGfbOqxIhTLfJjCZrCD xp+/y8cQccY4fkWe6deCbVxmWZ84k0KDIvxLAQHU3pqH6jCuP2lw2ySOUIO4JevmD44KK wdcW3HPRftvvac/jR5Mhkfa5+bR0FSU5UOtwAdIXlD6XMKAPJ9dEBW8hjqza935salURH uMR4gRsVP1aybFRNyK03FVcYmVsVoIpDMG3FsRsO6YHurWa3i6xrOSKLThKDjI5axNiYH XkQpuRbH8POwL95aPu1SFwbmgLCDg8WoWRmHCEUbzJQdDrMnoGMElOVHQojTgo3SVAA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=qQ4XWWuW; 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 10FFD606A331; Sat, 7 Nov 2026 14:54:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=qQ4XWWuW Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1BFD1F0089F; Sat, 7 Nov 2026 14:54:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063259; bh=Oez1XYfl6F+k0FWfTkgVHRG13rsZsDZwG6VhqyoAUnA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qQ4XWWuW4OYLIO4EnXZqb7BCTqa0zoOrozK+tx0bt9aDwAbmDVhmZB3hB+JlLf3Bj OhP5Jvp1Mj4f0nM/IUbfXTTAXzxDwjNo4bLsJK4+kx7gobzcEgP61I5bnjAOcmghw5 7+B9LEYCbPaY/2QKXpGpSB+ynWWYHVf5nZ4/ga6s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Nathan Rebello , Seungjin Bae , Heikki Krogerus , Sasha Levin Subject: [PATCH 6.18 460/869] usb: typec: ucsi: ccg: Validate altmode index in GET_CURRENT_CAM response Date: Sat, 7 Nov 2026 08:52:22 -0500 Message-ID: <20261107134909.277381611@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Sasha Levin --- drivers/usb/typec/ucsi/ucsi_ccg.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c index 6c1f62c78ac25..18236d5c30922 100644 --- a/drivers/usb/typec/ucsi/ucsi_ccg.c +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c @@ -383,14 +383,28 @@ 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, @@ -633,8 +647,10 @@ static int ucsi_ccg_sync_control(struct ucsi *ucsi, u64 command, u32 *cci, switch (UCSI_COMMAND(command)) { case UCSI_GET_CURRENT_CAM: - if (uc->has_multiple_dp) - ucsi_ccg_update_get_current_cam_cmd(uc, (u8 *)data); + if (!ret && uc->has_multiple_dp && + (*cci & UCSI_CCI_COMMAND_COMPLETE) && + !(*cci & UCSI_CCI_ERROR)) + ret = ucsi_ccg_update_get_current_cam_cmd(uc, (u8 *)data); break; case UCSI_GET_ALTERNATE_MODES: if (UCSI_ALTMODE_RECIPIENT(command) == UCSI_RECIPIENT_SOP) { -- 2.53.0