From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F337B3CA491; Fri, 31 Jul 2026 08:06:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785485195; cv=none; b=CLWT8HQBDyHsSHzEIjW0NYI2TZ+WdF0USqF0LT+kTwiIE56lPLDvuLpJpQBbrxNAXRR5RBG4CZucQCR2wtSDBSEFserOL06gMiN/G12b5y0p4pzF4/YaZktRrsl0P/k74PUOFOotvAJavPt/WLZMj+RJurwNMWpzjw9O65T188k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785485195; c=relaxed/simple; bh=rJISz485z0GX96GNUrLIFr0nQsKGxAVGVuLA51W4+5Y=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=tKuCeYMoPmzstT2lrRJ9c/sV0/9Y/mWpe72YHMeFT3K96u+j+DspM8dDVh8GWZOOGFmlI94x9V1t/FN4yGDEmW2Ij0e4KvVyo8/fZ3ranaQpki5FLYvG06Czf849ZTsais4nAiehsW6qaZBrja9W31YPANjrxkdkk/bKv9sFJmY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YNZxXxdP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YNZxXxdP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1589A1F000E9; Fri, 31 Jul 2026 08:06:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785485193; bh=kWtYNBXgx1ERnjuPzRf0p7LW+RSZjWnKR1InaA5DbMU=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=YNZxXxdPuUa8QYFJYecg20/DzUICGSXsOM3OK3CBujNOpH9wCPVnZeveBbVI7ip+M 9G+lcDYptuzH6dH2TOFgAWJ9v4Or6906TErwgQFO1OmIBD8lwLoJiKwg1iblfc+BbZ Ak/cWzyf1CjHSZWtfR+tfc6G5HDoISvGN51pyWCQ= From: Greg Kroah-Hartman Date: Fri, 31 Jul 2026 10:06:10 +0200 Subject: [PATCH 2/2] serdev: use tty_port_tty_get() in ttyport_write_buf() to prevent UAF Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260731-aisle-tty-serdev-v1-2-2401a3189327@linuxfoundation.org> References: <20260731-aisle-tty-serdev-v1-0-2401a3189327@linuxfoundation.org> In-Reply-To: <20260731-aisle-tty-serdev-v1-0-2401a3189327@linuxfoundation.org> To: Markus Probst , linux-serial@vger.kernel.org Cc: Rob Herring , Jiri Slaby , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Joshua Rogers , stable X-Mailer: b4 0.16-dev-401aa X-Developer-Signature: v=1; a=openpgp-sha256; l=1578; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=CIoA1U7goq1GlxfkNWw/iYNPnQOup6iGI8gPBqnZteU=; b=owGbwMvMwCRo6H6F97bub03G02pJDFk54aWGJ9vMRZMubW2rVfIwmz5tMeesuM656qqN/797P PxUNdWgI5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACZiLs8w32frovxLqQfTnvT9 t/J8V5y87dc+b4YFRxa8lp5vOW/z43eBC5zEb9ce2XZiOgA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 From: Joshua Rogers ttyport_write_buf() snapshots serport->tty as a raw pointer without taking a reference, while ttyport_close() can concurrently release the tty via tty_release_struct(), leading to a use-after-free. Use tty_port_tty_get() to obtain a reference-counted tty pointer, matching the pattern already used by ttyport_write_wakeup(). Assisted-by: AISLE:Snapshot Cc: stable Signed-off-by: Joshua Rogers Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serdev/serdev-ttyport.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c index 48ce5b3f8308..4d37c8130dd7 100644 --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -85,13 +85,21 @@ static const struct tty_port_client_operations client_ops = { static ssize_t ttyport_write_buf(struct serdev_controller *ctrl, const u8 *data, size_t len) { struct serport *serport = serdev_controller_get_drvdata(ctrl); - struct tty_struct *tty = serport->tty; + struct tty_struct *tty; + ssize_t ret; if (!test_bit(SERPORT_ACTIVE, &serport->flags)) return 0; + tty = tty_port_tty_get(serport->port); + if (!tty) + return 0; + set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); - return tty->ops->write(serport->tty, data, len); + ret = tty->ops->write(tty, data, len); + tty_kref_put(tty); + + return ret; } static void ttyport_write_flush(struct serdev_controller *ctrl) -- 2.55.0