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 57F09421F16; Fri, 22 May 2026 14:22:25 +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=1779459752; cv=none; b=LsFoiJ/A15RIChmVPJd6nQ4SgFYwItfui6qrDwU8uejbMWPJ+T2A0Ek9vYMMwNCD+09o56pQBchTE5BZz5GgsKlz+dD+DP54+nmm0/7xcLf9wz4ymgFX5tEb/EpsxkKdWZQDBnWswdDXnTzsu1pO0ZGZmDUB1MGgOTT07LqvKVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779459752; c=relaxed/simple; bh=SmnPE+UUgKqkAGj5Fh4vh1PzGk9CDM/x9mSnHpezBMg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=eJXno5Pv3Dk05jwvj2LLcgcqywS58vb6bTMmAiqiyZfzaIvG5k+Y+V3NeHxvtel1KrONeleTyzMdH/a1f2xq7tuc7kTQ2hch5IEra9ejfKyyQ/+KH9RP0m+IfSuGnfgF0Bo3DsG6RrDlbQpZNAEeDbEJeQU+AnpNH7w1KijGdMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vmci/S5q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vmci/S5q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 247FF1F00A3D; Fri, 22 May 2026 14:22:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779459743; bh=SOegj8RlYd8aMl5fWMItxIVNwvXG8Gl6pyLcTMwAtXo=; h=From:To:Cc:Subject:Date; b=Vmci/S5qS1Nv6tBRlfoxUjxTQZLlycIXd6yxB1llgeOd9oh1Z3vuzx6FUPbzafR2Y ZDYyFqpIoeOt/0WmTjkpTEqSbaD/pr2S0Yk3l3e4zpbvpAHWnrBOjm3dDWROO8Mvv1 ztE87WxduvtYvnRwDbDa2sBpJmj0mzEsB+bNb+43672CtAAgmBkzPKtsfgD55SaBNP B40f1uDHlgV0oZhNpeelk94FZTUN3ag8kv4suxYyNRpRXEeTGaGfLuakApq0iowFgG mtUncK5FZ7d4VsduaLFwrj5gO0RmoivOZkcn4JGCpR9Lbbpstl6q1fnZnIUh78PSaV esGNT07jSJThQ== Received: from johan by xi.lan with local (Exim 4.98.2) (envelope-from ) id 1wQQlZ-00000003yX4-07F8; Fri, 22 May 2026 16:22:21 +0200 From: Johan Hovold To: Johan Hovold Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] USB: serial: safe_serial: fix memory corruption with small endpoint Date: Fri, 22 May 2026 16:22:18 +0200 Message-ID: <20260522142218.947657-1-johan@kernel.org> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Make sure that the bulk-out buffer size is at least eight bytes to avoid user-controlled slab corruption in "safe" mode should a malicious device report a smaller size. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold --- drivers/usb/serial/safe_serial.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/usb/serial/safe_serial.c b/drivers/usb/serial/safe_serial.c index 238b54993446..d267a31dcccf 100644 --- a/drivers/usb/serial/safe_serial.c +++ b/drivers/usb/serial/safe_serial.c @@ -259,6 +259,7 @@ static int safe_prepare_write_buffer(struct usb_serial_port *port, static int safe_startup(struct usb_serial *serial) { struct usb_interface_descriptor *desc; + int bulk_out_size; if (serial->dev->descriptor.bDeviceClass != CDC_DEVICE_CLASS) return -ENODEV; @@ -279,6 +280,16 @@ static int safe_startup(struct usb_serial *serial) default: return -EINVAL; } + + /* + * The bulk-out buffer needs to be large enough for the two-byte + * trailer in safe mode, but assume anything smaller than eight bytes + * is broken. + */ + bulk_out_size = serial->port[0]->bulk_out_size; + if (bulk_out_size > 0 && bulk_out_size < 8) + return -EINVAL; + return 0; } -- 2.53.0