From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CA68C43441 for ; Thu, 29 Nov 2018 14:28:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14EEB2147C for ; Thu, 29 Nov 2018 14:28:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="U5SQ73SU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 14EEB2147C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388041AbeK3Bdx (ORCPT ); Thu, 29 Nov 2018 20:33:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:34750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733011AbeK3Bdw (ORCPT ); Thu, 29 Nov 2018 20:33:52 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BD129213A2; Thu, 29 Nov 2018 14:28:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543501700; bh=jXu99XRM2fys48vFQm8x+MG749JNQ5fEs0B9Y6XNrlI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U5SQ73SU7H8Jf34uTCZ5vCsD4LelZKAjCqyjLTRQqRwRDmR0rp46P1wUYPtBbiFvJ ROPflTkpAz6DW28pFJf6xHQwUSbFJLnkLBHuVSVg/DC+DGWkicTwseYCzf4bmq+5+u LCO0JKpDDAPlS1LPO2fh/ILO/jF2ow1/bD3UfknE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, aszlig , Milan Broz , Daniel Zatovic , Willy Tarreau Subject: [PATCH 4.14 090/100] tty: wipe buffer if not echoing data Date: Thu, 29 Nov 2018 15:13:00 +0100 Message-Id: <20181129140106.581594215@linuxfoundation.org> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181129140058.768942700@linuxfoundation.org> References: <20181129140058.768942700@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Greg Kroah-Hartman commit b97b3d9fb57860a60592859e332de7759fd54c2e upstream. If we are not echoing the data to userspace or the console is in icanon mode, then perhaps it is a "secret" so we should wipe it once we are done with it. This mirrors the logic that the audit code has. Reported-by: aszlig Tested-by: Milan Broz Tested-by: Daniel Zatovic Tested-by: aszlig Cc: Willy Tarreau Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -154,17 +154,28 @@ static inline unsigned char *echo_buf_ad return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)]; } +/* If we are not echoing the data, perhaps this is a secret so erase it */ +static void zero_buffer(struct tty_struct *tty, u8 *buffer, int size) +{ + bool icanon = !!L_ICANON(tty); + bool no_echo = !L_ECHO(tty); + + if (icanon && no_echo) + memset(buffer, 0x00, size); +} + static int tty_copy_to_user(struct tty_struct *tty, void __user *to, size_t tail, size_t n) { struct n_tty_data *ldata = tty->disc_data; size_t size = N_TTY_BUF_SIZE - tail; - const void *from = read_buf_addr(ldata, tail); + void *from = read_buf_addr(ldata, tail); int uncopied; if (n > size) { tty_audit_add_data(tty, from, size); uncopied = copy_to_user(to, from, size); + zero_buffer(tty, from, size - uncopied); if (uncopied) return uncopied; to += size; @@ -173,7 +184,9 @@ static int tty_copy_to_user(struct tty_s } tty_audit_add_data(tty, from, n); - return copy_to_user(to, from, n); + uncopied = copy_to_user(to, from, n); + zero_buffer(tty, from, n - uncopied); + return uncopied; } /** @@ -1962,11 +1975,12 @@ static int copy_from_read_buf(struct tty n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail); n = min(*nr, n); if (n) { - const unsigned char *from = read_buf_addr(ldata, tail); + unsigned char *from = read_buf_addr(ldata, tail); retval = copy_to_user(*b, from, n); n -= retval; is_eof = n == 1 && *from == EOF_CHAR(tty); tty_audit_add_data(tty, from, n); + zero_buffer(tty, from, n); smp_store_release(&ldata->read_tail, ldata->read_tail + n); /* Turn single EOF into zero-length read */ if (L_EXTPROC(tty) && ldata->icanon && is_eof &&