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=-0.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 8A927C3279B for ; Tue, 10 Jul 2018 18:30:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 591F820B6F for ; Tue, 10 Jul 2018 18:30:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 591F820B6F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com 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 S2388193AbeGJSau (ORCPT ); Tue, 10 Jul 2018 14:30:50 -0400 Received: from mail-io0-f199.google.com ([209.85.223.199]:39666 "EHLO mail-io0-f199.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733118AbeGJSat (ORCPT ); Tue, 10 Jul 2018 14:30:49 -0400 Received: by mail-io0-f199.google.com with SMTP id x14-v6so19906947ioa.6 for ; Tue, 10 Jul 2018 11:30:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to:cc; bh=ifq854zl8sX7iVxD/kBhdvsIc519fNkLgpjRawS7BBQ=; b=elVTi7D3iFgFZIrc1u2mdvmhNYTqsT7/MAfBxWQeWT1XkLcdOgso9n1U2Pe9VOn/Tk mnmvo2TGXim2nxAGO4z1cy3Su2LexLrKWplhOpETBrgtMFvBuDtaUBzT58mq41qbDpTg 2dcAgYFVHELpzeJPcfCxf330BtwcQf7EgjHZAzxaDbxz+01qWMr5JOjaiQQXfmcVfIbU mVhxPp3nNornM94TDmOcCwlGxsxAzAi4gZB09NjkaNSjv8jwjd+3rQ6QRJiFawKq8FW+ uz+Re2FZYL1xEHoAblx4VwtQ3O25duZGMcezi+KGofPEtsp/etasYQy1QMufujzrPkYU 2eDw== X-Gm-Message-State: APt69E0BYZ6Ic1Uj4VCuJqtIAaYNdvNx9MsbTz81Ou4nAHqeQ7Kwlp8M 1IQhltM9o0vRNG0vLvQaL5l5hT1CLdmTOR21U1CXoOJTynqW X-Google-Smtp-Source: AAOMgpfusj/OUx3qB98isbvhTbCMfTdusBzr6U08OnEtuSVQZsBUJQyTp9uUO2FSbKvZW8elNvbWYQ36pA/ro5YNI3P2xNnfc5XG MIME-Version: 1.0 X-Received: by 2002:a5e:860d:: with SMTP id z13-v6mr11124843ioj.1.1531247437634; Tue, 10 Jul 2018 11:30:37 -0700 (PDT) Date: Tue, 10 Jul 2018 11:30:37 -0700 In-Reply-To: <20180710182450.302954707@linuxfoundation.org> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000009569c60570a953e0@google.com> Subject: Re: [PATCH 4.9 08/52] vt: prevent leaking uninitialized data to userspace via /dev/vcs* From: syzbot To: Greg Kroah-Hartman Cc: glider@google.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > 4.9-stable review patch. If anyone has any objections, please let me > know. > ------------------ > From: Alexander Potapenko > commit 21eff69aaaa0e766ca0ce445b477698dc6a9f55a upstream. > KMSAN reported an infoleak when reading from /dev/vcs*: > BUG: KMSAN: kernel-infoleak in vcs_read+0x18ba/0x1cc0 > Call Trace: > ... > kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1253 > copy_to_user ./include/linux/uaccess.h:184 > vcs_read+0x18ba/0x1cc0 drivers/tty/vt/vc_screen.c:352 > __vfs_read+0x1b2/0x9d0 fs/read_write.c:416 > vfs_read+0x36c/0x6b0 fs/read_write.c:452 > ... > Uninit was created at: > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 > kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189 > kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315 > __kmalloc+0x13a/0x350 mm/slub.c:3818 > kmalloc ./include/linux/slab.h:517 > vc_allocate+0x438/0x800 drivers/tty/vt/vt.c:787 > con_install+0x8c/0x640 drivers/tty/vt/vt.c:2880 > tty_driver_install_tty drivers/tty/tty_io.c:1224 > tty_init_dev+0x1b5/0x1020 drivers/tty/tty_io.c:1324 > tty_open_by_driver drivers/tty/tty_io.c:1959 > tty_open+0x17b4/0x2ed0 drivers/tty/tty_io.c:2007 > chrdev_open+0xc25/0xd90 fs/char_dev.c:417 > do_dentry_open+0xccc/0x1440 fs/open.c:794 > vfs_open+0x1b6/0x2f0 fs/open.c:908 > ... > Bytes 0-79 of 240 are uninitialized > Consistently allocating |vc_screenbuf| with kzalloc() fixes the problem > Reported-by: syzbot+17a8efdf800000@syzkaller.appspotmail.com > Signed-off-by: Alexander Potapenko > Cc: stable > Signed-off-by: Greg Kroah-Hartman > --- > drivers/tty/vt/vt.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > --- a/drivers/tty/vt/vt.c > +++ b/drivers/tty/vt/vt.c > @@ -785,7 +785,7 @@ int vc_allocate(unsigned int currcons) / > if (!*vc->vc_uni_pagedir_loc) > con_set_default_unimap(vc); > - vc->vc_screenbuf = kmalloc(vc->vc_screenbuf_size, GFP_KERNEL); > + vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL); > if (!vc->vc_screenbuf) > goto err_free; > @@ -872,7 +872,7 @@ static int vc_do_resize(struct tty_struc > if (new_screen_size > (4 << 20)) > return -EINVAL; > - newscreen = kmalloc(new_screen_size, GFP_USER); > + newscreen = kzalloc(new_screen_size, GFP_USER); > if (!newscreen) > return -ENOMEM; Can't find the corresponding bug.