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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 9E3FFC2D0A3 for ; Tue, 3 Nov 2020 21:09:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EC9E21534 for ; Tue, 3 Nov 2020 21:09:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604437744; bh=pdImw8MX1nGDEbGReoB8McG7j1JBtWfBX0D9bkBbf6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DzD/nsjv0S5UrMnJ/MWG2++KD7C3tQNTtDs55oqlNuYzjE2mk0ahGpsssv5/nfX28 KFeU4FXgdJLrY77TnNpTOXu7ZwMF1ADG6ImlsfOlmOQEAKrtAd47W9dliiAxS9Ffaa s+CLTUz+wg9RxCiMfG0kd75GvGBvLh9UhcWzCFek= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388411AbgKCVIF (ORCPT ); Tue, 3 Nov 2020 16:08:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:47340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388367AbgKCVH5 (ORCPT ); Tue, 3 Nov 2020 16:07:57 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 6D4F6207BC; Tue, 3 Nov 2020 21:07:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604437676; bh=pdImw8MX1nGDEbGReoB8McG7j1JBtWfBX0D9bkBbf6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OtSYiajSNK4h/EnssHMVy2tMUKACnq/Bo+jf9RhGgRcLW2xuuklIvzf32TaB+uzpg 2oAHxCBsiTPHKDxGaD6IJc6hXBL2QXfOQBYQiUW/pEI39VadPBo3DEADsVkL1075gD IeXWm9weRYfgc1Wv6QX8lFgiKW9Am3q/8FsoTcgY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Minh Yuan , Michael Ellerman , Jiri Slaby , Greg KH , Linus Torvalds Subject: [PATCH 4.19 179/191] tty: make FONTX ioctl use the tty pointer they were actually passed Date: Tue, 3 Nov 2020 21:37:51 +0100 Message-Id: <20201103203249.418136352@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203232.656475008@linuxfoundation.org> References: <20201103203232.656475008@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds commit 90bfdeef83f1d6c696039b6a917190dcbbad3220 upstream. Some of the font tty ioctl's always used the current foreground VC for their operations. Don't do that then. This fixes a data race on fg_console. Side note: both Michael Ellerman and Jiri Slaby point out that all these ioctls are deprecated, and should probably have been removed long ago, and everything seems to be using the KDFONTOP ioctl instead. In fact, Michael points out that it looks like busybox's loadfont program seems to have switched over to using KDFONTOP exactly _because_ of this bug (ahem.. 12 years ago ;-). Reported-by: Minh Yuan Acked-by: Michael Ellerman Acked-by: Jiri Slaby Cc: Greg KH Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt_ioctl.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -244,7 +244,7 @@ int vt_waitactive(int n) static inline int -do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op) +do_fontx_ioctl(struct vc_data *vc, int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op) { struct consolefontdesc cfdarg; int i; @@ -262,15 +262,16 @@ do_fontx_ioctl(int cmd, struct consolefo op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = cfdarg.chardata; - return con_font_op(vc_cons[fg_console].d, op); - case GIO_FONTX: { + return con_font_op(vc, op); + + case GIO_FONTX: op->op = KD_FONT_OP_GET; op->flags = KD_FONT_FLAG_OLD; op->width = 8; op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = cfdarg.chardata; - i = con_font_op(vc_cons[fg_console].d, op); + i = con_font_op(vc, op); if (i) return i; cfdarg.charheight = op->height; @@ -278,7 +279,6 @@ do_fontx_ioctl(int cmd, struct consolefo if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc))) return -EFAULT; return 0; - } } return -EINVAL; } @@ -924,7 +924,7 @@ int vt_ioctl(struct tty_struct *tty, op.height = 0; op.charcount = 256; op.data = up; - ret = con_font_op(vc_cons[fg_console].d, &op); + ret = con_font_op(vc, &op); break; } @@ -935,7 +935,7 @@ int vt_ioctl(struct tty_struct *tty, op.height = 32; op.charcount = 256; op.data = up; - ret = con_font_op(vc_cons[fg_console].d, &op); + ret = con_font_op(vc, &op); break; } @@ -952,7 +952,7 @@ int vt_ioctl(struct tty_struct *tty, case PIO_FONTX: case GIO_FONTX: - ret = do_fontx_ioctl(cmd, up, perm, &op); + ret = do_fontx_ioctl(vc, cmd, up, perm, &op); break; case PIO_FONTRESET: @@ -969,11 +969,11 @@ int vt_ioctl(struct tty_struct *tty, { op.op = KD_FONT_OP_SET_DEFAULT; op.data = NULL; - ret = con_font_op(vc_cons[fg_console].d, &op); + ret = con_font_op(vc, &op); if (ret) break; console_lock(); - con_set_default_unimap(vc_cons[fg_console].d); + con_set_default_unimap(vc); console_unlock(); break; } @@ -1100,8 +1100,9 @@ struct compat_consolefontdesc { }; static inline int -compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd, - int perm, struct console_font_op *op) +compat_fontx_ioctl(struct vc_data *vc, int cmd, + struct compat_consolefontdesc __user *user_cfd, + int perm, struct console_font_op *op) { struct compat_consolefontdesc cfdarg; int i; @@ -1119,7 +1120,8 @@ compat_fontx_ioctl(int cmd, struct compa op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = compat_ptr(cfdarg.chardata); - return con_font_op(vc_cons[fg_console].d, op); + return con_font_op(vc, op); + case GIO_FONTX: op->op = KD_FONT_OP_GET; op->flags = KD_FONT_FLAG_OLD; @@ -1127,7 +1129,7 @@ compat_fontx_ioctl(int cmd, struct compa op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = compat_ptr(cfdarg.chardata); - i = con_font_op(vc_cons[fg_console].d, op); + i = con_font_op(vc, op); if (i) return i; cfdarg.charheight = op->height; @@ -1218,7 +1220,7 @@ long vt_compat_ioctl(struct tty_struct * */ case PIO_FONTX: case GIO_FONTX: - ret = compat_fontx_ioctl(cmd, up, perm, &op); + ret = compat_fontx_ioctl(vc, cmd, up, perm, &op); break; case KDFONTOP: