From patchwork Tue Apr 28 18:25:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 226820 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=-6.8 required=3.0 tests=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 491A1C83004 for ; Tue, 28 Apr 2020 18:49:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27CD1214D8 for ; Tue, 28 Apr 2020 18:49:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588099752; bh=0sOTq4s30ooeuz5sbfz4jOZfhxiqi4UmbeG8VQrVoww=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W5yByxs9qlwtUFXLBS28FijVrOUjxivq+lAR38BGobKR/luJfOa9gUe7ZIBnftyAy 1tt0lB4c/KbP/+6LaebwugAvkNzAFbsy1K/DvrgIf0bgfV0Osask+UCkevss3A55IM aDgh2jRSP8bhqQycZOpxmO7x3K83CP7J6L35dQJo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730587AbgD1StE (ORCPT ); Tue, 28 Apr 2020 14:49:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:59408 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730911AbgD1SkU (ORCPT ); Tue, 28 Apr 2020 14:40:20 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 173482076A; Tue, 28 Apr 2020 18:40:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588099219; bh=0sOTq4s30ooeuz5sbfz4jOZfhxiqi4UmbeG8VQrVoww=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WT1iPFX+mjgqv8Elp3qaDdgSuJzeaqekiamvVVegIh+i1k7rCRC8vaHY/snEp/Gpe v0nxggMBOEPTD7pCptoKbLHsds29Nn6CbnUapzF8epg4aTbOUIeWyR8KExiwWKP9o3 ZciZkyaCn5IR/1A16UltmuVjOdVoumNehrnzjzxs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicolas Pitre , Sam Ravnborg Subject: [PATCH 4.19 116/131] vt: dont use kmalloc() for the unicode screen buffer Date: Tue, 28 Apr 2020 20:25:28 +0200 Message-Id: <20200428182239.834497789@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428182224.822179290@linuxfoundation.org> References: <20200428182224.822179290@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Nicolas Pitre commit 9a98e7a80f95378c9ee0c644705e3b5aa54745f1 upstream. Even if the actual screen size is bounded in vc_do_resize(), the unicode buffer is still a little more than twice the size of the glyph buffer and may exceed MAX_ORDER down the kmalloc() path. This can be triggered from user space. Since there is no point having a physically contiguous buffer here, let's avoid the above issue as well as reducing pressure on high order allocations by using vmalloc() instead. Signed-off-by: Nicolas Pitre Cc: Acked-by: Sam Ravnborg Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2003282214210.2671@knanqh.ubzr Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -81,6 +81,7 @@ #include #include #include +#include #include #include #include @@ -350,7 +351,7 @@ static struct uni_screen *vc_uniscr_allo /* allocate everything in one go */ memsize = cols * rows * sizeof(char32_t); memsize += rows * sizeof(char32_t *); - p = kmalloc(memsize, GFP_KERNEL); + p = vmalloc(memsize); if (!p) return NULL; @@ -366,7 +367,7 @@ static struct uni_screen *vc_uniscr_allo static void vc_uniscr_set(struct vc_data *vc, struct uni_screen *new_uniscr) { - kfree(vc->vc_uni_screen); + vfree(vc->vc_uni_screen); vc->vc_uni_screen = new_uniscr; }