Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7FD2C54EAA for ; Thu, 26 Jan 2023 00:50:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236315AbjAZAuP (ORCPT ); Wed, 25 Jan 2023 19:50:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229652AbjAZAuN (ORCPT ); Wed, 25 Jan 2023 19:50:13 -0500 Received: from sonata.ens-lyon.org (domu-toccata.ens-lyon.fr [140.77.166.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE4F1FF14; Wed, 25 Jan 2023 16:50:12 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by sonata.ens-lyon.org (Postfix) with ESMTP id 2F8632013E; Thu, 26 Jan 2023 01:50:10 +0100 (CET) Received: from sonata.ens-lyon.org ([127.0.0.1]) by localhost (sonata.ens-lyon.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DyMmoyeiM7Ic; Thu, 26 Jan 2023 01:50:10 +0100 (CET) Received: from begin (adijon-658-1-86-31.w86-204.abo.wanadoo.fr [86.204.233.31]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by sonata.ens-lyon.org (Postfix) with ESMTPSA id C20302013C; Thu, 26 Jan 2023 01:50:09 +0100 (CET) Received: from samy by begin with local (Exim 4.96) (envelope-from ) id 1pKqSv-00HVPW-0x; Thu, 26 Jan 2023 01:50:09 +0100 Message-ID: <20230126004921.616264824@ens-lyon.org> User-Agent: quilt/0.66 Date: Thu, 26 Jan 2023 01:49:12 +0100 From: Samuel Thibault To: gregkh@linuxfoundation.org, Daniel Vetter , Helge Deller Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Sanan Hasanov , Samuel Thibault Subject: [PATCH] fbcon: Check font dimension limits References: <20230126004911.869923511@ens-lyon.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org blit_x and blit_y are uint32_t, so fbcon currently cannot support fonts larger than 32x32. The 32x32 case also needs shifting an unsigned int, to properly set bit 31, otherwise we get "UBSAN: shift-out-of-bounds in fbcon_set_font", as reported on http://lore.kernel.org/all/IA1PR07MB98308653E259A6F2CE94A4AFABCE9@IA1PR07MB9830.namprd07.prod.outlook.com Kernel Branch: 6.2.0-rc5-next-20230124 Kernel config: https://drive.google.com/file/d/1F-LszDAizEEH0ZX0HcSR06v5q8FPl2Uv/view?usp=sharing Reproducer: https://drive.google.com/file/d/1mP1jcLBY7vWCNM60OMf-ogw-urQRjNrm/view?usp=sharing Reported-by: Sanan Hasanov Signed-off-by: Samuel Thibault Index: linux-6.0/drivers/video/fbdev/core/fbcon.c =================================================================== --- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c +++ linux-6.0/drivers/video/fbdev/core/fbcon.c @@ -2489,9 +2489,12 @@ static int fbcon_set_font(struct vc_data h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) return -EINVAL; + if (font->width > 32 || font->height > 32) + return -EINVAL; + /* Make sure drawing engine can handle the font */ - if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || - !(info->pixmap.blit_y & (1 << (font->height - 1)))) + if (!(info->pixmap.blit_x & (1U << (font->width - 1))) || + !(info->pixmap.blit_y & (1U << (font->height - 1)))) return -EINVAL; /* Make sure driver can handle the font length */