From patchwork Sat Jun 25 22:06:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Helge Deller X-Patchwork-Id: 584993 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 167DBC43334 for ; Sat, 25 Jun 2022 22:06:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233330AbiFYWGj (ORCPT ); Sat, 25 Jun 2022 18:06:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233356AbiFYWGi (ORCPT ); Sat, 25 Jun 2022 18:06:38 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96233120A2 for ; Sat, 25 Jun 2022 15:06:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1656194792; bh=mfIE/8o3iwMRsFJsNJhA3Pd2VIEUX0hccvso4RX5yvg=; h=X-UI-Sender-Class:From:To:Subject:Date:In-Reply-To:References; b=WJHoAeSPlSYPNGbfAMaOlN2IUpzuW4qmkwj1Z6BCOzN4csh8I1mO/qYr3mJl3qDk7 bOUWdLXnzHGD+UYHBvOTMS+Lda34lPhe0RAvqA7kxRLQiHaPa1gPE8l8Hu+hiRvfB2 xVQmhCex9vEBx5CsjT0jMOFc82uSdHBN9UDzmLII= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from p100.fritz.box ([92.116.162.44]) by mail.gmx.net (mrgmx105 [212.227.17.168]) with ESMTPSA (Nemesis) id 1MnakX-1nLkDS3m45-00jYPm; Sun, 26 Jun 2022 00:06:31 +0200 From: Helge Deller To: dri-devel@lists.freedesktop.org, daniel.vetter@ffwll.ch, linux-fbdev@vger.kernel.org Subject: [PATCH v3 2/4] fbcon: Add fbcon_modechange_possible() check Date: Sun, 26 Jun 2022 00:06:28 +0200 Message-Id: <20220625220630.333705-3-deller@gmx.de> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220625220630.333705-1-deller@gmx.de> References: <20220625220630.333705-1-deller@gmx.de> MIME-Version: 1.0 X-Provags-ID: V03:K1:e+aos6YQxRDiH+Yn5SqvV3sqRII1FoViM9WVKEVVgoLWnKZVYm4 d9N3mCqhC8Sz6QnEvBFpLwuShwHoqsJNX/CpxCj7yG92vTX7nYOYPpk6rY/rW1Zjlo3dJza 2xYiVBlAA3Sjzt1IHIiIDUjNQ+kEvQZWdziWMyAAi6A/GtqqckgnlHOmwy7B/9hVVCpCqoP B3FDFfd2V46GU8RtB54TA== X-UI-Out-Filterresults: notjunk:1;V03:K0:2ShdSY/THac=:FbquMf56hrvbvSPduWiwHz nTPQZuAPtdClfucIggVA9/mBNDnddtrD/iSeKWLTs256Qk5wZyLNrdOQbgH52DGioPijiFDNG aa0YbN2cIneptduIkW3n2GqxZwhZpz620SGV19j6vQdKEUM/F3us7WwxQa7zU5+yrurp5peC+ Xgzv/kh7I/1UgB6FTA8SB5mQcB9BQ4gvIdN6MEmwml7jplOulrSe2azdWviAPObmyNYLV//Sb MEhx3+iM7DbQkQcAOD/LJ6A6y5M1XMmb1wXbEY2mkIUARKkKNT7pxv7ph/73L/gQyEYRwRZ99 PAZUlXXpX+byOrADBjTGfN4tU8A0XoLjrOF89EUbV/x6Nk/16sPy2cAnHeyCCYBj+M/5ceEbc aw8fqnwZWurFN/VmiNUxHXGIYV6/lfUAwjmI1RE9SgHHDClOPJa64Mhpxku9xELIAFZj/l+N1 V/TvsMtiGKj31uo+upJ34MAXp0EYhZ2Cg9vfKj1cvPQP/qWOwyB51fgCc/qFacNvsKDy0jmft WwsZqJ0NEalnfd7Vouqq+TUUUc9YOBX7/ApDXW6xAW/mDM8UvGSM1QQ6onkJ90tMTkXXAAvJT uCq+dBjAoKTVfAEqK3kJBevvq5j+B+jzNkifpTU7NT1mW8Vu6fPfgsQ74pRrVpzBBz+xddJhj gBMXoBjbrjUbOhZz263vxAwdd/wKeODcgEVdAgb5HZYPJXOlsJeZ2du+l+hWZ+hQsDDiCcRma rdg52IwWGlYmIaj3ziO78MlP9kIZfc3eCrNt+23td+YuZFJ3lBRpfnkc9NGo+5WKmW5tWBLGm zOcplZtmJcluivq16JwT2Q0KZ0WsmHST4W9PQe9+/A2v2ZaH9Ds+Yd/P0fB3OPVT7d5xmuihA s2xtFVnMVph5Ahz6nFQ65p9aSfWY6gUmg/8roo80ywnpjIBy2PbHqcObSdtuRR3Ux9u9Bq5dN JUnV5wjmRVU/49j+T7UWBRW8ileuV7xx6fJWH/QE+ei46OchdvAQm11TpdU8/aaDQgRFUgwnq 8I5REr5gCrj0VNcAtN17A9mKHDmvA6RdCPbP8ToteEBSWMTCZ7IBK9G9zOtHxM9eQOGdE7t+i Tw+qaIxXCkOoLdv9kCLzKmu8kTgYmfJgylJBv77RS8k8bl91UDwfK3+yA== Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org We need to prevent that users configure a screen size which is smaller than the currently selected font size. Otherwise rendering chars on the screen will access memory outside the graphics memory region. This patch adds a new function fbcon_modechange_possible() which implements this check and which may be extended with other checks later if necessary. The new function will be called from the FBIOPUT_VSCREENINFO ioctl handler in fbmem.c, which will then return -EINVAL to the user if the new screen size is too small. Signed-off-by: Helge Deller Cc: stable@vger.kernel.org # v5.4+ --- drivers/video/fbdev/core/fbcon.c | 27 +++++++++++++++++++++++++++ include/linux/fbcon.h | 4 ++++ 2 files changed, 31 insertions(+) -- 2.35.3 diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index e162d5e753e5..2ab7515ac842 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2736,6 +2736,33 @@ void fbcon_update_vcs(struct fb_info *info, bool all) } EXPORT_SYMBOL(fbcon_update_vcs); +/* let fbcon check if it supports a new screen resolution */ +int fbcon_modechange_possible(struct fb_info *info, struct fb_var_screeninfo *var) +{ + struct fbcon_ops *ops = info->fbcon_par; + struct vc_data *vc; + int i; + + WARN_CONSOLE_UNLOCKED(); + + if (!ops || ops->currcon < 0) + return -EINVAL; + + /* prevent setting a screen size which is smaller than font size */ + for (i = first_fb_vc; i <= last_fb_vc; i++) { + vc = vc_cons[i].d; + if (!vc || fbcon_info_from_console(i) != info) + continue; + + if (vc->vc_font.width > FBCON_SWAP(var->rotate, var->xres, var->yres) || + vc->vc_font.height > FBCON_SWAP(var->rotate, var->yres, var->xres)) + return -EINVAL; + } + + return 0; +} +EXPORT_SYMBOL(fbcon_modechange_possible); + int fbcon_mode_deleted(struct fb_info *info, struct fb_videomode *mode) { diff --git a/include/linux/fbcon.h b/include/linux/fbcon.h index ff5596dd30f8..2382dec6d6ab 100644 --- a/include/linux/fbcon.h +++ b/include/linux/fbcon.h @@ -15,6 +15,8 @@ void fbcon_new_modelist(struct fb_info *info); void fbcon_get_requirement(struct fb_info *info, struct fb_blit_caps *caps); void fbcon_fb_blanked(struct fb_info *info, int blank); +int fbcon_modechange_possible(struct fb_info *info, + struct fb_var_screeninfo *var); void fbcon_update_vcs(struct fb_info *info, bool all); void fbcon_remap_all(struct fb_info *info); int fbcon_set_con2fb_map_ioctl(void __user *argp); @@ -33,6 +35,8 @@ static inline void fbcon_new_modelist(struct fb_info *info) {} static inline void fbcon_get_requirement(struct fb_info *info, struct fb_blit_caps *caps) {} static inline void fbcon_fb_blanked(struct fb_info *info, int blank) {} +static inline int fbcon_modechange_possible(struct fb_info *info, + struct fb_var_screeninfo *var) { return 0; } static inline void fbcon_update_vcs(struct fb_info *info, bool all) {} static inline void fbcon_remap_all(struct fb_info *info) {} static inline int fbcon_set_con2fb_map_ioctl(void __user *argp) { return 0; }