From patchwork Tue Sep 1 15:11:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 310352 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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 08DD4C433E7 for ; Tue, 1 Sep 2020 16:15:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D86AD2078B for ; Tue, 1 Sep 2020 16:15:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598976905; bh=plGUxLET0oujABFoLlyotfUbHiJsGU5G4XC+4kPwuu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SMMri8g/n7PSP79icMSfEodnUFCW6B56BZWskymhS8bCgKP8M36ekDcfGBUMh70LZ F+hiRxZTBFGEA3Y+kVpgoHF7N/eOHzECS50kgijzdWK21b3xGB5l0gejI9n5XnI9rN Ogxadat+XuuHyJUnpGmNWcv48jyQGZYdnXDmAZMY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731464AbgIAQO7 (ORCPT ); Tue, 1 Sep 2020 12:14:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:40712 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731208AbgIAPfJ (ORCPT ); Tue, 1 Sep 2020 11:35:09 -0400 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 0FA4F205F4; Tue, 1 Sep 2020 15:35:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974508; bh=plGUxLET0oujABFoLlyotfUbHiJsGU5G4XC+4kPwuu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2ctY0z4MFJT4OtXb2YISyTISO+KiQeulO2lX3nj67ebU+1IhRPdC7BPfb+O9GZPj0 +z5CDaTZDt8ULG18FYTYyvQ7rctYAf/4uM7dCwDq8I70uuO826OeFYnUhC6JuZdWPn 5nLDD5rCL5tmtnfEjpQ+f+EPBUXFEhM/c7M+rLyY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Vetter , Tetsuo Handa , Sasha Levin , syzbot , kernel test robot Subject: [PATCH 5.4 204/214] fbmem: pull fbcon_update_vcs() out of fb_set_var() Date: Tue, 1 Sep 2020 17:11:24 +0200 Message-Id: <20200901151002.703499832@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901150952.963606936@linuxfoundation.org> References: <20200901150952.963606936@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: Tetsuo Handa [ Upstream commit d88ca7e1a27eb2df056bbf37ddef62e1c73d37ea ] syzbot is reporting OOB read bug in vc_do_resize() [1] caused by memcpy() based on outdated old_{rows,row_size} values, for resize_screen() can recurse into vc_do_resize() which changes vc->vc_{cols,rows} that outdates old_{rows,row_size} values which were saved before calling resize_screen(). Daniel Vetter explained that resize_screen() should not recurse into fbcon_update_vcs() path due to FBINFO_MISC_USEREVENT being still set when calling resize_screen(). Instead of masking FBINFO_MISC_USEREVENT before calling fbcon_update_vcs(), we can remove FBINFO_MISC_USEREVENT by calling fbcon_update_vcs() only if fb_set_var() returned 0. This change assumes that it is harmless to call fbcon_update_vcs() when fb_set_var() returned 0 without reaching fb_notifier_call_chain(). [1] https://syzkaller.appspot.com/bug?id=c70c88cfd16dcf6e1d3c7f0ab8648b3144b5b25e Reported-and-tested-by: syzbot Suggested-by: Daniel Vetter Signed-off-by: Tetsuo Handa Reported-by: kernel test robot for missing #include Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/075b7e37-3278-cd7d-31ab-c5073cfa8e92@i-love.sakura.ne.jp Signed-off-by: Sasha Levin --- drivers/video/fbdev/core/fbmem.c | 8 ++------ drivers/video/fbdev/core/fbsysfs.c | 4 ++-- drivers/video/fbdev/ps3fb.c | 5 +++-- include/linux/fb.h | 2 -- 4 files changed, 7 insertions(+), 12 deletions(-) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index e72738371ecbe..97abcd497c7e0 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -952,7 +952,6 @@ static int fb_check_caps(struct fb_info *info, struct fb_var_screeninfo *var, int fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var) { - int flags = info->flags; int ret = 0; u32 activate; struct fb_var_screeninfo old_var; @@ -1047,9 +1046,6 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var) event.data = &mode; fb_notifier_call_chain(FB_EVENT_MODE_CHANGE, &event); - if (flags & FBINFO_MISC_USEREVENT) - fbcon_update_vcs(info, activate & FB_ACTIVATE_ALL); - return 0; } EXPORT_SYMBOL(fb_set_var); @@ -1100,9 +1096,9 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, return -EFAULT; console_lock(); lock_fb_info(info); - info->flags |= FBINFO_MISC_USEREVENT; ret = fb_set_var(info, &var); - info->flags &= ~FBINFO_MISC_USEREVENT; + if (!ret) + fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL); unlock_fb_info(info); console_unlock(); if (!ret && copy_to_user(argp, &var, sizeof(var))) diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c index d54c88f88991d..65dae05fff8e6 100644 --- a/drivers/video/fbdev/core/fbsysfs.c +++ b/drivers/video/fbdev/core/fbsysfs.c @@ -91,9 +91,9 @@ static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var) var->activate |= FB_ACTIVATE_FORCE; console_lock(); - fb_info->flags |= FBINFO_MISC_USEREVENT; err = fb_set_var(fb_info, var); - fb_info->flags &= ~FBINFO_MISC_USEREVENT; + if (!err) + fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL); console_unlock(); if (err) return err; diff --git a/drivers/video/fbdev/ps3fb.c b/drivers/video/fbdev/ps3fb.c index 5ed2db39d8236..ce90483c50209 100644 --- a/drivers/video/fbdev/ps3fb.c +++ b/drivers/video/fbdev/ps3fb.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -824,12 +825,12 @@ static int ps3fb_ioctl(struct fb_info *info, unsigned int cmd, var = info->var; fb_videomode_to_var(&var, vmode); console_lock(); - info->flags |= FBINFO_MISC_USEREVENT; /* Force, in case only special bits changed */ var.activate |= FB_ACTIVATE_FORCE; par->new_mode_id = val; retval = fb_set_var(info, &var); - info->flags &= ~FBINFO_MISC_USEREVENT; + if (!retval) + fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL); console_unlock(); } break; diff --git a/include/linux/fb.h b/include/linux/fb.h index 756706b666a10..8221838fefd98 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -400,8 +400,6 @@ struct fb_tile_ops { #define FBINFO_HWACCEL_YPAN 0x2000 /* optional */ #define FBINFO_HWACCEL_YWRAP 0x4000 /* optional */ -#define FBINFO_MISC_USEREVENT 0x10000 /* event request - from userspace */ #define FBINFO_MISC_TILEBLITTING 0x20000 /* use tile blitting */ /* A driver may set this flag to indicate that it does want a set_par to be