From patchwork Mon Jul 19 14:51:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 479972 Delivered-To: patch@linaro.org Received: by 2002:a02:c94a:0:0:0:0:0 with SMTP id u10csp4251143jao; Mon, 19 Jul 2021 08:49:15 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzPXmAWxqHzBUWe832LnuuUYXd6ng16vhFeIG8h6y2dnxFaG2ZGDxfZbrLPYCfkwvWMQDKa X-Received: by 2002:a05:6402:3089:: with SMTP id de9mr35524122edb.69.1626709754984; Mon, 19 Jul 2021 08:49:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1626709754; cv=none; d=google.com; s=arc-20160816; b=lP/aDZojSA5pxHAkP2eIUGAVKLwO7fN9+ViBsvY72kbtw8cmtWI7lcN5UILRA8XgYD frN/d1Rd7t3qEihMgeCi67Rse8dYn65QPaJ8KMt54u3ZZFd2nKwnHrZiZWfcfcdsUMT3 3xQj6CH92iFWwbY+6X+BWbWcQXJCQRswtVcnQSwNCBAUY7abi7cqhsUebXPRu/MQRW8/ y6LWjJW1fmzAEfF/KiJEeSwunjCLsFG3JPRTs4+X9Qjy5B7rxLJBYLh20yP4WyTK6kJs D6DdO9E3KN36wagqGDF7baeSclXSmCfq+0diOQy1fPsecgJV31vXLEFW8vPUuTSUzVBl hvFg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=bJBFLsV0tnxkpBSzfMTI/neALXcTtbOWB8Eei9iKf3k=; b=ElqmKmSJPQwywxyNjdpZB/9Q+AmIDguwLdIqzNLXkQG6rG+WG3Bnb/pKQhpU6IJntn SexdIOvGcnVOevGnT3ltHgx2B4n/RG8PYv6e98Ji1l5XMy3O6k+Q/wUe2kd+f2GpCm5m eAxVTC2200rCshwQOq6z2xPssNIzdELVZsiVleNsuOLe4K+C313L3lGNW6e0WdfDaYwJ M2foUx3GEiYBgL0Xe5W0sF0oY2VYzU9HrYQKWqM5dCdX3m6/GbkwywPS/LLIasr7Twqy UwMJCGVg9OCmchLCbnB4VWJ2HhJZIGBVmhdJ25Yuo6jhMj8CF8A/JwoJlXwG5CQ/WPai ADQw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=FL8Tnf1a; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id x22si21782145edd.466.2021.07.19.08.49.14; Mon, 19 Jul 2021 08:49:14 -0700 (PDT) Received-SPF: pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=FL8Tnf1a; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344613AbhGSPIZ (ORCPT + 12 others); Mon, 19 Jul 2021 11:08:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:39496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343548AbhGSPF6 (ORCPT ); Mon, 19 Jul 2021 11:05:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E43EB606A5; Mon, 19 Jul 2021 15:46:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626709597; bh=TUKg6115f2BCoUDBCrHrgrDCCZlSJ/qcFV4GC2dSTU8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FL8Tnf1aY75awXokZNvh8UE57gARtu+WYqy0TkkUj3vRYBQ0RZ82wI1N6ysu+BV/C FSxFyHxJbUIC3mpnleSilfHvhEwe59J7aAKar0LLqNHjaH48zmj1QptJT9x8YitPHN xa2nCEENlXnk01nnvkDiIbYaD6CugoS++krv02Ws= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhen Lei , Daniel Vetter Subject: [PATCH 5.4 007/149] fbmem: Do not delete the mode that is still in use Date: Mon, 19 Jul 2021 16:51:55 +0200 Message-Id: <20210719144903.173252259@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144901.370365147@linuxfoundation.org> References: <20210719144901.370365147@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Zhen Lei commit 0af778269a522c988ef0b4188556aba97fb420cc upstream. The execution of fb_delete_videomode() is not based on the result of the previous fbcon_mode_deleted(). As a result, the mode is directly deleted, regardless of whether it is still in use, which may cause UAF. ================================================================== BUG: KASAN: use-after-free in fb_mode_is_equal+0x36e/0x5e0 \ drivers/video/fbdev/core/modedb.c:924 Read of size 4 at addr ffff88807e0ddb1c by task syz-executor.0/18962 CPU: 2 PID: 18962 Comm: syz-executor.0 Not tainted 5.10.45-rc1+ #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ... Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x137/0x1be lib/dump_stack.c:118 print_address_description+0x6c/0x640 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report+0x13d/0x1e0 mm/kasan/report.c:562 fb_mode_is_equal+0x36e/0x5e0 drivers/video/fbdev/core/modedb.c:924 fbcon_mode_deleted+0x16a/0x220 drivers/video/fbdev/core/fbcon.c:2746 fb_set_var+0x1e1/0xdb0 drivers/video/fbdev/core/fbmem.c:975 do_fb_ioctl+0x4d9/0x6e0 drivers/video/fbdev/core/fbmem.c:1108 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 18960: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0x108/0x140 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1541 [inline] slab_free_freelist_hook+0xd6/0x1a0 mm/slub.c:1574 slab_free mm/slub.c:3139 [inline] kfree+0xca/0x3d0 mm/slub.c:4121 fb_delete_videomode+0x56a/0x820 drivers/video/fbdev/core/modedb.c:1104 fb_set_var+0x1f3/0xdb0 drivers/video/fbdev/core/fbmem.c:978 do_fb_ioctl+0x4d9/0x6e0 drivers/video/fbdev/core/fbmem.c:1108 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 13ff178ccd6d ("fbcon: Call fbcon_mode_deleted/new_modelist directly") Signed-off-by: Zhen Lei Cc: # v5.3+ Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210712085544.2828-1-thunder.leizhen@huawei.com Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/core/fbmem.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -965,13 +965,11 @@ fb_set_var(struct fb_info *info, struct fb_var_to_videomode(&mode2, &info->var); /* make sure we don't delete the videomode of current var */ ret = fb_mode_is_equal(&mode1, &mode2); - - if (!ret) - fbcon_mode_deleted(info, &mode1); - - if (!ret) - fb_delete_videomode(&mode1, &info->modelist); - + if (!ret) { + ret = fbcon_mode_deleted(info, &mode1); + if (!ret) + fb_delete_videomode(&mode1, &info->modelist); + } return ret ? -EINVAL : 0; }