From nobody Sun Dec 14 06:23:44 2025 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 BCC22C00140 for ; Mon, 15 Aug 2022 19:49:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344745AbiHOTtb (ORCPT ); Mon, 15 Aug 2022 15:49:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344565AbiHOTr0 (ORCPT ); Mon, 15 Aug 2022 15:47:26 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9252A71737; Mon, 15 Aug 2022 11:49:40 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2FA88B810A1; Mon, 15 Aug 2022 18:49:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62311C433C1; Mon, 15 Aug 2022 18:49:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660589377; bh=THYaxhYxEtt5DwL3NnXBSqE1FH6qDsr39tfqXb4p+iA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rd/278UB4SHCwcCfdz8X7aX975cruP6mwc07y5q5MSq4mWpmAHNMYGhx1+igS2L6m eltcw3k3wKBUVHEhQZwUCa2Uv27JRoe5lkKqTCFCxGA9lciqR5xep4riebl1PaUSYe RmxUmjr7ZcuVRakvb54rZs0R2pj2w+x8Fznun5Uk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zheyu Ma , Helge Deller , Sasha Levin Subject: [PATCH 5.15 668/779] video: fbdev: s3fb: Check the size of screen before memset_io() Date: Mon, 15 Aug 2022 20:05:12 +0200 Message-Id: <20220815180405.892058097@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Zheyu Ma [ Upstream commit 6ba592fa014f21f35a8ee8da4ca7b95a018f13e8 ] In the function s3fb_set_par(), the value of 'screen_size' is calculated by the user input. If the user provides the improper value, the value of 'screen_size' may larger than 'info->screen_size', which may cause the following bug: [ 54.083733] BUG: unable to handle page fault for address: ffffc900030000= 00 [ 54.083742] #PF: supervisor write access in kernel mode [ 54.083744] #PF: error_code(0x0002) - not-present page [ 54.083760] RIP: 0010:memset_orig+0x33/0xb0 [ 54.083782] Call Trace: [ 54.083788] s3fb_set_par+0x1ec6/0x4040 [ 54.083806] fb_set_var+0x604/0xeb0 [ 54.083836] do_fb_ioctl+0x234/0x670 Fix the this by checking the value of 'screen_size' before memset_io(). Fixes: a268422de8bf ("fbdev driver for S3 Trio/Virge") Signed-off-by: Zheyu Ma Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/s3fb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/s3fb.c b/drivers/video/fbdev/s3fb.c index 5c74253e7b2c..a936455a3df2 100644 --- a/drivers/video/fbdev/s3fb.c +++ b/drivers/video/fbdev/s3fb.c @@ -902,6 +902,8 @@ static int s3fb_set_par(struct fb_info *info) value =3D clamp((htotal + hsstart + 1) / 2 + 2, hsstart + 4, htotal + 1); svga_wcrt_multi(par->state.vgabase, s3_dtpc_regs, value); =20 + if (screen_size > info->screen_size) + screen_size =3D info->screen_size; memset_io(info->screen_base, 0x00, screen_size); /* Device and screen back on */ svga_wcrt_mask(par->state.vgabase, 0x17, 0x80, 0x80); --=20 2.35.1