From patchwork Tue Apr 5 07:27:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 557728 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 E69C0C38A2C for ; Tue, 5 Apr 2022 09:08:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236638AbiDEJDT (ORCPT ); Tue, 5 Apr 2022 05:03:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238166AbiDEIaX (ORCPT ); Tue, 5 Apr 2022 04:30:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E89821262; Tue, 5 Apr 2022 01:21:43 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 0728160FF7; Tue, 5 Apr 2022 08:21:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C92CC385A1; Tue, 5 Apr 2022 08:21:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649146902; bh=JGWiwNllUTbrLCY26NOZmLgLRs444AfzJaIlZXaGIoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LhxSB9w1ydjnxxBX6ximbSUfH25t+lHuqtF7CEniX9scpFOx5dhUar3MLXcdQ6Mi0 iQEpmx1BNNl0A/0CEekGk/wea9wpSrdQOmxVEPlbFLyecVZd5eKrk+Mlfg2p9RHaZ/ kwelhSoGqMnqDF5V35GOAzWscHhZN6PQwaab5rBc= 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 5.17 0931/1126] video: fbdev: sm712fb: Fix crash in smtcfb_write() Date: Tue, 5 Apr 2022 09:27:58 +0200 Message-Id: <20220405070434.843747324@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Zheyu Ma [ Upstream commit 4f01d09b2bbfbcb47b3eb305560a7f4857a32260 ] When the sm712fb driver writes three bytes to the framebuffer, the driver will crash: BUG: unable to handle page fault for address: ffffc90001ffffff RIP: 0010:smtcfb_write+0x454/0x5b0 Call Trace: vfs_write+0x291/0xd60 ? do_sys_openat2+0x27d/0x350 ? __fget_light+0x54/0x340 ksys_write+0xce/0x190 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Fix it by removing the open-coded endianness fixup-code. Signed-off-by: Zheyu Ma Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/sm712fb.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/drivers/video/fbdev/sm712fb.c b/drivers/video/fbdev/sm712fb.c index b60a2730f0a8..092a1caa1208 100644 --- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1119,7 +1119,7 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, count = total_size - p; } - buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, GFP_KERNEL); + buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!buffer) return -ENOMEM; @@ -1137,24 +1137,11 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, break; } - for (i = c >> 2; i--;) { - fb_writel(big_swap(*src), dst++); + for (i = (c + 3) >> 2; i--;) { + fb_writel(big_swap(*src), dst); + dst++; src++; } - if (c & 3) { - u8 *src8 = (u8 *)src; - u8 __iomem *dst8 = (u8 __iomem *)dst; - - for (i = c & 3; i--;) { - if (i & 1) { - fb_writeb(*src8++, ++dst8); - } else { - fb_writeb(*src8++, --dst8); - dst8 += 2; - } - } - dst = (u32 __iomem *)dst8; - } *ppos += c; buf += c;