From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 15731C2D0A3 for ; Tue, 3 Nov 2020 20:47:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBAD622409 for ; Tue, 3 Nov 2020 20:47:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436456; bh=nH+Hai5haiaq1AHiyM7qvEhL+2pWHuukL45l/ygcukw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=haMmR0ZjWl1XFxnPQnJBhjcjIpulckR1jt8YLRYG/C7G7pUWavMTyS/qJ1qHWhGEk 2TI4oAR7kV3V0u4WT643nVPiNISvfKc+Sx6DaM+Rb2lZSggKSgpUax1mORAo5iQezZ hiX1XSrvlM6yWNf1uFo6LC6GQ/hqCUAXx35/6V1c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731361AbgKCUre (ORCPT ); Tue, 3 Nov 2020 15:47:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:37928 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731354AbgKCUra (ORCPT ); Tue, 3 Nov 2020 15:47:30 -0500 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 1661822404; Tue, 3 Nov 2020 20:47:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436449; bh=nH+Hai5haiaq1AHiyM7qvEhL+2pWHuukL45l/ygcukw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jy4ND1Pqp90bm7Hpj27Z2TzcCs+9Y5f2S0UrKMdp0u6SUju1k85YWsBK10rLvfX4S bzglcYDTWp2EVueEqX+i9tf5WXgE7CV/yxNNNyDigReRmUgUi7mSzxwlyyNs8rPGRb tygNTKEYDUFnj4GBAxi7lKTQrrLkgy35lDDmT9+Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Slaby Subject: [PATCH 5.9 254/391] vt: keyboard, simplify vt_kdgkbsent Date: Tue, 3 Nov 2020 21:35:05 +0100 Message-Id: <20201103203404.161112322@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203348.153465465@linuxfoundation.org> References: <20201103203348.153465465@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Slaby commit 6ca03f90527e499dd5e32d6522909e2ad390896b upstream. Use 'strlen' of the string, add one for NUL terminator and simply do 'copy_to_user' instead of the explicit 'for' loop. This makes the KDGKBSENT case more compact. The only thing we need to take care about is NULL 'func_table[i]'. Use an empty string in that case. The original check for overflow could never trigger as the func_buf strings are always shorter or equal to 'struct kbsentry's. Cc: Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20201019085517.10176-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/keyboard.c | 28 +++++++++------------------- 1 file changed, 9 insertions(+), 19 deletions(-) --- a/drivers/tty/vt/keyboard.c +++ b/drivers/tty/vt/keyboard.c @@ -1995,9 +1995,7 @@ out: int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) { struct kbsentry *kbs; - char *p; u_char *q; - u_char __user *up; int sz, fnw_sz; int delta; char *first_free, *fj, *fnw; @@ -2023,23 +2021,15 @@ int vt_do_kdgkb_ioctl(int cmd, struct kb i = array_index_nospec(kbs->kb_func, MAX_NR_FUNC); switch (cmd) { - case KDGKBSENT: - sz = sizeof(kbs->kb_string) - 1; /* sz should have been - a struct member */ - up = user_kdgkb->kb_string; - p = func_table[i]; - if(p) - for ( ; *p && sz; p++, sz--) - if (put_user(*p, up++)) { - ret = -EFAULT; - goto reterr; - } - if (put_user('\0', up)) { - ret = -EFAULT; - goto reterr; - } - kfree(kbs); - return ((p && *p) ? -EOVERFLOW : 0); + case KDGKBSENT: { + /* size should have been a struct member */ + unsigned char *from = func_table[i] ? : ""; + + ret = copy_to_user(user_kdgkb->kb_string, from, + strlen(from) + 1) ? -EFAULT : 0; + + goto reterr; + } case KDSKBSENT: if (!perm) { ret = -EPERM;