From patchwork Mon Nov 9 12:54:49 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: 322560 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 BC389C2D0A3 for ; Mon, 9 Nov 2020 13:46:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82274206B2 for ; Mon, 9 Nov 2020 13:46:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604929605; bh=z2FW9ugi5dedmmn4QtO7JOx61d2Qha7FZtph8t1rbxU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fzWvqRmmZ44gXKy4x543lLjVVcLfCknjner3BbYiJjONKSdXs3G/gJWXClsw+M3N+ cRajL4rOR6vVrrPXMoVE+RCFM19fA80f9OU0Voirgcqz+JYnLBWOBNNiqdKWLFvzrs sLoYtfXj/6cKo7JcQswBVKJrrYM0mk5INtriOBVw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730000AbgKINqp (ORCPT ); Mon, 9 Nov 2020 08:46:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:52040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729999AbgKIM5c (ORCPT ); Mon, 9 Nov 2020 07:57:32 -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 6CD8A20684; Mon, 9 Nov 2020 12:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604926652; bh=z2FW9ugi5dedmmn4QtO7JOx61d2Qha7FZtph8t1rbxU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l0pFRmFxkK7v5yhKFvIo4cBJb0+jtTIX4yNNkBgaPW0ABKbMBvQ6aBWXvq1XXqugd u3dEhmn4CTGpbcJWIATYoErIITH+V8rt53yoRZbHTLKUw2tpB5su7Xpt5QbCgSSMAM CZY1SI5ScvC+JMV8YjZ7G7CLQdjRfNLe3YVuUWiE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Slaby Subject: [PATCH 4.4 42/86] vt: keyboard, simplify vt_kdgkbsent Date: Mon, 9 Nov 2020 13:54:49 +0100 Message-Id: <20201109125022.867933622@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125020.852643676@linuxfoundation.org> References: <20201109125020.852643676@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -1973,9 +1973,7 @@ 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; @@ -2001,23 +1999,15 @@ int vt_do_kdgkb_ioctl(int cmd, struct kb i = kbs->kb_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;