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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C9F1C54EE9 for ; Fri, 9 Sep 2022 02:02:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229944AbiIICCt (ORCPT ); Thu, 8 Sep 2022 22:02:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229506AbiIICCr (ORCPT ); Thu, 8 Sep 2022 22:02:47 -0400 Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F17E9BB7B for ; Thu, 8 Sep 2022 19:02:46 -0700 (PDT) Received: by mail-pf1-x443.google.com with SMTP id e5so293923pfl.2 for ; Thu, 08 Sep 2022 19:02:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date; bh=foPxCX6VLJ9B+8nDtwn3UiII8jTDVry0sGuJiFsdc7w=; b=jbdPvMyHwvPar/AdBxG9kQhbdLM5EgNmI6zFroWElLZnIxopPf6hfVNCvskM0rB8Dr Bycmx9bHub+ICIPdGPVFtiSyqCyRwt/MIqU9JWZ/KDhwDeoF6J7vo2Et7Qrw2w7FoIZ3 tieDQuMIPCoyZ+cvzcigLltoNfSVFT4VgzVHxDJli8Dp/0zuivR2Vb0Gei5VoyfjZn5q cpx5Cnrun24KI0BebIHtkXC7qPFUU3vLzJVJnFaen2VcIxqt7R3bmun5xMeHJqDplmZe Ma2zKBJFpzJbw+2GEtL2YP0LmQU7yddOSlxFEXPzOq/g7CC0RDnkgDHQw/TsDRiqOGcA +oGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date; bh=foPxCX6VLJ9B+8nDtwn3UiII8jTDVry0sGuJiFsdc7w=; b=scZg2GR6wyM1CK/35mF1RJ5P3XA1pR8mLxAEY1LFj7BVjgiXti5AkCZ6s4EX3asZX4 CONFuhFXwhkKjqWnsD6A2jKYDsuoBf2aD+QSh8orwl3xPQm7tU+deiBCzev2FKk23H/2 zDq5eEaGhSCgujq8z6/aPlxdnNYiZQxHWzLPRRCuIB53HrxWuVV5ldElvpiH3m2YcS63 LstJ2RDiy/RXzhAQdYCFg51cFh+Z0JAidigNu4a2ee4+U1T884PkHBHv9BjWOR16KhXy PViaoj89EHU5CJC3S4A1cPPPH5uqD4QzpkVS0gyhqJPGwSBuHbl4D0aTcxc9Dc6wFn0f sFWA== X-Gm-Message-State: ACgBeo1Pzxv6QLGVdxPPF0UWwnGzlFoWbVZPYDtLDpzZJj4JiSwEH8t5 28Z0Ah9azvPOaM6Sdv33h70= X-Google-Smtp-Source: AA6agR6AamZKFaJCNBKOCxwSyKMe5Kbze5qsvU2r5M4OI2+9oVkyiJIK7It/78nP+ZWGTLcKYx7JRA== X-Received: by 2002:a63:5a0b:0:b0:434:4748:4e7a with SMTP id o11-20020a635a0b000000b0043447484e7amr10211259pgb.561.1662688965993; Thu, 08 Sep 2022 19:02:45 -0700 (PDT) Received: from [192.168.50.247] ([129.227.150.140]) by smtp.gmail.com with ESMTPSA id 2-20020a170902c20200b00177f3c40f9bsm200827pll.68.2022.09.08.19.02.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Sep 2022 19:02:45 -0700 (PDT) Message-ID: Date: Fri, 9 Sep 2022 10:02:41 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH] tty: vt: add a bounds checking in vt_do_kdgkb_ioctl() Content-Language: en-US To: Jiri Slaby , gregkh@linuxfoundation.org, changlianzhi@uniontech.com, dmitry.torokhov@gmail.com Cc: linux-kernel@vger.kernel.org References: <20220908075403.27930-1-hbh25y@gmail.com> <6236da54-c651-9dc7-f5ce-824be96b3e9d@kernel.org> From: Hangyu Hua In-Reply-To: <6236da54-c651-9dc7-f5ce-824be96b3e9d@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/9/2022 16:10, Jiri Slaby wrote: > On 08. 09. 22, 9:54, Hangyu Hua wrote: >> As array_index_nospec's comments indicate，a bounds checking need to add >> before calling array_index_nospec. >> >> Signed-off-by: Hangyu Hua >> --- >>   drivers/tty/vt/keyboard.c | 3 +++ >>   1 file changed, 3 insertions(+) >> >> diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c >> index be8313cdbac3..b9845455df79 100644 >> --- a/drivers/tty/vt/keyboard.c >> +++ b/drivers/tty/vt/keyboard.c >> @@ -2067,6 +2067,9 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry >> __user *user_kdgkb, int perm) >>       if (get_user(kb_func, &user_kdgkb->kb_func)) >>           return -EFAULT; >> +    if (kb_func >= MAX_NR_FUNC) > > kb_func is unsigned char and MAX_NR_FUNC is 256. So this should be > eliminated by the compiler anyway. > > But the check might be a good idea if we ever decide to support more > keys. But will/can we? I am not so sure, so adding it right now is kind > of superfluous. In any way we'd need to introduce a completely different > iterface/ioctls. If you say so, I think greg should be right. We don't need any bounds checking here. It may be a good idea to delete redundant array_index_nospec. Do i need to make a new patch? > >> +        return -EFAULT; > > EINVAL would be more appropriate, IMO. > >> + >>       kb_func = array_index_nospec(kb_func, MAX_NR_FUNC); >>       switch (cmd) { > > thanks, Thanks, Hangyu