linux-kernel - Re: [PATCH] rfkill: return ENOTTY on invalid ioctl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <07948380-e893-4b1f-e96d-cf889d57d512@intel.com>
Date:   Mon, 6 Nov 2023 11:30:05 +0100
From:   Przemek Kitszel <przemyslaw.kitszel@...el.com>
To:     Thomas Weißschuh <linux@...ssschuh.net>
CC:     Johannes Berg <johannes@...solutions.net>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        <linux-wireless@...r.kernel.org>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] rfkill: return ENOTTY on invalid ioctl

On 11/2/23 20:14, Thomas Weißschuh wrote:
> Hi!
> 
> On 2023-11-02 09:57:45+0100, Przemek Kitszel wrote:
>> On 11/1/23 20:41, Thomas Weißschuh wrote:
>>> For unknown ioctls the correct error is
>>> ENOTTY "Inappropriate ioctl for device".
>>
>> For sure!
>>
>> I would like to learn more of why this is not an UAPI breaking change?
> 
> "break" would mean that some user application worked correctly before
> but does not do so anymore with this change.
> 
> This seems highly unlikely and I was not able to find such an
> application via Debian code search.
> 
> In general I did *not* mark this change for stable so if some
> application would indeed break it gets detected before the patch hits
> a release.
> 
>>>
>>> ENOSYS as returned before should only be used to indicate that a syscall
>>> is not available at all.
>>>
>>> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
>>> ---
>>>    net/rfkill/core.c | 4 ++--
>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/rfkill/core.c b/net/rfkill/core.c
>>> index 14cc8fe8584b..c3feb4f49d09 100644
>>> --- a/net/rfkill/core.c
>>> +++ b/net/rfkill/core.c
>>> @@ -1351,11 +1351,11 @@ static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
>>>    			     unsigned long arg)
>>>    {
>>>    	struct rfkill_data *data = file->private_data;
>>> -	int ret = -ENOSYS;
>>> +	int ret = -ENOTTY;
>>>    	u32 size;
>>>    	if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
>>> -		return -ENOSYS;
>>> +		return -ENOTTY;
>>>    	mutex_lock(&data->mtx);
>>>    	switch (_IOC_NR(cmd)) {
>>>
>>> ---
>>> base-commit: 7d461b291e65938f15f56fe58da2303b07578a76
>>> change-id: 20231101-rfkill-ioctl-enosys-00a2bb0a4ab1
>>>
>>> Best regards,
>>

Thanks!

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@...el.com>