Re: [PATCH] autofs4: check dev ioctl size before allocating

Re: [PATCH] autofs4: check dev ioctl size before allocating

[Sasha Levin]

Ping? Anyone wants to take this?

On 03/15/2014 09:40 PM, Sasha Levin wrote:
> There wasn't any check of the size passed from userspace before
> trying to allocate the memory required.
> 
> This meant that userspace might request more space than allowed,
> triggering an OOM.
> 
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> ---
>  fs/autofs4/dev-ioctl.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
> index 3182c0e..86fa7af 100644
> --- a/fs/autofs4/dev-ioctl.c
> +++ b/fs/autofs4/dev-ioctl.c
> @@ -103,6 +103,9 @@ static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *i
>  	if (tmp.size < sizeof(tmp))
>  		return ERR_PTR(-EINVAL);
>  
> +	if (tmp.size > (PATH_MAX + sizeof(tmp)))
> +		return ERR_PTR(-E2BIG);
> +
>  	return memdup_user(in, tmp.size);
>  }
>  
> 

Re: [PATCH] autofs4: check dev ioctl size before allocating

[Ian Kent]

On Sat, 2014-04-05 at 11:06 -0400, Sasha Levin wrote:
> Ping? Anyone wants to take this?

Is this causing a problem for users?
If it is I'll send it to Andrew straight away.

I do have this on my queue but don't have any other patches to send so
it's just sitting there.

If it worries you I'll send it to Andrew now.

> 
> On 03/15/2014 09:40 PM, Sasha Levin wrote:
> > There wasn't any check of the size passed from userspace before
> > trying to allocate the memory required.
> > 
> > This meant that userspace might request more space than allowed,
> > triggering an OOM.
> > 
> > Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> > ---
> >  fs/autofs4/dev-ioctl.c |    3 +++
> >  1 files changed, 3 insertions(+), 0 deletions(-)
> > 
> > diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
> > index 3182c0e..86fa7af 100644
> > --- a/fs/autofs4/dev-ioctl.c
> > +++ b/fs/autofs4/dev-ioctl.c
> > @@ -103,6 +103,9 @@ static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *i
> >  	if (tmp.size < sizeof(tmp))
> >  		return ERR_PTR(-EINVAL);
> >  
> > +	if (tmp.size > (PATH_MAX + sizeof(tmp)))
> > +		return ERR_PTR(-E2BIG);
> > +
> >  	return memdup_user(in, tmp.size);
> >  }
> >  
> > 
> 

Re: [PATCH] autofs4: check dev ioctl size before allocating

[Sasha Levin]

On 04/05/2014 11:03 PM, Ian Kent wrote:
> On Sat, 2014-04-05 at 11:06 -0400, Sasha Levin wrote:
>> Ping? Anyone wants to take this?
> 
> Is this causing a problem for users?
> If it is I'll send it to Andrew straight away.
> 
> I do have this on my queue but don't have any other patches to send so
> it's just sitting there.
> 
> If it worries you I'll send it to Andrew now.

It's not really a pressing issue since /dev/autofs is accessible only to
root. I also doubt that it causes problems for actual users.

If there are no issues with the patch, I think it's best if you could
ack/sign off on it and if Andrew wants to take it now, he could. If he
doesn't, it could wait for whenever.

I just don't want it getting lost somewhere and never making it upstream.


Thanks,
Sasha

Re: [PATCH] autofs4: check dev ioctl size before allocating

[Ian Kent]

On Sat, 2014-04-05 at 23:11 -0400, Sasha Levin wrote:
> On 04/05/2014 11:03 PM, Ian Kent wrote:
> > On Sat, 2014-04-05 at 11:06 -0400, Sasha Levin wrote:
> >> Ping? Anyone wants to take this?
> > 
> > Is this causing a problem for users?
> > If it is I'll send it to Andrew straight away.
> > 
> > I do have this on my queue but don't have any other patches to send so
> > it's just sitting there.
> > 
> > If it worries you I'll send it to Andrew now.
> 
> It's not really a pressing issue since /dev/autofs is accessible only to
> root. I also doubt that it causes problems for actual users.
> 
> If there are no issues with the patch, I think it's best if you could
> ack/sign off on it and if Andrew wants to take it now, he could. If he
> doesn't, it could wait for whenever.
> 
> I just don't want it getting lost somewhere and never making it upstream.

OK, but since I'm going to send it I looked at it a bit closer.
Shouldn't the E2BIG be ENAMETOOLONG since it's a file path that's being
passed?

I can change that and send it if you agree with the change.

Ian

Re: [PATCH] autofs4: check dev ioctl size before allocating

[Sasha Levin]

On 04/05/2014 11:53 PM, Ian Kent wrote:
> On Sat, 2014-04-05 at 23:11 -0400, Sasha Levin wrote:
>> On 04/05/2014 11:03 PM, Ian Kent wrote:
>>> On Sat, 2014-04-05 at 11:06 -0400, Sasha Levin wrote:
>>>> Ping? Anyone wants to take this?
>>>
>>> Is this causing a problem for users?
>>> If it is I'll send it to Andrew straight away.
>>>
>>> I do have this on my queue but don't have any other patches to send so
>>> it's just sitting there.
>>>
>>> If it worries you I'll send it to Andrew now.
>>
>> It's not really a pressing issue since /dev/autofs is accessible only to
>> root. I also doubt that it causes problems for actual users.
>>
>> If there are no issues with the patch, I think it's best if you could
>> ack/sign off on it and if Andrew wants to take it now, he could. If he
>> doesn't, it could wait for whenever.
>>
>> I just don't want it getting lost somewhere and never making it upstream.
> 
> OK, but since I'm going to send it I looked at it a bit closer.
> Shouldn't the E2BIG be ENAMETOOLONG since it's a file path that's being
> passed?
> 
> I can change that and send it if you agree with the change.

Looks good to me, thanks!


Thanks,
Sasha