+1 That is why I am thinking if any check is needed can it be a
meaningful check such as "Is there room to store the file I am about to
upload" rather than some arbitrary value which will be wrong for someone
and as I point out even if you allow a large value that still does not
actually solve the problem.
On 04/11/15 09:26, Stuart Douglas wrote:
Is this actually a real world problem that users are running into?
If not then adding any kind of limit seems like it has the potential to
cause more problems than it will solve.
As others have pointed out I think the security angle is moot, as if you
can deploy to the server your deployment can DOS the server in any
number of ways, security manager or no security manager (the simplest
way is just to put while(true){} in a Servlet then send some requests,
after a while you will lock up every web thread and use 100% CPU, and
there is no way to configure the security manager to stop this).
Stuart
On Wed, 4 Nov 2015 at 20:12 Darran Lofthouse <darran.lofthouse(a)jboss.com
<mailto:darran.lofthouse@jboss.com>> wrote:
From within GWT is there any option to detect the file size before
uploading?
I wonder if it is better if we had something where we ask the server
"Can you accept a file of size X?" before commencing an upload rather
than setting some arbitrary limit. Something like that could also be
used in domain mode before deployments are distributed allowing them to
fail early.
You may have 8Gb free on your disk and have 2Gb deployments, after a
couple of deployments the space would be gone but the arbitrary value
would still allow 2Gb uploads.
Regards,
Darran Lofthouse.
On 04/11/15 01:13, Lin Gao wrote:
>> On 11/03/2015 02:41 AM, Lin Gao wrote:
>>> Hi,
>>>
>>> WildFly does not limit the deployment file size, users with
appropriate
>>> privilege(deployer) can select any file to deploy from both
CLI and web
>>> console.
>>>
>>> For the too big file, it may exhaust all available disk
space, and in
>>> some cases, even small file can exhaust the disk space if
the current
>>> disk space is not big enough.
>>>
>>> So shall we limit file size of the deployment in WildFly?
or shall we
>>> limit the available disk space? or shall we just show a
warning message
>>> to users?
>>>
>>> If we do, where in the management API configuration for
this should be
>>> done, if it is done this way?
>>>
>>> Arbitrary limits will break users, so if we have an
arbitrary limit it
>>> needs to be easily adjusted.
>>>
>>> In case of domain mode, different hosts may have different
disk space,
>>> which means they are likely have different capacity to hold
deployment
>>> files. For example, servers in server-group-A may have 2GB
available
>>> disk space, servers in server-group-B may have 200MB
available disk
>>> space. An unified limit for the whole domain seems not fair
for the
>>> servers with more available disk space.
>>>
>>> Also, WildFly does not limit type of the deployment file,
but it might
>>> need a separate discussion if necessary?
>>>
>>> Any thoughts?
>>
>> Is this in response to a real observed problem?
>
> Yes it is.
>
>> In general, if the user
>> doesn't have space for a deployment, the deployment will fail
with an
>> error and (I am fairly certain) will delete the partial
deployment. If
>> there is space, then the deployment will succeed regardless of size.
>
>> It's interesting that the JIRA you reference speaks in terms of
>> security. If an admin wants to lock down storage space, it's
probably
>> best to do it at the operating system level using e.g. disk quotas -
>> there are too many ways to get the application server to write
arbitrary
>> amounts of data to the file system, regardless of the presence of a
>> security manager or any other application-level control.
>>
>> I'm pretty sure that if an attacker has permission to upload
deployments
>> to the server, they already essentially have control over the
server.
>> This should be an OS level concern.
>
> The JIRA in question was a 'bug' related to security at first,
after several
> rounds of discussion, it is agreed that it is not a security
vulnerability, but
> an 'Enhancement'.
>
> The proposed requirement for the enhancement is:
>
> Provide an option in config to alert user that
> a) File is larger than a configurable limit
> b) File type is/is not valid.
>
> but it may need more discussion in community on both the
requirement and design
> if it will be done, that is why this thread comes out in first
place. :-)
>
>>> FYI:
https://issues.jboss.org/browse/WFCORE-1057
>>>
>
> Best Regards
> --
> Lin Gao
> Software Engineer
> JBoss by Red Hat
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