Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj wrote: > Unfortunately this in not an options since all the processes share > objects in memory which are about 1gig for each node. Having a copy of > this in each user process is just not an options. I think I'm going to > use RestrictedPython from zope3 svn which should take care of 70-80 % > of the problem. I wonder whether it is possible to fork() the program, restricting the memory usuage for the forked program. In most unix variants, forked programs share memory until that memory is written to. Of course this may not be useful if there's data going back and forth all the time. -- Jeremy Sanders http://www.jeremysanders.net/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
Unfortunately this in not an options since all the processes share objects in memory which are about 1gig for each node. Having a copy of this in each user process is just not an options. I think I'm going to use RestrictedPython from zope3 svn which should take care of 70-80 % of the problem. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj wrote: > 2. restrict the amount of memory a module uses as well. For instance > how can I restrict a user from doing a = range(100) or similar > tasks so that my whole compute farm does not come down. The safest way to do this in unix is to run the model in a separate process, and use ulimit (or the resource module) to limit the memory usage. -- Jeremy Sanders http://www.jeremysanders.net/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj wrote: > I have an application which allows multiple users to write models. > These models get distributed on a grid of compute engines. users submit > their models through a web interface. I want to > > 1. restrict the user from doing any file io, exec, import, eval, etc. I > was thinking of writing a plugin for pylint to do all the checks? Is > this is a good way given that there is no restricted python. What are > the things I should serach for in python code I'm not sure why you want to prevent e.g. all file io. Let the jobs run as users with very limited permissions. > 2. restrict the amount of memory a module uses as well. For instance > how can I restrict a user from doing a = range(100) or similar > tasks so that my whole compute farm does not come down. Use Sun Grid Engine. http://gridengine.sunsource.net/documentation.html -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
This can not be done at compile time but can be cought at execution time on linux by the following recipe: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/307871 vinjvinj -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
"vinjvinj" <[EMAIL PROTECTED]> writes: > No. I was hoping to leverage the work done for restricted pythonscript > by zope at: > > http://www.zope.org/Control_Panel/Products/PythonScripts/Help/PythonScript.py How does Pythonscript deal with xxx = 'x' * 10 as a memory DOS attack? -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
No. I was hoping to leverage the work done for restricted pythonscript by zope at: http://www.zope.org/Control_Panel/Products/PythonScripts/Help/PythonScript.py which is similar to what I want to do as well. vinjvinj -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj wrote: > I have so many things to do to get this to production and writing a > mini language would be a full project in itself. :-<. > > Is there an easy way to do this? If not, I'll go with the steps > outlined in my other post. Do you really think it will be faster to start parsing Python code, looking for potentially dangerous constructs? -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
I have so many things to do to get this to production and writing a mini language would be a full project in itself. :-<. Is there an easy way to do this? If not, I'll go with the steps outlined in my other post. vinjvinj -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
I'm more worried about incompetent users then malicious users. I'm going to take the following steps: 1. My users will be paying a decent amount of money to run models on the compute grid. If they are intentionaly writing malicious code then their account will be disabled. 2. Since their models will be fairly basic. - No imports in the code. - No special charters allowed. - No access to special builtins. The users write functions which get called man many times with different variables. I'm not sure how this would work with the rexec module especially since I'll be passing values to th functions and the functions will be returning either None, yes, or False. 3. Pylint has a pretty cool way to write your onw custom plugins. You can write custom handlers for each sort of available node at: http://www.python.org/doc/current/lib/module-compiler.ast.html this will allow me to compile a module and give users feedback on what is wrong and what is not allowed. 4. I'll set up a test sandbox where the models will be run with a smaller dataaset before then can be pushed into production. if the models pass the sandbox test then they will be run in production. I'm going to have write some custom performance monitoring functions to get notified when some models are running for ever and be able to terminate them. vinjvinj -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
Steven D'Aprano <[EMAIL PROTECTED]> writes: > I suspect your best bet might be to write a mini-language using > Python, and get your users to use that. You will take a small > performance hit, but security will be very much improved. > > What do others think? That is the only approach that makes any sense. Even with restricted execution there's no way to stop memory exhaustion with restricted Python statements. Consider xxx = 'x'*100 -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
vinjvinj wrote: > While I understand 2 is very hard (if not impossible) to do in single > unix process. I'm not sure why 1 would be hard to do. Since I have > complete control to what code I can allow or not allow on my grid. Can > i not just search for certain strings and disallow the model if it > fails certain conditions. It might not be 100% secure but will it not > get me at 90%... You might be able to think of and disallow the most obvious security holes, but how confident are you that you will think of the bad code that your users will think of? Are you concerned about malicious users, or just incompetent users? I suspect your best bet might be to write a mini-language using Python, and get your users to use that. You will take a small performance hit, but security will be very much improved. What do others think? -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
"vinjvinj" <[EMAIL PROTECTED]> writes: > While I understand 2 is very hard (if not impossible) to do in single > unix process. I'm not sure why 1 would be hard to do. Since I have > complete control to what code I can allow or not allow on my grid. Can > i not just search for certain strings and disallow the model if it > fails certain conditions. It might not be 100% secure but will it not > get me at 90%... Sure you can search for certain strings. Python lets you build strings dynamically, so you'd have to search for every possible way to create those strings. Further, Python provides lots of tools for introspection, meaning there are lots of ways to find these "forbidden" objects other than mentioning their name. You can get to *every* builtin function through any python module. For instance, are you going to prevent them from using regular rexpressions? If not, consider: >>> getattr(re, ''.join([chr(x + 1) for x in [94, 94, 97, 116, 104, 107, 115, >>> 104, 109, 114, 94, 94]]))['fi' + 'le'] is open True >>> String searches only prevent the most obvious abuses, and may well miss things that are merely not quite so obvious. If you think of your "security" as a notice to the end user that they are doing something wrong, as opposed to a tool that will prevent them from doing it, then you'll have the right idea. In which case, I'd still recommend looking into the rexec module. http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
While I understand 2 is very hard (if not impossible) to do in single unix process. I'm not sure why 1 would be hard to do. Since I have complete control to what code I can allow or not allow on my grid. Can i not just search for certain strings and disallow the model if it fails certain conditions. It might not be 100% secure but will it not get me at 90%... -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
"vinjvinj" <[EMAIL PROTECTED]> writes: > 1. restrict the user from doing any file io, exec, import, eval, etc. I > was thinking of writing a plugin for pylint to do all the checks? Is > this is a good way given that there is no restricted python. What are > the things I should serach for in python code Um - I've got a restricted python module: rexec.py. Of course, it doesn't work correctly, in that it isn't really secure. Python is very powerful, and creating a secure sandbox is difficult - so much so that the task has never been accomplished. If you want something that will keep the obvious things from working, rexec.py might be for you - but don't kid yourself that it's secure. If you need real security, I'd consider switching to Jython, which at least has a VM which was designed with building such sandboxes as a possibility. > 2. restrict the amount of memory a module uses as well. For instance > how can I restrict a user from doing a = range(100) or similar > tasks so that my whole compute farm does not come down. This is equivalent to trying to limit the amount of CPU time the module uses, which is better known as the halting problem. There's no algorithmic solution to that. If you want verify that some module will only use so much memory before executing it, the best you can do is verify that they don't do anything obvious. If you want to restrict them while they are running, you can probably get the OS to help. Exactly how will depend on your requirements, and the OS involved. http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: Using python for writing models: How to run models in restricted python mode?
On 7 Nov 2005 12:54:40 -0800, vinjvinj <[EMAIL PROTECTED]> wrote: >I have an application which allows multiple users to write models. >These models get distributed on a grid of compute engines. users submit >their models through a web interface. I want to > >1. restrict the user from doing any file io, exec, import, eval, etc. I >was thinking of writing a plugin for pylint to do all the checks? Is >this is a good way given that there is no restricted python. What are >the things I should serach for in python code > >2. restrict the amount of memory a module uses as well. For instance >how can I restrict a user from doing a = range(100) or similar >tasks so that my whole compute farm does not come down. There is currently no way to do either of these things. The most realistic approach at this time seems to be to rely on your operating system's capabilities to limit resource access and usage on a per-process. That is, run each piece of submitted code in a separate, unprivileged process, with the appropriate limits in place. Jean-Paul -- http://mail.python.org/mailman/listinfo/python-list
Using python for writing models: How to run models in restricted python mode?
I have an application which allows multiple users to write models. These models get distributed on a grid of compute engines. users submit their models through a web interface. I want to 1. restrict the user from doing any file io, exec, import, eval, etc. I was thinking of writing a plugin for pylint to do all the checks? Is this is a good way given that there is no restricted python. What are the things I should serach for in python code 2. restrict the amount of memory a module uses as well. For instance how can I restrict a user from doing a = range(100) or similar tasks so that my whole compute farm does not come down. Thanks for your help -- http://mail.python.org/mailman/listinfo/python-list
