I would like to use syscall statx() in app deployed in Cloud Foundry. Unfortunately it does not work due to
"EPERM: Operation not permitted".
but I can use stat() without any problems.
Is there any way to allow my app to work?
Hint: I believe, the problem could be the configuration of the seccomp profile in runtime garden-runC - it filters allowed syscalls and statx is not on the allowed list.
I found workaround: if privileged container support is enabled, statx() can be used and works well
https://github.com/cloudfoundry/cf-deployment/blob/main/operations/enable-privileged-container-support.yml
Unfortunately, this is really bad idea and it is decreases security. More details: https://docs.cloudfoundry.org/concepts/container-security.html
Related
I have a C++ program which I want to use on my clients machines. However, some of my clients are behind proxies. Therefore, I want my program to automatically detect these proxies.
I have tried many solutions, such as reading the registry for the proxy settings, trying the Windows API's, etc.
However none of them have worked out well. E.g. the registry sometimes holds the url for the PAC-file and sometimes the actual proxy-address itself. Besides that, I haven't been able to find any username and password related to the proxy if it is set on the client machine (which some users say they have).
So, basically my question is:
How can I automatically determine the proxy settings of my clients in C++ so I can use the proxy-settings in my LibCurl requests later on regarding:
Proxy-address
Proxy-port
Proxy-User
Proxy-Password
I can't get it to work and I have been trying it for two weeks now without any improvement...
You can not read proxy setting in a generic way, since every application is free to store it in any way it wants. You should be able to read Internet Explorer proxy by using WinHttpGetIEProxyConfigForCurrentUser function, and it would also work for users browsers which use this setting, like Google Chrome.
How can I automatically determine the proxy settings of my clients in C++ so I can use the proxy-settings in my LibCurl requests?
libproxy is the answer!
Libproxy home page on GitHub
Libproxy repo on GitHub
It has these features according to the home page:
support for all major platforms: Windows, Mac and Linux/UNIX (see upcoming 0.4 release)
extremely small core footprint
no external dependencies within libproxy core (libproxy plugins may have dependencies)
only 3 functions in the stable-ish external API (1.0 will offer full stability)
dynamic adjustment to changing network topology
a standard way of dealing with proxy settings across all scenarios
a sublime sense of joy and accomplishment
Recently we upgraded to ColdFusion 11 Enterprise and noticed that the full-fledged sandbox security tends to have a way bigger overhead than the Standard edition (CF10).
What can one do to make an existing CF app perform well with sandbox security?
Here are my findings so far:
install VisualVM by adding -Dcom.sun.management.jmxremote.port=8701 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false to CF Admin's JVM Arguments. Learn how to use it and pay special attention to the CPU Snapshot & Hotspot tab. http://boncode.blogspot.ca/2010/04/cf-java-using-free-visualvm-tool-to.html. FYI CF Server Monitor in the Enterprise edition is utterly useless because its memory/performance profiling overhead is way too big to be viable for a live production server, and it doesn't perform well under load to give you any useful data of what could be going wrong.
Disable IPv6, and add [serverip] [serverip] to the OS's hostfile to speed up the default DNS reverse proxy lookup on creating new physical DB connection by Security Manager. See: On Linux, Java issues reverse DNS lookups when a socket is opened. Why, and how can I stop it? (FYI, Windows is affected to)
remove as much <cfmodule> and <cfinclude> as possible as they will end up with many java.io.File.canRead() and java.io.File.exists() which will stress the disk IO under load. Even SSD suffers under load. I have tried Trusted Cache and it does not help. Instead, try using cached CFC's in application scope and make sure the code are thread safe and local-var'ed.
eliminate the use of <cfinterface>, inheritance with extends, and getMetaData() as much as possible as they will eventually calls java.io.File.lastModified() which will stress the disk IO under load. Bug?
eliminate the use of access="package" as it will end up with many java.security.AccessController.checkPermission calls.
less objects per request the better, as each object instantiation has a higher cost with the extra java.security.AccessController.checkPermission call.
I've done some digging and the main ideas I've seen floating around are using setuid/getuid and using the Authorization Services (which, for some reason gives me a symbol error when compiling but appears to be deprecated now).
My application needs to be able to request root access (for accessing a raw disk drive) at a certain point, preferably with the OS X authentication dialog (I'm new to OS X so I have no idea what to call that).
Authorization Services is pretty well supported, AFAIK.
Here's a link to a tutorial (with sample projects!) which you can use to launch a small tool in which you can get admin priviledges and then you can call the setpriority API on your calling process (documentation linked for you).
What would be the simplest way for an application I'm writing to block all Internet access on a Windows machine?
More details:
Windows: XP or higher
Application: A basic Win32 app written in C/C++.
Blocking: It needs to be able to block and unblock at will, ideally in a way that the user can't easily reverse. (By, say, right clicking on a network connection icon in the system tray.) Also, ideally, I'd like the method it uses to allow access to be restored should the user restart Windows or reset the machine, though I'd also be willing to have the app auto launch with Windows and unblock access upon startup if the machine was reset while in a blocked state.
Internet access: Primarily, I'd like to block conventional browsers from hitting conventional http/https sites. Secondarily, it would be nice to block IM clients and client-side social networking apps. It would also be nice, but not required, to still allow local networking for file sharing, etc. (Note that only the first requirement is absolute.)
Final notes: This is not meant to be a security utility, nor will its relationship to the user be adversarial (as, for example, with a parental control utility) so it's not important for it to use a scheme that can't be worked around by a determined user. (Consider that I intend for a reboot or reset to clear the blocking. This means that any workaround a user might discover that would take more effort than this is okay.)
Thanks!
p.s. I suspect that the Windows Firewall API won't work for me because this needs to work for users that haven't enabled the firewall or don't have admin privileges, but I'll be thrilled if I'm corrected on this.
It sounds like you're intending to run applications that you don't want to access the internet. Perhaps you could run them inside a virtual machine such as VirtualBox with networking disabled.
You could do it with a Winsock SPI. The Windows SDK has a sample (under Samples\netds\winsock\lsp) which implements what is called a layered service provider which allows you to hook all the user mode functions provided by Winsock and reject/modify the calls to block network access or redirect traffic to different locations. All installed winsock applications will be affected, so in your code you could have policys for what applications can go out and the like and disabled/enable on the fly. Now a determined person could find ways around this but it would be a pain.
That said this isn't trivial to do but the sample should get you most of the way there.
You cannot effectively or practically write your tool with only a user mode application.
What you need to write is a network I/O stack filter driver. This done by writing a Windows Driver. This is different from a Windows Win32 application. Drivers run in kernel mode and applications run in user mode.
On Windows Vista and later, the kernel mode Network Programming Interface (NPI) is designed for this. This is the same API that Windows Firewalls use. These are sometimes called the Winsock kernel (WSK) APIs.
In effect, you are writing a network firewall (more or less)
here are some links
Introduction to Winsock Kernel (WSK)
Windows Core Networking Blog
The Network Programming Interface Docs on MSDN
Note, your will likely need at least two components
Your driver
A Graphical application that a person can use to control your tool
If you want to do any monitoring, you will likely need a user mode service that collects data from your driver. This works better than trying to do this in the driver. In general, you should do the minimal amount of work in the driver.
A few notes:
You need to be very conscious of security when writing this kind of software. This is very much non trivial. Software that is network facing has the highest security requirements.
Be cognizant of performance.
Your driver and/or service must be aware of the context of a calling application. This is also a security boundary. For example, an application not running as administrator should not be able to control your driver.
take a look at firewall sourcecodes
I want to have an application or service that is running that, on some schedule, can disable access to the internet for all applications except for specific ones.
I'm trying to create a filter that can be turned on or off under programmatic control. Not just IP addresses and ports, but I want to be able to block specific applications as well, much like Zone Alarm and other software firewalls let you block.
For example, iexplore.exe, skype.exe, firefox.exe, aim.exe. But still need to allow other applications to connect as needed.
It has to work on Vista as well as XP, but I kind of expect that the method will be different on each of those platforms.
Basically, the filter has to tie the network communication back to the executable that is making the request and then allow or deny it.
Update:
On Vista at least, it looks like I want to use filters in the ALE layers of the WFP.
On XP, I'm still looking for the best way to do it. Do I really need to be writing device drivers and dealing with kernel stuff? I'm just a lowly application developer. Kill me now.
Update 2:
Currently looking at the PfCreateInterface and related Pf* API's for pre-Vista systems.
You can change both Vista and XP's firewall policies dynamically using the INetFwAuthorizedApplications interface from the Windows Firewall API.
Also see this question.
You'll have to write a device driver that filters traffic based on the executable requesting the traffic.
by limiting its access to internet using firewall. go to firewall setting advanced tab (win 7)
and do that
I'm not sure, but I think you'd need to do it by getting the program to run as a user that has limited permissions, the question is, can you make a user account that stops such things?
You'll need to redirect all (or at least many) calls to the WinSock API functions of any running program to your own replacement functions. That means getting into the memory of each running program and hijacking those functions, which is an... interesting... exercise. :-)
That might be enough of a pointer to get you started, or at least to suggest some more specific questions to ask.
Could you move aside (ie rename) the system's winsock DLL and replace it with your own ?
Yours should provide the same API, but check the the process name of incoming requests... return an error code to blocked applications and forward the calls from allowed apps onto the real DLL.