I have a bunch of programs which use IPC Semaphores to interact (semget).
One of the programs is an Apache module, which runs in (some sort of) restricted SELinux context (which I don't understand too well).
The module is capable of interacting with any regular files correctly, if of-course the files have their SELinux security context set appropriately.
However - when my (Module) goes to access the IPC Semaphore, the semget call fails with a EPERM. When SELinux is turned off, I don't get this error.
So - there is obviously something I need to do to set some sort of SELinux security context or something on the Semaphore for this to work. If it was a regular file, I could just call "chcon" on it. Since it's a System-V IPC Semaphore, I can't do that.
What can I do to make this work??
The basic steps to get SELinux working with the changes you need are:
- Enable permissive mode
- Capture denials
- Add a new policy module or modify an existing policy module
- Enable enforcing mode and test
Exactly how to do these steps depends on what Linux distribution you are using; here are references for CentOS, Debian, Gentoo, RedHat and Ubuntu. You can also find SELinux information from NSA. The best documentation I found is from Gentoo: step 1, step 2, step 3, step 4.
As @smassey noted, you most probably need to modify some IPC permission.
SELinux has persmission setting for more than just regular files, but also device and special files.
http://seedit.sourceforge.net/doc/access_vectors/access_vectors.html#SECTION00044000000000000000 is what you're looking for. Give read/write/etc permissions to the "sem" object.
Cheers
来源：https://stackoverflow.com/questions/7572974/configuring-selinux-permissions-on-svs-v-ipc-semaphores