(This is only valid for Linux).
Kore uses seccomp to filter which system calls its processes can make.
As an application developer you can extend the allow-list to better suit your application its needs.
Adding your own seccomp rules
If you wish to extend the allow-list, you can use the KORE_SECCOMP_FILTER macro. In the example below we allow ioctl(2) and shmat(2) are allowed.
#include <kore/seccomp.h> KORE_SECCOMP_FILTER("app", KORE_SYSCALL_ALLOW(ioctl), KORE_SYSCALL_ALLOW(shmat) )
In another example, we allow write() to stdout but no other file descriptor.
#include <kore/seccomp.h> KORE_SECCOMP_FILTER("app", KORE_SYSCALL_ALLOW_ARG(write, 0, STDOUT_FILENO), KORE_SYSCALL_DENY(write, EPERM) )
Kore provides a few handy macros that can be used in a KORE_SECCOMP_FILTER:
- KORE_SYSCALL_DENY(name, errno)
- KORE_SYSCALL_DENY_ARG(name, argidx, val, errno)
- KORE_SYSCALL_DENY_MASK(name, argidx, val, errno)
KORE_SYSCALL_DENY_WITH_FLAG(name, argidx, val, errno)
- KORE_SYSCALL_ALLOW_ARG(name, argidx, val)
- KORE_SYSCALL_ALLOW_MASK(name, argidx, val)
- KORE_SYSCALL_ALLOW_WITH_FLAG(name, argidx, val)