1# When yama is enabled in the kernel it might be used to filter any user 2# space access which requires PTRACE_MODE_ATTACH like ptrace attach, access 3# to /proc/PID/{mem,personality,stack,syscall}, and the syscalls 4# process_vm_readv and process_vm_writev which are used for interprocess 5# services, communication and introspection (like synchronisation, signaling, 6# debugging, tracing and profiling) of processes. 7# 8# Usage of ptrace attach is restricted by normal user permissions. Normal 9# unprivileged processes cannot interact through ptrace with processes 10# that they cannot send signals to or processes that are running set-uid 11# or set-gid. 12# 13# yama ptrace scope can be used to reduce these permissions even more. 14# This should normally not be done because it will break various programs 15# relying on the default ptrace security restrictions. But can be used 16# if you don't have any other way to separate processes in their own 17# domains. A different way to restrict ptrace is to set the selinux 18# deny_ptrace boolean. Both mechanisms will break some programs relying 19# on the ptrace system call and might force users to elevate their 20# priviliges to root to do their work. 21# 22# For more information see Documentation/security/Yama.txt in the kernel 23# sources. Which also describes the defaults when CONFIG_SECURITY_YAMA 24# is enabled in a kernel build (currently 1 for ptrace_scope). 25# 26# This runtime kernel parameter can be set to the following options: 27# (Note that setting this to anything except zero will break programs!) 28# 29# 0 - Default attach security permissions. 30# 1 - Restricted attach. Only child processes plus normal permissions. 31# 2 - Admin-only attach. Only executables with CAP_SYS_PTRACE. 32# 3 - No attach. No process may call ptrace at all. Irrevocable. 33# 34kernel.yama.ptrace_scope = 0 35 36