# When yama is enabled in the kernel it might be used to filter any user

# space access which requires PTRACE_MODE_ATTACH like ptrace attach, access

# to /proc/PID/{mem,personality,stack,syscall}, and the syscalls

# process_vm_readv and process_vm_writev which are used for interprocess

# services, communication and introspection (like synchronisation, signaling,

# debugging, tracing and profiling) of processes.

#

# Usage of ptrace attach is restricted by normal user permissions. Normal

# unprivileged processes cannot interact through ptrace with processes

# that they cannot send signals to or processes that are running set-uid

# or set-gid.

#

# yama ptrace scope can be used to reduce these permissions even more.

# This should normally not be done because it will break various programs

# relying on the default ptrace security restrictions. But can be used

# if you don't have any other way to separate processes in their own

# domains. A different way to restrict ptrace is to set the selinux

# deny_ptrace boolean. Both mechanisms will break some programs relying

# on the ptrace system call and might force users to elevate their

# priviliges to root to do their work.

#

# For more information see Documentation/security/Yama.txt in the kernel

# sources. Which also describes the defaults when CONFIG_SECURITY_YAMA

# is enabled in a kernel build (currently 1 for ptrace_scope).

#

# This runtime kernel parameter can be set to the following options:

# (Note that setting this to anything except zero will break programs!)

#

# 0 - Default attach security permissions.

# 1 - Restricted attach. Only child processes plus normal permissions.

# 2 - Admin-only attach. Only executables with CAP_SYS_PTRACE.

# 3 - No attach. No process may call ptrace at all. Irrevocable.

#

kernel.yama.ptrace_scope = 0