1#@!#!123s

: / etc / apparmor.d /
Filename : who
back
abi <abi/5.0>,
include <tunables/global>

profile who @{coreutil_dirs}who {
  include <abstractions/base>
  # who can theoretically take an arbitrary file argument but there seems to be
  # no common reason why one would want to pass a file not listed in the below
  # abstraction, or their rotated equivalents
  include <abstractions/wutmp>
  # rotated logs
  /var/log/wtmp.@{d} r,
  /var/log/btmp.@{d} r,
  
  # Despite listing information about consoles, <abstractions/consoles> does not
  # seem to be needed:
  # - Current logged-in users and their terminals is grabbed from files listed
  #   in <abstractions/wutmp>
  # - Any additional information about the terminals is obtained via a
  #   combination of dirfd=openat(AT_FDCWD, "/dev", O_RDONLY|O_PATH|O_DIRECTORY)
  #   and newfstatat(dirfd, terminal_name, out_ptr)
  # - O_PATH fds bypass mediation so /dev/ r, is not needed for the first step
  # - fstatat does not require permissions on the file itself, as stated in its
  #   man page
  # Overall result: the above calls are not mediated by LSMs

  @{coreutil_dirs}who mr,

  # who sends the "exists" signal via kill(pid, 0)
  capability kill,

  # Deny the writes allowed by abstractions/wutmp
  audit deny /var/** w,
  audit deny @{run}/utmp w,
  
  include if exists <local/who>
}