Lowered Process Capabilities for use in Ubuntu (Security)

Registered by Kees Cook on 2009-11-09

This session will review the Lower Process Capabilities idea that Fedora has started working on. It may be good to do this in Ubuntu as well. http://fedoraproject.org/wiki/Features/LowerProcessCapabilities

Blueprint information

Status:
Not started
Approver:
Robbie Williamson
Priority:
Medium
Drafter:
Kees Cook
Direction:
Approved
Assignee:
Kees Cook
Definition:
Discussion
Series goal:
Accepted for lucid
Implementation:
Informational Informational
Milestone target:
None

Related branches

Sprints

Whiteboard

Work items:
investigate whether permissions gain is worth the trouble: DONE

Status: Will approve based on outcome of investigation [robbie.w]

Details:
 - This doesn't appear to add any benefit over simply derooting daemons, which the bulk of has already happened. Especially since uid=0 can just change file ownership.
[root@fedora-12-i686 ~]# capsh --drop=cap_chown,cap_dac_override,cap_dac_read_search,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_linux_immutable,cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_ipc_owner,cap_sys_module,cap_sys_rawio,cap_sys_chroot,cap_sys_ptrace,cap_sys_pacct,cap_sys_admin,cap_sys_boot,cap_sys_nice,cap_sys_resource,cap_sys_time,cap_sys_tty_config,cap_mknod,cap_lease,cap_audit_write,cap_audit_control,cap_setfcap,cap_mac_override,cap_mac_admin --
[root@fedora-12-i686 ~]# capsh --print
Current: =ep cap_chown,cap_dac_override,cap_dac_read_search,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_linux_immutable,cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_ipc_owner,cap_sys_module,cap_sys_rawio,cap_sys_chroot,cap_sys_ptrace,cap_sys_pacct,cap_sys_admin,cap_sys_boot,cap_sys_nice,cap_sys_resource,cap_sys_time,cap_sys_tty_config,cap_mknod,cap_lease,cap_audit_write,cap_audit_control,cap_setfcap,cap_mac_override,cap_mac_admin-ep
Bounding set =
Securebits: 00/0x0
 secure-noroot: no (unlocked)
 secure-no-suid-fixup: no (unlocked)
 secure-keep-caps: no (unlocked)
uid=0
[root@fedora-12-i686 ~]# cd /etc
[root@fedora-12-i686 etc]# cat shadow
bash: shadow: Permission denied
[root@fedora-12-i686 etc]# chmod 0700 shadow
[root@fedora-12-i686 etc]# grep gdm shadow
gdm:!!:14557::::::
[root@fedora-12-i686 etc]# chmod 0000 shadow
[root@fedora-12-i686 etc]# ls -la shadow
----------. 1 root root 1029 2009-11-25 21:28 shadow
[root@fedora-12-i686 etc]# cat shadow
cat: shadow: Permission denied

(?)

Work Items