linux_old1/security/selinux
Andy Lutomirski 259e5e6c75 Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs
With this change, calling
  prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
disables privilege granting operations at execve-time.  For example, a
process will not be able to execute a setuid binary to change their uid
or gid if this bit is set.  The same is true for file capabilities.

Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that
LSMs respect the requested behavior.

To determine if the NO_NEW_PRIVS bit is set, a task may call
  prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
It returns 1 if set and 0 if it is not set. If any of the arguments are
non-zero, it will return -1 and set errno to -EINVAL.
(PR_SET_NO_NEW_PRIVS behaves similarly.)

This functionality is desired for the proposed seccomp filter patch
series.  By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the
system call behavior for itself and its child tasks without being
able to impact the behavior of a more privileged task.

Another potential use is making certain privileged operations
unprivileged.  For example, chroot may be considered "safe" if it cannot
affect privileged tasks.

Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is
set and AppArmor is in use.  It is fixed in a subsequent patch.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>

v18: updated change desc
v17: using new define values as per 3.4
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-14 11:13:18 +10:00
..
include SELinux: do not allocate stack space for AVC data unless needed 2012-04-03 09:49:41 -07:00
ss selinux: sparse fix: fix several warnings in the security server cod 2012-01-05 18:52:52 -05:00
.gitignore SELinux: add .gitignore files for dynamic classes 2009-10-24 09:42:27 +08:00
Kconfig selinux: Deprecate and schedule the removal of the the compat_net functionality 2008-12-31 12:54:11 -05:00
Makefile selinux: change to new flag variable 2010-10-21 10:12:40 +11:00
avc.c lsm_audit: don't specify the audit pre/post callbacks in 'struct common_audit_data' 2012-04-03 09:49:59 -07:00
exports.c selinux: sparse fix: include selinux.h in exports.c 2011-09-09 16:56:32 -07:00
hooks.c Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs 2012-04-14 11:13:18 +10:00
netif.c doc: Update the email address for Paul Moore in various source files 2011-08-01 17:58:33 -07:00
netlabel.c doc: Update the email address for Paul Moore in various source files 2011-08-01 17:58:33 -07:00
netlink.c selinux: sparse fix: fix warnings in netlink code 2012-01-05 18:52:51 -05:00
netnode.c net: remove ipv6_addr_copy() 2011-11-22 16:43:32 -05:00
netport.c SELinux: Fix RCU deref check warning in sel_netport_insert() 2011-12-21 11:28:56 +11:00
nlmsgtab.c selinux: sparse fix: fix warnings in netlink code 2012-01-05 18:52:51 -05:00
selinuxfs.c selinuxfs: merge dentry allocation into sel_make_dir() 2012-03-31 16:03:15 -04:00
xfrm.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00