security: Define CAP_SYSLOG

Privileged syslog operations currently require CAP_SYS_ADMIN.  Split
this off into a new CAP_SYSLOG privilege which we can sanely take away
from a container through the capability bounding set.

With this patch, an lxc container can be prevented from messing with
the host's syslog (i.e. dmesg -c).

Changelog: mar 12 2010: add selinux capability2:cap_syslog perm
Changelog: nov 22 2010:
	. port to new kernel
	. add a WARN_ONCE if userspace isn't using CAP_SYSLOG

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Acked-By: Kees Cook <kees.cook@canonical.com>
Cc: James Morris <jmorris@namei.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: "Christopher J. PeBenito" <cpebenito@tresys.com>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Serge E. Hallyn 2010-11-25 17:11:32 +00:00 committed by James Morris
parent 1d6d75684d
commit ce6ada35bd
3 changed files with 13 additions and 4 deletions

View file

@ -246,7 +246,6 @@ struct cpu_vfs_cap_data {
/* Allow configuration of the secure attention key */
/* Allow administration of the random device */
/* Allow examination and configuration of disk quotas */
/* Allow configuring the kernel's syslog (printk behaviour) */
/* Allow setting the domainname */
/* Allow setting the hostname */
/* Allow calling bdflush() */
@ -352,7 +351,11 @@ struct cpu_vfs_cap_data {
#define CAP_MAC_ADMIN 33
#define CAP_LAST_CAP CAP_MAC_ADMIN
/* Allow configuring the kernel's syslog (printk behaviour) */
#define CAP_SYSLOG 34
#define CAP_LAST_CAP CAP_SYSLOG
#define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)