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authorSerge E. Hallyn <serge@hallyn.com>2010-11-25 17:11:32 +0000
committerJames Morris <jmorris@namei.org>2010-11-29 08:35:12 +1100
commitce6ada35bdf710d16582cc4869c26722547e6f11 (patch)
treec2b5fd46c883f4b7285b191bac55940022662b43 /kernel/printk.c
parent1d6d75684d869406e5bb2ac5d3ed9454f52d0cab (diff)
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>
Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 9a2264fc42c..0712380737b 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -283,8 +283,14 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
return -EPERM;
if ((type != SYSLOG_ACTION_READ_ALL &&
type != SYSLOG_ACTION_SIZE_BUFFER) &&
- !capable(CAP_SYS_ADMIN))
+ !capable(CAP_SYSLOG)) {
+ /* remove after 2.6.38 */
+ if (capable(CAP_SYS_ADMIN))
+ WARN_ONCE(1, "Attempt to access syslog with "
+ "CAP_SYS_ADMIN but no CAP_SYSLOG "
+ "(deprecated and denied).\n");
return -EPERM;
+ }
}
error = security_syslog(type);