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linux/security/selinux/nlmsgtab.c
Miloslav Trmac 522ed7767e Audit: add TTY input auditing 
Add TTY input auditing, used to audit system administrator's actions.  This is
required by various security standards such as DCID 6/3 and PCI to provide
non-repudiation of administrator's actions and to allow a review of past
actions if the administrator seems to overstep their duties or if the system
becomes misconfigured for unknown reasons.  These requirements do not make it
necessary to audit TTY output as well.

Compared to an user-space keylogger, this approach records TTY input using the
audit subsystem, correlated with other audit events, and it is completely
transparent to the user-space application (e.g.  the console ioctls still
work).

TTY input auditing works on a higher level than auditing all system calls
within the session, which would produce an overwhelming amount of mostly
useless audit events.

Add an "audit_tty" attribute, inherited across fork ().  Data read from TTYs
by process with the attribute is sent to the audit subsystem by the kernel.
The audit netlink interface is extended to allow modifying the audit_tty
attribute, and to allow sending explanatory audit events from user-space (for
example, a shell might send an event containing the final command, after the
interactive command-line editing and history expansion is performed, which
might be difficult to decipher from the TTY input alone).

Because the "audit_tty" attribute is inherited across fork (), it would be set
e.g.  for sshd restarted within an audited session.  To prevent this, the
audit_tty attribute is cleared when a process with no open TTY file
descriptors (e.g.  after daemon startup) opens a TTY.

See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a
more detailed rationale document for an older version of this patch.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Miloslav Trmac <mitr@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:47 -07:00

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/*
* Netlink message type permission tables, for user generated messages.
*
* Author: James Morris <jmorris@redhat.com>
*
* Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
* as published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/if.h>
#include <linux/netfilter_ipv4/ip_queue.h>
#include <linux/inet_diag.h>
#include <linux/xfrm.h>
#include <linux/audit.h>
#include "flask.h"
#include "av_permissions.h"
struct nlmsg_perm
{
u16 nlmsg_type;
u32 perm;
};
static struct nlmsg_perm nlmsg_route_perms[] =
{
{ RTM_NEWLINK, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELLINK, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETLINK, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_SETLINK, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_NEWADDR, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELADDR, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETADDR, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWROUTE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELROUTE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETROUTE, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWNEIGH, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELNEIGH, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETNEIGH, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWRULE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELRULE, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETRULE, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWQDISC, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELQDISC, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETQDISC, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWTCLASS, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELTCLASS, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETTCLASS, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWTFILTER, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELTFILTER, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETTFILTER, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWACTION, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_DELACTION, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETACTION, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_NEWPREFIX, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
{ RTM_GETMULTICAST, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_GETANYCAST, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_GETNEIGHTBL, NETLINK_ROUTE_SOCKET__NLMSG_READ },
{ RTM_SETNEIGHTBL, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
};
static struct nlmsg_perm nlmsg_firewall_perms[] =
{
{ IPQM_MODE, NETLINK_FIREWALL_SOCKET__NLMSG_WRITE },
{ IPQM_VERDICT, NETLINK_FIREWALL_SOCKET__NLMSG_WRITE },
};
static struct nlmsg_perm nlmsg_tcpdiag_perms[] =
{
{ TCPDIAG_GETSOCK, NETLINK_TCPDIAG_SOCKET__NLMSG_READ },
{ DCCPDIAG_GETSOCK, NETLINK_TCPDIAG_SOCKET__NLMSG_READ },
};
static struct nlmsg_perm nlmsg_xfrm_perms[] =
{
{ XFRM_MSG_NEWSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_DELSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_GETSA, NETLINK_XFRM_SOCKET__NLMSG_READ },
{ XFRM_MSG_NEWPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_DELPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_GETPOLICY, NETLINK_XFRM_SOCKET__NLMSG_READ },
{ XFRM_MSG_ALLOCSPI, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_ACQUIRE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_EXPIRE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_UPDPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_UPDSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_POLEXPIRE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_FLUSHSA, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_FLUSHPOLICY, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_NEWAE, NETLINK_XFRM_SOCKET__NLMSG_WRITE },
{ XFRM_MSG_GETAE, NETLINK_XFRM_SOCKET__NLMSG_READ },
};
static struct nlmsg_perm nlmsg_audit_perms[] =
{
{ AUDIT_GET, NETLINK_AUDIT_SOCKET__NLMSG_READ },
{ AUDIT_SET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
{ AUDIT_LIST, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV },
{ AUDIT_ADD, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
{ AUDIT_DEL, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
{ AUDIT_LIST_RULES, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV },
{ AUDIT_ADD_RULE, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
{ AUDIT_DEL_RULE, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
{ AUDIT_USER, NETLINK_AUDIT_SOCKET__NLMSG_RELAY },
{ AUDIT_SIGNAL_INFO, NETLINK_AUDIT_SOCKET__NLMSG_READ },
{ AUDIT_TTY_GET, NETLINK_AUDIT_SOCKET__NLMSG_READ },
{ AUDIT_TTY_SET, NETLINK_AUDIT_SOCKET__NLMSG_WRITE },
};
static int nlmsg_perm(u16 nlmsg_type, u32 *perm, struct nlmsg_perm *tab, size_t tabsize)
{
int i, err = -EINVAL;
for (i = 0; i < tabsize/sizeof(struct nlmsg_perm); i++)
if (nlmsg_type == tab[i].nlmsg_type) {
*perm = tab[i].perm;
err = 0;
break;
}
return err;
}
int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
{
int err = 0;
switch (sclass) {
case SECCLASS_NETLINK_ROUTE_SOCKET:
err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
sizeof(nlmsg_route_perms));
break;
case SECCLASS_NETLINK_FIREWALL_SOCKET:
case SECCLASS_NETLINK_IP6FW_SOCKET:
err = nlmsg_perm(nlmsg_type, perm, nlmsg_firewall_perms,
sizeof(nlmsg_firewall_perms));
break;
case SECCLASS_NETLINK_TCPDIAG_SOCKET:
err = nlmsg_perm(nlmsg_type, perm, nlmsg_tcpdiag_perms,
sizeof(nlmsg_tcpdiag_perms));
break;
case SECCLASS_NETLINK_XFRM_SOCKET:
err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
sizeof(nlmsg_xfrm_perms));
break;
case SECCLASS_NETLINK_AUDIT_SOCKET:
if ((nlmsg_type >= AUDIT_FIRST_USER_MSG &&
nlmsg_type <= AUDIT_LAST_USER_MSG) ||
(nlmsg_type >= AUDIT_FIRST_USER_MSG2 &&
nlmsg_type <= AUDIT_LAST_USER_MSG2)) {
*perm = NETLINK_AUDIT_SOCKET__NLMSG_RELAY;
} else {
err = nlmsg_perm(nlmsg_type, perm, nlmsg_audit_perms,
sizeof(nlmsg_audit_perms));
}
break;
/* No messaging from userspace, or class unknown/unhandled */
default:
err = -ENOENT;
break;
}
return err;
}
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