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linux/net/netlabel/netlabel_mgmt.c
Paul Moore 23bcdc1ade SELinux: enable dynamic activation/deactivation of NetLabel/SELinux enforcement 
Create a new NetLabel KAPI interface, netlbl_enabled(), which reports on the
current runtime status of NetLabel based on the existing configuration.  LSMs
that make use of NetLabel, i.e. SELinux, can use this new function to determine
if they should perform NetLabel access checks.  This patch changes the
NetLabel/SELinux glue code such that SELinux only enforces NetLabel related
access checks when netlbl_enabled() returns true.

At present NetLabel is considered to be enabled when there is at least one
labeled protocol configuration present.  The result is that by default NetLabel
is considered to be disabled, however, as soon as an administrator configured
a CIPSO DOI definition NetLabel is enabled and SELinux starts enforcing
NetLabel related access controls - including unlabeled packet controls.

This patch also tries to consolidate the multiple "#ifdef CONFIG_NETLABEL"
blocks into a single block to ease future review as recommended by Linus.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
2007-07-19 10:21:11 -04:00

700 lines
18 KiB
C
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/*
* NetLabel Management Support
*
* This file defines the management functions for the NetLabel system. The
* NetLabel system manages static and dynamic label mappings for network
* protocols such as CIPSO and RIPSO.
*
* Author: Paul Moore <paul.moore@hp.com>
*
*/
/*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/genetlink.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include "netlabel_domainhash.h"
#include "netlabel_user.h"
#include "netlabel_mgmt.h"
/* NetLabel configured protocol count */
static DEFINE_SPINLOCK(netlabel_mgmt_protocount_lock);
static u32 netlabel_mgmt_protocount = 0;
/* Argument struct for netlbl_domhsh_walk() */
struct netlbl_domhsh_walk_arg {
struct netlink_callback *nl_cb;
struct sk_buff *skb;
u32 seq;
};
/* NetLabel Generic NETLINK CIPSOv4 family */
static struct genl_family netlbl_mgmt_gnl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = NETLBL_NLTYPE_MGMT_NAME,
.version = NETLBL_PROTO_VERSION,
.maxattr = NLBL_MGMT_A_MAX,
};
/* NetLabel Netlink attribute policy */
static const struct nla_policy netlbl_mgmt_genl_policy[NLBL_MGMT_A_MAX + 1] = {
[NLBL_MGMT_A_DOMAIN] = { .type = NLA_NUL_STRING },
[NLBL_MGMT_A_PROTOCOL] = { .type = NLA_U32 },
[NLBL_MGMT_A_VERSION] = { .type = NLA_U32 },
[NLBL_MGMT_A_CV4DOI] = { .type = NLA_U32 },
};
/*
* NetLabel Misc Managment Functions
*/
/**
* netlbl_mgmt_protocount_inc - Increment the configured labeled protocol count
*
* Description:
* Increment the number of labeled protocol configurations in the current
* NetLabel configuration. Keep track of this for use in determining if
* NetLabel label enforcement should be active/enabled or not in the LSM.
*
*/
void netlbl_mgmt_protocount_inc(void)
{
rcu_read_lock();
spin_lock(&netlabel_mgmt_protocount_lock);
netlabel_mgmt_protocount++;
spin_unlock(&netlabel_mgmt_protocount_lock);
rcu_read_unlock();
}
/**
* netlbl_mgmt_protocount_dec - Decrement the configured labeled protocol count
*
* Description:
* Decrement the number of labeled protocol configurations in the current
* NetLabel configuration. Keep track of this for use in determining if
* NetLabel label enforcement should be active/enabled or not in the LSM.
*
*/
void netlbl_mgmt_protocount_dec(void)
{
rcu_read_lock();
spin_lock(&netlabel_mgmt_protocount_lock);
if (netlabel_mgmt_protocount > 0)
netlabel_mgmt_protocount--;
spin_unlock(&netlabel_mgmt_protocount_lock);
rcu_read_unlock();
}
/**
* netlbl_mgmt_protocount_value - Return the number of configured protocols
*
* Description:
* Return the number of labeled protocols in the current NetLabel
* configuration. This value is useful in determining if NetLabel label
* enforcement should be active/enabled or not in the LSM.
*
*/
u32 netlbl_mgmt_protocount_value(void)
{
u32 val;
rcu_read_lock();
val = netlabel_mgmt_protocount;
rcu_read_unlock();
return val;
}
/*
* NetLabel Command Handlers
*/
/**
* netlbl_mgmt_add - Handle an ADD message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated ADD message and add the domains from the message
* to the hash table. See netlabel.h for a description of the message format.
* Returns zero on success, negative values on failure.
*
*/
static int netlbl_mgmt_add(struct sk_buff *skb, struct genl_info *info)
{
int ret_val = -EINVAL;
struct netlbl_dom_map *entry = NULL;
size_t tmp_size;
u32 tmp_val;
struct netlbl_audit audit_info;
if (!info->attrs[NLBL_MGMT_A_DOMAIN] ||
!info->attrs[NLBL_MGMT_A_PROTOCOL])
goto add_failure;
netlbl_netlink_auditinfo(skb, &audit_info);
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (entry == NULL) {
ret_val = -ENOMEM;
goto add_failure;
}
tmp_size = nla_len(info->attrs[NLBL_MGMT_A_DOMAIN]);
entry->domain = kmalloc(tmp_size, GFP_KERNEL);
if (entry->domain == NULL) {
ret_val = -ENOMEM;
goto add_failure;
}
entry->type = nla_get_u32(info->attrs[NLBL_MGMT_A_PROTOCOL]);
nla_strlcpy(entry->domain, info->attrs[NLBL_MGMT_A_DOMAIN], tmp_size);
switch (entry->type) {
case NETLBL_NLTYPE_UNLABELED:
ret_val = netlbl_domhsh_add(entry, &audit_info);
break;
case NETLBL_NLTYPE_CIPSOV4:
if (!info->attrs[NLBL_MGMT_A_CV4DOI])
goto add_failure;
tmp_val = nla_get_u32(info->attrs[NLBL_MGMT_A_CV4DOI]);
/* We should be holding a rcu_read_lock() here while we hold
* the result but since the entry will always be deleted when
* the CIPSO DOI is deleted we aren't going to keep the
* lock. */
rcu_read_lock();
entry->type_def.cipsov4 = cipso_v4_doi_getdef(tmp_val);
if (entry->type_def.cipsov4 == NULL) {
rcu_read_unlock();
goto add_failure;
}
ret_val = netlbl_domhsh_add(entry, &audit_info);
rcu_read_unlock();
break;
default:
goto add_failure;
}
if (ret_val != 0)
goto add_failure;
return 0;
add_failure:
if (entry)
kfree(entry->domain);
kfree(entry);
return ret_val;
}
/**
* netlbl_mgmt_remove - Handle a REMOVE message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated REMOVE message and remove the specified domain
* mappings. Returns zero on success, negative values on failure.
*
*/
static int netlbl_mgmt_remove(struct sk_buff *skb, struct genl_info *info)
{
char *domain;
struct netlbl_audit audit_info;
if (!info->attrs[NLBL_MGMT_A_DOMAIN])
return -EINVAL;
netlbl_netlink_auditinfo(skb, &audit_info);
domain = nla_data(info->attrs[NLBL_MGMT_A_DOMAIN]);
return netlbl_domhsh_remove(domain, &audit_info);
}
/**
* netlbl_mgmt_listall_cb - netlbl_domhsh_walk() callback for LISTALL
* @entry: the domain mapping hash table entry
* @arg: the netlbl_domhsh_walk_arg structure
*
* Description:
* This function is designed to be used as a callback to the
* netlbl_domhsh_walk() function for use in generating a response for a LISTALL
* message. Returns the size of the message on success, negative values on
* failure.
*
*/
static int netlbl_mgmt_listall_cb(struct netlbl_dom_map *entry, void *arg)
{
int ret_val = -ENOMEM;
struct netlbl_domhsh_walk_arg *cb_arg = arg;
void *data;
data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).pid,
cb_arg->seq, &netlbl_mgmt_gnl_family,
NLM_F_MULTI, NLBL_MGMT_C_LISTALL);
if (data == NULL)
goto listall_cb_failure;
ret_val = nla_put_string(cb_arg->skb,
NLBL_MGMT_A_DOMAIN,
entry->domain);
if (ret_val != 0)
goto listall_cb_failure;
ret_val = nla_put_u32(cb_arg->skb, NLBL_MGMT_A_PROTOCOL, entry->type);
if (ret_val != 0)
goto listall_cb_failure;
switch (entry->type) {
case NETLBL_NLTYPE_CIPSOV4:
ret_val = nla_put_u32(cb_arg->skb,
NLBL_MGMT_A_CV4DOI,
entry->type_def.cipsov4->doi);
if (ret_val != 0)
goto listall_cb_failure;
break;
}
cb_arg->seq++;
return genlmsg_end(cb_arg->skb, data);
listall_cb_failure:
genlmsg_cancel(cb_arg->skb, data);
return ret_val;
}
/**
* netlbl_mgmt_listall - Handle a LISTALL message
* @skb: the NETLINK buffer
* @cb: the NETLINK callback
*
* Description:
* Process a user generated LISTALL message and dumps the domain hash table in
* a form suitable for use in a kernel generated LISTALL message. Returns zero
* on success, negative values on failure.
*
*/
static int netlbl_mgmt_listall(struct sk_buff *skb,
struct netlink_callback *cb)
{
struct netlbl_domhsh_walk_arg cb_arg;
u32 skip_bkt = cb->args[0];
u32 skip_chain = cb->args[1];
cb_arg.nl_cb = cb;
cb_arg.skb = skb;
cb_arg.seq = cb->nlh->nlmsg_seq;
netlbl_domhsh_walk(&skip_bkt,
&skip_chain,
netlbl_mgmt_listall_cb,
&cb_arg);
cb->args[0] = skip_bkt;
cb->args[1] = skip_chain;
return skb->len;
}
/**
* netlbl_mgmt_adddef - Handle an ADDDEF message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated ADDDEF message and respond accordingly. Returns
* zero on success, negative values on failure.
*
*/
static int netlbl_mgmt_adddef(struct sk_buff *skb, struct genl_info *info)
{
int ret_val = -EINVAL;
struct netlbl_dom_map *entry = NULL;
u32 tmp_val;
struct netlbl_audit audit_info;
if (!info->attrs[NLBL_MGMT_A_PROTOCOL])
goto adddef_failure;
netlbl_netlink_auditinfo(skb, &audit_info);
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (entry == NULL) {
ret_val = -ENOMEM;
goto adddef_failure;
}
entry->type = nla_get_u32(info->attrs[NLBL_MGMT_A_PROTOCOL]);
switch (entry->type) {
case NETLBL_NLTYPE_UNLABELED:
ret_val = netlbl_domhsh_add_default(entry, &audit_info);
break;
case NETLBL_NLTYPE_CIPSOV4:
if (!info->attrs[NLBL_MGMT_A_CV4DOI])
goto adddef_failure;
tmp_val = nla_get_u32(info->attrs[NLBL_MGMT_A_CV4DOI]);
/* We should be holding a rcu_read_lock() here while we hold
* the result but since the entry will always be deleted when
* the CIPSO DOI is deleted we aren't going to keep the
* lock. */
rcu_read_lock();
entry->type_def.cipsov4 = cipso_v4_doi_getdef(tmp_val);
if (entry->type_def.cipsov4 == NULL) {
rcu_read_unlock();
goto adddef_failure;
}
ret_val = netlbl_domhsh_add_default(entry, &audit_info);
rcu_read_unlock();
break;
default:
goto adddef_failure;
}
if (ret_val != 0)
goto adddef_failure;
return 0;
adddef_failure:
kfree(entry);
return ret_val;
}
/**
* netlbl_mgmt_removedef - Handle a REMOVEDEF message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated REMOVEDEF message and remove the default domain
* mapping. Returns zero on success, negative values on failure.
*
*/
static int netlbl_mgmt_removedef(struct sk_buff *skb, struct genl_info *info)
{
struct netlbl_audit audit_info;
netlbl_netlink_auditinfo(skb, &audit_info);
return netlbl_domhsh_remove_default(&audit_info);
}
/**
* netlbl_mgmt_listdef - Handle a LISTDEF message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated LISTDEF message and dumps the default domain
* mapping in a form suitable for use in a kernel generated LISTDEF message.
* Returns zero on success, negative values on failure.
*
*/
static int netlbl_mgmt_listdef(struct sk_buff *skb, struct genl_info *info)
{
int ret_val = -ENOMEM;
struct sk_buff *ans_skb = NULL;
void *data;
struct netlbl_dom_map *entry;
ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (ans_skb == NULL)
return -ENOMEM;
data = genlmsg_put_reply(ans_skb, info, &netlbl_mgmt_gnl_family,
0, NLBL_MGMT_C_LISTDEF);
if (data == NULL)
goto listdef_failure;
rcu_read_lock();
entry = netlbl_domhsh_getentry(NULL);
if (entry == NULL) {
ret_val = -ENOENT;
goto listdef_failure_lock;
}
ret_val = nla_put_u32(ans_skb, NLBL_MGMT_A_PROTOCOL, entry->type);
if (ret_val != 0)
goto listdef_failure_lock;
switch (entry->type) {
case NETLBL_NLTYPE_CIPSOV4:
ret_val = nla_put_u32(ans_skb,
NLBL_MGMT_A_CV4DOI,
entry->type_def.cipsov4->doi);
if (ret_val != 0)
goto listdef_failure_lock;
break;
}
rcu_read_unlock();
genlmsg_end(ans_skb, data);
ret_val = genlmsg_reply(ans_skb, info);
if (ret_val != 0)
goto listdef_failure;
return 0;
listdef_failure_lock:
rcu_read_unlock();
listdef_failure:
kfree_skb(ans_skb);
return ret_val;
}
/**
* netlbl_mgmt_protocols_cb - Write an individual PROTOCOL message response
* @skb: the skb to write to
* @seq: the NETLINK sequence number
* @cb: the NETLINK callback
* @protocol: the NetLabel protocol to use in the message
*
* Description:
* This function is to be used in conjunction with netlbl_mgmt_protocols() to
* answer a application's PROTOCOLS message. Returns the size of the message
* on success, negative values on failure.
*
*/
static int netlbl_mgmt_protocols_cb(struct sk_buff *skb,
struct netlink_callback *cb,
u32 protocol)
{
int ret_val = -ENOMEM;
void *data;
data = genlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
&netlbl_mgmt_gnl_family, NLM_F_MULTI,
NLBL_MGMT_C_PROTOCOLS);
if (data == NULL)
goto protocols_cb_failure;
ret_val = nla_put_u32(skb, NLBL_MGMT_A_PROTOCOL, protocol);
if (ret_val != 0)
goto protocols_cb_failure;
return genlmsg_end(skb, data);
protocols_cb_failure:
genlmsg_cancel(skb, data);
return ret_val;
}
/**
* netlbl_mgmt_protocols - Handle a PROTOCOLS message
* @skb: the NETLINK buffer
* @cb: the NETLINK callback
*
* Description:
* Process a user generated PROTOCOLS message and respond accordingly.
*
*/
static int netlbl_mgmt_protocols(struct sk_buff *skb,
struct netlink_callback *cb)
{
u32 protos_sent = cb->args[0];
if (protos_sent == 0) {
if (netlbl_mgmt_protocols_cb(skb,
cb,
NETLBL_NLTYPE_UNLABELED) < 0)
goto protocols_return;
protos_sent++;
}
if (protos_sent == 1) {
if (netlbl_mgmt_protocols_cb(skb,
cb,
NETLBL_NLTYPE_CIPSOV4) < 0)
goto protocols_return;
protos_sent++;
}
protocols_return:
cb->args[0] = protos_sent;
return skb->len;
}
/**
* netlbl_mgmt_version - Handle a VERSION message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated VERSION message and respond accordingly. Returns
* zero on success, negative values on failure.
*
*/
static int netlbl_mgmt_version(struct sk_buff *skb, struct genl_info *info)
{
int ret_val = -ENOMEM;
struct sk_buff *ans_skb = NULL;
void *data;
ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (ans_skb == NULL)
return -ENOMEM;
data = genlmsg_put_reply(ans_skb, info, &netlbl_mgmt_gnl_family,
0, NLBL_MGMT_C_VERSION);
if (data == NULL)
goto version_failure;
ret_val = nla_put_u32(ans_skb,
NLBL_MGMT_A_VERSION,
NETLBL_PROTO_VERSION);
if (ret_val != 0)
goto version_failure;
genlmsg_end(ans_skb, data);
ret_val = genlmsg_reply(ans_skb, info);
if (ret_val != 0)
goto version_failure;
return 0;
version_failure:
kfree_skb(ans_skb);
return ret_val;
}
/*
* NetLabel Generic NETLINK Command Definitions
*/
static struct genl_ops netlbl_mgmt_genl_c_add = {
.cmd = NLBL_MGMT_C_ADD,
.flags = GENL_ADMIN_PERM,
.policy = netlbl_mgmt_genl_policy,
.doit = netlbl_mgmt_add,
.dumpit = NULL,
};
static struct genl_ops netlbl_mgmt_genl_c_remove = {
.cmd = NLBL_MGMT_C_REMOVE,
.flags = GENL_ADMIN_PERM,
.policy = netlbl_mgmt_genl_policy,
.doit = netlbl_mgmt_remove,
.dumpit = NULL,
};
static struct genl_ops netlbl_mgmt_genl_c_listall = {
.cmd = NLBL_MGMT_C_LISTALL,
.flags = 0,
.policy = netlbl_mgmt_genl_policy,
.doit = NULL,
.dumpit = netlbl_mgmt_listall,
};
static struct genl_ops netlbl_mgmt_genl_c_adddef = {
.cmd = NLBL_MGMT_C_ADDDEF,
.flags = GENL_ADMIN_PERM,
.policy = netlbl_mgmt_genl_policy,
.doit = netlbl_mgmt_adddef,
.dumpit = NULL,
};
static struct genl_ops netlbl_mgmt_genl_c_removedef = {
.cmd = NLBL_MGMT_C_REMOVEDEF,
.flags = GENL_ADMIN_PERM,
.policy = netlbl_mgmt_genl_policy,
.doit = netlbl_mgmt_removedef,
.dumpit = NULL,
};
static struct genl_ops netlbl_mgmt_genl_c_listdef = {
.cmd = NLBL_MGMT_C_LISTDEF,
.flags = 0,
.policy = netlbl_mgmt_genl_policy,
.doit = netlbl_mgmt_listdef,
.dumpit = NULL,
};
static struct genl_ops netlbl_mgmt_genl_c_protocols = {
.cmd = NLBL_MGMT_C_PROTOCOLS,
.flags = 0,
.policy = netlbl_mgmt_genl_policy,
.doit = NULL,
.dumpit = netlbl_mgmt_protocols,
};
static struct genl_ops netlbl_mgmt_genl_c_version = {
.cmd = NLBL_MGMT_C_VERSION,
.flags = 0,
.policy = netlbl_mgmt_genl_policy,
.doit = netlbl_mgmt_version,
.dumpit = NULL,
};
/*
* NetLabel Generic NETLINK Protocol Functions
*/
/**
* netlbl_mgmt_genl_init - Register the NetLabel management component
*
* Description:
* Register the NetLabel management component with the Generic NETLINK
* mechanism. Returns zero on success, negative values on failure.
*
*/
int netlbl_mgmt_genl_init(void)
{
int ret_val;
ret_val = genl_register_family(&netlbl_mgmt_gnl_family);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_add);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_remove);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_listall);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_adddef);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_removedef);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_listdef);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_protocols);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_mgmt_gnl_family,
&netlbl_mgmt_genl_c_version);
if (ret_val != 0)
return ret_val;
return 0;
}
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