/*
* common LSM auditing functions
*
* Based on code written for SELinux by :
* Stephen Smalley, <sds@epoch.ncsc.mil>
* James Morris <jmorris@redhat.com>
* Author : Etienne Basset, <etienne.basset@ensta.org>
*
* 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/stddef.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <net/sock.h>
#include <linux/un.h>
#include <net/af_unix.h>
#include <linux/audit.h>
#include <linux/ipv6.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/sctp.h>
#include <linux/lsm_audit.h>
/**
* ipv4_skb_to_auditdata : fill auditdata from skb
* @skb : the skb
* @ad : the audit data to fill
* @proto : the layer 4 protocol
*
* return 0 on success
*/
int ipv4_skb_to_auditdata(struct sk_buff *skb,
struct common_audit_data *ad, u8 *proto)
{
int ret = 0;
struct iphdr *ih;
ih = ip_hdr(skb);
if (ih == NULL)
return -EINVAL;
ad->u.net.v4info.saddr = ih->saddr;
ad->u.net.v4info.daddr = ih->daddr;
if (proto)
*proto = ih->protocol;
/* non initial fragment */
if (ntohs(ih->frag_off) & IP_OFFSET)
return 0;
switch (ih->protocol) {
case IPPROTO_TCP: {
struct tcphdr *th = tcp_hdr(skb);
if (th == NULL)
break;
ad->u.net.sport = th->source;
ad->u.net.dport = th->dest;
break;
}
case IPPROTO_UDP: {
struct udphdr *uh = udp_hdr(skb);
if (uh == NULL)
break;
ad->u.net.sport = uh->source;
ad->u.net.dport = uh->dest;
break;
}
case IPPROTO_DCCP: {
struct dccp_hdr *dh = dccp_hdr(skb);
if (dh == NULL)
break;
ad->u.net.sport = dh->dccph_sport;
ad->u.net.dport = dh->dccph_dport;
break;
}
case IPPROTO_SCTP: {
struct sctphdr *sh = sctp_hdr(skb);
if (sh == NULL)
break;
ad->u.net.sport = sh->source;
ad->u.net.dport = sh->dest;
break;
}
default:
ret = -EINVAL;
}
return ret;
}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
/**
* ipv6_skb_to_auditdata : fill auditdata from skb
* @skb : the skb
* @ad : the audit data to fill
* @proto : the layer 4 protocol
*
* return 0 on success
*/
int ipv6_skb_to_auditdata(struct sk_buff *skb,
struct common_audit_data *ad, u8 *proto)
{
int offset, ret = 0;
struct ipv6hdr *ip6;
u8 nexthdr;
ip6 = ipv6_hdr(skb);
if (ip6 == NULL)
return -EINVAL;
ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr);
ipv6_addr_copy(&ad->u.net.v6info.daddr, &ip6->daddr);
ret = 0;
/* IPv6 can have several extension header before the Transport header
* skip them */
offset = skb_network_offset(skb);
offset += sizeof(*ip6);
nexthdr = ip6->nexthdr;
offset = ipv6_skip_exthdr(skb, offset, &nexthdr);
if (offset < 0)
return 0;
if (proto)
*proto = nexthdr;
switch (nexthdr) {
case IPPROTO_TCP: {
struct tcphdr _tcph, *th;
th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
if (th == NULL)
break;
ad->u.net.sport = th->source;
ad->u.net.dport = th->dest;
break;
}
case IPPROTO_UDP: {
struct udphdr _udph, *uh;
uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
if (uh == NULL)
break;
ad->u.net.sport = uh->source;
ad->u.net.dport = uh->dest;
break;
}
case IPPROTO_DCCP: {
struct dccp_hdr _dccph, *dh;
dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
if (dh == NULL)
break;
ad->u.net.sport = dh->dccph_sport;
ad->u.net.dport = dh->dccph_dport;
break;
}
case IPPROTO_SCTP: {
struct sctphdr _sctph, *sh;
sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
if (sh == NULL)
break;
ad->u.net.sport = sh->source;
ad->u.net.dport = sh->dest;
break;
}
default:
ret = -EINVAL;
}
return ret;
}
#endif
static inline void print_ipv6_addr(struct audit_buffer *ab,
struct in6_addr *addr, __be16 port,
char *name1, char *name2)
{
if (!ipv6_addr_any(addr))
audit_log_format(ab, " %s=%pI6c", name1, addr);
if (port)
audit_log_format(ab, " %s=%d", name2, ntohs(port));
}
static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
__be16 port, char *name1, char *name2)
{
if (addr)
audit_log_format(ab, " %s=%pI4", name1, &addr);
if (port)
audit_log_format(ab, " %s=%d", name2, ntohs(port));
}
/**
* dump_common_audit_data - helper to dump common audit data
* @a : common audit data
*
*/
static void dump_common_audit_data(struct audit_buffer *ab,
struct common_audit_data *a)
{
struct inode *inode = NULL;
struct task_struct *tsk = current;
if (a->tsk)
tsk = a->tsk;
if (tsk && tsk->pid) {
audit_log_format(ab, " pid=%d comm=", tsk->pid);
audit_log_untrustedstring(ab, tsk->comm);
}
switch (a->type) {
case LSM_AUDIT_DATA_NONE:
return;
case LSM_AUDIT_DATA_IPC:
audit_log_format(ab, " key=%d ", a->u.ipc_id);
break;
case LSM_AUDIT_DATA_CAP:
audit_log_format(ab, " capability=%d ", a->u.cap);
break;
case LSM_AUDIT_DATA_FS:
if (a->u.fs.path.dentry) {
struct dentry *dentry = a->u.fs.path.dentry;
if (a->u.fs.path.mnt) {
audit_log_d_path(ab, "path=", &a->u.fs.path);
} else {
audit_log_format(ab, " name=");
audit_log_untrustedstring(ab,
dentry->d_name.name);
}
inode = dentry->d_inode;
} else if (a->u.fs.inode) {
struct dentry *dentry;
inode = a->u.fs.inode;
dentry = d_find_alias(inode);
if (dentry) {
audit_log_format(ab, " name=");
audit_log_untrustedstring(ab,
dentry->d_name.name);
dput(dentry);
}
}
if (inode)
audit_log_format(ab, " dev=%s ino=%lu",
inode->i_sb->s_id,
inode->i_ino);
break;
case LSM_AUDIT_DATA_TASK:
tsk = a->u.tsk;
if (tsk && tsk->pid) {
audit_log_format(ab, " pid=%d comm=", tsk->pid);
audit_log_untrustedstring(ab, tsk->comm);
}
break;
case LSM_AUDIT_DATA_NET:
if (a->u.net.sk) {
struct sock *sk = a->u.net.sk;
struct unix_sock *u;
int len = 0;
char *p = NULL;
switch (sk->sk_family) {
case AF_INET: {
struct inet_sock *inet = inet_sk(sk);
print_ipv4_addr(ab, inet->inet_rcv_saddr,
inet->inet_sport,
"laddr", "lport");
print_ipv4_addr(ab, inet->inet_daddr,
inet->inet_dport,
"faddr", "fport");
break;
}
case AF_INET6: {
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *inet6 = inet6_sk(sk);
print_ipv6_addr(ab, &inet6->rcv_saddr,
inet->inet_sport,
"laddr", "lport");
print_ipv6_addr(ab, &inet6->daddr,
inet->inet_dport,
"faddr", "fport");
break;
}
case AF_UNIX:
u = unix_sk(sk);
if (u->dentry) {
struct path path = {
.dentry = u->dentry,
.mnt = u->mnt
};
audit_log_d_path(ab, "path=", &path);
break;
}
if (!u->addr)
break;
len = u->addr->len-sizeof(short);
p = &u->addr->name->sun_path[0];
audit_log_format(ab, " path=");
if (*p)
audit_log_untrustedstring(ab, p);
else
audit_log_n_hex(ab, p, len);
break;
}
}
switch (a->u.net.family) {
case AF_INET:
print_ipv4_addr(ab, a->u.net.v4info.saddr,
a->u.net.sport,
"saddr", "src");
print_ipv4_addr(ab, a->u.net.v4info.daddr,
a->u.net.dport,
"daddr", "dest");
break;
case AF_INET6:
print_ipv6_addr(ab, &a->u.net.v6info.saddr,
a->u.net.sport,
"saddr", "src");
print_ipv6_addr(ab, &a->u.net.v6info.daddr,
a->u.net.dport,
"daddr", "dest");
break;
}
if (a->u.net.netif > 0) {
struct net_device *dev;
/* NOTE: we always use init's namespace */
dev = dev_get_by_index(&init_net, a->u.net.netif);
if (dev) {
audit_log_format(ab, " netif=%s", dev->name);
dev_put(dev);
}
}
break;
#ifdef CONFIG_KEYS
case LSM_AUDIT_DATA_KEY:
audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
if (a->u.key_struct.key_desc) {
audit_log_format(ab, " key_desc=");
audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
}
break;
#endif
case LSM_AUDIT_DATA_KMOD:
audit_log_format(ab, " kmod=");
audit_log_untrustedstring(ab, a->u.kmod_name);
break;
} /* switch (a->type) */
}
/**
* common_lsm_audit - generic LSM auditing function
* @a: auxiliary audit data
*
* setup the audit buffer for common security information
* uses callback to print LSM specific information
*/
void common_lsm_audit(struct common_audit_data *a)
{
struct audit_buffer *ab;
if (a == NULL)
return;
/* we use GFP_ATOMIC so we won't sleep */
ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
if (ab == NULL)
return;
if (a->lsm_pre_audit)
a->lsm_pre_audit(ab, a);
dump_common_audit_data(ab, a);
if (a->lsm_post_audit)
a->lsm_post_audit(ab, a);
audit_log_end(ab);
}
