389 lines
8.5 KiB
C
389 lines
8.5 KiB
C
/*
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* common LSM auditing functions
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*
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* Based on code written for SELinux by :
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* Stephen Smalley, <sds@epoch.ncsc.mil>
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* James Morris <jmorris@redhat.com>
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* Author : Etienne Basset, <etienne.basset@ensta.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2,
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* as published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <net/sock.h>
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#include <linux/un.h>
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#include <net/af_unix.h>
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#include <linux/audit.h>
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#include <linux/ipv6.h>
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#include <linux/ip.h>
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#include <net/ip.h>
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#include <net/ipv6.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/dccp.h>
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#include <linux/sctp.h>
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#include <linux/lsm_audit.h>
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/**
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* ipv4_skb_to_auditdata : fill auditdata from skb
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* @skb : the skb
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* @ad : the audit data to fill
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* @proto : the layer 4 protocol
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*
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* return 0 on success
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*/
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int ipv4_skb_to_auditdata(struct sk_buff *skb,
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struct common_audit_data *ad, u8 *proto)
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{
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int ret = 0;
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struct iphdr *ih;
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ih = ip_hdr(skb);
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if (ih == NULL)
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return -EINVAL;
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ad->u.net.v4info.saddr = ih->saddr;
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ad->u.net.v4info.daddr = ih->daddr;
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if (proto)
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*proto = ih->protocol;
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/* non initial fragment */
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if (ntohs(ih->frag_off) & IP_OFFSET)
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return 0;
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switch (ih->protocol) {
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case IPPROTO_TCP: {
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struct tcphdr *th = tcp_hdr(skb);
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if (th == NULL)
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break;
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ad->u.net.sport = th->source;
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ad->u.net.dport = th->dest;
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break;
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}
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case IPPROTO_UDP: {
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struct udphdr *uh = udp_hdr(skb);
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if (uh == NULL)
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break;
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ad->u.net.sport = uh->source;
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ad->u.net.dport = uh->dest;
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break;
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}
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case IPPROTO_DCCP: {
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struct dccp_hdr *dh = dccp_hdr(skb);
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if (dh == NULL)
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break;
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ad->u.net.sport = dh->dccph_sport;
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ad->u.net.dport = dh->dccph_dport;
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break;
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}
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case IPPROTO_SCTP: {
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struct sctphdr *sh = sctp_hdr(skb);
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if (sh == NULL)
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break;
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ad->u.net.sport = sh->source;
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ad->u.net.dport = sh->dest;
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break;
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}
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default:
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ret = -EINVAL;
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}
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return ret;
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}
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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/**
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* ipv6_skb_to_auditdata : fill auditdata from skb
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* @skb : the skb
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* @ad : the audit data to fill
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* @proto : the layer 4 protocol
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*
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* return 0 on success
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*/
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int ipv6_skb_to_auditdata(struct sk_buff *skb,
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struct common_audit_data *ad, u8 *proto)
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{
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int offset, ret = 0;
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struct ipv6hdr *ip6;
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u8 nexthdr;
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ip6 = ipv6_hdr(skb);
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if (ip6 == NULL)
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return -EINVAL;
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ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr);
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ipv6_addr_copy(&ad->u.net.v6info.daddr, &ip6->daddr);
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ret = 0;
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/* IPv6 can have several extension header before the Transport header
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* skip them */
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offset = skb_network_offset(skb);
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offset += sizeof(*ip6);
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nexthdr = ip6->nexthdr;
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offset = ipv6_skip_exthdr(skb, offset, &nexthdr);
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if (offset < 0)
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return 0;
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if (proto)
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*proto = nexthdr;
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switch (nexthdr) {
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case IPPROTO_TCP: {
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struct tcphdr _tcph, *th;
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th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
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if (th == NULL)
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break;
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ad->u.net.sport = th->source;
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ad->u.net.dport = th->dest;
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break;
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}
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case IPPROTO_UDP: {
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struct udphdr _udph, *uh;
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uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
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if (uh == NULL)
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break;
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ad->u.net.sport = uh->source;
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ad->u.net.dport = uh->dest;
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break;
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}
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case IPPROTO_DCCP: {
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struct dccp_hdr _dccph, *dh;
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dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
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if (dh == NULL)
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break;
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ad->u.net.sport = dh->dccph_sport;
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ad->u.net.dport = dh->dccph_dport;
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break;
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}
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case IPPROTO_SCTP: {
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struct sctphdr _sctph, *sh;
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sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
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if (sh == NULL)
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break;
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ad->u.net.sport = sh->source;
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ad->u.net.dport = sh->dest;
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break;
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}
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default:
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ret = -EINVAL;
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}
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return ret;
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}
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#endif
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static inline void print_ipv6_addr(struct audit_buffer *ab,
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struct in6_addr *addr, __be16 port,
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char *name1, char *name2)
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{
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if (!ipv6_addr_any(addr))
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audit_log_format(ab, " %s=%pI6c", name1, addr);
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if (port)
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audit_log_format(ab, " %s=%d", name2, ntohs(port));
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}
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static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
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__be16 port, char *name1, char *name2)
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{
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if (addr)
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audit_log_format(ab, " %s=%pI4", name1, &addr);
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if (port)
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audit_log_format(ab, " %s=%d", name2, ntohs(port));
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}
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/**
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* dump_common_audit_data - helper to dump common audit data
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* @a : common audit data
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*
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*/
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static void dump_common_audit_data(struct audit_buffer *ab,
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struct common_audit_data *a)
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{
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struct inode *inode = NULL;
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struct task_struct *tsk = current;
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if (a->tsk)
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tsk = a->tsk;
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if (tsk && tsk->pid) {
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audit_log_format(ab, " pid=%d comm=", tsk->pid);
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audit_log_untrustedstring(ab, tsk->comm);
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}
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switch (a->type) {
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case LSM_AUDIT_NO_AUDIT:
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return;
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case LSM_AUDIT_DATA_IPC:
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audit_log_format(ab, " key=%d ", a->u.ipc_id);
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break;
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case LSM_AUDIT_DATA_CAP:
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audit_log_format(ab, " capability=%d ", a->u.cap);
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break;
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case LSM_AUDIT_DATA_FS:
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if (a->u.fs.path.dentry) {
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struct dentry *dentry = a->u.fs.path.dentry;
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if (a->u.fs.path.mnt) {
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audit_log_d_path(ab, "path=", &a->u.fs.path);
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} else {
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audit_log_format(ab, " name=");
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audit_log_untrustedstring(ab,
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dentry->d_name.name);
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}
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inode = dentry->d_inode;
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} else if (a->u.fs.inode) {
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struct dentry *dentry;
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inode = a->u.fs.inode;
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dentry = d_find_alias(inode);
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if (dentry) {
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audit_log_format(ab, " name=");
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audit_log_untrustedstring(ab,
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dentry->d_name.name);
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dput(dentry);
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}
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}
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if (inode)
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audit_log_format(ab, " dev=%s ino=%lu",
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inode->i_sb->s_id,
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inode->i_ino);
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break;
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case LSM_AUDIT_DATA_TASK:
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tsk = a->u.tsk;
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if (tsk && tsk->pid) {
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audit_log_format(ab, " pid=%d comm=", tsk->pid);
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audit_log_untrustedstring(ab, tsk->comm);
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}
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break;
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case LSM_AUDIT_DATA_NET:
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if (a->u.net.sk) {
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struct sock *sk = a->u.net.sk;
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struct unix_sock *u;
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int len = 0;
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char *p = NULL;
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switch (sk->sk_family) {
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case AF_INET: {
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struct inet_sock *inet = inet_sk(sk);
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print_ipv4_addr(ab, inet->inet_rcv_saddr,
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inet->inet_sport,
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"laddr", "lport");
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print_ipv4_addr(ab, inet->inet_daddr,
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inet->inet_dport,
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"faddr", "fport");
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break;
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}
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case AF_INET6: {
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struct inet_sock *inet = inet_sk(sk);
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struct ipv6_pinfo *inet6 = inet6_sk(sk);
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print_ipv6_addr(ab, &inet6->rcv_saddr,
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inet->inet_sport,
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"laddr", "lport");
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print_ipv6_addr(ab, &inet6->daddr,
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inet->inet_dport,
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"faddr", "fport");
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break;
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}
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case AF_UNIX:
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u = unix_sk(sk);
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if (u->dentry) {
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struct path path = {
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.dentry = u->dentry,
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.mnt = u->mnt
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};
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audit_log_d_path(ab, "path=", &path);
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break;
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}
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if (!u->addr)
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break;
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len = u->addr->len-sizeof(short);
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p = &u->addr->name->sun_path[0];
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audit_log_format(ab, " path=");
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if (*p)
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audit_log_untrustedstring(ab, p);
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else
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audit_log_n_hex(ab, p, len);
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break;
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}
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}
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switch (a->u.net.family) {
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case AF_INET:
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print_ipv4_addr(ab, a->u.net.v4info.saddr,
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a->u.net.sport,
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"saddr", "src");
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print_ipv4_addr(ab, a->u.net.v4info.daddr,
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a->u.net.dport,
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"daddr", "dest");
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break;
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case AF_INET6:
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print_ipv6_addr(ab, &a->u.net.v6info.saddr,
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a->u.net.sport,
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"saddr", "src");
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print_ipv6_addr(ab, &a->u.net.v6info.daddr,
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a->u.net.dport,
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"daddr", "dest");
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break;
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}
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if (a->u.net.netif > 0) {
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struct net_device *dev;
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/* NOTE: we always use init's namespace */
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dev = dev_get_by_index(&init_net, a->u.net.netif);
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if (dev) {
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audit_log_format(ab, " netif=%s", dev->name);
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dev_put(dev);
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}
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}
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break;
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#ifdef CONFIG_KEYS
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case LSM_AUDIT_DATA_KEY:
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audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
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if (a->u.key_struct.key_desc) {
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audit_log_format(ab, " key_desc=");
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audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
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}
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break;
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#endif
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} /* switch (a->type) */
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}
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/**
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* common_lsm_audit - generic LSM auditing function
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* @a: auxiliary audit data
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*
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* setup the audit buffer for common security information
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* uses callback to print LSM specific information
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*/
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void common_lsm_audit(struct common_audit_data *a)
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{
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struct audit_buffer *ab;
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if (a == NULL)
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return;
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/* we use GFP_ATOMIC so we won't sleep */
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ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
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if (ab == NULL)
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return;
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if (a->lsm_pre_audit)
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a->lsm_pre_audit(ab, a);
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dump_common_audit_data(ab, a);
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if (a->lsm_post_audit)
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a->lsm_post_audit(ab, a);
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audit_log_end(ab);
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}
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